2.4 blowing black smoke

1480 views
6 replies
4 following
K
2.4 blowing black smoke
cr_rider avatar
cr_rider
+1y
hey i've got a 1990 dodge ram 50 which has the mitsubishi 2.4 fuel injected. I bought it and it seemed to me as if it was running rich. its smoking at start and heavily smoking if i dump the throttle. I replaced the plugs and wires, cleaned the cap and roter, changed O2 sensor, and cleaned the TPS. Still blowing black smoke and running ruff. Possibly mass air flow sensor? or ECU? has anyone had this problem with this engine? would appreciate the help.

Thanks Jesse
davethedude avatar
davethedude
+1y
It has been my experience that if there is an odd problem it is usually the ecu. If the ecu has not been repaired or replaced, I would start there.
cr_rider avatar
cr_rider
+1y
i'll try and put in another from a parts truck and post results
sleeps avatar
sleeps
+1y
ECU's dont go bad that often. You could have a stuck injector.
cr_rider avatar
cr_rider
+1y
but wouldnt it show signs on just one cylinder if it was a stuck injector? compression checked and all cylinders hold pressure at 170 all plugs look the same black carbon build up, not oil
rallytruck avatar
rallytruck
+1y

bad ECU is the number 1 cause of "weird" problems on the 2.4.
Don't assume a junk yard ECU will be good. Most likely the truck was scrapped because the owner couldn't figure out that the ECU was the cause.
sleeps avatar
sleeps
+1y
I have owned alot of mitsubishis, never had one ECU go bad. And all had over 130k miles on them. Had a lot of "backyard and do it yourselfers" tell me ECU's go bad alot, but when you talk to Master Techs who been in the buisness along time, they have a very different answer.

People assume the ECU is bad because they dont know how to properly diagnos the problem. So they just mask it with other junk. But go ahead and keep changing ECU's, maybe it will work. I am not saying they dont go bad, but not at the rate people change them. Take the time and do the correct diagnosis before spending money on parts, hoping it will fix it.