What the F is wrong with my car?, I just want to roll it off a clif. Options

[Eric Taylor]

So today I got the new trigger contact's installed and put the distro carefully back in, so I hopefully did not adjust the timing to far. Go to hit the key and it turns over just like a champ, hit the gas, it's a little hesatent, but run's alright, I know the plugs are black so I go to pull and clean them, thinking the car will run great with a clean set of plugs. Well I just put them back in and hit the key. The car ran crappier than ever, still spitting fluid out the exaust, still hesatating under power, like it's running super rich, which is my main problem with this piece of crap. So basicaly i'm pissed. So far I have not had a chance to drive the thing much over a mile yet since buying it in June of 03, and have replaced the following:
Entire clutch assembly
Points
Cap
Rotor
Plugs
Plug Wires
FI Wireing harness
MPS
CHT
FI Trigger Contact's
Set and rest the fuel pressure

I'm at a total loss for what could be wrong. So here are my symptoms. The care bog's down under power, and is totally undrivable except for in and out of the garage. The plugs are Black when you pull them and there is fluid coming out the tail pipe. The only thing's I can think of are injectors, or that this engine has been screwed with so that a 1.7 injection system just plain won't work with it. I know it has been re-built in the past, but I have no idea weather it was top/bottom end or the spec's. Sorry for the long post, but I just plain don't know what to do. Help!
Thanks,
Eric

[steve@ottosvenice.com]

Give me a call we will get it running. Just relax there are No unsolvalbe problems. Steve

[Eric Taylor]

Sounds like a plan steve. Talk to you tomorrow.
Eric

[r_towle]

I have been there.
Check for a vacuum leak at the hose connecting the MPS and were it connects to the plenum.
Also, make sure its plugged in correctly.

Could be a bad vacuum line there.

If the MPS is not connected right,it will run like a pig, very very rich, it will run, but just like you said, sluggish and lots of fuel.

I ended up putting clamps on both ends of the large vacuum line connected to the MPS to fix it.
Rich

[Eric Taylor]

humm, could be a good place to start. I've got a clamp on one side, i'll try the other.
Eric

[mightyohm]

It's really a shame but I think a lot of 914 owners start out in this position. A lot of 914's are pretty f'd up when they are sold. Don't feel too bad. You'll figure it out. If fuel is pouring out the exhaust it might be worth pulling all the injectors out (including the cold start injector) to make sure one is not stuck open.

Maybe someone else in your area can help you out.

[Bleyseng]

What kind of vacuum is the engine pulling at idle?? should be about 15hg steady. If its real low the MPS will read it wrong and the mix will be rich.

Geoff

[Rick_Eberle]

I had a similar problem a few years ago, though mine was intermittent. I'd be driving along fine and then it would bog down, lose power, and leave a trail of smoke. Then it would be fine again for a while.
One day in the driveway it ran so rich that fuel was coming out the exhaust pipes - luckily that stuff that passes for gas in California didn't go boom!

I also replaced the trigger points, tested the injectors, MPS, temp sensors, etc, but it turned out to be the FI brain. A straight, simple swap for a used one solved all the rich running problems.

See if someone will loan you a brain out of their car to test it out.

Oh, change the oil - mine was diluted by fuel.

Cheers,
Rick

[Bleyseng]

Yeah, that does happen but the ECUs rarely go bad but its worth a try to swap it out for a good one.

Geoff

[Eric Taylor]

Sounds like a good idea. Anyone have a good 72 1.7 brain laying around to try?
Eric

[nebreitling]

eric, sorry to hear about this. your pain is palpable, and we've all been there with these damned little cars. no advice here, just moral support. i like steve's motto -- there are no unsolvable problems. stick with it, you'll figure it out.

in the meanwhile, relax with a beer. tarp the car for a day or two, it'll be there when you're ready.

[keith]

Hey, I'll drive my shitty running car halfway to Newport and we can run them in to each other. Was running ok until I fired it up to go to JP's. I wont hijack your thread I'll post my problems in another.

Keith

[mike_the_man]

Another thing to check could be the cold start injector. It could be stuck open, or something could be grounded out, causing it to spray the entire time. I know how frustrating this can get, I'm in the same boat too. Take a day or two off, then try again with a clear mind.

Good luck,

[Eric Taylor]

Thanks everyone. It's good to know I'm not alone in this battle. I forgot, but I bypassed the aar, and CSV.
I just can't imagine it's a simple problem at this point.
Eric

[Bleyseng]

Unplug the CVS when starting it up to see if that is the problem or crimp the fuel line.

[ArtechnikA]

wish i could be more help, i'm pretty clueless with EFI.
but it appears you have replaced just about everything, leaving you with only two possibilities:

1) it's something else
2) something you thought you replaced with a "known good" isn't.

only a few things will make the car run THAT rich.
bad temp sensors is one - measure the resistance *at the ECU connector pins* to verify that the complete end-to-end signal path is correct.

bad MPS is another - these aren't as easy to test at the ECU connector but you ahoul carefully Ohm the circuits. unfortunately, there are no easy workarounds for what the MPS does that you can plug in 'just to test.'

very, very bad Cold Start Valve is a remote possibility. atr this point, either physically remove it from the manifold and check by looking to verify that it never sprays, or remove and plug the feed line (or both...)

i've seen worn, crappy trigger points do this, but good new ones tend to be good.

