Full Version: Emissions problems ....
A few of my new friends in law enforcement convinced me to get my '76 2.0L registered, which means an emissions test. The PO had problems (back in '98) and the car hasn't been clean since then; that's one reason I had been putting this off.
I've already replaced points, rotor, cap, wires, and plugs. Adjusted dwell (which I feel pretty sure about) and timing (which I'm less sure about). For the timing, I used the handy template from Pelican Parts website, and put a visible mark on the impeller. But its so hard to work through that viewport that I might be off by a little either way.
Also, I ran 3 tanks of gas w/ injector cleaner (and *did* see some improvement during that time). I found that my decel valve did not work, and removed it. I had problems w/ the AAR wire shorting to ground, blowing a fuse, so I removed it. All of my vacuum hoses are new. And although my idle is still high (1146), I haven't been able to track down any leaks... The screw in the TB is all the way shut, and the knob on the FI box is all the way (oh jeez, which way was it ? - I think it was CW).
I adjusted the valves before the RRC (about 1000) mi of driving. That (simultaneously w/ timing) made a major improvement, as two exhaust valves were too tight. Towards the end of the RRC I did a little spirited driving (awesome) and on the trip home pushed kinda hard up a pass. Since then the engine has a slight roughness, so maybe valves need re-adjusting.
Anyway, the car idles at 1146 RPM, and the numbers there are : HC 1156 PPM (limit 600) and CO % 3.73 (limit 3.50). Of course, like an idiot, I didn't get the car fully warmed up before (it takes like 15 minutes of serious driving).
Anyway, my main goal right now is to get the thing to pass, fast and cheap. Failing that, if I put $75 into diagnosing the problem (at a legit business) I can get a waiver.
I won't need to do this again, as my county is cancelling its emissions program in Dec. '06
My other goal is to know what's wrong. I just got the car, and I know its burning a little oil (rings and/or valve guides) so I'm deciding how to proceed : I'm toying w/ a mild Subaru swap if I can do it cheap enough...
Any hints appreciated....
One suggested method is to add 10% by volume of alcohol to the fuel. Best way is to have just enough gas to get you there and back and add the alcohol. Never had to do it, but it has been purported it will work in reducing the emissions levels.
$75 seems cheap....might try to fight testing if the "build date" on the vehicle is early '75. All '76 vehicles were left over '75s according to reports.
$75 seems cheap....might try to fight testing if the "build date" on the vehicle is early '75. All '76 vehicles were left over '75s according to reports.
| QUOTE (SLITS @ Sep 30 2005, 09:37 AM) |
| might try to fight testing if the "build date" on the vehicle is early '75. All '76 vehicles were left over '75s according to reports. |
Hmm... Interesting...
1) How do I check the "build date" ? Is that something that you decode from the VIN ?
(mine is 4762901855, btw. has a "76" in it...)
2) If it is really a '75, what does that change ? Are the limits different ?
3) What kind of alcohol ? Methanol, Ethanol
, isopropyl ?
The build date is right there on the VIN plate with the VIN, on the door jamb (driver's side, rear jamb). Said plate may also say "catalyst" or "non catalyst", depending on whether or not the car has one.
Over 1100ppm HC is insanely bad, btw. Either you have a serious misfire (caused by bad ignition or way too lean idle mixtures), or you have a fuel leak into the manifold from a bad injector or cold start valve. A properly operating D-Jet car should be under 300ppm HC. If it has a functioning catalyst, it should be under 100ppm. Heavy oil in the exhaust from bad rings or valve guides may also be a factor. Because your CO numbers aren't nearly so insane, I'd be inclined to think misfire or oil. I'm surprised you aren't choking from smoke out the exhaust with numbers that high.
Find a mechanic with a smog setup that's friendly enough to help you pass by working "on the meter". Warm the car up completely (makes a BIG difference). Get your idle down to 900rpm. If you can't, you have an air leak someplace. Timing that's too advanced can also cause a high idle. Futz with the idle mixture. Way too lean is just as bad as too rich. If none of this fixes the problem, my bet is you're burning too much oil, and you need to rebuild.
