My 1992 Corvette ran fine before I parked it for the winter. I recently went to start it and I am having some issues. Initially, it fires up with no problems, but begins to idle rough. I almost have to keep pressure on the gas to keep it from bogging out and stopping. After a minute, it will idle itself...although still rough. The big issue is, like clockwork, it cuts completely off at about 5 minutes into idling and will not restart. It takes about an hour for it to start again and it will do the very same thing. I ran codes and got a 15 - 43 -and 26. I just wanted to get some ideas from seasoned people before i go replacing every possible thing i can think of. I already got fuel filter and plugs...thinking fuel pump this weekend. Any ideas or help would be awesome.

 

A can of dry gas won't hurt it either!

 

Do you have low fuel pressure, or is this a stab in the dark? How many lbs of fuel pressure do you have static, at start up, and during an event?

 

Just a stab...my parents gave me the car (mom got new CTS and dad picked up a 07' vette) so I have no money in it now. It only has 90k miles, but it needs some work. Transmission getting rebuilt in a few weeks. I put dry gas in it, that didn't do the trick (dad suggested that too) but mom has been a corvette owner and says she thinks it's fuel pump. Maybe I need to grab a gauge and test before I jump on that, even though its not that expensive of a whim.

 

Here's the codes.

i'm wondering if it may be the coolant temp sensor

http://chevythunder.com/199295_lt1_t....htm#Code%2043

 

Interesting, I will try to replace the thermastat/s and the coolant sensor prior to testing the fuel pump today.

 

here's some info on a Coolant temp sensor.

I'm not saying that is your issue, but my philosophy is to always address known issues when trying to diagnose an issue. Take care of them first.

many times one issue will trigger another.

http://www.howstuffinmycarworks.com/...mp_sensor.html

(yes I know it's on a Kia, but they all work the same way)

 

Great info. That is definitely where I am going to start. Sounds a lot like what I'm going through. Praying it's not the Optispark...are there any specific codes thrown off when the Opti goes bad?

 

36 I think, but they don't always throw a code from what I understand.

 

And I wouldn't go Opti hunting until I ruled out a fuel delivery issue.

 

Cocur. Always start with the Basics Fuel, Fire and Air

 

"cuts off completely at 5 minutes and will not restart. Takes an hour"......

For you smart guys, at 5 minutes the engine should be going into closed loop.....Closed loop and it dies....... wait an hour to cool back to open loop......repeat the cycle. Comments,suggestions, ideas?

 

Easy. (You've heard this speech before).

They need three things to run.

1. Suitable compression.
2. The correct mixture of fuel and air.
3. A suitably strong spark delivered at the correct time.

That's it. If those three conditions are met, they run. If one or more are missing or deficient, they either don't run correctly or at all. Narrow down which of the three is causing the issue, figure out why it's causing the issue, and correct the issue. Then it runs. Troubleshooting 101.

Why do I list them in this order? Because this is the order that is easiest to troubleshoot a no-start condition.

Given that it starts and runs fine for a few minutes, it's safe to eliiminate #1. Then we move on to #2. Test fuel pressure at key-on, start up, and shut down (voluntary or otherwise). Test it during a no-start event. It should have between 38-45 psi under all conditions, and should hold this pressure after shut down for several minutes.

How could a fuel delivery issue cause a shut-down after 5 minutes? A flakey fuel pump can run fine until it heats up, and then can start having spasms. There are other possibilities, but this is one. If the pump is going on strike when it heats up, we test voltage to determine pump or ecm issue.

Am I positive that this is the issue? No. But it's where I would start. We will do one of two things....confirm a fuel delivery issue and correct it, or move on to ignition / emissions. Then we troubleshoot that and correct the issue, the car runs, and everyone is happy.

Or, if the owner has unlimited time and money, he can start throwing parts and $$ at it (spray and pray) and he may get lucky.....or he may spend $3K on parts he didn't need, and six months before fixing it....and may screw something else up in the process making it doubly difficult to troubleshoot. It ain't my money or time, I don't care either way. But given that he drives a C4 in the first place, I'm betting he has limited amounts of both.

Happy wrenching (or guessing, as the case may be).

 

Well honestly money is not really the issue. Like I said, it was given to me. So if I spend 3k, then I have a $3k C4 that is in really good shape, runs well and I'm happy with. Thats assuming it will cost that much. I doubt it, because my mother had it and babied it. I love the advice, especially since I am new to posting here. You guys are full of knowledge and maybe since I am mechanically inclined (even though most of my auto work has been with Audi...sorry) I can tackle this head on and enjoy my passed down project.

 

Added a few photos of the project to my profile guys. Check it out. Not a bad starting point, even though it needs a little work.

 

Frack, not sure you got my point. Engine shuts down at about the time it would go into closed loop. My question is"Is this significant?". "Start" is not the issue, it will start, it won't keep running. Again, what would change during a 5 minute run? That is the key question IMHO.

 

The closed loop is significant.

It is of my opinion he should take care of those codes and the issues surrounding them first.

Then move on if they don't correct his problems.

These things have codes and throw them for a reason. Just saying!!

 

Okay, woke up early this morning and got started. First thing I checked all the connections to a few sensors I was told to check out. Everything looked good. Next, I cleaned the throttle body, replaced filter, and reassembled. Started right up...ran for 10 minutes...started rough idle, then died. Would not restart. I immediately ran codes...same ones. Then I sent power to the "G" plug in the ALCL...nothing. Fuel pump didn't energize. It has been 30 minutes and it won't start and fuel pump still not energizing. I think I have located a possible issue. Maybe the fuel pump is starting the car while it's cold, warms up and dies. Thats my guess, so I'm going to check it a few more times and wait a few hours till it cools. Then test the "G" and start it. Looks like I have an idea of what I might be shopping for later today.

 

Does the pump run when you turn the key on? Also, take a relay out and replace it with the fuel pump relay just to check it. They're all the same.

But it's starting to sound like a fuel delivery issue.

 

Gonna check that...guess i need to take the fuse out of the damn antenna first...its noisy.