Sometimes I can't hear the surge tanks prime and car won't start. HELP ME PLEASE

[Jay-rad]

Hi guys, need help. Sometimes my car won't start, it cranks fine but has no fuel pressure. When it does this I can't hear the fuel pumps prime. The first time it did this it magically started 2 hours later, the second time I'd parked at work, It wouldn't start the next day so I towed it to the mechanics but magically could start a week later so they did nothing. It is a VX commodore s2 with a worked 5.7L (Forged internals, bigger cam) + vortech V2 supercharger. The fuel system is a ASE Turbo 3L surge tank (Twin internal wahlbro 270lphr pumps), a turbosmart fuel pressure regulator and bigger injectors. Also has 3200 stall and LSD. It had been working great the weeks leading up to this, anyone else had similar problems? How can I diagnos the problem when the car is running? I'm too worried to drive it in case it stops again. Thanks

 

[BoganEditionVUSS]

are you still running the factory fuel pump relay up front?

 

[devilly]

blocked fuel filter springs to my mind,or injectors.cheapest places to start is injector cleaner then fuel filter.before it totally blocks the pump and blows it.

 

[Jay-rad]

are you still running the factory fuel pump relay up front?

Hi thanks for replying. It does have the factory fuel pump relay for the stock in-tank pump, and i can hear the high pitch noise of it prime, but it also has a separate Narva brand relay which was put in for the surge tank/ wahlbro pumps. Actually I spent today running around sourcing all new fuses and relays. Today I replaced the narva relay, all the original fuses that are engine related and I have on order the factory fuel pump relay. I drove it about 50km today and all went well. I thought I'd try and troubleshoot as many problems first before I take it to the mechanics, apparently it is hard to diagnose when it it still running fine. I went and saw Jake from Jakes Performance in Canberra and I have it booked in with him in a weeks time, he reckons the placement of the relay isn't good (because of the supercharger the aftermarket radiator overfill canister was moved to the drivers side near the battery) and the relay is close to this and getting unnecessarily hot. Also he said the twin 270 wahlbro pumps are overkill and probably causing the fuel to get hot. So maybe the fuel tank venting is inadequate, and I should remove one of the pumps in the surge tanks so it Isn't recycling so much hot fuel. But still this is just his best guess. He also suggested dodgy wiring and a poor earth. It has never actually stopped while driving, it just sometimes won't start after a big drive. Also I undid the fuel cap after the drive today but couldn't hear any pressure release so not sure if it's a venting problem :/

 

[Jay-rad]

blocked fuel filter springs to my mind,or injectors.cheapest places to start is injector cleaner then fuel filter.before it totally blocks the pump and blows it.

Yeah good call I might actually replace the filter just for peace of mind.

 

[devilly]

i had a problem a while ago with relays getting hot to the touch. i just got some brand new gm ones and they haven't got hot since i put them in.you say it don't restart after a big drive.dunno why but i'm thinking you should carefully check your lines to see if any are hot,and also back of alternator.

disconnect battery, then check all lines going to and from battery terminals make sure they have a solid good connection.then to the alternator the screw and wires could have a loose connection,if your handy with a multi-meter then you can check more stuff.

but it sounds like you have it booked in so hope all goes well.

 

[Jay-rad]

i had a problem a while ago with relays getting hot to the touch. i just got some brand new gm ones and they haven't got hot since i put them in.you say it don't restart after a big drive.dunno why but i'm thinking you should carefully check your lines to see if any are hot,and also back of alternator.

disconnect battery, then check all lines going to and from battery terminals make sure they have a solid good connection.then to the alternator the screw and wires could have a loose connection,if your handy with a multi-meter then you can check more stuff.

but it sounds like you have it booked in so hope all goes well.

Hi, yeah I wanted to do that today but my car is so low i couldn't get a jack underneath it. My guess is wiring too, so I'll pass that on and let Jake do his thing. Cheers.