I know i searched for it:

Engine is 1973 2.0 with 9550 cam

017 CHT

037 MPS


I have been watching the AFR gauge i just installed. Car runs rough for the first 2 min on startup. WAAAAY to rich. I already removed the resistor wich dropped the value 270ohms to try and lean it out. Now on startup the gauge is no longer pegged for the first 2min. It is 20% leaner but i need another 20% to get to the Stoich area of the gauge.

I have the fuel pressure right on 29, it was at 30 and i swear it is just a bit leener at 29.

When i get it warmed up it stays in the rich but its not all the way. Once opend up on the highway it goes from rich to stoich, wich seems correct.



How in the hell do i lean it more??

time to adjust the MPS ??

brad anders site says DO NOT ATTEMPT

It runs really good once warmed up.

I mean really really good.

Should i just leave it alone? Can the MPS adjustment affect idle only, cause highway seems fine.

do you have numbers to back up the gauge, or is it one with just zones?

is this a narrow band AFM?

brant

no numbers, narrow band.

bars

1-4 lean

5-14 stoich

15-20 rich

i am on 18 at startup

this drops to 16-17 at idle when warm

highway steady between 14-16

sounds like the mps is leaking and running full rich.

tested with vacuum and holds steady

Joe,
I don't ever see more than the 1 light on my NB gauge when the engine is warm idling, or cruising at very light throttle settings.
The richest you want to ever see with that gauge is 16-17 at wide open throttle. It shouldn't ever be anywhere near that rich except when the engine is first started cold.
You really don't want to operate in the middle of the stoich range for long.
I agree with Curt. Check the MPS by sucking on the hose to see if it leaks.

Then the inner center screw needs to be adjusted anti-clockwise.

I thought that middle stoich was the target?

Stoichiometric is where head temps will be the highest.
Light cruise can be lean, while more than 20-30% throttle should be somewhat rich.

I have been approaching this wrong, I did notice higher oil temp with stoich

teach me

idle should be where?

part load where?

full throtle?

The narrow-band gauge is USELESS FOR TUNING. Pegged lean on the gauge could be 14.9:1 instead of 14.7:1, or it could be 18:1 -- you cannot tell from the gauge.

If you want an actual idea of what the mixture is doing, you ABSOLUTELY MUST use a wide-band meter.

Trying to adjust your MPS using a narrow-band sensor is pretty close to taking a hammer to it. You'll never get it back the way it was, and you have better odds of winning the lottery than getting the mixture to a really good place through the range.

--DD

I was taught (or at least what I remeber) that a NB O2 sensor voltage range is equivelant to A/F ratio of 14.0 to 15.4.
You can see on the graph how quickly the voltage changes.

Jim

Click to view attachment

I say that's BS. I'm getting very good results using a NB gauge.
However, it would be meaningless to rely solely on the gauge. One must apply a little common sense too.
A good understanding of how the gauge functions, what fuel mixture is desired, and what the effect of the various adjustments has on mixture is enough to make the NB gauge quite valuable.

IMO, one can become fixated on achieving the "perfect" numbers with a wide band AFM, and never pay attention to what the engine is telling them, through sounds for instance.

That said, I don't recommend using narrow band on a high dollar modified engine, and I don't recommend using either type on a dedicated track engine.

The people I don't understand are those who don't add any instrumentation at all after spending $10K or more on a hi-po powerplant, and simply relying on someone to tell them what are the right jets to use.

Joe
Check out this thread -- my AFR table is in there, it will give you good targets for various load/rpm combinations. The final table is on page 2.

In general,

* Highway cruise -- 13.0 or 13.5:1
* Part throttle / accelerating -- 12.5:1
* WOT -- 12.0 or 11.5:1

The only time you should be stoich or leaner is when you lift the throttle or are engine braking.

IMO, those numbers aren't right at all Rich.
11.5 is waaayy tooo rich under any operating conditions!

If you can do that, you're a better man than I. The readings from the NB sensor are highly temperature-dependent and, as far as I can tell, are almost completely unreliable anywhere but right at 14.7:1 AFR. If you can get more information than that from the NB gauge, I am quite impressed.

--DD

I couldn't make it through the linked thread.... to tired... sorry

but 11.5 isn't right

12.7-ish... (maybe 12.5, maybe 13.0) is the best for WOT
anything more rich than that is potentially washing down your cylinder walls and hurting your motor... 11's and 10's are not going to create more HP or help....

