Splutter!

[mrtom22]

Hi guys! Recently refitted my standard G40 engine after my turbo engine pooped itself, all was well until i drove the car warm, and as soon as it hit boost it spluttered and misfired like mad, now the only thing left from the conversion is the walbro fuel pump i had fitted to keep up with my G60 injectors, could that be the cause? If so what fuel pump would you recommend me fitting that doesnt have the pricetag of a new G40 specific one?



Thats what it sounds like, also takes an age to start when its warm, which i believe is just temp sensor related!

[mrtom22]

I should mention that the standard G40 injectors are now fitted

[z3i]

Sounds like timing dude, too much advance

Only does it on boost? runs fine in all other situations?

[mrtom22]

Tried timing it with a gun, replaced the leads, cleaned the sparkplugs, tried another coil, it ran fine before i took it out and it was only the pump i changed, its fine in other situations yeah, just as soon as you hit the gas it bogs and splutters!

[Andy]

Did you have a 6 psi boost switch fitted with the turbo conversion, and have you gone back to the standard WOT switch? What chip and injectors are you using?

[mrtom22]

I did but i removed it and rewired the old WOT setup, im running the correct chip and G40 injectors, could the uprated fuel pump be throwing in way too much fuel or will the map regulate that?

[z3i]

Ecu will regulate it, doesn't matter what pump you have, hence having a return line in the fuel system to the tank

[Andy]

I did but i removed it and rewired the old WOT setup, im running the correct chip and G40 injectors, could the uprated fuel pump be throwing in way too much fuel or will the map regulate that?

The ECU doesn't regulate fuel pressure - the mechanical fuel pressure regulator does. There is a limit as to how much fuel this can return to the tank, but unless you've fitted a 500l/h pump I can't see this being an issue.

Easy way to check is to stick a fuel pressure gauge on the end of the fuel rail.

Personally I'd go through the Digifant diagnostic guide on here, and pay close attention to making sure that MAP sensor hose connection; WOT switch/wiring and ignition timing are all correct.

[mrtom22]

Okay I will do! Thank you for your help guys

[z3i]

Sorry what andy said, what i meant was the ecu regulates the amount entering the cylinder through the injector

[Alexiskayak_7]

I think you lamda sensor is gone bad mate

[Andy]

Lambda isn't used on full throttle...

[Alexiskayak_7]

Oh I didn't mentioned it at his first post..
Are you sure timing is fine?
Also ppp made the chip?