Another mechanic said it could possibly be the ignition module...? I guess i'm just gonna have them hook it up and tell me what it is... its getting too costly guessing..

but any thought on this is appreciated..

Thanks

 

I went through a similar problem recently on my 1991. The most common response to my situation was "fuel injectors". Apparently they are easy enough to test with an ohm meter (sorry, I am not a mechanic so I can't give you too much detail). You need to check them when the engine begins to misbehave. I can tell you that my mechanic put in 11 hours and tried the ECM, the TPS, and several other things. I printed out the responses to my thread on the forum and pushed him to go after the injectors. BINGO!!

 

......you have a few things working against you from what I can tell.

Do you have a factory service manual? Please get one for your year chassis and one for your year motor...therefore you may have to buy two sets from Helminc.com....sorry but I don't know much about when your motor was offered, so you might have to buy two sets.

The cutting out issue seems to be related to operating temp. Next, figure out if it is also related to "closed loop" operation or not...for this a scanner while the motor is running will provide some good base line info to compare to the page in the FSM that has a data snap shot of a normal motor in closed loop operation.

If you can tell the shop to run a scan of the ignition module that might help....it proly shoul be done from cold start thru to normal operating temp to get a full picture...that's when the heat related failure should occur if that is the root.

Failing to name the ing module, next are the injectors. Here again a scan at idle will give you the fuel numbers of your motor in closed loop to compare to the FSM's numbers in closed loop. Or you can take an ohm reading of each injector cold and then after normal operating temps is attained....either way you will know the electrical condition of the injectors. Typically if you have early style Multi-techs (GM OEM) they could likely have coil failure....the later GM stuff, after 91?, will not likely have coil failure. Another way to kind of tell it's the injectors w/bad coils is if the car starts up cold fine and as it heats up a miss developes and you can smell it getting leaner & leaner at the tail pipes....this works if it's more than proly two failing injectors, ya can smell it being lean. If it's two or less I doubt that the smell would be obvious, but it would be there none the less.

You have an opti-spark system....my car doesn't so I can't offer any insight...ZR-1's have no distrubutor....someone else can offer up a diagnostic on the opti system. But my injector tips will be a valid diagnostic chart to follow....oh, forgot the other way injectors fail is they stick open and flood the motor....pull the plugs & lookie see if they are wet.


Tom

 

A couple things. First a fuel pressure guage is a cheap investment! $40. at autozone, and a Digital Voltage Ohm meter, $15-$20. With those two tools we can help you check for leaky injectors, bad injector coils and fuel pump. IT may seem difficult for you, but believe me, it's a piece of cake and we CAN walk you through it!!!!! Also, the ignition module is suspect, it's very easy to remove it and take it to Autozone, they'll check it for FREE, they have the equipment and will run it through at least 10 cycles..that needs to be done, because they start showing failure as they heat up!

Lastly, I did experience a similar problem, not on the vette, but cat related, plugged cat in my case....a muffler shop should be able to check that for you.

 

Here is mine: start listening the advice you are getting and stop throwing money at it in random.

Diagnose the problem first and only fix what is broken. Start by reading this thread again and then go do it (test the parts or get them tested). Report back with your findings. Asking for advice and then following none of it isn't very helpful in your situation. If you would have checked the fuel pressure like cuisinart said in post #3 and #5 you would be $300 richer now and possibly already know whats wrong.

So, now you know by the expensive way that it is not the fuel pump. But you still don't know if fuel pressure is ok and if other parts in the fuel system are ok. Check it and then check the ignition module like others already said.

 

Go to your parts store, buy a code reader and go from there. You should have the OBD 1 system. Its simply a matter of plugging it in and reading the codes to point you in the right direction. I've seen them as cheap as 50.00. I'm sure when your vevicle cuts out it sends a code to the computer as to why it shut off. Stop guessing and hoping you find the right thing. The code reader will pay for itself very quickly, sure you can run paper clips and other*******ways to try and read the codes. You got a computer in that car, its telling you whats wrong you just arent getting the info its trying to give you....G

 

Reading thru the post you don't say if the engine is getting spark during the no start situations. This will tell if it is fuel or electrical. When my 96 was having this problem It wouldn't get spark. Took me forever to track down the problem as no codes where being thrown. After extensive testing I replaced the computer and have not had the issue since. It seems my computer was having issues with heatsoak.