Car stalling AGAIN, Updates- none of them good. Options

[BeatNavy]

Can you be more specific about where air is coming from? Doesn’t seem right.

Sort of grasping but have you done a compression check?

[rjames]

Can you be more specific about where air is coming from? Doesn’t seem right.

Sort of grasping but have you done a compression check?

It's ok, I'm grasping too. I haven't done a compression check but planning on borrowing the tool to do so tomorrow.

Air is coming from the hole in the tin just above where #4 is stamped in the tin, and also through where the CHT wire comes out of. I’m told head leaks are loud, but no abnormal sounds though.

[yellowporky]

Did you ever rule out the ecu?

[rjames]

Did you ever rule out the ecu?

I did

[yellowporky]

If all of your components check out, replaced your FI harness and you are still having problems i would suspect the power feed to the fuel pump and the ground. It would be the only thing that you have not replaced. When cold it works and when it runs and gets hot looses connection until it cools down again.
Also when building my car i bought new relays from 914 rubber and some of them did not work when i plugged them in so i had to spread the out the legs and then was all good. Maybe you are having a loss of connection a like that?

[rjames]

If all of your components check out, replaced your FI harness and you are still having problems i would suspect the power feed to the fuel pump and the ground. It would be the only thing that you have not replaced. When cold it works and when it runs and gets hot looses connection until it cools down again.
Also when building my car i bought new relays from 914 rubber and some of them did not work when i plugged them in so i had to spread the out the legs and then was all good. Maybe you are having a loss of connection a like that?

Thanks- Verified fuel pump is running and fuel pressure is at spec when it stalls,

I’m still hoping someone can tell me why I am feeling air come out the passenger side engine tin when the car is running. I’m worried there is an issue with the head seal but from what I’ve read it would be really noisy if that was the case. No?

[toadman]

Can you be more specific about where air is coming from? Doesn’t seem right.

Sort of grasping but have you done a compression check?

It's ok, I'm grasping too. I haven't done a compression check but planning on borrowing the tool to do so tomorrow.

Air is coming from the hole in the tin just above where #4 is stamped in the tin, and also through where the CHT wire comes out of. I’m told head leaks are loud, but no abnormal sounds though.

On my car the hole in the tin above the #4 holds a small plastic spark plug wire guide. Also, there should be a rubber seal in the hole where the CHT wire comes through the tin. For optimum cooling you should "seal" all holes in the tin with the factory component that is meant to go there or something else. For example, missing spark plug wire seals let out gobs of cooling air.

Regarding your intermittent stalling, I read this whole thread one time and I recall that you mentioned that you checked your grounds but I don't recall you saying which ones you checked. Did you check the tri-prong FI ground on the top of the engine, the ground under the relay board behind the driver and the transmission-to-body ground on the trunk floor? My apologies if have repeated something.

[yellowporky]

if he replaced his fuel injection harness the grounds on top of the engine would go with the harness
i believe a bad trans to body ground would make it hard to crank the engine when warm.
Has to be in the harness to the brain because he says everything else is new and checks good when it wont start.
The air that you are feeling blowing when the engine is running is from the cooling fan. Unless i misunderstood you.

[rjames]

if he replaced his fuel injection harness the grounds on top of the engine would go with the harness
i believe a bad trans to body ground would make it hard to crank the engine when warm.
Has to be in the harness to the brain because he says everything else is new and checks good when it wont start.
The air that you are feeling blowing when the engine is running is from the cooling fan. Unless i misunderstood you.

I replaced the ignition harness but not the injection harness.

[rjames]

Compression #s with engine warm, all plugs removed and throttle open:
110, 110, 130, 131

[rjames]

Just wanted to dust the cobwebs off of this thread with an update. I installed a new Bowlsby injection harness (work of art!), and so far...so good. I'm probably jinxing things just by posting this. I hate intermittent issues, and given how intermittent this issue was, I won't be confident that the car won't stall on me again for some time.

Two questions remain:

1) If I leave the air temp sensor plugged in (sensor on the plenum), when cold the car runs fine, but when it warms up, the idle hunts like crazy. If I unplug it the idle is steady both when cold and when it's warmed up.

2) I can't get the idle lower than 1100 rpms. This seems to be an issue others have after installing the 123 distributor and happens whether I configure the distributor it for retard or advance. I don't have a vacuum leak, but I did notice something on both my original throttle body and the NOS one I found last year: When the idle screw is all the way in, a fair amount of air is still being pulled from the top of the butterfly. If the adjuster is all the way in, shouldn't it completely (or nearly completely) block any air from getting in?
(borrowed pic)

[BeatNavy]

Just wanted to dust the cobwebs off of this thread with an update. I installed a new Bowlsby injection harness (work of art!), and so far...so good. I'm probably jinxing things just by posting this. I hate intermittent issues, and given how intermittent this issue was, I won't be confident that the car won't stall on me again for some time.

