Thread: HELP!!! V8 Won't Fire After Head Rebuild

I just went through trying to diagnose a fuel pressure prob last week on a d1 v8. in hindsight, beg/borrow/steal a fuel pressure gauge which has the appropriate fitting for the Schrader valve. Takes the guess work out of it. My pump was down and the regulator was knackered. your description of fuel exiting the Schrader valve was similar to mine so there’s a good chance it’s something to do with your problem.

My car would fire up then die within a few seconds. There was black smoke out the exhaust ie very rich. When tested for pressure it was around 50-55 psi so the reg was not releasing pressure. You say you’ve a strong smell petrol out the exhaust so if it’s like my situation then there’s a chance your reg is shot. I disconnected the line on the tank side of the regulator and when the pump was priming there was no fuel getting past the reg. there is not enough info in this test to tell you whether your reg is shot or your fuel pump can’t get up to pressure (based on my limited knowledge of how these things hang together!)


If you can’t get access to a fuel pressure gauge, here’s an option :

There is a commodore pump (VN?) which fits, I got one for $116 at repco. Pretty easy to change. (my car already had a hole cut in the carpet above the petrol tank access) There is a link in The Good Oil if I remember correctly so please check that plus there are a number of threads on it. the regulators are around $200 so swap in the new fuel pump and see where that leaves you first.

Bosch fuel pump is BFP772. It is a good fit. You can adapt the original pressure hose to it, takes some careful work though. Trade is usually about $80 to $100 if you can wangle it.

Originally Posted by Tyresqueal

Just changed out the head gaskets, cam and followers on my 3.9 V8 and I'm having trouble getting the old girl to fire back up again. I'm aware of the issues surrounding timing mark inaccuracies and I'm pretty confident that I've aligned everything up correctly.

However, in my rush to get everything back together for a trip at the weekend (which didn't happen as a result of this issue), I think I may have screwed up the timing between the cam and the crank by 180 degrees. Is it possible to do this? My understanding is that the cam turns twice as fast as the crank so this could make sense. Any thoughts will be greatly appreciated .

Hi, there has been alot of talk about ignition timing. You said you have replaced the cam. Did you dial this in correctly. It might pay to double check no1 inlet lobe to see how much lift you have at tdc on the overlap stroke or degrees at .050" lift.

Cheap experiment

Pull / disconnect the plug to the MAF .... Does it fire up now?


If you have fuel smells out the exhaust ... hold you foot flat out on the gas pedal to stop fuel flow from the injectors

Other than that .... Forget fuel pumps / ect .... follow Clarkies advice about "Startyabastard" octane in a can "aerostart" or "circuit board cleaner" will do

Yes, last night I tried removing the air filter to let more air through and that didn't work. Then tried disconnection the MAF and it still didn't start. Going to pick up a fuel pressure tester kit on way home from work tonight and buy a can of 'easy start' to give it a blast with that.

Will keep everyone posted and keep up the good advice - this one has me really scratching my head - not to mention all the guys in the workshop at work.

Originally Posted by 400HPONGAS

. Its easier to have a mate just jog the starter LMAO !!!

Not with a screwdriver down the hole!

Most V8's will only stop in 4 spots due too relative compression strokes in the cylinders anywhy, unless you have time to leak of compression

Easy to turn by hand

From what I've read ... you have had plenty of fuel coming out your exhaust and this thing has not given a "peep" of a start



Dumb question .... sure you have not mixed up the number 1 injector lead with the ECU Temp sender unit? ... will result in NO cold start fuel (choke)

Hope you checked that .....

Originally Posted by mike 90 RR

From what I've read ... you have had plenty of fuel coming out your exhaust and this thing has not given a "peep" of a start



Dumb question .... sure you have not mixed up the number 1 injector lead with the ECU Temp sender unit? ... will result in NO cold start fuel (choke)

Hope you checked that .....

Oh man, I wish it was something that simple - i labelled all the injector wires with masking tape before I removed them, but it's a good piece of advice for others who attempt the same thing.

For those of you following this thread I was indoor cricketing last night, so no update today. I bought some "start ya bastard" and will try that tonight, but it goes against everything I was taught as a young apprentice - my mechanic tutor would smack me across the knuckles with his steel ruler!