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Misfire cylinder 2(actually 1) only under load

sseilmnop

sseilmnop

LaBarge Supercharged
I have Aeroforce scan gauge and it indicates misfire only under heavy load for cylinder 2. For some reason my Aeroforce says 2 but its actually cylinder 1. If I pull cylinder 1 plug wire I get misfires displayed on scan gauge on cylinder 2. So cylinder 1 is 2 and 2 is 1 for the scan gauge..


So what have a done.

Replaced spark plug....no help
Replaced plug wire.....no help
Swapped coil packs.....no help
Swapped ignition module....no help

I'm getting sputtering under heavy acceleration.....50-80 misfires.


What next? It gives no misfires under normal driving and light acceleration.
 


put all six stock injectors back in and have the same problem same cylinder. Idles fine but this problem has been getting slowly worse, now under any kind of load I get a ton of misfire cylinder 1.

Any one ever see a scan gauge show the wrong cylinder?
 
Are the connectors making a good connection? When I first bought my car the little clips inside the injector plug on the harness were too loose to make a good connection to the injector. I know it's a long shot, but it only takes a minute to check. I haven't had misfires show up on the wrong cylinder, but I don't use an aeroforce either. I almost wonder if it's confused since 1 is right after 2 in the firing order?
 


Do you have another way to chexk.mis mires using torque or dhp? Agree it may be a injector connector or britle wiring on connector.
 
I double checked the #1 connector on the injector and wires look good, nothing frayed, pulled or burned. Replaced all the coil packs and took it for a ride today. Ran great, though it was fixed but the engine wasn't all the way up to temperature. Turned around and wend back down and up a long hill and it was back, cylinder #2 misfire but not as high a count. I had absolutely no misfires with the engine below 150 degrees.

I just put a big fan on the engine. I'm going to swap all the plugs and wires when it cools down. I will be heading to advance or autozone to get compression gauge if it still does it with all different plugs and wires.

Can the PCM do weird stuff like this?
 
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Sounds like being in closed loop vs. open loop has something to do with it. Might be a sensor of some sort. MAF and 02 are good?
 
Do I have to be at top dead center to put air pressure to the cylinder? Or can I just put pressure on it and have it spin its self to the bottom of stroke.
 


I like to pull all the plugs so it's easier to turn the motor by hand. Take a small length of hose that fits in a sparkplug hole. Have a helper feel the end of the hose as you turn the motor by hand. If if no helper, do what I did and rob a squeaker out of a dog toy to shove in the end of the hose. Instant TDC locater. :)

With motor at TDC for that cylinder, pump air into it while watching/listening for it in the intake, exhaust, crankcase, and cooling system.

The piston needs to be at the top of its stroke, with both valves closed. If your not fully at TDC, the compressed air will turn the motor as it pushes the piston down.
 
Okay, gave up on TDC #2. Pulled alternator, valve cover and both rocker arms. Put air to it and it is coming out the exhaust.

No bubbles in coolant.
Nothing coming out crankcase PCV hose.
Nothing coming out the TB intake.
 
with the rocker off still hit the top of the valve with a mallet. it may seal, if it dont seal theres some thing wrong with that valve or its seat.
 
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