Two questions remain:

1) If I leave the air temp sensor plugged in (sensor on the plenum), when cold the car runs fine, but when it warms up, the idle hunts like crazy. If I unplug it the idle is steady both when cold and when it's warmed up.

2) I can't get the idle lower than 1100 rpms. This seems to be an issue others have after installing the 123 distributor and happens whether I configure the distributor it for retard or advance. I don't have a vacuum leak, but I did notice something on both my original throttle body and the NOS one I found last year: When the idle screw is all the way in, a fair amount of air is still being pulled from the top of the butterfly. If the adjuster is all the way in, shouldn't it completely (or nearly completely) block any air from getting in?
(borrowed pic)

So I'll give you two (IMG:style_emoticons/default/piratenanner.gif) (IMG:style_emoticons/default/piratenanner.gif) and one (IMG:style_emoticons/default/sad.gif) as a partial victory, pending additional info. Hopefully the wiring harness was the ticket. It would make sense. Intermittent issues could easily be caused by a sketchy wiring harness. Fingers crossed.

In terms of your questions: 1) you are lean at idle. Unplugging the air temp sensor is going to somewhat richen your mixture, and the hunting idle was because it was lean.

2) I think that's normal. I'll go see if I can find one of my TB's and compare, but there are several versions of them, so I may not be able to answer that definitively. Yes, with my 2056, D-Jet, 123 Dizzy, using curve "B" I couldn't get the idle below 1100. I kind of got used to it.

Rock on (IMG:style_emoticons/default/aktion035.gif)

[rjames]

So I'll give you two (IMG:style_emoticons/default/piratenanner.gif) (IMG:style_emoticons/default/piratenanner.gif) and one (IMG:style_emoticons/default/sad.gif) as a partial victory, pending additional info. Hopefully the wiring harness was the ticket. It would make sense. Intermittent issues could easily be caused by a sketchy wiring harness. Fingers crossed.

In terms of your questions: 1) you are lean at idle. Unplugging the air temp sensor is going to somewhat richen your mixture, and the hunting idle was because it was lean.

2) I think that's normal. I'll go see if I can find one of my TB's and compare, but there are several versions of them, so I may not be able to answer that definitively. Yes, with my 2056, D-Jet, 123 Dizzy, using curve "B" I couldn't get the idle below 1100. I kind of got used to it.

Rock on (IMG:style_emoticons/default/aktion035.gif)

@BeatNavy I'll take as many (IMG:style_emoticons/default/piratenanner.gif) as I can get. Thanks and I appreciate all of your help along the way on this one. (IMG:style_emoticons/default/beerchug.gif)

So maybe I should go back and re-calibrate the MPS with the air temp sensor plugged in (and engine warmed up). The perfectionist in me hates knowing it's unplugged.


RE throttle body: I found a pick of a bunch of different stock versions, including ones that didn't have the hole drilled through the butterfly plate. If I cover up that hole the engine dies (which supports my belief that I don't have a vacuum leak). However, if I cover up just a bit of the port that's associated with the idle adjustment screw, I can easily get the idle below 1000 RPMs.
I also found a thread that a rebuilder of TBs had posted here a while back saying that part of his service was to ensure that the idle bleed screw fully sealed the port when screwed in all the way. (IMG:style_emoticons/default/idea.gif) It would make sense to me that it should function that way.

[orthobiz]

Thanks rj for helping me to think about my 1974 2.0 liter running problem last year (it was the timing all along!)

Anyway, my 1974 1.8 had an intermittent problem with dropping out and stalling and it was the ignition switch. Maybe a long shot, but I didn't see you mention it. I could stop the stalling by manually holding the switch ever slightly like I was going to start the car.

I was going to try to be clever and say maybe it's your driveway since it seems to stall there a lot...

Good luck!

Paul

[rjames]

Ok I'm back to updating my thread that seemingly never ends. I thought I had my problem of high and/or surging idle and/or intermittent stalling issue fixed with the new ignition and new injector harnesses.

Nope.

Car hasn't stalled again, but almost did. Started the car the other day and after it warmed up the idle was a perfect and steady 1000rpm. Which was strange since I couldn't get it below 1200rpm previously. AFR was 13.5 too, even though the last time I had driven it it was 10.5 at idle. (IMG:style_emoticons/default/huh.gif)

Drove ~ 15 minutes to the grocery store. All good. When I got back to the car the idle was now at 1100rpm. Another 15 minutes of driving and idle increased to 1200rpm.
More time driving and the idle started fluctuating from 600-1200rpm. At one point at a stop sign the engine almost stalled- idle just dropped to almost 0 like the engine had just been turned off, but the idle came back up before that could happen.

