sick cc

ok guys, heres the low down, my c6 was bone stock last year when I picked it up with 105k miles, never had a lick of issues with it. rebuilt the motor and did head/cam kit/ fast 102, full exhaust and such. had it tuned in the spring and noticed wven while on the dyno when it was shut off for a while, when it was being restarted it would just turn over, hit stop button, hit start again it would fire right up, idle nice and everything. well I never thought much of it, I drove it all this summer like that only have it happen every now and again and never any other issues. well its winter time and I want to get this taken care of while the car is apart. installed a fuel pressure guage, getting 55-60 as soon as its fired. well tonight I was out and parked it, came back 15min. later, it started, barley and I looked at fuel pressure and it was around 20. tried again, same thing. 3rd time it fired right up and was fine, fuel pressure around 57psi. I noticed a while back the fuel pump relay had some browning spots on it from heat, replaced it and still had the problem here and there. iv pretty much figured its gotta be a faulty connection in the fuse block in the engine bay since some have reported this issue. in short, most of the time its getting good contact, instant 55-60 fuel pressure at start up, other times even recently if it sits for a while it will just crank or when it does fire off, it barley idles (low fuel pressure). planning on replacing the fuel pump this winter while trans is removed anyways just for insurance because of the high miles on the pump. does anyone here have any other suggestions or have had to deal with this? thanks!

sick cc

well just pulled the fuse block off to inspect the male and female ends of the connectors below and honestly they all "look" fine. none being bent/lodged any way. everything is clean and free of debris. anything else to look for while in here? I DID NOT split the box, do yous think I should?

sevinn

Follow the big grey wire from the fuse block to the junction behind your battery and make sure that connection is OK. I had a similar issue on my 05.

You should also make sure fuel pressure isn't bleeding off faster than it should after you kill the car.

sick cc

I'll check that connections tomorrow as well, I just wasn't sure which one it was but I'll trace it back. The pressure does bleed down about 20 psi in about. Hour after shut down, as started before it shoots straight to 57 psi as soon as the ignition is triggered, absolutely almost no delay. I originally though for the check valve was bad in the fuel pump but people say that the pressure bleeding off is normal.

sick cc

got the 4 bolts out of the fuse block so it could be separated, did a continuity test on ALL of the copper line sand checked over the fuel pump pins very carefully, no signs of burning/arcing. every thing seems to look gooda nd tested fine. one thing I noticed, the fuel pump relay seems to fit somewhat snug on 3 of the 4 connectors, the one pin dosnt seem to show as much contact as the other 3.

sick cc

Lookin at the original fuel pump relay, contact looks great. Here's a pic of the heat marks on the fuel pump relay and ac comp. relay.

saplumr

Did you look at the bottom of the fuel relay circuit when you seperated the top half from the bottom half? Clearly sounds like a fuse block problem. if it starts fine one time and won't the next or simply stalls out but restarts after the relay cools off.

sick cc

yea all the copper wires checked out good, all the "male" pins look fine, also the "female" ones seem to look fine also. no corrosion or arcing marks. no melted plastic or anything. could the replacement relay I purchased earlier this year been bad from the start? could this be a possible ground issue? gonna pull the battery tray off tomorrow and check for this bulk head some people have said to check out. where exactly is this bulk head at and is it a large connector or what? traced the large grey wire outa of the fuse block and it goes into the main harness back against the firewall.

sick cc

gonna check some of the wiring towards the back of the car/grounds today. does anyone know if a racetronix fuel pump hot wire harness will help my issue if it is in the fuse block? im putting a new OEM fuel pump and sending unit in the car this winter so I was thinking the hot wire harness may help me. not gonna run a boost a pump though.

saplumr

The Racetronix harness connects to the alternator with a remote fuse. Most are used with BAP's mounted in the driver side rear fender liner. But yes it takes the load off the relay.

sick cc

ok well I put everything back together with a new relay, greased the connection pins. if it does the whole no start thing again, ill be adding the harness then since my drivetrain is getting swapped this winter along with new fuel pump both tanks. if that dosnt cure it, then I guess replace the fuse block even though it looks fine and checked out good.

saplumr

Honestly, I doubt there is any problem with the fuel pump. Anything is possible but very unlikely.

sick cc

I was just planning on replacing it because of the miles. 119k on it now, the last 8k have been with my rebuilt motor/injectors and such. plus ill have the drive train out anyways.

Justasheet

sick cc

gonna order a new fuse block tonight and try that, replacing fuel pumps and adding a hot wire kit this winter, may not know the end result till spring unless the new fuse block takes care of the issue, we are supposed to get some snow soon.

sick cc

did a continuity test on the grey fuel pump wire, everything checked out fine there. hopefully this new fuse box solves this issue, I also heard a while back sometimes double roller timing chains cause this problem time to time, im using a slp double roller with high volume oil pump, didn't have to alter the cam sensor/mounting at all though, just had to grind a little out of the front cover in a few spots, polished them out and you cant tell.

Justasheet

Please keep posting your results.
Jeff

sick cc

will do, just hoping to get this ironed out cause I dealt with it all summer long/8k miles worth lol. mod season is here in PA so I figured id start with this issue, roll cage and trans/diff upgrade to also come in a few weeks.

chpmnsws6

Did you figure out the issue? My 05 will only start about half the time. Key it off and back on and half the time it starts. It always has 50+ psi fuel pressure, runs fine once started, and its throwing no codes. I changed the cam position sensor hoping that was the issue.

Dano523

Just a FYI, but you have a couple of relays that are showing signs of over heating and need to be replaced before they go south as well. If you check on ebay, should be able to pick up 8866 relays for under $5 each.

For now, just play musical chairs with the fuel pump relay and another 8866 relay in the fuse box that is not going to be use much, to swap there positions for testing now.

Also, if you want to jump out the relay to check for pump pressure to make sure it not just the relay that has the problem, here you go.

https://www.corvetteforum.com/forums...d-no-muss.html