Ok new to the site seeking desperate help! Just bought a 99 dodge ram 1500 a week ago. it has 120k on it with the 5.2L engine. This thing will not run and when it does it runs really really really rough. it backfires out the exhaust and there is a greyish smoke coming out the exhaust as well as a black sute like liquid that smells of strong gas. I replaced the whole throttle body with one that i know worked off of my old 98 ram so that cancels out the IAC valve and the TPS. what else should i look for? Crank sensor? cam sensor? cap and rotor? also one more thing it did run fine for about 30 seconds when it was cold but i sprayed starting fluid down the air box. after that i couldnt get it to start again.... i drained the gas tank and replaced with new gas and i cleaned the sensors on the throttle body that i put in. any ideas guys? i bought this as a work truck and dont want to put alot of coin into it. Oh and it has a new ignition coil

 

Welcome to DF.

Lotsa possibilities there. Getting any codes? Plenum been fixed? Got a scanner?

Think the first thing I would do is check and see what temp the PCM thinks the engine is. You only have one temp sensor, check it, and make sure it is plugged in good, and the connection is clean.

 

no codes. i had to put a new battery in it. doesnt run long enough for it to trigger any codes. temp seems to be working as far as that goes. i just cant do much as the longest i have got it to run was about 30 seconds tops.. the guy i bought the truck off of said that it ran out of gas so he put gas in it from a 5 gal tank and then it started doing what its doing now. So i figured okay bad gas..... nope wasnt that. when it did run it was back firing/popping bad. about every 5 seconds it did that. once it died i couldnt get it started. even with starting fluid. it wasnt showing any signs of even wanting to fire what so ever. no popping. nothing..... plenum seems fine. when i had TB off there was no oil present down in the intake.. maybe any sensors i should check for?

 

should i just go out and spend $300 and replace the cap, rotor, plugs, wires, crank sensor, temp sensor, IAC valve and TPS? i was reading that it maybe the O2 sensor pre cat? but not sure...

 

O2 sensor doesn't play a role until the engine gets to 108 degrees.

Check your fuel pressure. (need a gauge.)

 

ok i will do that. i can hear the fuel pump turn on but i will go out and get a gauge for it and test it. i read that it should have anywhere from 45-54 psi. Does that sound about right?

 

Yep. If it is initially low when you turn the key on, cycle the key on/off a couple times, to see if it will build pressure. (depending on what initial value is. If it's really low, just replace the pump. )

 

ok will do. i thought a fuel pump either worked or it didnt work. but i will test it

 

if it were mine,1st thing id do pull all the plugs and look at them,replace any that are fouled then go from there,run it for a while and see if the same plugs keep fouling,if so then we can investigate furthur...also if your fuel pressure is below 50psi then the pump is about shot..

 

Ok so i tested the fuel pump today. that read at 45(psi) i also noticed that the oil smelled like gas when i took out the dipstick. probably from being flooded maybe? the truck ran today for about 1 to 2 minutes. it ran good. i could rev it up to 4000rpms and everything, then it started sputtering and backfiring after the 2 minutes. seems to me it only likes to run when its cold but then once it warms up it will start backfiring and sputtering. Not sure what else i should check for? i also found a vacuum line that was broke, i got a pic of it in the attachments section if anyone could tell me where it goes...