vr6 turbo problem

[omar_magdy 2]

hey guys ,

i have golf mk3 vr6 turbo , running megasquirt fuel only till now , MAF removed , the engine runs perfectly fine to red-line .. but only up to about 80% throttle. If full throttle, the engine misfires and cutting :S i need help .

thnx

[legvw 0]

Are you using a MAP instead of a Maf?

Sounds like you need to trim in more fuel or to knock the timing back slightly. Is the TPS setup properly?

[omar_magdy 2]

yes i am using megasquirt MAP only and TPS is not connected to megasquirt

[legvw 0]

How does your ecu know where the throttle is? Shouldn't it be connected?

[matty.vrt 120]

I was thinking the same thing like how do you trim your fuel for part and full throttle openings.

[omar_magdy 2]

my ecu dont know where the throttle is ,when i diconnect the TPS i hear knocking under boost but the engine runs perfectly fine to red-line

[legvw 0]

Your ecu needs to know the signal from the TPS, as matty said, so you can tune your car.

Most maps use throttle postiton against rpm or manifold pressure. But they all use throttle position.

Knock isn't good mate, DON'T RUN FOR TOO LONG WITH THE ENGINE KNOCKING!!!

It probably knocks because the timing an the fuelling is so far out because the ecu doesn't know where the throttle is, just knows the rpm/pressure.

[AJmk2 2]

Im running megasquirt on my car and also no MAF. How have you got your acceleration enrichment , is it map based or tps?

I have my TPS turned off completely and run only map based enrichment and mine runs fine. Could also be your set up though like too much timing ect.

Some boosted maps on MSruns.com for comparison.

[omar_magdy 2]

I have my TPS turned on but to ecu not to MS and running map based enrichment . i am using MS fuel only but i will try to use it fuel & ignition .thnx for u all ..

[FishWick 21]

Not a good idea using MAP as the only load. If the sensor dies, you have no way to drive the engine. I don't know how transient fuelling is supposed to work without knowing pedal speed either (ie. TPS) but I'm no megasquirt expert :-)

[AJmk2 2]

Yes standard engine timing is much too advanced for boost and will cause a lot of knock , i would not run like it.

Map also looks at the rate of change of air pressure for acceleration enrichments.