Help - Misfiring and Hesitation

[Shoppinit]

I was thinking that maybe that n°8 injector was stuck open

Or is lazy, so metering more or less when the duty cycle is low, say at idle, but then not closing properly when the duty cycle is increased.

[Bennyd]

Just out of interest, why does the car run OK with one of the MAFs plugged out? This one is confusing me.

[Shoppinit]

Because it then using default "safe" fueling information, instead of working out the fueling from the MAF sensors and O2 sensors, etc.

[Ryan_Pestell]

does the airbox move at all ? can you pull it up slightly at the back where the MAFS are located, i had this on a friends car who i borrow his coilpacks to test mine, and spent a while trying to find why the idle wasnt right and the car had a hesitation, it was the airbox wasnt seated properly the maf's themeselves where fouling on the inlet manifold recess, so sounds like they were pushed in, but actually werent.

if you can move your airbox up at the back of it this is the problem, the other option could be the O ring seals that seat the MAF's have pinched or be missalligned.

[Bennyd]

Did some investigation last night. Airbox was definitely not on properly, I've reseated it so I see what happens, its so easy to get this wrong.
Also injector no. 8 was struct open, it flooded cyclinder no.8, so a new injector is on its was. Hopefully that'll be it.
I'll keep ye posted.

Thanks.

[bilko1]

Did some investigation last night. Airbox was definitely not on properly, I've reseated it so I see what happens, its so easy to get this wrong.
Also injector no. 8 was struct open, it flooded cyclinder no.8, so a new injector is on its was. Hopefully that'll be it.
I'll keep ye posted.

Thanks.

The injector staying open and flooding the cylinder can cause hydraulic lock on that cylinder which in turn can bend the conrod Please tell me you didn't turn the key with a flooded cylinder or at least had the plugs out.

[Bennyd]

There was hydraulic lock, but the engine only turned about half a rev before it stopped and it didn't fire. Had to remove the spark plug to clear the cylinder.

[Bennyd]

New injector installed this evening, car started fine but, when I turned she off I could hear a noise coming from the rear. The intank fuel pump was making a "dum-dum-dum" noise, not very fast. So I tried to start the car again but she struggled to start, a good 20 seconds of turning the engine over and then she just about started, VCDS showed no fault codes but when I put her into drive there was alot of misfires on cyclinder no. 8. Putting her back into neutral and the misfires stop. So I checked the second fuel pump by putting my hand on it, it didn't seem to be running so I plugged out the connector and checked the voltage going to it and got nothing, 0volts. Could this be the fuel pump module acting up? And where is it?

[Shoppinit]

When you say "second fuel pump" do you mean the one on the exterior of the tank? Did you test the voltage when cranking? I'm not sure the fuel pump runs with just the ignition on. You should have 12volts when you start cranking that drops quickly to 10V.

[Bennyd]

Ya, its the external pump. Hopefully I'll have the car fixed in a week or so, its gone to Unit20.

[Bennyd]

Just to let ye know, UNIT20 sorted the car. It was a faulty ECU. When it got hot it started to send the wrong signal to the fuel pump control module(I think).
Thanks UNIT20.