New ZR-1. New Issue. Stalling Once Warm.

[Matt B]

Your Code 61 indicates trouble in the Secondaries system, probably because there is a vacuum leak avoiding the ports to open properly. Is the vacuum pump (located in the very front right corner under the hood) running at startup for a few seconds and then cycling every few seconds? If not it may already be stuck or burnt, if yes and it keeps running there is a vacuum leak.
As far as the injectors are concerned you will find a good guide how to measure their resistance here: http://zr1specialist.com/HAT%20Web/articles%20index.htm
Marc's page is generally a great source of highly valuable information and so is Marc himself of course. You may consider his service to resolve your issues.
If your car shows injector issues these have to be resolved immediately as faulty injectors can cause a lot of trouble down the road.

Again, good luck!

Sent from my SM-G991B using ZR-1 Net Registry mobile app

[Atari_Prime]

Originally Posted by Matt B

Your Code 61 indicates trouble in the Secondaries system, probably because there is a vacuum leak avoiding the ports to open properly. Is the vacuum pump (located in the very front right corner under the hood) running at startup for a few seconds and then cycling every few seconds? If not it may already be stuck or burnt, if yes and it keeps running there is a vacuum leak.
As far as the injectors are concerned you will find a good guide how to measure their resistance here: http://zr1specialist.com/HAT%20Web/articles%20index.htm
Marc's page is generally a great source of highly valuable information and so is Marc himself of course. You may consider his service to resolve your issues.
If your car shows injector issues these have to be resolved immediately as faulty injectors can cause a lot of trouble down the road.

Again, good luck!

Sent from my SM-G991B using ZR-1 Net Registry mobile app

Where did you find that code information? I haven't been able to find that anywhere. I found another post with someone who had the same code and couldn't find it either.

As far as start a procedure: If I turn on the car but not the ignition, there is a clunk coming from the front of the car. It cycles about every three seconds. For at least 25 to 30 seconds it does not stop. I don't know how long it would continue beyond that. I would compare the clunk noise to the dull cocking of a rifle.

[Atari_Prime]

Originally Posted by DRM500RUBYZR-1

OK.
Three times since you drove it home I have suggested you attempt to determine the source of the "Burning Smell" that you repeatedly stated on the other Forum.
You state the ABS /ASR light is on.
Kindly FIRST focus on finding out what is overheating to the point of creating a discernable odor.
If you burn the car up, it won't much matter why it also ran poorly before then.
You can lead a horse to water.........................

Marty

Hi Marty. While I will grant it as possible it could be brake related, based on other data it seems unlikely. If this helps, tonight I did a small test. Leaving it in valet mode I put it in reverse backed up a few inches without any issue and then put it in first and went forward a few inches without any issue. It behaved like a perfectly normal car. No attempt to die at all. Also those codes I mentioned only popped up during that one drive and have never popped up before or since that time. Granted, also I'm not using the brake that often sitting in the driveway. I have a pressure gauge arriving tomorrow. Provided I can find the Schrader valve which I understand to be next to the alternator I plan on doing a couple of tests. That may require me to go out for a drive. We'll see if those codes reappear. Also I'm contemplating going through the fuse panel and simply ripping out all the old fuses and replacing them with new ones just in case any of them are dead or dying. I can't think of any reason why that would be a bad idea. At the moment my strongest theory is that the secondary pump is failing and whatever issue is only occurring after the car gets into the higher RPMs under load or warmed up, or it's a simple as a clogged fuel filter. I don't have the equipment to change the fuel filter at home, I don't trust the nearby dealership to do it, and the mechanics I think I can trust can't get to it for several weeks. So there's that. Fun fun.

[Matt B]

Codes are in the shop manual (which I highly recommend) in the Central Control Module (CCM) diagnosis section (and in the article linked earlier). However I'm speaking about a 91, maybe it's different in your 94 case. In my case it was a faulty secondary vacuum selenoid and stuck check valve leading to an inoperable pump which in turn leads to a lack of vacuum at persisting WOT condition in high gear acceleration (4th+). Then the engine control sets a rev limit, too.
As said you can easily verify the correct vacuum operation by monitoring the pump (or pull the vacuum line off the pump and hook up a manually operated pump to see how well vacuum is held)

When your car is that low mile (like mine is, only 18.5k mls of which the last 1000 took 10 years) it's recommendable to first fully service everything and then carefully wake her up. I found a lot of issues, oil & vacuum leaks, defect sensors, selenoids, Stone Age fluids etc.

