Scoty

When I switch on the ignition, the car jerks as fuel pressure builds up. Is this normal behaviour when the fuel pump and FPR have been uprated?
It only jerks when fuel pressure is low, but it seems like a hell of a lot of pressure building up to "move" the car.

Scoty

markpm

Try taking it out of gear mate!

Scoty

markpm

Sorry, couldnt resist!

I dont know the problem, but Im sure someone will be along soon to sort you out...!

Trout

iTrader: (1)

Sounds to me like leaking injector o-rings and so there is fuel leaking into the cylinders and firing as the ignition primes.

I certainly have experienced this is in the past. Took them out and used grease rather than oil and that seemed to work the magic.

Rannoch

Scoty

Hi Rannoch,

Sorry, sometimes my posts lack in information I should include
I have also took the inlet manifold off to fit 10 mm spacers I made, do the parallel fuel mod, fit a new FPR and a 75mm turbo inlet. The uprated fuel pump was fitted by a garage.

I had problems getting the FPR working and AlanG gave me some great help and now it's working.

This new fault has happened after I have done these modifications.

Would you still recommend I check the injectors?

I've checked all the boost hoses,all electrics are reconnected, the only other thing is the 3 breathers are venting to atmosphere at the moment, but I don't think that would make any difference.

submannz

When the fuel pressure is low, if you turn the ignition to the accessory position with out starting the car and leaving it like that for a few seconds for the fuel pressure to build before starting, does that help, or is that what you mean?

[Edited by submannz - 5/20/2003 11:58:24 PM]

Scoty

Hi submannz,

Yes that's what I mean, I usually dont start the car for a few seconds once ingnition is turned on to let the fuel pump prime up, and it's then that this has happend.

First time it happened I was waiting for something to go bang.
It sounds like the fuel pump is working much harder than normal when the car jerks.

submannz

What problems did you have with the FPR? I imagine the problem is still related to that.

Scoty

After I had re-fitted the inlet manifold on to the car, I still had no turbo inlet made or a bracket for relocating the PS res, so I couldn't start the car, but I wanted to get the FPR set up and get fuel pressure so I could check for leaks.

I couldn't get any pressure showing on the FPR, even after adjusting it full open and closed, I also had a small petrol leak at number 3 injector at the turbo.
I took the adapter supplied with the FPR back off the rail at injector 3 and noticed that half of the rubber ring seal was missing, so I checked all the fuel lines were clear, and opened the FPR to make sure it wasn't logged in side somewhere.
AlanG went over the hole set up with me to check if I had got everything connected correctly and it came down to a few things that could be wrong.... a faulty regulator or blocked return pipe.
I had blocked the tank breather and left the petrol cap off temporarily and Alan told me to unblock it.
About half an hour after unblocking the petrol tank breather the FPR started working!!!


The FPR is working fine now, with 2.6 bar registering on vacum and 3.2 bar on zero vacum.

The best way I can describe the fault I have now is sometimes when I switch the ignition on to let the fuel pressure build up before starting the car, the fuel pump sounds as if it's under heavy load and drawing a lot of power, and the engine jerks or squirms causing the car to move also

submannz

In that case it might be your fuel pump momentum that is moving the car, I would suggest that it may be binding up on something