Thread: D1, starts immediately, won’t idle more than few secs or rev

Well as the title suggests, that’s what’s happening. Got a D1 with a 4.6 running 14cux. Have just put it all back together with a thor manifold, started within the first quarter of a revolution. Thought you beauty, that’s another job done. alas, not to be. The bugger just won’t idle for more than a few seconds. Using all of the 14cux sensors ie stepper/tps/fuel temp/water temp etc etc and 3.9 fuel rail.

It has injected gas and it’s hard to say whether it runs on that or not, it switched over and ran but cut out after a few seconds – out of gas. I seem to vaguely remember (geez, it was only earlier today) I could rev it.

So it was leading me to the petrol side. had a set of newly reconditioned yellow top injectors in with this change (never had them in before) so pulled them out this arvo and put the old green tops back in. nup, same issue.

checked the timing with a timing light which was fine, well it should be it starts easily. Whilst it idles for a few seconds I dash around to the exhaust to have a whiff, no petrol smell which I would have thought there would be.

I have a set of lambda indicators in the dash and when the car starts I can see them hover around lambda then as the car slowly begins to die I can see the mixture getting weaker and weaker. Revving it just makes it die instantly. I also have the software for the lpg and can see injector opening times. At startup petrol are ok then as it starts to die I can see the injectors opening up more but the engine still konks out. So it’s trying to compensate for the decreasing revs by upping the injector time but no go.

So I am starting to think petrol supply. turn the key to ignition and prime the petrol pump and hold down the schraeder valve at the same time and sure enough it’s a boy. Plenty of petrol gushing out. If I prime it then depress the schraeder valve immediately once stopped priming it still gushes out as it releases the pressure. However if I increase this period to say 5 seconds after priming and then depress the schraeder valve the pressure is all but gone and no fuel comes out.

So I am starting to think pressure regulator or not sure if there is meant to be a oneway valve at the fuel pump end. Something is letting the pressure release quickly and maybe also not allowing the pressure in the fuel rail to get to the correct pressure for the injectors to discharge fuel correctly.

If I had a pressure gauge I’d put it on the schraeder valve but even then how do you determine it’s the pump not able to get up to pressure or the regulator is not able to hold any pressure? Maybe clamp off the return line or will this damage the fuel pump? Or is this one of those things you’ve just got to replace the part (regulator) to know for sure?

Anyways, had enough thinking about it today. Time to go and walk the dogs.

(the fuel rail etc had been apart for the last 4 months with no fuel in it, maybe some rubber seal in the regulator has dried out and lost its ability to seal? 4 months is not that old for fuel i would have thought to make the car perform like this?)

appreciate any suggestions.

thanks,

brett.

bee utey - have used the schraeder valve to check for fuel many times in the past. the amount of flow coming out now is the same as has been in the past. what is different now is the pressure disappearing so quickly. and bugger, the shop is not open this morning though normally is saturdays so couldn't get fuel regulator.

any other ideas out there? what if i clamp off the return line or restrict it almost completely to replicate the restriction of the regulator? would this potentially cause damage to the fuel pump?