Over 1100ppm HC is insanely bad, btw. Either you have a serious misfire (caused by bad ignition or way too lean idle mixtures), or you have a fuel leak into the manifold from a bad injector or cold start valve. A properly operating D-Jet car should be under 300ppm HC. If it has a functioning catalyst, it should be under 100ppm. Heavy oil in the exhaust from bad rings or valve guides may also be a factor. Because your CO numbers aren't nearly so insane, I'd be inclined to think misfire or oil. I'm surprised you aren't choking from smoke out the exhaust with numbers that high.
Find a mechanic with a smog setup that's friendly enough to help you pass by working "on the meter". Warm the car up completely (makes a BIG difference). Get your idle down to 900rpm. If you can't, you have an air leak someplace. Timing that's too advanced can also cause a high idle. Futz with the idle mixture. Way too lean is just as bad as too rich. If none of this fixes the problem, my bet is you're burning too much oil, and you need to rebuild.
You have to have an AAR to get the idle down, unless you completely block the port. Is this an air pump car? You need that to dilute the exhaust. Is it an EGR car? You'll need that to work to keep the combustion temps down. Is this a Cat equipped car? You need that to keep the HCs and CO down. Adjust the valves to .016" (that'll lower the HCs), be sure the dwell is at 47 +/- 3 degrees, and the timing right on. I dunno why you had to make new timing marks, they're right on the fan. Set the idle mixture screw to the midpoint. Pretest the car, and adjust then idle mixture and speed to the cleanest/best idle. RUN REGULAR (87 OCTANE) FUEL FOR THE TEST!!!!!!
BTW, the whole "build date" thing is a bogus waste of time. Another case iof misinformation made fact by it's appearance on the internet. Even if it weren't, it only applied in CA to cars that were ACTUALLY TESTED before the deadline, which is nearly a year ago. The MY is whatever your state says it is, and they ain't gonna change it just 'cause you want 'em to.
The Cap'n
BTW, the whole "build date" thing is a bogus waste of time. Another case iof misinformation made fact by it's appearance on the internet. Even if it weren't, it only applied in CA to cars that were ACTUALLY TESTED before the deadline, which is nearly a year ago. The MY is whatever your state says it is, and they ain't gonna change it just 'cause you want 'em to.
The Cap'n
Build date and year model in many states are different, and year model is what most states use in determining smog rules. This is true in Calif.
Your idle is too fast for starters, so make sure your throttle valve is correctly shutting down, if it is, you might have a vacuum leak someplace, or running a bit rich.
Is your car catalyst equiped?
Some basic things you should do are check the compression, make sure it is good, else all bets are off on a cheap repair, so go for the $75 waiver, and save for a rebuild later.
What about the four plugs, how is the color, black and dry or black and oiley? or a nice dry tan color? I suspect black, cause running rich, hopefully dry which means it is not worn piston rings if they are black and wet, that means probably oil in the combustion chamber (compression test will determine cause) If all four plugs are black, they are all rich, which would mean a systemic problem (injectors firing too much, fuel pressure too high, or could start injector leaking) if only one plug is bad, then maybe it is cylinder specific like a leaky injector on that cylinder only.
You can test the injectors for leaks and drips by removing them from the manifold, keeping them connected to the hoses, and then prime the fuel pump by turning the key several times, let teh fuel pump run, and have a helper check for drips. As long as you do not crank the enigne, no fuel should drip out of them. (also test the cold start injecotr for drips this same way. just be away of fire, do this outside, have a helper to watch for leaks. have a fire extingusher handy.
You have a lot of unburned gas in the exhaust (high HC) and the high CO indicates that you have used up the Oxygen pretty much, cause if you had low CO (and higher CO2) that means you have enough oxygen.
Sounds like rich running rather than an ignition issue. If you had high HC and low CO that would indicate failure to ignite the mixture, as since the fuel did not burn, no CO would form, and HC would be high. (ie mixture could be correct, but spark failed to burn it)
However when HC is high, AND CO is high, that indicates too much fuel is being dumped into the system, it is burning, but not all of it, cuase there is not enough Oxygen to burn all the fuel, so unburnt (HC) and partially burnt(CO) gasses are produced.
