I will try that to see what I get. What am I looking for with the other test you talked about earlier which is to command open loop in speed density mode?
I will try that to see what I get. What am I looking for with the other test you talked about earlier which is to command open loop in speed density mode?
So I used eehack to cut individual cylinders on it once it is warmed up. It certainly seems like cylinder #8 isnt pulling its weight at idle. I get virtually no change in sound or RPM when I shut it down. Also the #8 header tube runs considerably cooler than the others. Now if I rev it up to 2500 or so RPM then I cut #8 it seems as though it is running just like the other cylinders. I pulled and cleaned all those injectors but one thing I was not able to test for was leakage. I wonder if that #8 injector could be failing to seal up and running fuel into that cylinder at idle, keeping it from combusting properly? I will try to switch it around with its neighbor when it cools off a bit and see what happens.
are your injectors original?
i would just replace them
Steveo, They are the bosch red 4 hole 31 lb hour. Switching the injectors around doesnt seem to affect anything, or I would be happy to replace them. It really seems to me the more I play with it that the entire back 4 cylinders are not pulling as hard as the front 4 when I shut them down, with # 8 being the worst. I also ran the cylinder balance test and come up with the following numbers which seem to be split between the front and back 1/2 of the motor. 1=31 2=35 3=34 4=34 5=39 6=41 7=43 8=41. I dont really understand what the #s on this test mean, but it seems as though the cylinders that affect the idle the most when I shut them down are the ones with the lowest #s in the balance test which is the opposite of what I would think would happen. Does this information give anybody any clues?
Last edited by Fastmax32168; 05-27-2021 at 04:21 PM.
Even more info. I got paranoid that perhaps I had an internal engine issue so I pulled #8 and did a compression test on it. At 210 lbs cranking compression I guess I can dismiss that fear. However the plug is all black and sooty, not wet, but running way too fat, whereas when I pulled #4 plug it looks normal like it should. So there is definitely something going on here with #8.
Low spark at #8 or spark plug going bad? Unless the injector doesn`t freak out at low pulse.
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