Serious misfire 97 5.0

[smcgee1979]

For some reason my Explorer is only running on 3 cylinders. I've changed plugs, wires, and coils.

A few months ago something shorted ignition and I ended up with 3 gallons of fuel in crankcase. Suspected Ignition starter switch. Replaced switch and changed oil. Cat converters were cloggedbecause of rich problem...gutted them for now to see what problem is. Truck has 80k on body and 9 on engine.

I changed the upper intake gasket this weekend and problem seems to be worse. before gasket change truck was missing on 3 cylinders now truck is running on 3 cylinders.

OBD P0354 is only code that comes up.

Please help.

Thanks in advance

 

[Birdy]

Is it sparking on the dead cylinders? If not, I think I would inspect the wiring, since you changed the coils already. If nothing looks rubed through anywhere or shorted on that engine harness, and you lost spark, I would suspect the pcm.

 

[drbenz]

If you had a quantity of gas in the oil I would check the injectors to see if any are leaking (more like dumping) fuel into the intake. Even if the plug isn't fireing there shouldn't be large amounts of fuel in the oil.

 

[smcgee1979]

I checked spark by grounding wires with a test light, only 4 7 and 6 are firing. I took the upper intake off to check wiring and swap a few injectors from original motor. Also forgot to mention I drove it half mile last night and manifold on drivers side was glowing. Kinda weird. I wont be able to get a pcm until after Christmas since the kids will have to come first.

 

[smcgee1979]

still scratching my head!!!

we are back to running on 5 cylinders again. better than 3 i guess. i checked the compression and it was 110 for every cylinder but #5. That one was 100. I dont know what the spec is for the compression and havent had alot of time to look for it. I checked for power to the coils and thats good. and there is 1.5 - 1.6 ohms resistance on the coils. Im not so sure that the problem is with the engine but maybe something electrical. Ive replaced the pcm, crank sensor, cam sensor, short bar, coils, plugs and wires and the ignition starter switch because of a suspected short there but i still have an issue with turning the key on and off without starting it. The cel, abs, and battery light stay on with the key out unless i start the engine and turn it back off.

I did notice today while doing the compression test that when you crank the engine and take the key out the lights dont stay on. kinda weird, but thats why i say i dont think its in the engine. cylinders 1, 2 and 8 are misfiring. any help would be appreciated.

 

[jhowell]

If the exhaust manifold is glowing red, it's due to unburned gas being dumped into the exhaust.

The OBD code you mentions corresponds to an issue with the coil. How old are your coils?

You mentioned an "original" engine. So an engine replacement has been done. Is the old engine a 5.0, or a V6?

The lights on the dash are not normal. Between them, the misfiring, and the OBD code, I'd say you've got some wiring issues to figure out.

 

[smcgee1979]

when putting the intake back together i had 2 plug wires crossed which caused the engine to run on 3 cylinders, causing the exhaust manifold on the drivers side to glow. the original engine is a 5.0 but had a spun bearing. the engine in it now i picked up for $700 last summer had 5 miles on it when i bought it. it now has 9000 miles on it and runs like poo. after replacing wires, plugs, crank sensor, cam sensor, dpfe sensor, fuel pressure regulator, fuel injectors on cylinder 1, 2, and 8. for testing purposes the converters have been gutted due to the truck running rich and clogging them, and recently changed the pcm with a used 1 from the salvage yard. there is still no change in idle or with the spark. I checked compression yesterday and 1,2,3,4,6,7,8 is at 110psi and no 5 is at 100psi. i know that it is supposed to be done at operating temp, but the engine was cold. i read somewhere that compression between cylinders shouldnt be more than 10% difference. im gonna start looking for an old intake with a carb and a distributor and see if i get the same running conditions with bypassing the pcm. I have 4 coils and 2 were from the original engine and the other 2 are from the current engine but all test good. no matter which coil i use on either side the same cylinders do not fire. im pretty much dazed and comfused about it all and i am unsure what to do next.