Intermittent stalling, idling/driving: possible ECU problem?

[Legacy777]

Thank you very much for the pictures!!!

The housings appear to be the same, so now all I need to do is find one of these electronic combination meters.

Thanks again!

[Bartek]

No problem at all

[Alphius]

That is interesting. I would love it if US market cars had that. The cable speedo is my least favorite part of my car. It's interesting the small differences in that combo meter. The orange part of the needles goes into the black center on the tach/speedo, there's no alternate speed (MPH) markings in the center which makes the speedometer look much cleaner and matches the tach better.

[Legacy777]

We've got mph & kmh for the north american cars since Canada & other countries use kmh vs. mph.

[Alphius]

We've got mph & kmh for the north american cars since Canada & other countries use kmh vs. mph.

I know, but I wish it wasn't so... I've always felt it clutters up the speedo. Even though I can do the translation for common speeds easily in my head, the regulations have forever doomed us to a life of ugly speedometers... First World Problem!

[Bartek]

Hi lads.
It's back again.
Once - for now. Driving uphill, gauges dropped to zero, felt complete lack of power, then it pulled again in a second. No road bump, warm engine, completely random.
Damn
Any, any hints please????

[Legacy777]

So what fixed the problem last time, or did it just magically fix itself for a while?

[Bartek]

No green idea (as we say it here in Poland)
I just don't know. This is this kind of gremlin, that makes you thinking of getting rid of the car ((
Now nothing is happening but I'm scared already.
New battery bought me half a year of easy life.
But, there still was a chance that I accindentally wiggled something. Still no clue what could it be.

Where to start from?

[Legacy777]

Unfortunately, it sounds like you've got a wiring issue somewhere. What I would suggest doing is using a multimeter and just go through every single pin on the ECU to verify the wiring is good and has 0 ohms of resistance. Also, when you're doing this, wiggle the wiring harnesses around to see if anything changes.

My mom had 1990 Toyota pickup that intermittently cut out on her. Several dealerships couldn't find anything wrong, but one dealership actually took the time to troubleshoot the wiring and found that there was a cut in the engine wiring harness that was causing the engine to cut out. I think this harness was near the exhaust manifold so the high temps from the exhaust I think played a role in the problem occurring.

Intermittent wiring issues are just extremely tedious.

[Bartek]

Eeeeeerrrrrr....Josh, stupid question.
I became more 'acoustic sensible' while driving and noticed some strange thing.
When I let off pedal clutch there's some sound that's very much like sound of brake switch click under the brake pedal.
I'm starting to think that perhaps some wire interfere with bare metal of pedal and grounding it or something?
Correct me if I'm wrong - clutch shouldnt have any electrical switch, right?

[Legacy777]

Yes the clutch has two switches. One for the cruise, and is engaged when the clutch is not depressed at all, and one for the starter interlock circuit which keeps the car from starting unless the clutch is fully depressed.

I'm not sure these would cause your issues, but anything's possible. If you look under the dash you should see the two switches on the clutch pedal.

[Bartek]

If I say 'bump' is there a chance someone would kill me?

Strange thing, two last times car died it was in some kind of traffic. No moving, steady stop, idling. Once few days ago - means summer, and last time it was much colder but still - little traffic jam. Engine fully warmed which brings CPS to my mind - everytime car needed a little time (30 and 15 minutes to get CEL ready and start the engine). So temperature problem in this case, I guess.
Twice I got problem with crank gasket and it sutter oil all over the place - twice timing belt replaced. Thinking of oil contaminating sensor.

I did some experiment yesterday - I unplugged sensor and try to start the engine. CEL was present but after cranking it dissapeared. It needed key to off and once again to on to get CEL lit on.
I'm thinking anyway of replacing crank sensor. I just need to start over again

[Bartek]

And one more question.
I can't find main grounding point. My leggy has watercooler so not much I can see there. I just can't identify this location. Any hints?

[Legacy777]

Are you looking for the grounding point for the ECU and all the sensors, or the ground point from the battery?

The ECU & sensor grounds should be on the back side of the intake manifold on the driver's side. It's almost where the intake manifold meets the heads.

Unfortunately, I don't have any good pictures showing that ground spot.

[Bartek]

Is this more or less this location?
I can see some grounding but it looks to me like gnd from battery.
One thick black wire.

[Bartek]

Nailed it. Fusebox under hood. Tried to reach ground point and removed washer tank. Then, just in case wiggled some wires. There is some gremlin, relay clicking and CEL flashing but after 2 hours of senseless action decided to give it to electrician. Let you know what he will find...I hope he will.

[Legacy777]

The ground spot you identified is for the starter. It's not where the ECU grounds. I'm not sure if the new manifolds ground in the same spot or not....I would kind of guess they don't.

I guess let us know what the electrician finds out.

[Bartek]

Nothing
Completely nothing. He couldn't recreate the problem. I think I'm on my own again.
Yes, I've found ECU grounding point. Truth is it is extremely hard to get to but now I don't think that's my problem.
In the beginning I was sure that no 1 is the culprit - no matter if I was wiggling wires or relay itself - it was clicking and causing break in power delivery to ECU. Then I dismounted whole thing and wiggled again - nothing, but wiggling the rest ended up in clicking. Then I realized plug no 2 is crucial - if this plug is off no CEL is present. It is all I know so far.

[Bartek]

It ends up with ECU replacement. Other possibilities just have been excluded. Will report in a few months to confirm.

[alexandermf]

My problem ended up being that yellow wire in what you have labeled as two... It runs power to all the important relays... Go figure after I replaced everything else... Ended up getting new fuse block from junkyard and fired it up

Sent from your bathroom closet

[Bartek]

Yup, I've seen your story. I am still not sure if it is not my case. About year ago I had changed battery and everything was fine for another 6 months. Then car became undrivable. Now I changed ECU beacuse I ran out of options.

Does my case look familiar to you? I mean lack of CEL and so?