Engine/Transmission (1994 - 1998) Need Help Quick

[JimDavis]

I have a 98 12 valve auto that idles great in park and neutral but put it in gear and the idle drops to 600 rpm and black smoke. I have adjusted the idle with no luck same problem just a higher idle in park. It is also stack shifting I can get to third befor 25 mph. I changed tps sensors with another used one I had and same problem and voltage test of the tps are fine and on a computer tps is fine. I've run out of patience with it and it is at a shop and they want to change the injection pump. I really don't want to change the pump without confirmation of the problem. Could it be overflow valve, lift pump, fuel heater? Need help quick please.

 

[Signal73]

sounds like a transmission problem, not an injection pump problem. get it out of that shop before they cost you more money then your issue should.

 

[JimDavis]

I took it by the transmission shop and he said not the transmission. That was my first thought also.

 

[Vaughn MacKenzie]

Does it sound like the trans is loading it down excessively or it is more like once the engine is brought below ~700 RPM it's weak and starts smoking? It sounds more like an engine issue to me, even if the trans was dragging it down it shouldn't smoke to speak of. Is it smooth or sort of surging, missing, etc. ?

 

[JimDavis]

It sounds like engine. No surging the idle is smooth. The shop where it is at said come get it they can't figure it out. Everything test fine.

 

[Signal73]

has the timing been checked?

 

[JimDavis]

Not that I know of.

 

[JimDavis]

I like the pump timing idea it seams to fit with the problem. Any ideas on a good shop in San Diego area or anyone want to donate some times and tools I'll bring the food and beer.

 

[Signal73]

as a quick check you can use the alternator or a barring tool to bring the engine up to TDC using the timing pin, then on the injection pump take off the acorn nut that holds the timing pin in and use a mirror to see if the blade in the pump is centered in the opening.





Timing pin on engine under pump:



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Timing pin on pump:



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[JimDavis]

Thanks I will try that after I get it back home.

 

[JimDavis]

Another thought what would pump timing have to do with transmission shifting funny?

 

[Signal73]

same thing I was wondering about the pump supposedly going bad!

 

[JimDavis]

Well I finally got my truck home and have not had time to work on it, wife broke her elbow and been busy taking care of the family. Found out something interesting though the truck runs fine cold and once it hits operating temp the problems occur. It has to be electrical. I changed the TPS with a used one I had and both are good no glitches when running on diagnostic computer. No codes are coming up computer seems to function fine. Any ideas?

 

[tp0d]

Try pulling the OD solenoid relay pack from the PDC behind the drivers battery... . This will disable your TC lockup, and will prove if you have an issue with the TC, at the least. The relay is labelled "transmission". Its also the relay that is jumped when adding a mystery switch.

It definetly sounds like a transmission problem. Go back to your transmission guy, or even dodge, and have them plug their ODBII, or similar scanner into it, and go for a drive. My transmission guy did this for me, and found a bad solenoid pack that was causing weird shifts. Its amazing how much data comes out of the transmission when its running. . If your transmission guy gives you any heck, then find a new one.

The black smoke in gear says there is load on the engine, when there shouldnt be, at idle. Does it do the same thing in reverse?

good luck

-j

edit--- hope the wife is doin well, broken elbow, geez that sucks

 

[DPashko]

I had the same problem with my 97 the RPMs dying right off in gear, and even when I first start it in the morning it would not come up to proper idle until it ran for a few minutes. I have new lift pump, overflow valve checked out good,changed fuel filter, changed the transmission fluid and filter, changed the TPS, adjusted the TV cable, and adjusted the idle a couple times... each thing I did it got a bit better... but still was not 100%, then last week I had a set of 215 injectors, took them apart, cleaned them up and installed them and the truck starts great now seems to idle a bit smoother and it is a bit quieter idling now. I think it was mostly an injector but the other little things I did, did help somewhat. My truck has 305 000 KM on it and the 215 injectors I installed have 265 000 KM on them. Maybe something to try if dont find anything else... Good luck!

 

[surfbeetle]

Jim,



Here's a dodge diesel only shop. I haven't tried them yet. They are in Lakeside. JT DIESEL PERFORMANCE - San Diego Dodge Cummins Shop



I have gone to Diesel System Serivces in El Cajon

619 749 6226.

 

[tp0d]

One thing I forgot... If this is a Cali truck, does it have the EGR hooked up?

If the EGR solenoid is doing something bad, particularlly when the truck is hot, this could be causing an issue. I have no experience with an EGR truck, so I`m just guessing.

Have you tried checking codes using the 3-key cycle method?

-j

 

[JimDavis]

Just wanted to post an update in case anyone else runs into this problem. It was the torque converter. Haven't had much time lately but finally got it finished up and back on the road yesterday and she runs great again. Thanks for all the help.

 

[Signal73]

sounds like your first thought was your best thought. best of luck with the new T/C