Cadillac Repair Questions? Ask a Mechanic for Answers ASAP
hi there, I am Cam. Can you tell me more about the fuel pressure, when is that pressure set? Driving or just with the pump on? Does it hold while driving and under load?
Ok, was that with the pump running or after it shut off, and how long did that pressure hold when shutting off?
But with the pump running only, what is that reading? Spec is 55-62
OK, that is low. Spec on this engine is 55-62 psi. Not at 53 psi, that should allow you to drive it even at lower speeds. Which cylinders are misfiring then?
Was the exhaust tested for being plugged?
Ok, is it a dead misfire or occasional?
And I see you did not check the actual flow test of the injectors, is that correct?
OK, Next we need to actually flow test the injectors. This is done with a scanner and fuel pressure gauge. The test, which is a built in test on the scanner powers the fuel pump to prime the system. Then it pulses each injector for the same period of time. You record the initial pressure then ending pressure and compare. The drop in all injectors needs to be all with in 10% of each other.
Thats a large difference between them all, but how long did each cycle? normally the pressure drops to ~35 psi. I am assuming you swapped coil packs around to rule out coils, wires, plugs and such?
That #5 is almost no drop and that tells me its plugged. I would take out the injectors and see what the back side of them looks like.
Yes I am still here. No fine debris? I would swap them around see if the misfire moves since you have them out. I will be around monday if you need .