Thread: Idle badley apply throttle and stall

You could try disconnecting the vacuum hose off the pressure regulator or clamping the return hose - you should get full pump pressure that way.
A fuel pressure gauge is a handy tool to have though.

Turns out it was not the fuel pump. (Not sure if it is still fuel pressure reg) I have blown compressed air though the hoses and it seems all clear. (Hope it did't stuff the reg doing this) Can't be sure the lines were blocked before hand though. Also removed a rag from the petrol tank. (I've got no idea why it was there or how it was there)
I've now got the car to not only idle but sort of run now. I can rev it up now but it back fires a little at low revs. I let it idle for about 30 mins using 98 octane fuel with fuel system cleaner. I advanced the timing to 12 degrees BTDC (from 6) and it back fired a little less at low rev and went for a drive. No power at all and ran rough. It seemed like i was applying way too much throttle for the revs i was doing. (2nd gear 70 kph nearly full throttle) and i haven'y checked but i think i used about 15 liters of fuel in approx. 5kms of driving.
Runs fine on gas, but i do not currently have both the gas mixer and flapper fitted at the same time. I have to swap them over to check one or the other.

If i remove the fuel pressure reg how should i expect the engine to run? I'm thinking i have leaking injectors or maybe blocked injectors but want to test regulator first.

Originally Posted by Scouse

You could try disconnecting the vacuum hose off the pressure regulator or clamping the return hose - you should get full pump pressure that way.
A fuel pressure gauge is a handy tool to have though.

Does no vac equal max flow? How does the pressure reg operate?

Carefully lift the plastic lid off your air flow meter. With the engine running you will see the arm move with increasing revs. Use your hand to gently apply extra movement to the arm as you rev it. This increases the mixture. If you get better power then you can easily move the adjustment wheel by lifting the two wire clips and rotating the toothed wheel in the direction of movement. Keep track of how much you move it so your experimenting is reversible. It's really quite trivial to adjust, I've done it often enough. Glue or tape the lid down before you test drive or it'll blow off!

Does no vac equal max flow? How does the pressure reg operate?

Pressure regs maintain a constant pressure over the internal manifold pressure via the connecting vacuum hose. Removing the hose will only give you more pressure at idle as it will see atmospheric pressure instead of varying vacuum. Don't bother, adjusting the MAF is easier.