Way to test injector with efilive?

[87gmc]

Ok I have a slight miss in the car with codes p0300 and p0307. I have checked spark plug, coil, wire and everything seems good. I'm trying to figure out if maybe its a bad injector. My lftf on that side are around +5 and other side are -10 (which while scanning looks lazy).

Is there anything i can do with efilive to check it? I used the cylinder balance test but it showed 7 was the strongest by about 100 rpm. I figured it was a reverse effect of the reading. Any help I would appreciate it.

[Blacky]

There is an injector test built into the PCM, but it is not implemented in EFILive. If it was implemented, you would still need to attach a fuel rail pressure gauge to accurately test each injector's flow.

As for the cylinder balance test, the highest displayed RPM indicates the weakest cylinder.

Regards
Paul

[mistermike]

I would think that if it's an intermittent injector problem you might have to run a fair number of cylinder balance tests to try to catch it misbehaving. If it happens all the time, it shouldn't be too hard to isolate. You can always swap injectors around to see if the problem moves to a different cylinder.

[87gmc]

well its always on the number 7 cylinder. I pulled the plug wire on it today and let the engine run a bit. After about 15min of idling I pulled the plug and it was dry as a dirt. Can this be a sign that the injector is bad? Also on efilive number 7 is the only one with misfires

[mistermike]

I would swap that injector for one on the other bank. Also, #7 is notorious for running lean. If the car has been used with any power adders, or really beat on, you might want to do a compression check on that cylinder.

[87gmc]

I would swap that injector for one on the other bank. Also, #7 is notorious for running lean. If the car has been used with any power adders, or really beat on, you might want to do a compression check on that cylinder.

How many lbs shoud i be looking for? Its a stock engine and never had power adders on this one. I'm just curious is to why the spark plug is complety dry. It didnt even smell anything like gas. I just unplugged the spark plug wire and let it idle for 15min and pulled the plug it was dry as a bone.

[87gmc]

well i pulled number 7 out and it like someone had filled it with dirt. After cleaning and cleaning all the other injectors the thing feels like a whole different car even before it started missing.

Thanks to efilive i was able to kill the fuel pump while idling which made less of a mess of taking the fuel rail off and i was able to narrow it down to one cylinder. also my 02's seem to be back to normal

Thanks EFILIVE!!!!!!!!!!!!!! :D

[joecar]

There is an injector test built into the PCM, but it is not implemented in EFILive. If it was implemented, you would still need to attach a fuel rail pressure gauge to accurately test each injector's flow.

Yes, the test is spelled out in the factory manual.
A fuel pressure gauge is about $40 (I got one; it also tells you if your fuel pump and/or filter is okay).
The test would be nice to have since it allows you to single out any injector that is behaving differently than the others.

I wish the PCM had a similar test for testing the ignition coil packs
(in this case you would connect the spark tester (looks like a spark plug with a grounding clip attached to the side of it)).