Fire on deacceleration... After changing fuel pressure regulator.
Turbo Mini Forums

Hi at all,

changed my fuel pressure regulator as the membrane had chacks. Was the original one from 89 and thrown fuel out to the ECU and Plenum.


After that I had struggle to start the engine. But after a couple of minutes of warming up and adjusting the mixture it had its power back.

On WOT it runs at about 11.4 AFR with 8 PSI boost. Before the change it was about 12.1 AFR at WOT.
Part Throttle is now also a bit richer than before, but this is good. Before was a bit on the lean side.

Problem is deacceleration. Even in neutral if spits up to 30cm of fireflames when I lift the throttle pedal. Its cool, but to extreme for driving around the town...


So now, hopefully you are still reding, is this caused by to high ore to low fuelpressure?

Haven´t messured it yet as I haven´t found my Gauge. It is now just for interest. I will adjust fuel pressure at the weekend.

Give it less fuel pressure

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

Thanks!

But can you please explain me why it has this behaviour with high fuel pressure?

Too high fuel pressure means fuel getting into engine on closed throttle,on into the exhaust where the hot turbo will ignite it.Looks good though!

'Where does the engine go?'

The only thing I can think is that the fuel pressue is too high, allowing the fuel to force open the needle valve in the float bowl.

This would cause an over rich mixture, difficult startibng and possibly the flame-thrower.

Take the dashpot off, and switch the fuel pump on. See if fuel is leaking out of the jet. If it it adjust the regulator til it is not.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Flames are loocking good, yes, but a bit to eye catching here in Germany... Even with straight cut primarys...



Thanks everyone, will give feedback after adjusting!

Just put a TUV sticker on the tail pipe and say it's approved, hahaha!

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Hahahaha.... Have a Bastuck with ABE, but sadly not for the ERA...

Edited by enne on 8th May, 2013.

completely unrelated but are you sure the choke seals are not leaking?

Yes i moved to the darkside

Instagram @jdm_brett

Choke seals are ok.



For setting the fpr i read two different methods. One is setting fp at idle at 4 psi and the other is setting fp with no engine running, so at atm, to 4 psi.... which is correct?

The regulator needs to be set for 4psi without the engine running ideally. Fuel pressure then rises as boost rises, or if n/a it's constant whatever the rpm I think.

Have you got any oil in the dashpot? I had this once, it was due to putting a new carb on that was totally dry, so big overrun flames. Spectacular but better with oil in the dashpot.

Yes, it is full of oil. But thanks.

Thanks!

Hi everyone,

i now checked the fuelpressure.

It is erratic between 0,25 and 0,35 bar (3.6 and 5 psi).


Is it ok, that it is erratic?
In middle, the pressure is a bit to high and i will set it a bit lower.

Thanks for help!

Edited by enne on 10th May, 2013.

As above, have you tried taking the dashpot off and seeing if the float valve is passing fuel?

If the valve is faulty it may be leaking even at the correct pressure.

Edited by Kean on 10th May, 2013.

Pulled the dashpot before i bought a new fuel gauge. The float valve it good. No fuel is passing.