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Went to cruise night last night car ran great ! Pulled in driveway turned off car , went to restart and would barely run, very rough. parked in garage and this morning won't start. Will turn over. Pulled codes PO0171 C fuel trim system lean bank 1. PO174 C fuel trim system bank 2. PO300 C Engine misfire detected. A few years ago my car won't start and found bad relay for fuel pump relay # 35 replaced with new relay solved problem . I replaced relay with new one again hoping this would solve my current problem . I was not so lucky this time. Looking for help to get car running so I can get it to local corvette shop. I also add fuel to make sure gage was working correctly and that there was fuel.Thanks in advance for any help. Dave
Last edited by Borntorun04/17; Jun 19, 2016 at 11:46 AM.
Is your profile correct that you own a 2004 model C5?
There are well-known issues with fuel tanks on 2004 model C5s that are dependent on what VIN you have, specifically with cross-over leaks and fuel evap issues. I do not believe that there is a sticky on the topic but a quick forum or Google search will likely bring up the VIN range that affected cars fall under.
Once you clear the codes per above you may do a check to see if your car was ever subjected to the recalls for the fuel issue and if it was actually serviced (if you're not the original owner and don't know if it was or not).
I tried clearing codes car still will not start. Yes my car is a 2004 coupe auto with 16,000 miles. Two years ago I had the crossover, tank replaced. No plug or wires were replaced. All stock.
Last edited by Borntorun04/17; Jun 19, 2016 at 01:21 PM.
If it were me I would go back to basics on a crank but no start condition.
Engine needs FUEL and SPARK to start/run. I would start by measuring the fuel pressure at the fuel rail. No/low fuel pressure means no start and/or misfire. Fuel pressure should be about 58 lbs on engine crank...
Thanks Chuck I was just getting ready to copy and post one of your old replys...you can see under the grounds pic I am suspect of the fuel pump also... gotta have fuel and fire and at the right place and the the right time.
Listening is certainly not the best was to try and diagnose the problem. Use of a pressure gage will tell you immediately. You should see the pressure come up to about 65 Lbs and hold at that pressure. Further even if the pump does not come on the cause might not be a failed pump. Electrical corrosion on grounds and connectors, intermittant fuel pump relay problems ( #35 in the engine compartment fuse box) may be preventing it from coming on and even if you do hear it come on for prime it may not be building sufficient pressure to let the car start.
Last edited by 73Corvette; Jun 19, 2016 at 01:47 PM.
G107 looks good. Going to check G401 that evolved with fuel pump and sending unit. Tried another relay again car started but won't restart after turning off. Fuse for fuel pump is good.
If car ran after third relay but won't start again could it be the box that the relays and fuse are connected too. Relay seems snug no loose or movement when relay is connected. Would putting a little solder on prong end of relay help with connection ?
Last edited by Borntorun04/17; Jun 19, 2016 at 02:17 PM.
What is all involved hooking fuel rail pressure gage.? Take plastic covers off and disconnect fuel rail and hook up to gage then turn on car / start. I can turn a wrench but I'm not a mechanic.
Should be a plastic cover over a schrader valve on the end of the fuel rail (my car is no longer stock (maggie installed) so I cannot take pics for you). Most parts store will loan you a fuel pressure gauge for a refundable deposit when you return the gauge. Take plastic cap off the schrader valve and connect the gauge to the valve. Crank car and observe pressure during/after crank. Should get to about 58 lbs and hold there for at least several minutes. If pressure is way low car may start and stall or not start at all.
If pressure is not around 58lbs you need to investigate the electrical and fuel pump further to determine why there is no pressure.
If pressure is 58lbs and holds there for several minutes then you need to investigate the spark to see if you are getting spark.
Just a little up date. Grounds look good to me , switched out # 35 relay again and car started and ran great. Still concerned why it won't start earlier. Car at local corvette shop checking it out . I'm hoping it won't start in morning for them so they can find what is causing problem and not become a intermittent problem. Shop will check fuel pressure tomorrow. I was thinking good chance it could be something to do with the fuse box that relay is plugged in too. I will let you know what they find out. Thanks for all the help and suggestion . Dave
Won't Start
