runnin on 4 cyls

[Four0Sport]

my 4.0 is down. keeps burning the last 2 plugs on the pass side and gas is dripping out of my tail pipe. so much so that its burning in my exhaust and turning the manifolds back into a red light show. no power, no idle, sounds like a boat motor thrown under water. i was thinkin stuck valves but im not sure. any feedback or knowledge would be greatly appreciated. even though i have my 97 5.0 AWD i wanna get my 93 back on the road asap.

thanks again.

 

[dogfriend]

Leaking injectors? Injectors stuck open? You can listen to them while the engine is running to see if they sound the same as the others.

 

[mynameisaric]

wow.. that sucks.. cant really give you any advice though. did you do any engine maintanence before it started doing this? or did it just start doing this one day out of the blue?

 

[sprint29]

It does sound like fuel injectors stuck open. That is the only thing I can think of that put that much fuel into your exhaust system. You mentioned that it keeps burning the spark plugs. Do you mean that it is burning the electrodes off of the plugs? Usually when an injector is stuck open , even a small amount, that cylinder won`t even fire. Wait a minute. After thinking about this a minute, what if the injectors aren`t stuck open and they are operating okay. That would allow the spark plugs to fire, allowing for the 2 plugs to burn. Now, as to the exhaust getting red hot, what if the timing has moved and it firing way to late. It wouldn`t run right, if at all. And, it could fire when the air/fuel mixture is entering your exhaust system. I have seen this before. I have even seen an exhaust system blown apart by the explosion when it fires after so much fuel accumulates in the exhaust. Check and see if something has moved in the timing dept. Crank sensor? Pickup? Spun harmonic balancer? I can`t reason away just the 2 plugs burning though. Just some ideas. Good luck

 

[marragtop]

Probably a REALLY stupid question, but any chance you have some wires crossed?

 

[Four0Sport]

wires arent crossed. i started noticing a miss when id hit a hill or put any type of load on the ignition so i changed the plugs and wires. platinum plugs and decent wires. it ran fine for about a week then started doing the same thing, only worse. its in time, i checked over most of the simple things like tps, iac, maf, o2 sensor. had a mechanic i know take a look at it and hes sure its a problem in the head. ive always regularly maintained the truck, in fact this is the first time ive ever had a problem with the drivetrain. id just hate to go through the trouble of buying a used 4.0 to put in it if whats in it could be fixed. then again if a cylinder is filling up with fuel id hate to see that the rings and cylinder wall were washed out.

 

[Bwana Bob]

Check the fuel pressure regulator (FPR). If it doesn't work properly, fuel pressure will be too high, about 85 psi when it should be 35 psi. Also, the rubber diaphragm inside the FPR can rupture, causing raw fuel to be sucked into the intake manifold through the vacuum line. Disconnect the FPR vacuum line at the vacuum hose tree on the intake manifold and see if gas dribbles out of it. Also check fuel pressure with a gauge at the fuel rail test port on top of the engine.


Bob

 

[PTBishop]

Do you have your old wires? make sure your wires didn't rub the exhaust and burn a hole through them...with it running can you hear them arching? try putting on 2 of your old wires, on the ones that are missing, if your old wires didn't do it all the time, one or two might still be good