Now with airpumps, if so equiped, a failed air pump can lead to higher CO and not effect the HC so much. If you run a catalyst, a failed cat will cause increases in HC, CO and if a three way cat NOx (NOx is also reduced by an EGR valve, although some cars get away with only a threeway cat no egr)
do you have the data on the other gasses measured (ie O2, CO2, NOx even if they passed)?
give us some more details if you have them on the test results,(and limits) and if you have a catalyst / air pump etc...
good luck
PS $75 is a deal to waive the smog. In my area Test Only cars (many older sports cars fall under this catagory) must get a special smog test and it costs nearly $75, if you fail, you got to spend like $100 trying to repair it, else they waive it for two years, then you have to deal with it in two years, only one waiver. also all 76 and later year model cars are required to meet these requirements forever, no future cut off age in sight. (and the same nazi's that came up with this (thanks arnold shwartznigger) want to add older cars to this program, we have to constantly fight them).
You is lucky in Colorado to have resonable (all relative here) smog laws.
good luck.
Your idle is too fast for starters, so make sure your throttle valve is correctly shutting down, if it is, you might have a vacuum leak someplace, or running a bit rich.
Is your car catalyst equiped?
Some basic things you should do are check the compression, make sure it is good, else all bets are off on a cheap repair, so go for the $75 waiver, and save for a rebuild later.
What about the four plugs, how is the color, black and dry or black and oiley? or a nice dry tan color? I suspect black, cause running rich, hopefully dry which means it is not worn piston rings if they are black and wet, that means probably oil in the combustion chamber (compression test will determine cause) If all four plugs are black, they are all rich, which would mean a systemic problem (injectors firing too much, fuel pressure too high, or could start injector leaking) if only one plug is bad, then maybe it is cylinder specific like a leaky injector on that cylinder only.
You can test the injectors for leaks and drips by removing them from the manifold, keeping them connected to the hoses, and then prime the fuel pump by turning the key several times, let teh fuel pump run, and have a helper check for drips. As long as you do not crank the enigne, no fuel should drip out of them. (also test the cold start injecotr for drips this same way. just be away of fire, do this outside, have a helper to watch for leaks. have a fire extingusher handy.
You have a lot of unburned gas in the exhaust (high HC) and the high CO indicates that you have used up the Oxygen pretty much, cause if you had low CO (and higher CO2) that means you have enough oxygen.
Sounds like rich running rather than an ignition issue. If you had high HC and low CO that would indicate failure to ignite the mixture, as since the fuel did not burn, no CO would form, and HC would be high. (ie mixture could be correct, but spark failed to burn it)
However when HC is high, AND CO is high, that indicates too much fuel is being dumped into the system, it is burning, but not all of it, cuase there is not enough Oxygen to burn all the fuel, so unburnt (HC) and partially burnt(CO) gasses are produced.
Now with airpumps, if so equiped, a failed air pump can lead to higher CO and not effect the HC so much. If you run a catalyst, a failed cat will cause increases in HC, CO and if a three way cat NOx (NOx is also reduced by an EGR valve, although some cars get away with only a threeway cat no egr)
do you have the data on the other gasses measured (ie O2, CO2, NOx even if they passed)?
give us some more details if you have them on the test results,(and limits) and if you have a catalyst / air pump etc...
good luck
PS $75 is a deal to waive the smog. In my area Test Only cars (many older sports cars fall under this catagory) must get a special smog test and it costs nearly $75, if you fail, you got to spend like $100 trying to repair it, else they waive it for two years, then you have to deal with it in two years, only one waiver. also all 76 and later year model cars are required to meet these requirements forever, no future cut off age in sight. (and the same nazi's that came up with this (thanks arnold shwartznigger) want to add older cars to this program, we have to constantly fight them).
You is lucky in Colorado to have resonable (all relative here) smog laws.
good luck.
Jeff,
any chance the timing marks are not accurate.
The high idle and bad test results sound like a timing issue.
If you pull the valve covers, the rockers will be loose when its on TDC for that particular cylinder...
I'd use that, the visual on the distributor, and a can of brake clean to wash oil off of the timing marks... all to recheck that you absolutely have the correct timing mark.
then reset the timing (remember to disconnect the vacum advance/retard while you do it)
see if you get the same idle issue.
(unless you have a vacuum leak)
brant
any chance the timing marks are not accurate.
The high idle and bad test results sound like a timing issue.
If you pull the valve covers, the rockers will be loose when its on TDC for that particular cylinder...
I'd use that, the visual on the distributor, and a can of brake clean to wash oil off of the timing marks... all to recheck that you absolutely have the correct timing mark.
then reset the timing (remember to disconnect the vacum advance/retard while you do it)
see if you get the same idle issue.