ECU failures are rare but they do occur. in fact, IIRC, one of the few failure modes is that all the injectors turn on, all the time.

[Jeffs9146]

only a few things will make the car run THAT rich

Bad/defective plug or plug wire!

Jeff

[ArtechnikA]

Bad/defective plug or plug wire!

you really think one bad plug will foul all 4 and spit gas out the back ?
1 dead hole will make an engine run crappy but i don't think that's the scenario here. my money's on some kind of MPS issue...

(but WTFDIK - i don't do EFI ...)

[mightyohm]

The CSV can still be stuck open even if the wire is not connected.

[dmenche914]

don't do the cliff thing!!

At anyrate, it appears your are too rich, good thing is the ignition system is working, and that's half the battle!

You probably also want to make sure valves are adjusted ok, and also make sure it passes a compression test.

With the above too items done (compression test is easy and fast to do, and the valve adjust is not to bad, just a pain to get at) we will have a reasonable idea that the engine is basically good.

as other posted noted, make sure the vacumm lines are good, pull off the hoses one at a time (so as not to mix them up) and check the ends, often the cloth outside is ok, but the rubber is chewed up on the ends, so cut a bit off the bad end, enough to hit good rubber, and re-intstall. The big hoses on the intake runners can't be removed too easy, (runners must come off) so just make sure thay are tight, they shouldn't rotate very easy if at all, and if they do not have hoseclamps, you might want to add them,a nd tighten then up

check the pressure sensor for leaks, just suck on the ruber hose to it, and it should hold vacuum. if it leaks, your mixture will be wrong. The four wires must make good contact

the head temp sensor can also cause problems, it should be high resistance when cold, I think something like 2k or 3 K ohms and when hot should drop to maybe a 100 - 200 someodd ohms, if the wire is broken, or bad connection, it will be high ohms, and that will make you rich (not millionaire rich!) Since you can't run the car, to even get it hot, just check the sensor cold for 2k-4k ohms or so, much higher than that will be a problem.

You might want to check the spray pattern of the injectors, one or more could be constantly leaking fuel. (by the way, were all four plugs equally black ???) It would be unusual to find all four going bad at once, but it could happen, if only one plug is black, check that injector first.

Also consider the fifth cold start injector, it could be leaking (ie stuck open) or be getting a signal to always be on. (it turns on by grounding out via the cold start sensor, located near the dizzie) Just disconnect the plug tot he fifth injector, unless you have a real cold climant, you won't miss it, if it is constantly firing at least this will fix that, and is simple to do.

Also a 1.7 motor should have yellow injectors (blue for 1.8, and green for 2.0) make sure thay are the right ones.

Finanly you may have a problem in the wire harness to the brain (for example,t he head temp sensor could be fine and dandy, but the wire to the brain could be broken open, thus the brain is always seeing high resitance on this sensor, same for pressure sensor, or trigger points (but to trigger points having bad connection would cause lean condition)

What I did to solve this problem is remove the brain connector, and ohm out each pin to the snsors,/ injectors, and fix any bad wires, I did find a few on my car. Warning do NOT ohm out any wire that goes to the brain with the brain connected, an ohm meter does send a small current thru the wire tested, and if hooked to the brain may fry the brain!!!!!) Also be careful to never short the injector wires out, this will also fry the brain (the power transistors, ask me how I know!!!)

My brain pins got this: (1970 1.7) some years may be different

Note: all to grounds should use engine block as the ground point.

B16 ign turned on should be 12 volts to ground
B24 same as B16
B23 (head temp), should be about 2600 ohms to ground when cold
B17 (throttle switch) 4 ohms to ground when throttle closed
B9 (throttle switch) should be 4 ohms to ground, with ten pulses as throttle moved, count them!
B11 to ground, 4 ohms or less
B3, B4, B5, B6 all go to injectors, should be about 5 ohms to ground.
B7 to B15 (press. sensor coil) 100 ohms
B8 to B10 (press. sensor coil) 370 ohms
B12 to B21 (trigger points, should pulse as dizzie rotated 4 ohms, then open as trigger points move
B12 to B22 same as B12 to B21.
B1 to B13 (air temp sensor) 320 ohm (about 80 F day temp)

thats what i got when probing my brain connector.

Again WARNING: DO NOT probe when connector is attached to brain. Ohm and volt values are approx, for cold engine, yours may vary slightly, but should be close.

Also disconnect battery when removing / attaching the brain connector. reconnect battery for tests that require voltage to be read. Ohms tests do not need battery attached.




At any rate, it is just a matter of tracking down the problem, my first 914 barely ran, and after sorting out several leaks, (the pressure sensor failed my suction test) and several bad wires, and head temp sensor, the car ran great. I wrote down my tests, and ohm readings when I went thru the engine, and even did the brain connector tests (the final say if the sensors are talking to the brain) Made a detailed drawing of the pin outs, and what they connected too. Once i did this, the car ran as new, and with the knowledge was able to diagnois problems on freinds 914's also

the stock FI system on the 1.7 is in my opinion very nice, just may need to be made more reliable after 30+ years of wear and tear. bad wires can be re-soldered, grounds cleaned and tightened, etc... Not too difficult if you go thru it in an orderly fashion, and have a good manual and schematic, and Volt / ohm meter,

Feel free to post again if you run into road blocks, let us know what you have done, what you have found, and we will try to help out.

good luck dave