I am gonna swap gauges, not that I dont trust this gauge, but for a guy just reading "Bosch Fuel Injection Fundementals" it would be a lot easier for me to understand what is going on with a wide band gauge. Plus, I am having a lot of fun driving and tuning.



Let me see if I got this right;

the variables in tuning can be adjusted with

fuel pressure

throtle position switch

mps adjustments

aar

and the bypass screw

what about fuel octane and timing?

Your gauge is working fine Joe. The data you're getting is good.
Check your AAR first. Make sure it's open right after startup by pulling the hose from the AAR to the airbox (not the one to the plenum) to make sure ifs sucking air. After a few minutes it should stop sucking.
Next, try adjusting the mixture screw on the ECU to lean it out during warm idle. Anywhere from 1-5 is good for now.
14-16 on the highway is not quite rich enough. You may need to raise the fuel pressure a little until more precise adjustments can be made to the MPS.
My MPS Tuning Kits will be ready soon.

Chris,

I made some adjustments on my lunchbreak.

Fuel pressure ia @ 30psi

AAR is now working properly (swiched the vacume hose)

startup is awesome now.

I am pegged green for about 1 min

then i am @ 3 green lights warm idle (ecu knob fully counterclockwise) (270 ohm resistor inline)

cant get her on the highway till this evening.

I will report back

I have never run anything less than premium, I was thinking to fill up on 89 tonight to see what happens?

After reading that incredibly long AFR thread, sounds like I could benifit from lower octane gasoline.

Engine and driver are VERY happy with 87 octane.

Temp gauge did not even pass the letter "T" except for the one time I tried to make it go past . The NB gauge says that I am right where I need to be



Next step:

Replace oil temp gauge and sender with new gauge with actual numbers

Hook up the 4 CHT's and find a place to mount the gauge

Drive the hell out of it.

As long as it doesn't knock, your in good shape.
I need to use 89 in my 1.9L.

Car runs perfect (2.0) d-jet with 89 oct. no-ethanol here . - our local HESS carries it but it is 25cents more than regular, but less than premium and now i have had not had a bad tank of gas since!- and the car sits most of the summer , ran it last 2 days with no problem - after sitting for a month- i do pu the stable and sea foam in as well now every tank.

someone correct me if I'm wrong...


I thought that federally all gas sold in the US now has ethanol, MTBE?
(10 or 15%, which changes stoich by the same 15%)

I thought it was a federal law to suppliment the corn growers and drop emissions.

I believe president bush signed this into law just before his term ended.

I run premium or the engine pings but I am running 9 to 1 CR. Pulled the 914 out of storage of a year and it started right up. Last night I drove around a bit to get the cobwebs out of it and will drive it for the next week or so. I always add Stable to the tank before putting it away.

87 started to rattle on accleration today.

Filling up on 89 tonight. we will get this right

\

MTBE is not ethanol. It is (hopefully I can remember this correctly!) Methyl Tertiary Butyl Ether. It's gnarly stuff--it's a carcinogen, and leaches into the ground water if it leaks out of the tanks. It was pulled out of gasoline once people realized what it was doing.

Most gasoline sold in the US now has ethanol in it, but it's plain old corn-based alcohol. No ether.

You're lucky if you have a place to get E0 (no ethanol). You can't get that in California, for one.

--DD

How do you get your car to idle lean?

My idle is now 2 green bars rich. If I turn the ECU knob counterclockwise even 1 click there is a tiny hunt. Each click i go counterclockwise the hunt gets more and more

I realize that I dont have numbers to go with the gauge, but my question is, if some of you guys are idling lean, is your idle stable, and if so how did you do it?

I just worked on mine yesterday, exact same thing- what i did was make snd adjustment to the MPS. The epoxy plug was removed, so i removed the filull load stop plug and made a very slight adj to the inner screw. I now have a smooth idle at 850 rpm when warmed up. No hunt.
lean run will hunt just like vac leak, r u sure that is ruled out? Afterward i drove her for 30 minutes. , oil temp was never over 190 (90degrees out) maybe u can tweek the mps?

89 octane (rattle gone)

I think the only way to fix my AFR is with MPS adjustments, and a wideband gauge. No matter how much I figit with it, I cannot get it right. So,

step 1. Read

step 2. remove epoxy plug

step 3. adjust

Leaving it a little rich at idle won't hurt for now.
You will probably have to lower the fuel pressure again to get rid of it, but don't do that unless you can adjust the driving mix into the proper range.