(unless you have a vacuum leak)
brant
Jeff,
Your car is burning quite a bit of oil. Like I mentioned in Moab, mostly on decel. But after following you for a few (hundred) miles, I notice that you burn oil most heavily on hard acceleration (up Vail pass for example) and on deceleration, but there is still noticeable smoke (sometimes) when we were just cruising. I have a feeling this may be your biggest hurdle to passing the test.
I also noticed your valves getting louder the more you drove your car (Fri to Sunday). I have a feeling your valves may be tightening up. I do not know what this means though.
If you can double check your timing with advance/retard line disconnected (as Brant suggested) and get it properly warmed up and then have it tested again (for free during your grace period) then see what it does. If it still fails miserably, you may be better off gathering your receipts and getting it waived.
When you check your timing, look for the marks at the back of the impeller, closest to the engine. You really have to crane your neck around to see them, but you should have a white one for TDC (or a 0) and a red one for 27' BTDC on the 2.0.
-ben
Your car is burning quite a bit of oil. Like I mentioned in Moab, mostly on decel. But after following you for a few (hundred) miles, I notice that you burn oil most heavily on hard acceleration (up Vail pass for example) and on deceleration, but there is still noticeable smoke (sometimes) when we were just cruising. I have a feeling this may be your biggest hurdle to passing the test.
I also noticed your valves getting louder the more you drove your car (Fri to Sunday). I have a feeling your valves may be tightening up. I do not know what this means though.
If you can double check your timing with advance/retard line disconnected (as Brant suggested) and get it properly warmed up and then have it tested again (for free during your grace period) then see what it does. If it still fails miserably, you may be better off gathering your receipts and getting it waived.
When you check your timing, look for the marks at the back of the impeller, closest to the engine. You really have to crane your neck around to see them, but you should have a white one for TDC (or a 0) and a red one for 27' BTDC on the 2.0.
-ben
Wow,
A lot to catch up with !
Yes, the car has an air pump. One of the air injectors is missing and
that port sealed off.
Ben Said :
> Your car is burning quite a bit of oil. Like I mentioned in Moab,
> mostly on decel. But after following you for a few (hundred) miles, I
> notice that you burn oil most heavily on hard acceleration (up Vail
> pass for example) and on deceleration, but there is still noticeable
> smoke (sometimes) when we were just cruising. I have a feeling this
> may be your biggest hurdle to passing the test.
So the car is burning oil. (Time to switch back to dino ..) I can't
see any smoke when I drive, and the car passed the "viusal" test fine,
but Ben and others at RRC mentioned it. It makes sense to me that that
could cause excess HC.
Ben again :
> When you check your timing, look for the marks at the back of the
> impeller, closest to the engine. You really have to crane your neck
> around to see them, but you should have a white one for TDC (or a 0)
> and a red one for 27' BTDC on the 2.0.
As for the timing, I originally looked pretty closely for the marks and didn't see
them. I was looking on the "outer" surface of the impeller, that
faces up as you look in the hole. This is where it would line up with
the little notch in the stationary part of the housing. Are you saying
that they are on the narrow vertical surface facing the rear of the
car ? I'll have a closer look-see.
As for adjusting the timing, does it make any sense to go "by ear" :
i.e., adjust slightly BTDC/ATDC to tweak the idle ? Again, I don't
*think* I have any exhaust leaks, but I'll sure check again.... The
car idles at around 800 when totally cold, but it goes up after that.
And yes, when I did the timing, the car was totally warmed up and
distributor vac line (to retard) was pulled and plugged.
Catalytic converter is there, that's about all I know. The EGR valve
is hooked up, but the plumbing stops at the firewall; i.e., no exhaust
gas actually gets fed in. This shouldn't be the cause of the high
idle, as it feeds in pre-throttle. If anything, my uninformed guess is
that this would cause engine to run lean, since O2 is not being
displaced by exhaust gasses. (But I never understood the idea of EGR)
No info on exhaust O2, NOx. Exhaust CO2 is 3.8% at idle, no limit
indicated.
Cap'n : The AAR port is blocked off. Also you mentioned setting valves
to .016" . That's way looser than the Haynes value (.006/.008",
IIRC). Is this suggestion for emissions testing only, or for general
operation ? Having larger values here means the intake/exhaust valves
open less and for shorter duration, right ? Wouldn't that effectively
make the engine run *more* rich ? (less air, same fuel).
