So here it is, I'm a 12 year ASE Master Tech(but not for Dodge), this is my first problem Dodge, a 2000 1500 ram 4wd 5.9L V8 Gasoline engine. I'm going to spout off what I've checked and the results of that check. So the problem is extremely rough running, specifically, the "front" 4 cylinders aren't producing(cyl 1,2,3,4) I did an injector balance test and there is no change in RPM/running by unplugging the injectors 1,2,3,4. Unplugging the other 4 get me running rougher. All 8 spark plugs firing, new cap, rotor, wires. All 8 injectors fire with a noid light. All engine/computer grounds are clean and tight. Fuel pressure is a steady 49 psi running or static. I manually fired each injector with full (49psi) and saw it drop with every "pulse". Compression in each cylinder is around 150 psi. Cam sensor(inside distributor), crank sensor and computer have all been eliminated as culprits due to swapping of known good parts. The intake/plenum gaskets have been replaced due to leakage but had no effect on the running issue. Strange thing with the computer though, it's clearly misfiring it's *** off but it takes a long time to register misfires. I do occasionally get a P0202, P0203, P0204 P0208 injector faults. Cyl 1,2,3,4 also have new fuel injectors. I unplugged the injectors for 5,6,7,8 and the truck doesn't start but will run the exact same with the other 4 unplugged. I ohm'd out the injector wires to the ECM and they're perfect. Coolant sensor was replaced due to breakage of the connector. The intake air temp sensor was a suspect but it ohms out nearly identical to the coolant temp sensor.

I haven't had a vehicle kick my *** like this in years and I'm hoping one of you guys/girls will help save me.

Mark

 

did you check the wires going to the injectors, making sure none are bare or broken, or stretched and its not showing much outside the case. If not you may have a broken camshaft, iv seen it with a 5.2L but always a first for a 5.9L

 

sorry i take that back front would be working fine back for would be no reponse, not a camshaft break sorry Mark, how are the injector o-rings im sure new if you have got new injectors

 

yes, the injectors came with new seals and I was sure to get all the old ones(3 seals each) out during the procedures. The good compression kinda rules out a broken valve spring, rocker or cam. I like the feedback though, it's good to bounce ideas off another gear head.

 

I feel bad for you sspdfreek, got to hate thoughs little ghosts you can never seem to find is there any gas getting in the oil??? any what color are the plugs on your back 4 cylinders??

 

I would have to think gas is getting into the oil from the front 4 cyl wash. The front plugs are ashy when dry but are wet from gas after running, the rear plugs are a little black. there's less than a quarter mile on the plugs and the truck drove in the shop with newish autolites.

 

wow well the only thing i can think is a cracked plenum or plate, hard to say when not visually looking at it, and you said u have spark off all 8 wires, but you got yourself a tough little gig goin good luck and if i can think of anything else ill try and help you out!

 

Thanks! I had the intake in my hand today, replaced the plenum gasket. I was really hoping to find an old shop rag or something restricting the air going to the front cylinders but nope. The plenum gasket was leaking so i got it all cleaned up and fixed with a nice fel-pro set. Wasn't too hopeful that it would fix my problem but it's good piece of mind in the long run.

 

I'd hang a scope on those front four injectors to see the pulses, rather than just relying upon a noid light. I have a feeling that the injector driver in the PCM is faulty and the injector driver waveforms are going to be sloppy as hell.

 

Computer was swapped out with no change.