You are trying to reinvent the wheel here as this cam always makes the idle rich at cold startup idle. (Low vacuum due to valve overlap)

"It runs really good once warmed up. I mean really really good. "

That's what matters! Warm up idle is nothing so leave it alone and ignore the stupid gauge at idle.

I am not concerned with the warmup idle so much, if i drive for an hour it is still 3 green bars rich at idle, and that is my hot idle. Its the same 3 green lights i get while acclerating WOT. That is too rich for idle afr!

The ECU knob is about 5 clicks from all the way lean. If I try to adjust the knob even one more click the idle begins to surge and the gauge begins to surge.

And thats at 1200 rpm




This is a job for MPS Tuning right?

Can't you get the idle down to about 800-850?
That's where mine idles warm.

I dont like it that low, with my spirited driving and no decel valve the engine rpms drop hard when hot, it almost chokes. Mabey thats related to my afr problem, at 1000-1200 rpm it stays smooth with all kinds of driving.

Whats the big advantage turning the idle to 850?

fuel consumption?

car is already running quite cool. I also dont like the oil pressure gauge to go below 10psi. seems to me that if i idle that low the pressure would follow. no?

still playing

Got running lean at cruise

half pedal i got 2-3 green bars

all the way down WOT I get 3 solid bars usually with excellent acceleration but... sometimes i get all the way pegged lean with no power till i let up off the gas a little. Whats up with that, it always happens when a bright red boxter is approaching me from the right

I show pressure steady at 30psi









p.s. I did pass the boxter, and I passed him good

mabey the rpm was too low, and I should have downshifted? I was in 5th gear about 3500rpm and I put the pedal down flat?

im thinking if i down shifted, i would not have gone lean mabey??

5th gear is not a rapid acceleration gear. 2056 still does not have the grunt to make that work. Should have dropped to 4th until you hit 80, then went back to 5th. I'm not so sure your issue was tuning so much as gearing.

Zach

1000-1100 is where the idle speed has to be set with a 9550 cam to keep the vacuum up.

Playing with a narrow banc is playing so yes, to tune a MPS use a wide band setup!

turned up the fuel pressure to 31 and tried again. This time a black 911 with the top off and AC/DC jammin. I approached from the rear 5th gear about 3500rpm, dropped to 4th when i was right there, pedal flat, he was gone.

took him about 5 min to find me, then i smiled and went my way.

Think I resolved the lean full throttle with 1 psi more of pressure

does that sound right.





I am not touching the mps till i get my wideband and Tangerine tuning kit

Did the 911 know he was racing?
Sounds like the engine is purring.
I want mine in the car bar right now.
Zach

does it really matter

I just noticed today, after the car has been warmed up, if I pinch the vacume hose between the pcv valve and the manifold the idle drops. Is that normal, or is that a worn pcv valve.?

When should it be open and when should it be closed??

So, I seem to have everything running exactly where I want it, The car runs really well with great acceleration. The only thing that I cannot figure out is the cold startup.

Every time the car sits overnight, it really wants to crank and crank for about 10 secs before catching and then it always runs waaaay rich for about 3 min. It also has a little white smoke for a couple secs.

I have leaned out the idle with the ecu knob and the bleed screw. It Idles great right now. I set it to 1100rpm. I like 1100 so Im gonna keep it there.

I have unplugged the cold start and plugged the fuel hose, so thats not it.

I have also checked the aar, working great.

I have removed the 250 ohm resistor, it helped a tiny bit.

Whats next.? I dont think the MPS adjustments are gonna help me with cold start right? Is there any other tricks to lean out a cold start. Is this just the way a 2056 likes to run?

Is your starter new? Mine (2.0L) used to crank for a long time until the starter finally gave out. Started like a champ after I spent $40 at Pepboys for a refurbished one. Funny how much troubleshooting I had done with the long cranking cold starts...

Starter is not new but cranks fast and strong, charging system is tip top. 120amp alternator. I am just trying to fine tune cold startup. You can smell the fuel out the pipe for the first min.

You know.....nowhere in your posts did you say....at least I didn't see...so I stand corrected if so.....

Have you flow tested or checked your injectors for leakage and flow?

Sent them to cruzin performance about a week before installed, all were very close and the pattern was perfect.


(keep in mind this condition is gone if the car has been running within 4hrs or so. Starts and idles perfect. It only does this if it sits overnight, or 9hrs while i am in the office.

I still think you should turn the warm idle down to 800-900.
My 1911 idles perfectly smooth there.
(It has the same cam as yours)