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Ok I’m out of ideas , I have an 05 hemi ram that had two cylinders low on compression , 5 and 7 . I pulled and rebuilt the motor the compression is now about 170-175 across all cylinders. It’s still running rough. Before the rebuild I tried new copper 570’s , new coils, new wires , and new injectors. Prior to rebuild I had codes for cylinder 5 misfire that one had 50psi and then multiple cylinder misfire. I have pulled the valve covers off to double check my work and verify the cam lift and as well as pushrods are seated properly. Now with it running I can pull the injector wires for cylinders 5 and 6 with no change in the idle speed. This is a non mds motor BTW. I pulled the injector harness to inspect and found no flaws. I set the timing with the crank at 6 and the cam at 12 . I don’t know what else I’m missing. Yes I cleaned the throttle body proir to the rebuild as well. The egr valve pipe is cool to the touch for the first few minutes so I don’t suspect it’s stuck open ?
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One issue at a time …
You state:
“I can pull the injector wires for cylinders 5 and 6 with no change in the idle speed”
Have you checked the injector wiring using a node light to ensure your getting a signal to trigger the injectors in question?
Next would be to check the injector flow rate by using a fuel pressure gauge attached to the fuel rail and some type of tester like this …To see if indeed all the injectors are flowing equally and at the recommended rate.
Get through those and see what the results say.I did a basic pressure check , it was holding steady at 60 psi and I did a noid light test at the same time. All good. I don’t have that flow test unit pictured , I did flush the fuel rail when I replaced the injectors.
You need to confirm injector flow rate is at MFG recommended rate across all injectors.
Fuel pressure holding at 60PSI only confirms fuel pump / pressure regulator function and non leaking injectors, not injector flow rate.
Same to same about flushing the fuel rail.
This need to be confirmed before moving forward with trouble shooting.
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