Resolved Galant VR4 sometimes starts, dies when warmed up

[KyleGVR4]

I recently purchased a 91 GVR4. I purchased it knowing it had an issue and am seeking some advice.

The issue is that the car will occasionally start, but it will never run more than about 15 minutes. Once warmed up, it dies and doesn't restart until it cools back off. The car is 100% stock, which is why I decided to buy it in the first place. It has about 150k original miles with a good service history. Previous owner suspected it was the ECU, as did I. He was on his 2nd ECU. However, I borrowed a friends ECU and the car behaved basically identically to the way it did with the ECU that came with the car, so I began having second thoughts. There was a clicking / cackling noise coming from around the intake manifold area. I went ahead and put on a new set of coils and ignition control module this evening. My problem still exists. Bummer. So I took apart the ECU that my friend loaned me, and it clearly has had leaking caps, which is now making me lean back toward it being an ECU issue. By the way, that noise near the intake manifold persists even with the new equipment on the car when I have my buddies ECU plugged in. Plugged in my ECU and the cackling stopped, but the car didn't start with that ECU either. (Some days it starts, some days it doesn't, but when it does, it always starts hard). Cackling also could be coming from some other electronic gizmo somewhere nearby.

At this point in time I'm thinking somehow there was a massive coincidence where both of these ECU's had similar problems that would allow the car to run until it basically warmed up, and then for whatever reason, it would just die.

I've read a lot about the 1Gs and get conflicting information from what I've found, from "could be the temperature sensor" to cam sensor, etc. I'd appreciate any opinions & input on either what to check next or about how stupid I was to spend $150 and still have the same problem.

By the way -
I can hear the fuel pump cycling and working. Initially I thought it could be the culprit, but I'm less inclined to think that now. Can't tell you why.

I'm kind of (very) stumped. When the car starts it runs and drives nicely, but the timer is running, so I've only driven far enough to run through the gears on a test drive before I bought it. I say this to avoid any input and assessments that it's a broken timing belt or other major mechanical issue.

On an unrelated note - is it normal for these cars to crank without the clutch depressed? Weirded me out a bit when it did.

 

[KyleGVR4]

Hmm... No responses yet.

Update: Buddy of mine loaned me a couple more ECUs. One had been rebuilt and appeared to be in good shape with no evidence of leaky caps. Another appeared also to have minimal leakage. I tried both ECU's and the car still wouldn't start. Maybe easier if we break this issue up into chunks. Since it's now been a number of days since the car did start, I'm going to call that priority number 1.

So new coil pack, new ICM, and let's assume that the ECU I have is good enough to start the car. Put a fresh 2 gallons of 93 in the car, so should be plenty of fuel. I can hear the fuel pump relay clicking and the pump whining when I crank the car. What other items should I be focused on?

 

[DSM1G90]

Previous owner bypassed the clutch safety switch so the motor can start without depressing the clutch pedal - to save on the thrust bearings on the crank, for pressing in the clutch while starting puts load on the crank thrust bearings.

What about fuel filter? Could be needing a change why you're dying after awhile.

When you swapped ECU's, do the "MD" numbers on each unit match up with each other?

 

[Tyeler18]

Had this problem on a friends carb swapped tb injection firebird. It'd run for 20 mins than die when it actually started. PO put an electric fuel pump in with no FPR, ended up it would start overfueling and die. May want to check your FPR for possible leaks, although I still think an overheating fuel pump would definitely cause problems. Try and get fuel pressure gauge and see what your pressure is while trying to start and once its died.

 

[KyleGVR4]

DSM1G- The rebuilt ECU is labeled for a 91-94 AWD turbo. My working assumption is that any turbo 91-94 ECU will work. I will check on the numbers however and see if I can google my way to decoding it for sure.

Tyeler- Once I get the car running again, your recommendation would be worth looking into.

Did a little more researching and tinkering yesterday in the garage. It's probably worth mentioning that this car was absolutely filthy under the hood and so I washed it with Dawn dish washing soap and water. Suffice to say, there wasn't a dry area way within the engine bay. After the wash I did start the car, drove it around the block and then let it idle for a few minutes and get up to operating temp before backing it into my garage. I tell you this because after doing some more research I now strongly suspect my cam angle sensor for the following reasons:

1. I have heard water can do a number on them. I took it apart and it dropped maybe a few drops of water out. I hit with a hair dryer for about 20 minutes and then reassembled it.

2. I verified that every spark plug wire was not sparking.

3. I removed all spark plugs and they weren't coated with gasoline as I would have expected with all the cranking I'd been doing.

Again, after doing a bit of research I now suspect my CAS to be the culprit. I did test the power running to the CAS, getting 12 volts, 5 volts, and 5 volts. The other wire is the ground. When I had it out of the head and put back together I spun it by hand with the key on and could get no response. I'd heard that I should have heard spark and or fuel injectors clicking. I had neither.

I was unable to do the test with the multimeter to determine verify the 5 volts was pulsing as I spun the CAS within the respective leads, because frankly I am not sure how to hook up the multimeter when the harness is plugged into the CAS. It is waterproofed and aside from tearing up the harness or one of the lines running to it to get a reading, I am stumped.

However, with the audible test and the subsequent visual verification of the plugs and no spark on any cylinder, I think this is my most likely culprit.

I'd appreciate any feedback on my newbie diagnosis.

 

[KyleGVR4]

Well, progress, I think.

This evening I swapped out the CAS for another and the car fired up and ran great. I drove it around the neighborhood and then let it idle for an extended amount of time until the fan started kicking on and off, at which time I set the timing to 5 degrees BTDC.

I need to get the car tagged and I'll start logging some miles to make sure everything is solid. Idle is rock solid and the car purrs like a kitten. This is certainly the first and only time since I've owned the car that it hasn't died on me.

I'll check back in soon with more updates.

 

[KyleGVR4]

I've put about 100 miles on the car now. Plugged my factory ECU back in for the majority of them and have had no issues. So that was it. CAS intermittently would operate and if the car did start, after warming up, the CAS would die, hence the car would quit running.

 

[WRXkiller92]

I'm sorry to be late but this same exact thing happened to my buddy's 1G, the CAS wiring came undone, spliced it back together and worked fine.