its a 94 Ram With the 3.9 V6 and i been working on it for a friend today and im lost with it. it wouldn't start so i put all new plug wires cap and rotor fuel filter,fuel pump and it ran but half ***.

the way its running to me seems like i have the spark plug wires wrong, it cranks right up but sounds like its running on 3 or 4 cylnders and when u rev it up fast it back fires from both intake and muffler pretty bad. i changed the MAP sensor and no help.


all the spark plugs are black is hell from too much gas i guess its getting plenty of good fire i think so im thinking its a sensor out making it dump fuel into the engine and flooding it



what could be wrong? every single cylnder is being flooded i can remove 3 injectors and it doesn't run any rougher.

 

Check the coolant temp sensor. Just on the drivers side of the thermostat housing. Two wire connector.

 

the guy changed it but it looks like he put the wrong one because the electrical clip is on upside down and the sensor is much difference electrical connector.



will that sensor really cause this much problems?

 

Are you sure the wires are run completely right? Are they all in the right spots and not crossing or tangled?

 

plug wires? Yes They are all ran nice and straight. and their brand new no cross firing.

 

when i removed the MAP sensor the truck evened out a good bit so i replaced it and same thing. it runs better with MAP sensor off and not connected.

 

pulled all the plugs out and their all black like too much fuel is going into cyls.

 

Yes, it will. If the PCM thinks its REALLY cold out, which is probably the case here, it will DUMP gas trying to get a mixture that will burn.

 

Best to find out the actual cause before throwing parts $$$$ at it blindly. The coil can be off, I have had a V8 ram run on 4 cylinders only because I hit a bump really hard. The coil wire was on & looked right, but unerneath it was no snapped on. Also, I have seen repair manuals from chiltons & haynes have the firing order printed in reverse of what it actually is. The factory serice manual is free on a sticky on this forum - well worth the 10 seconds to download. Have you had the codes read yet?