Here are my conclusions/hunches so far :
* High HC is probably due to buring oil, due to bad rings/valve guides.
* Idle setting on FI box is too lean, causing misfiring, causing high
CO and high HC.
* Valves need adjusting again.
* I need to spend $75 and get the waiver ! (Too bad I replaced all the ignition stuff already...)
A lot to catch up with !
Yes, the car has an air pump. One of the air injectors is missing and
that port sealed off.
Ben Said :
> Your car is burning quite a bit of oil. Like I mentioned in Moab,
> mostly on decel. But after following you for a few (hundred) miles, I
> notice that you burn oil most heavily on hard acceleration (up Vail
> pass for example) and on deceleration, but there is still noticeable
> smoke (sometimes) when we were just cruising. I have a feeling this
> may be your biggest hurdle to passing the test.
So the car is burning oil. (Time to switch back to dino ..) I can't
see any smoke when I drive, and the car passed the "viusal" test fine,
but Ben and others at RRC mentioned it. It makes sense to me that that
could cause excess HC.
Ben again :
> When you check your timing, look for the marks at the back of the
> impeller, closest to the engine. You really have to crane your neck
> around to see them, but you should have a white one for TDC (or a 0)
> and a red one for 27' BTDC on the 2.0.
As for the timing, I originally looked pretty closely for the marks and didn't see
them. I was looking on the "outer" surface of the impeller, that
faces up as you look in the hole. This is where it would line up with
the little notch in the stationary part of the housing. Are you saying
that they are on the narrow vertical surface facing the rear of the
car ? I'll have a closer look-see.
As for adjusting the timing, does it make any sense to go "by ear" :
i.e., adjust slightly BTDC/ATDC to tweak the idle ? Again, I don't
*think* I have any exhaust leaks, but I'll sure check again.... The
car idles at around 800 when totally cold, but it goes up after that.
And yes, when I did the timing, the car was totally warmed up and
distributor vac line (to retard) was pulled and plugged.
Catalytic converter is there, that's about all I know. The EGR valve
is hooked up, but the plumbing stops at the firewall; i.e., no exhaust
gas actually gets fed in. This shouldn't be the cause of the high
idle, as it feeds in pre-throttle. If anything, my uninformed guess is
that this would cause engine to run lean, since O2 is not being
displaced by exhaust gasses. (But I never understood the idea of EGR)
No info on exhaust O2, NOx. Exhaust CO2 is 3.8% at idle, no limit
indicated.
Cap'n : The AAR port is blocked off. Also you mentioned setting valves
to .016" . That's way looser than the Haynes value (.006/.008",
IIRC). Is this suggestion for emissions testing only, or for general
operation ? Having larger values here means the intake/exhaust valves
open less and for shorter duration, right ? Wouldn't that effectively
make the engine run *more* rich ? (less air, same fuel).
Here are my conclusions/hunches so far :
* High HC is probably due to buring oil, due to bad rings/valve guides.
* Idle setting on FI box is too lean, causing misfiring, causing high
CO and high HC.
* Valves need adjusting again.
* I need to spend $75 and get the waiver ! (Too bad I replaced all the ignition stuff already...)
When you check your timing...
YES - look toward the back of the impeller, not the front where you see the notch, I believe there are 2 notches opposite each other, look at the back one and you shoudl see painted notches ont he impeller fan.
If you only have to spend $75 to get the waiver, gather your receipts and you should have spent enough by now. I had to spend $400 to get my 83 Datsun waived a few years back in EPC.
YES - look toward the back of the impeller, not the front where you see the notch, I believe there are 2 notches opposite each other, look at the back one and you shoudl see painted notches ont he impeller fan.
If you only have to spend $75 to get the waiver, gather your receipts and you should have spent enough by now. I had to spend $400 to get my 83 Datsun waived a few years back in EPC.
The EGR is there to reduce NOx, which are rise as combustion temps rise. It should have little to no effect on HC or CO.
Catalytic convertors don't last forever, and they tend to die really fast if you're running very rich or burning lots of oil. Fitting a new one can make a huge difference AFTER the mixture and oil problems have been sorted.
Getting a waiver now is probably a sound idea, but longer-term, fixing the car is sounder still.
Catalytic convertors don't last forever, and they tend to die really fast if you're running very rich or burning lots of oil. Fitting a new one can make a huge difference AFTER the mixture and oil problems have been sorted.
