Hi everyone, I’m having a big problem with my C5!
its a 1999 C5 auto with 82k miles. Has a cam, ls7 lifters, full exhaust, and an A&A supercharger. I haven’t driven the car in the in about two weeks and I fired it up today and it idled perfect for about 5 mins then I drove it down the road and was at a stop light and all of a sudden it just died. Ive never had a problem with this car dying ever. I tried to restart it and it just cranked then I tried again and it started up but sounded absolutely terrible like on one cylinder or it was running out of gas is what I felt like. Then it wouldn’t start again and I pushed it into a parking lot. I then went and put a gallon of gas in because it was somewhat low and then tried to start the car and it started and sounded awful again and then died and I couldn’t get it to start again. Battery then died. I was lucky enough to push it home and it is now on a trickle charger. Any idea where I should start? Any chance my fuel pump went bad? It’s A&A’s upgrades fuel pump with less than a 1k miles. I’m lost I have no clue what happened! No oil leaking, no smoking, no check engine lights. Car sounded like it was on 1 cylinder or something. Honestly thought the motor blew but idk how when it was just idling and doesn’t make any sounds like that while cranking. Any help would be unbelievably appreciated!

 

do you have a speed density tune?... if so it will not throw any codes for misfires and you will have to diagnose it manually, just tossing that out there... first thing I would do is charge the battery and a quick test to verify if the fuel pump is working is to pull the fuel pump relay and jump pins 30 and 87 and you will hear the pump turn on if everything else in that circuit is good... if that checks out then try to start the car and see what happens and pull the codes

 

Ok I am charging the battery all night and was also going to try doing a fuel pressure test. I can hear the fuel pump coming on but that’s about it. Can’t understand how the car just dies and won’t restart/can’t stay running after driving just fine.

 

is it speed density tuned?... like I said it won't throw any codes or turn on the cel if it's tuned that way, I lost the whole passenger side bank out of nowhere in my car due to a bad wire in my coil extension harness and it ran like total dog sh*t but no cel

 

I don’t think so. It was tuned at a shop in Wisconsin called Late model throttle.

 

I checked all the codes by doing the options then fuel button 4 times. I let it run threw it with several codes shown but all ended with H which tells me they are old. Then I let it finish and I know you can push reset I believe after that and manually look at current codes but it just says no codes.

 

did you write them down?

 

You mean all of the ones that had an H at the end of them? No I did not, but i didnt clear them. I could do it again and write them all down. I just figured since they had an H at the end of all of them then they would be irrelevant? Also I read some info about it could be a crank position sensor or possibly the fuel pump relay? I would assume that if I did a fuel pressure test then if the relay was bad it would show a low amount of pressure? As for the cpk sensor I have no idea how to check that or even where its located lol. Let me know what you think, really appreciate the help! I thought maybe fuel pump because of the signs its showing but its got less than a thousand miles on it. Unless something happened to the wiring of it or something like that...I had to take it back to the shop once already because it was leaking alot and they messed up a line and had to have that fixed already. I'm really hoping my motor didnt break. I dont get it, literally car drove just fine days before and also started great yesterday and ran just fine then just idling it died and every time ive tried to restart it, it sounds like its broken or running on a cylinder. I don't get it!

 

I'd give the engine a couple of good toots of Brake Kleen in the intake manifold vacuum line from the PCV or brake booster and see if it starts or tries to start...at least you can see if you have a fuel delivery problem....I'd check the Injector 1 and 2 fuses and make sure you have good voltage to each...each injector fuse feeds all 4 injectors and coils on each bank...I would check power and grounds to the injectors and coils too...if you can get the car to start and run somewhat pull off the plug wire at the coil packs and see if there is spark at each one...also with the injector connector removed see if you have 12 volts on the PINK wire with key on...to check for "control" (PCM supplies the ground) connect a 12 volt test light to battery POSITIVE and with the engine running or cranking probe the control wire which is the striped wire...the test light will dimly flash if you have good "control" !!...the area of some wiring damage is the rear of the fuel rail on the left side...chaffing damage occurs in this area !!...I put an extra layer of plastic wire loom there.

 

When checking codes, if there are many, just take a video with your phone. You can then write down the codes while watching the video.

 

A common symptom of a failing ignition switch is sudden dieing and can include an OK restart or, as you experienced a restart with poor running or a crank, no start. Often includes multiple DIC warnings, REDUCED POWER and or check engine light.

Not sure how to diagnose otherwise. Contacts in the switch become burned over time and start making intermittent contact and strange symptoms.

https://www.corvetteforum.com/forums...ch-repair.html

https://www.corvetteforum.com/forums...-car-dies.html