If the secondary system was never used it's very likely that the secondary intake section is packed with deposits and needs to be carefully cleaned by driving with secondaries active for an extended period. I just pulled my plenum to fix that defective selenoid and took the chance to inspect primary and secondary intake valves with an endoscopic camera. There is A LOT of deposits though they actually were used. Primaries instead a super clean.

Again, given that I just made the same experiences like you, I really recommend to work though the car first and then put load on her.

[Atari_Prime]

Originally Posted by Matt B

Codes are in the shop manual (which I highly recommend) in the Central Control Module (CCM) diagnosis section (and in the article linked earlier). However I'm speaking about a 91, maybe it's different in your 94 case. In my case it was a faulty secondary vacuum selenoid and stuck check valve leading to an inoperable pump which in turn leads to a lack of vacuum at persisting WOT condition in high gear acceleration (4th+). Then the engine control sets a rev limit, too.
As said you can easily verify the correct vacuum operation by monitoring the pump (or pull the vacuum line off the pump and hook up a manually operated pump to see how well vacuum is held)

When your car is that low mile (like mine is, only 18.5k mls of which the last 1000 took 10 years) it's recommendable to first fully service everything and then carefully wake her up. I found a lot of issues, oil & vacuum leaks, defect sensors, selenoids, Stone Age fluids etc.

If the secondary system was never used it's very likely that the secondary intake section is packed with deposits and needs to be carefully cleaned by driving with secondaries active for an extended period. I just pulled my plenum to fix that defective selenoid and took the chance to inspect primary and secondary intake valves with an endoscopic camera. There is A LOT of deposits though they actually were used. Primaries instead a super clean.

Again, given that I just made the same experiences like you, I really recommend to work though the car first and then put load on her.

I have read through the article prior, that's where the info about the ECM codes not being visible comes from. And I couldn't find code 61, strange.


A local club member had some simple advice for me that wasn't too far off of one of your recommendations. He said to put in some injector cleaner and go drive it for an hour at freeway speeds and then put another bottle and do it again.



Soon I am going to try to change out the serpentine belt. Hopefully won't be too difficult if I can figure out the tensioner.

[Atari_Prime]

I found some more codes, but not 100% sure they are correct for the year.



Some information indicates the following:


H58 (EBCM Assembly fault)

H83 (low brake fluid)


...what is an EBCM? Electronic Brake Control Module?


Anyway, going to check the fuses, and have the brake fluid flushed on Monday. Hopefully be able to pull more codes too with a reader. Maybe some tests will show what's up.

[DRM500RUBYZR-1]

It is exactly what I expected to be problematic.
THE EBTCM essentially pumps the brakes to avoid lockup in a panic stop and depending upon year, assists in traction control.
Your first two posts (although difficult to track due to multiple threads),
clearly stated that you sensed the brakes were on.
Congratulations, you were correct.
Change out the fluid using the procedure in the FSM doing so carefully.
I would also inspect or replace your brake hoses and carefully evaluate the performance of your master cylinder as well as the EBCM.
Hopefully overheated brake pads were causing your smell, which may also need to be replaced due to the overheating.
Again overheated clutch or brake linings have a distinctive odor.

Correct these things before moving on to engine performance issues.
Keep us posted on findings and progress.
Marty

[1991 Corvette ZR-1]

Originally Posted by Atari_Prime

Where did you find that code information? I haven't been able to find that anywhere. I found another post with someone who had the same code and couldn't find it either.

As far as start a procedure: If I turn on the car but not the ignition, there is a clunk coming from the front of the car. It cycles about every three seconds. For at least 25 to 30 seconds it does not stop. I don't know how long it would continue beyond that. I would compare the clunk noise to the dull cocking of a rifle.

If this is still an issue, have someone key the car to on but not start and listen up front. The clunking noise you?re talking about could be one of the headlight motors. Whenever I disconnect the battery and need to reconnect the battery, the driver side headlight motor chatters for a second or two. A bad ground connection could be causing something similar for you. But for running as long as you say it is, it may be the vacuum pump on the front passenger side in front of the overflow bottle.