Getting a waiver now is probably a sound idea, but longer-term, fixing the car is sounder still.
There's some really good theory being documented here.
Some of these guys are talking about CA smog laws. And although CO's laws are based on CA's, they are not the same. We do have it easier believe it or not. And of course we have a rolling 25 year exemption still, so even a 76 only has to pass one time per owner IF you get collector plates after smogging it.
I've been smogging cars in Colorado for a long time. A lot of classic cars (Triumph Spitfires, Chevys, 914's, etc...) and I think I can help you get your car to pass.
What were your tested versus required parameters at 2500rpm BTW?
Some of these guys are talking about CA smog laws. And although CO's laws are based on CA's, they are not the same. We do have it easier believe it or not. And of course we have a rolling 25 year exemption still, so even a 76 only has to pass one time per owner IF you get collector plates after smogging it.
I've been smogging cars in Colorado for a long time. A lot of classic cars (Triumph Spitfires, Chevys, 914's, etc...) and I think I can help you get your car to pass.
What were your tested versus required parameters at 2500rpm BTW?
Good to have freinds noting oil smoke and valve noise. You didn't acknowledge the valve noise, but I'd check the valve clearance again, if they have changed drastically since last adjustment, then someting ain't right in the the valve train. This can cause burning oil (worn valve guides) and screw up the vacuum "signal' that helps control the D-Jet system. So if your valves are going bad, get the waiver and save for a rebuild. Might be interesting to do compression test both before and after a valve adjust. Also if you wait until a bad valve fails totally, you may end up scrapping the head, pistons cylinder etc... I hate it when valves break, constantly changing valve clearance (ie getting tighter) means the valve is stretching, valve head is wearing, or the seat is receding. Lossening valves mean the seat might be dancing around or the cam is going flat. Maybe the rocker adjusters are getting worn out, check their profile
EGR leaks will generally cause lean running as they (older ones) run off a vacumm signal, and a leak in the egr diaphram will cause extra air to enter the intake. The EGR works by keeping the combustion cooler by adding spent exhaust gasses to the intake. The spent exhaust gasses will not burn, so they are in effect "inert" for combustion in the engine, this "inert" gas dilutes the regular fuel/air mixture causing a cooler burn. NOx only forms above certain temperature, below that temp (i thinks it is something like 1400F) no NOx can form (Nitrogen is non-reactive unless really hot, so it will not react with Oxygen untill it gets that hot, else it stays as harmless N2) Some parts of the engine exceed this critical temp, things like exhaust valves and such that get the hottest will allow N2 to form NOx when O2 is present. Irony of it is that smog control for HC works best on a hotter engine. A colder engine will produce more HC than a hotter one generaly, so upping the heat as other smog measures require actually increases NOx, the egr is there to reduce the NOx. A three way catalyst is a neater solution for NOx, it uses the chemical reaction in the cat to reduce NOx.
Anyway lets see some compression numbers on the engine.
Do not just replace the catylst. Nothing will kill a new cat faster than a car burning any oil, or running with wrong mixture. You'll just waste a new cat, might make you "pass' but it will not last long until the real problems are fixxed.
Cats also have a limited life, and die, but frankly your HC leaves are near double that for my non-cat 1970 914, so your problems run deeper than just a dead cat. a new cat will mask the problem possibly, but die quickly as long as you are burning oil and/or running rich
EGR leaks will generally cause lean running as they (older ones) run off a vacumm signal, and a leak in the egr diaphram will cause extra air to enter the intake. The EGR works by keeping the combustion cooler by adding spent exhaust gasses to the intake. The spent exhaust gasses will not burn, so they are in effect "inert" for combustion in the engine, this "inert" gas dilutes the regular fuel/air mixture causing a cooler burn. NOx only forms above certain temperature, below that temp (i thinks it is something like 1400F) no NOx can form (Nitrogen is non-reactive unless really hot, so it will not react with Oxygen untill it gets that hot, else it stays as harmless N2) Some parts of the engine exceed this critical temp, things like exhaust valves and such that get the hottest will allow N2 to form NOx when O2 is present. Irony of it is that smog control for HC works best on a hotter engine. A colder engine will produce more HC than a hotter one generaly, so upping the heat as other smog measures require actually increases NOx, the egr is there to reduce the NOx. A three way catalyst is a neater solution for NOx, it uses the chemical reaction in the cat to reduce NOx.
