97 dakota sport 3.9 club cab. had the cat changed by dealer along with O2 sensor (upstream). the check engine lite came on and i took it back. they said that it didnt have a code. on a whim took it to advanced auto to have it scanned and they said no code. i can manually get 2 codes. 950 auto shift manual control circiut high. 999 shift solenoid F control circuit high. then the truck wouldnt start at all. had it towed to my mechanic. he changed the spark plugs and the truck started up first try! he said when he took out the spark plugs that they were soaked with gas. he changed the oil and said that raw gas was in there too. he then drove it and as long as the truck is under load it drives great. but when you come to a stop sign it stalls out. you have to keep your foot on the throttle. ive already changed the idle control valve. since there are no codes its random hit or miss on what needs replaced. throttle control valve, map sensor? anybody have this problem? any ideas?

 

I think a big problem here is that you have gas in your oil. Are you having any blue smoke coming out of your exhaust? It sounds as if you have an injector leaking when the engine is off, or a bad valve guide seal. Either way, it is terrible for the motor. When the fuel gets into the cylinder, it "washes down" the inside of the cylinder which removes all the oil from the walls. This will kill your piston rings. If the guide seals turn out to be the problem then you are looking at a total head rebuild. 9 times out of ten you have to remove the entire head just to get to the valve guide seals. Also, check the fuel pressure regulator and the vacuum hose to it.

 

hey virused. how do i check to see if the injectors leaking? i would rather not replace all 6, im sure there pricey. replace each one or do they look defective? there is no blue smoke when truck is running. in fact when you are driving it runs great. its just when you come to a stop. im having them check everything you said.

 

I guess one way you could check the integrity of the injectors would be to remove the injectors, take a shop air hose with a rubber nipple on it, and put slight pressure on the inlet of the fuel rail. Keep in mind that you don't want to put too much pressure on the injectors or the fuel rail, and I am not sure what the normal psi is of the rail/injectors. Either way, I dont think you would need much to see a leaking injector. After you begin to apply some psi, watch the injectors to see if anyone of them begins to drip. Have you checked the fuel pressure regulator and vacuum line running to it? That is the easiest thing to check first.

Anyone have any better ideas to check injector integrity?

 

If you decide to try what I suggeested, keep in mind that you would want to do this with the truck turned off.

 

Injectors should be ~40psi. I know the 30 lb/hr injectors in my 5.0 want about 42-45 psi.

 

thanks im gonna check it out in the morning. i was also told that it could be the diaphram inside the fuel rail.

 

heres the update. checked the fuel pressure and it is 30 psi all the time. even at idle and under load. got a code that says misfire in cylinder 4. im pretty sure ill have to change the spark plugs again. just changed plugs, wires, cap and rotor 3 days ago. is my truck different that the fuel pressure regulator is in the gas tank? i thought most were on the fuel rail.

 

I will have to check the service manual to see where it is located. As far as the number 4 misfiring, that is where you would wan to start.