Stealth Stalls after 15 minutes - Now won't start at all

Hey Guys -

I am trying to get my car back on the road and am having a couple of issues. I have researched many of the stalling / no start threads, but have yet to find one that resembles my issue. Trying to keep is short - I drove the car into the garage a few years ago, disconnected the battery covered it and let it sit. I started it once in a blue moon. I had to move it back home about a year ago. Replaced the battery, started it right up, pulled it out. It Idled for about 15 - 20 minutes, then abruptly stalled. Like you turned off the key. Wouldn't start back up. After it cooled down about a half hour it started back up. This issue would repeat like clockwork: run for 15 -20 minutes, abrupt stall - about when the top radiator hose got hot. At that time I though I had fuel, but no spark when it stalled. I got frustrated and sidetracked and the car sat for the last 9 months. With a little more free time on my hands, I went back at it again. Now it won't start at all. I have plenty of spark. Trying to decipher the obvious issues. ECU - or IAC, but I have not found any direct correlations to my issue.

Sound Familiar? Any Help or thoughts would be greatly appreciated.

JD

I bet right before it stalls you can hear a click.

I'd look at the caps on the ECU first, and also at the MFI relay on the passenger side of the console.

Thanks Stealthee. The first time it stalled i definitely heard something. I was outside the car, and my first thought was: "That wasn't good" . I pulled the ECU and checked the caps. They didn't look puffed, and I didn't smell anything. I will pull it again. I will check the MFI relay. Thanks for the tips.

I am going to add some more comments / questions to this thread. Looks like I opened it in the wrong section. Can a moderator move it to the Non Turbo Engines section. I will add to this tomorrow here in FAQ, if it is still here. Thanks.

So Stealthee was right. I put in a new MFI relay, and the car started. It idled for about 5 minutes, then abruptly stalled like before. Shorter than the previous run of 15 minutes. I realized that I had used my first ECU. I had purchased a used one, and switched to that one. The car fired right up, ran for a few minutes, then the idle started bouncing around. It stalled, and I thought the IAC could be bad. I pulled and tested the IAC, and got approx 30 ohm across 1-2, 2-3, 4-5, 5-6. I put it back together and started it again. As expected, same result. Started fine, perfect Idle for 3 minutes, then started rough idling until it quickly stalled. Thoughts on my next move? Fuel filter? Anything else obvious I am missing? I have videos, but they are too big to upload, even zipped.

Any help would be greatly appreciated. Thanks JD

If you got a YouTube account you could upload it there and post the link here.

One thing to keep in mind is the car may run like crap until the ECU "relearns"

Other things to look into is the PTU. Once it stalls check to see if you have spark. If you have spark see if you have fuel, you could always spray some starter fluid in the TB to see if it fires. The ECU itself could be a culprit. You may want to open it up and inspect the caps.

Thanks Stealthee. I will work on getting the videos up. I am coming full circle, because I started with the PTU. I discredited that because it had no change in what happened. With the original ECU, I had no spark after it stalled. I have not confirmed with the second used ECU. Now that i know the IAC tests OK, maybe I can put the original ECU back in and see if it runs rough. Possibly I have the first ECU with bad caps, and the second needs to relearn (or is bad also). I will get the vids and maybe an ECU caps pic up in the next few days.

Here are pictures of the ECU and caps. With the naked eye, they look pretty good. When I looked at my own pictures, and zoomed in, looks like one may be starting to leak. Do you agree.

Attachment 9793.

Attachment 9795

Here is a video of what is going on. Starting, abrupt stall, then the rough idle after running for 3 minutes. I put a close up of the CAPS at the end of the video.

Thank you very much.

https://youtu.be/WQQNomA1f6o

Hey guys, Any thoughts on my situation above? The IAC tests out good, and I replaced the PTU and MFI & I have 2 ECUs running very similar stall modes. Do the caps look bad on the video above? I can get that ECU repaired. The second one does not have leaky caps now, but appears to have had them replaced before, with some board damage. How about the MAF, or another temperature, or possibly O2 sensors? I am thinking that is stalls out as soon as temperature starts to rise. What is my next move? :confused3:

Any ideas would be greatly appreciated. Thanks

JD

This is where a scan tool/data logger that can view live data would help greatly. You just monitor and look for the input that drops out. it's not O2 sensors, the ECU has a 12.5% trim limit on those. MAF is easy enough to test, when it's rough just unplug it and see if it helps, though that also is the test for an intake leak. I'm betting there's a bad wire that becomes an open as the wire itself gets hot, I've seen that before. On Levi's car IIRC one of the PTU wires about a foot from the PTU would fail as it warmed up and acted like bad PTU with no spark.

What kind of diagnostic device would you recommend?

Those capacitors look original, and they need replacing. Caps go bad over time, and it's the #1 component that goes bad in old electronics. When the capacitors bulge or leak, that's an obvious sign, but they also go bad without bulging and leaking. I just repaired a unit last month that looked perfect, you couldn't see any bad capacitors from viewing from the outside. Anyhow, that person is happy now, it's fixed, and problems are gone.

For diagnostic device, see here:
https://www.3sgto.org/threads/17224-...rs-on-our-cars

Here's pic of the ECU I repaired with good looking capacitors. Age is the problem, they need replacing.
https://i.imgur.com/wH4XYTi.png