I did notice that when the idle is fluctuating (usually going from ~600-1200 rpm) it will continue to fluctuate even if I step on the gas a bit and hold it there- say increase the RPMs to 1500rpm, the rpms will continue to drop to about 1200 and then go back to 1500. So this issue is happening even when the ECU is not seeing an 'idle' state because the TPS is seeing idle anymore.

The nagging feeling that maybe there is a vacuum leak wouldn't go away so I connected my vacuum gauge via a T off of the throttle body retard port and it shows 17.inHg at 1100rpm and when it surges to 1200rpm it reads 18.5in.Hg. Of course when I did this test the idle wasn't dropping below 1100rpm so I don't know what the reading would be then, will try and capture that. My guess is that it will be less than 17in.Hg just by virtue of the slower engine speed. In other words- I don't think i have a vacuum leak because I would expect the vacuum to drop at higher idle RPMs if that was the case.

This feels like an issue with the FI system or the engine itself. But I've got a new ignition harness, new FI harness, new CHT, 123 distributor, injectors tested, verified fuel pressure, etc. I've tried swapping ECUs and I've got a rebuilt MPS that holds vacuum. I suppose I could try putting the vacuum gauge between the manifold and and the MPS and see if the MPS diaphragm is intermittently failing? Could this be a thing?

What about the engine itself? What are the symptoms of leak at the heads? Compression issue? (Current #s are 110, 110, 130, 131) Other? Car seems to have plenty of power.

[porschetub]

Ok I'm back to updating my thread that seemingly never ends. I thought I had my problem of high and/or surging idle and/or intermittent stalling issue fixed with the new ignition and new injector harnesses.

Nope.

Car hasn't stalled again, but almost did. Started the car the other day and after it warmed up the idle was a perfect and steady 1000rpm. Which was strange since I couldn't get it below 1200rpm previously. AFR was 13.5 too, even though the last time I had driven it it was 10.5 at idle. (IMG:style_emoticons/default/huh.gif)

Drove ~ 15 minutes to the grocery store. All good. When I got back to the car the idle was now at 1100rpm. Another 15 minutes of driving and idle increased to 1200rpm.
More time driving and the idle started fluctuating from 600-1200rpm. At one point at a stop sign the engine almost stalled- idle just dropped to almost 0 like the engine had just been turned off, but the idle came back up before that could happen.

I did notice that when the idle is fluctuating (usually going from ~600-1200 rpm) it will continue to fluctuate even if I step on the gas a bit and hold it there- say increase the RPMs to 1500rpm, the rpms will continue to drop to about 1200 and then go back to 1500. So this issue is happening even when the ECU is not seeing an 'idle' state because the TPS is seeing idle anymore.

The nagging feeling that maybe there is a vacuum leak wouldn't go away so I connected my vacuum gauge via a T off of the throttle body retard port and it shows 17.inHg at 1100rpm and when it surges to 1200rpm it reads 18.5in.Hg. Of course when I did this test the idle wasn't dropping below 1100rpm so I don't know what the reading would be then, will try and capture that. My guess is that it will be less than 17in.Hg just by virtue of the slower engine speed. In other words- I don't think i have a vacuum leak because I would expect the vacuum to drop at higher idle RPMs if that was the case.

This feels like an issue with the FI system or the engine itself. But I've got a new ignition harness, new FI harness, new CHT, 123 distributor, injectors tested, verified fuel pressure, etc. I've tried swapping ECUs and I've got a rebuilt MPS that holds vacuum. I suppose I could try putting the vacuum gauge between the manifold and and the MPS and see if the MPS diaphragm is intermittently failing? Could this be a thing?

What about the engine itself? What are the symptoms of leak at the heads? Compression issue? (Current #s are 110, 110, 130, 131) Other? Car seems to have plenty of power.

Obviously you did the compression test with warm engine ? you do have a high percentage variance in compression ,did you reset the valves before the test?.
Good luck.

[rjames]

Yes, engine was warm when I checked the compression and valves adjusted.

[rhodyguy]

A local member had the same 'hunting' (fluctuation) problem. The stacked elbow looked good but was broken in a spot you couldn't see. Have you verified the internal plenum tubes are not cracked? The bottom side as well as the top.

[Highland]

I know this theory may be completely invalid, but where is your PCV plugged into? Is it the stock location? Just wondering if an aging valve can cause inconsistencies in idle performance. I moved mine above the TB. Things seems to steady out but I made a bunch of other adjustments and changes, so hard to say.

[rjames]

A local member had the same 'hunting' (fluctuation) problem. The stacked elbow looked good but was broken in a spot you couldn't see. Have you verified the internal plenum tubes are not cracked? The bottom side as well as the top.

'75- no stacked elbow and no PCV.

And a vacuum leak wouldn't account for the engine almost cutting out- the RPMs would go up, plus I measured no loss of vacuum when I put the vacuum gauge on the TB, even when the idle was fluctuating.