I have a 408 iron block in my 2002 Z28 and when i first got it back it ran great but then i started having a problem with it shuting off after about 20 minutes (sometimes more somtimes less) of driving. It acts as if its running out of fuel, but if i let it sit for about 5 minutes it will run like nothing happend, I took it back to the places the installed everything and they couldnt find out what the problem was. Any suggestions would be great!

 

We have a forum specifically for the LSx-based engines.... I'll move your question there.

 

If they did the work like you said:

Make them fix it correctly, get your money back, or sue them in that order

Scan it to see if it's throwing any funny codes and go from there.. A "strange" fuel issue can be anything from fuel filter, pump, injectors, tuning, MAF, etc, etc, etc.

 

When i brought it back to them they said it wouldnt do it for them cuz sometimes it will run for 20 minutes and sometimes for almost at hour without acting up. And it started doing this almost 8 mouths after the car was built.

 

Here is a question with that time thing. Will it do it if you just let it idle for that long. or do you actually have to drive it first.

 

I have never let it idle long enough to know but it has happend when i was putting in my driveway after a 15 minute ride and i let it sit for about a minute and it started but after about 30 seconds of idle it started missing like it was running out of fuel then shut off.

 

Get a method of mon1tor1ng your fuel pressure. Could be your problem 1s there as stated above.

 

Clean shutoff? Sputter and die?

Sounds like an electrical gremlin...I would start by checking engine grounds, bulkhead and other connectors.

 

I had something similar. I would drive my car for 20-30 minutes, park it, and go into a store. I would come out 15-20 minutes later and the engine started OK, but as soon as I began to pull out it ran really rich and began to behave like a carb vapor lock problem - misfiring with no power or throttle repsonse for several seconds. It would clear up and run fine after that. Problem? O2s not switching from fouling and a tuning issue.

Cecil county? Who did the work? You may have to drop the car off with the shop and ask that they drive the car home - insisting upon no abuse and that you'll monitor the miles.

 

Sounds like crank sensor issues. It is up behind the starter in the block. Maybe a wire that is just about broken or too close to a header or something. I messed mine up when swapping headers once and the car acted the same way until I spliced in a new connector.

-Geoff

 

F-body central did the work and i will NEVER deal with them again.

 

Thanks for the help i will have to check that out and see what happends.

 

I figured that, which is why I asked to verify. Might want to travel a little further south to PSI in Glen Burnie. Jeff built his shop on fixing FBC problem cars. Leave him a message if he doesn't answer the phone, or contact him through the other LS1 board, GrannySShifting is his username.

 

Thanks alot for the help!

 

Hey man i tryed to find that guy but i cant seen to find are you sure thats the right username?