Engine miss

[iracemine]

meh..... prob injectors.

 

[sagebel]

I got it to fail CCT today. First it failed on #3. I swapped out my new grey CPS for the old black one and re-ran the test. #2 (P0266) and #7 (P0281) failed once and I even re-ran the test to confirm the problem. I'll keep monitoring it this week and pull the injectors next weekend.

 

[sagebel]

Cannot get CCT to fail again. When slowly changing engine rpm between 2100 and 2500 rpm there is a definite miss. Any ideas?

 

[JLDickmon]

does the map sensor data wander at that RPM?

 

[sagebel]

Haven't checked that yet. I'll put it on the list for tomorrow.

 

[sagebel]

I got the miss to occur between 2300-2350 rpm. MAP was 16.6-16.7psi, Manifold Gauge pressure was 1.81 - 1.88psi. I also had the alternator tested and it passed. Not sure it the load tester tests the regulator and the guy at Advanced Auto couldn't answer that question.

 

[sagebel]

Replaced alternator. No change. I pulled my new (to me) 7x16 enclosed trailer home today and felt the miss more frequently. Whenever the engine slightly increased rpm I could feel it. Didn't feel it where I normally do when empty. Probably because the truck needed more rpm quicker.

 

[sagebel]

Did some more logging today. Injector pulse width is falling less than 1.0ms when the missing occurs. Not sure if the miss is causing pulse width to drop or if pulse width is droping causing the miss.

 

[JLDickmon]

pulse width causing the miss, most likely.. especially on 1-2 injectors.. if the whole system drops, then that's a IDM issue.. one or two, likely a couple of jeetered squirters.

 

[sagebel]

Thanks JL. How would "fuel desired" impact the issue? Fuel desired is also dropping or is slow to go up on acceleration. Is there any way to isolate 1-2 injectors and the IDM? Really trying to get this narrowed down this weekend.