Anyway lets see some compression numbers on the engine.
Do not just replace the catylst. Nothing will kill a new cat faster than a car burning any oil, or running with wrong mixture. You'll just waste a new cat, might make you "pass' but it will not last long until the real problems are fixxed.
Cats also have a limited life, and die, but frankly your HC leaves are near double that for my non-cat 1970 914, so your problems run deeper than just a dead cat. a new cat will mask the problem possibly, but die quickly as long as you are burning oil and/or running rich
PS if your EGR is not hooked up to the exhaust,and is still operating, you will be dumping extra air into the intake system (rather than inert exhaust) this will lean you out when egr is activated. so either get the egr runnign as stock, or disable it from opening the valve and sucking air, or block it off so it is sealed.
The .016" adjustment is for testing puropses only. It promotes a more complete burn, reducing the HCs dramatically. Might check the MPS for leakage, as well as the hose leading to it. The Cap'n
| QUOTE (dmenche914 @ Sep 30 2005, 06:01 PM) |
| Good to have freinds noting oil smoke and valve noise. You didn't acknowledge the valve noise, but I'd check the valve clearance again, if they have changed drastically since last adjustment, then someting ain't right in the the valve train. This can cause burning oil (worn valve guides) and screw up the vacuum "signal' that helps control the D-Jet system. So if your valves are going bad, get the waiver and save for a rebuild. Might be interesting to do compression test both before and after a valve adjust. Also if you wait until a bad valve fails totally, you may end up scrapping the head, pistons cylinder etc... I hate it when valves break, constantly changing valve clearance (ie getting tighter) means the valve is stretching, valve head is wearing, or the seat is receding. Lossening valves mean the seat might be dancing around or the cam is going flat. Maybe the rocker adjusters are getting worn out, check their profile |
Yeah, it is good to have friends notice these things. I've never actually seen the smoke myself, and I guess I haven't really learned what normal vs. excessive valve noise is. But I do think the valves are out of adjustment. Before the RRC I adjusted them (first time) and the engine ran much smoother. On the return from RRC, after climbing Vail pass, it seemed to start running rough again. Yesterday I noted that cylinder 3 isn't running very strong (pulled spark wire, no change). It was running okay before, so I'm guessing this one has a valve that's off. I think I'll get in there today and set all 4 to .016", as the Cap'n suggested.
Also I found that my timing was pretty far off, due to, well, user error. I think the idiot who set the timing last time forgot to do so at 3500 RPM, not idle. Made a difference.
Question about the distributor advance/retard : Previously, I had the vac line going to the back side of the diaphram (closer to spark wires). After setting the timing (correctly), I found that the engine sputtered and nearly died under load (but not at high RPM while revving in neutral). So I switched the line to the front side of the diaphragm (away from spark wires) and it ran much better. At RRC I peeked at a few cars (all earlier models) and saw hoses connected to both. What is the correct hookup for a 1976 2.0L D-jet ?
Another idea I had is that since some component of the high HC is probably due to burning oil, I'm gonna switch to SAE 40 dino + Lucas oil stabilizer, instead of 5W30 synthetic. If I can cut down on the leakage, it should clean up some. Again, my main goal right now is to pass or get a waiver; then I'll have to decide how to procede w/ this engine.
I spent most of the day yesterday replacing th GD fuel filter. Thought I'd something quick and easy before my morning coffee. Coaxed the fuel pump/filter out of the ample "easy access" hatch in the front trunk (would it kill 'em to make it one inch larger ???), and the crispy, crackly fuel hose started getting soaked. No problem : just replace it. After several tries, I got some 7/16" hose that fit the puel pump nicely. I got a generic FRAM filter at flaps and it had a 5/16" inlet. No problem, just fit up an adapter. Turns out, that adapter does not exist on this planet. At least not at any of the 7 stores I checked. Ended up buying a brass fitting w/ lots of meat and machined the thing myself. Not beautiful, but it works. Anyway, I'm still waiting for the last of the fumes to evaporate, but I think the car is smelling (a little) better than before.
I "think" the vacuum port on the advance unit that points away from the dizzy is advance and the one that points towards the dizzy is retard. And the 76 should use retard only. Someone will correct me if I'm wrong; Certainly Cap'n Krusty will tomorrow.
If nothing else, this is a bump for ya.
