mk1 C5 2.2 injector correction flow rates.

[waynedance]

Got some information from a Launch diagnostic tool.

Seen to have a slight fault with the car, under hard acceleration I am getting a little hesitation. Sitting at idle and pressing the accelerator at approx 1500 revs the engine hip cups/misfires.

Do these figures look ok for the injectors?
Injector 1 0.35 mm3
Injector 2 -1.92 mm3
Injector 3 2.24 mm3
injector 4 -0.67 mm3
These values were taken with the engine at idle, the values did seem to go towards zero when revs increased.

[Peter.N.]

I would suspect that the variation in readings is due to different leak off values, if the fuel injected was as the readings the engine would be all over the place. You can check by running separate pipes from each injector leak off into 4 similar receptacles and checking the amount from each injector.

Peter

[RichardW]

My take on these numbers is that they are not to do with leak off rates - rather they are the correction values the ECU is having to apply to the injection pulse width to get a smooth idle. So 2 with big(er) numbers suggests the injectors are blocked or leaky - no2 leaky (-ve correction) and No 3 blocked (+ve) in your case. No 3 more likely to be causing problems with smooth running I'd have thought - try some injector cleaner? I don't think the ECU can see the leak off rates - all it would know about these was that it was having to wind in the fuel pressure regulator to maintain the rail pressure. A leak off test will tell if the top works on the injector are in poor shape though....

[Peter.N.]

Sorry - showing my ignorance again.

[waynedance]

Been trying to find out what tolerances are +/- but can not see any information. Only use Shell fuels and use Forte Diesel treatment regularly.

I think I worry too much and look for faults that are not there.