If nothing else, this is a bump for ya.
| QUOTE (Gint @ Oct 2 2005, 05:06 PM) |
| I "think" the vacuum port on the advance unit that points away from the dizzy is advance and the one that points towards the dizzy is retard. And the 76 should use retard only. Someone will correct me if I'm wrong; Certainly Cap'n Krusty will tomorrow. If nothing else, this is a bump for ya. |
Yeah, I was pretty sure that was the case --that's why I hooked it up that way
But the car runs way,way better (hard accel) with it this way. Hmmmm.
And not that it matters too much for emissions testing, but I repaired my AAR valve (see recent threads) and I'll plumb it in tomorrow or so.
Like I mentioned in the Colo pics thread, I went and got my engine all heated up so I didn't get to adjust valves yet (engine is supposed to be totally cold...).
The saga continues...
| QUOTE (jsteele22 @ Oct 2 2005, 07:04 PM) | ||
Yeah, I was pretty sure that was the case --that's why I hooked it up that way But the car runs way,way better (hard accel) with it this way. Hmmmm. And not that it matters too much for emissions testing, but I repaired my AAR valve (see recent threads) and I'll plumb it in tomorrow or so. Like I mentioned in the Colo pics thread, I went and got my engine all heated up so I didn't get to adjust valves yet (engine is supposed to be totally cold...). The saga continues... |
That's because you get more advance that way, so it runs stronger. But you may be getting too much because it wasn't designed to run with that much advance. It can be a double edge sword. For emissions testing though a little retard is actually better. The factory moved away from more advance for that reason (I vaguely remember reading that somewhere over the years). I can't tell you why, I only have my own empirical data to go on. I'm sure the more knowledable club members can enlighten us.
For posterity, I just wanted to add a followup.
Since the original (failed) emmissions test, I made a few changes. One (huge) one was the timing. I think that the first time I set my timing, I actually set it at idle, rather than at 3500 RPM, which is where it is specified. Also, since I know the engine burns (and leaks) oil, I switched to a SAE 40 plus Lucas Oil Stabilizer (Bottle o' Snot). Engine's a little on the sluggish side when I start up cold, but runs fine when warm. I don't plan on driving on those -40 degree days... Also, following Cap'n's advice, I set the valves to .016". Afterwards the engine ran smoother (the valves were in need of adjusting) but I was suprised that there wasn't a horrible clatter from having the valves set so loose - sounded just like normal. I replaced the fuel filter, some old fuel line, nearly all of the FI hose in the engine bay (including the short stubs to the injectors, which were pinching a little) and the fuel injector seals. I don't have the tools for compression or leakdown, so I didn't know what these numbers were. And I did use 87 octane.
So I took the car in on Monday, and the HC problem was gone. The CO was somewhat above the limits ( I think it was 3%, and limit is 2.5%, but I don't have it here w/ me.) So I left it at the garage and let the guy do his thing. For $35 (including the $15 test fee) he tweaked the mixture, switched the retard line over to advance (which consensus here says is *not* the right place ...) and got the numbers low enough to pass. So I'm one step closer to being legal -- gonna go back to the DMV this afternoon (had to get a VIN verification).
A frosty virtual beer to all who helped...
Way to go Jeff! 
Sent you an email on this subject. I've got the reverse problem. My 76' passed HC easily, failed CO by a long ways. Talk to you this weekend if you are at SCR. :headbang:
Dan
Dan
Be sure to set them valves back to .006 inch clearance before driving much that way. Excessiver cleance is power robbing, and can lead to more wear as the valve stems are bumped a bit more with more clearance (the rocker speed increases the further it travels, do to cam profile. If it hits the further away valve stem, it will hit it faster, it can damage the stem and or adjuster screws on the rockers
who is this Shelby guy?
do we let just anyone on here now?
just teasing Dan!
good to see you on here.
brant
do we let just anyone on here now?
just teasing Dan!
good to see you on here.
brant
Aiiieeeeaaaarrrrrgggghhhhhh !!!!!!!! One little space on the title had the wrong signature on it, now I've got to track down Mr. Buttle (or is it Tuttle ?) to sign 2 power of attorneys, a document of sale from 1998, an application for title, and a transfer of title to me. The guy I bought it from bought it from a guy who (...) bought it and didn't register. Had that one spot not been signed, I'd be a legal driver at his very moment.
Wish me ruck......
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