Engine/Transmission (1994 - 1998) problems with my 12valve

[Lonestar]

I have been driving my new to me 98' 2500 4X4 around for about a month now, and have several items that are concerning me. The truck has a long crank to start compared to my other 12valves. The engine turns over almost 2 times before it starts, where as my last truck would fire almost as soon as I touched the key. The truck also idles at around 600rpms on a cold engine, but once warm it idles at around 850. I know that the slow start has something to do with the idle speed as well, but if I raise the idle speed when cold, it'll want to race when warm I'm afraid.



Secondly, I am still having problems with the shift timing in the transmission. Seems like no matter how much throttle I give it, it shifts 1-2 at 10mph, then 2-3 at 15mph. I have adjusted the TV cable, and it has helped a little, but I cant seem to get any more adjustment out of the cable. Where do I look next?



I also am noticing a lot of blow by smoke or steam out of the blow by tube. I know a little is ok, but if you look at the truck from the front, you would think that it is burning something out the bottom of the truck. I know that a vaccum leak can add to this, but all my vaccum driven accessories function properly.



My last problem I am having is I don't think I am making enough boost. The truck is all stock except for a #6 slid forward a little. At WOT, I am only building about 23psi, and that is all it will do. I would have thought it would be pushing over 30psi with a #6 plate??





Sorry so long, just trying to get everything in top condition. Thanks in advance for the help



KEEP ON TRUCKIN'

Lonestar

 

[blacksheepdiesel]

Lonestar,

Adjust the idle when engine is warm and in drive with parking brake on, wheels chocked. It will help with engine starting. If not satisfied then check fuel supply and return hoses and replace if they look the least bit bad. Have you replaced fuel filter? Found a '95 fuel filter one time that had rusted from the outside in near the water drain fitting on the bottom. It really didn't leak but did allow enough air in that starting was harder than normal.

Also, does the starter sound like its turning the engine over at proper speed? Batteries and all connections good?

Have you checked the timing on the injection pump? I would recommend setting it at 16. 5* which will help with starting, although that is just a side benefit.

Godspeed,
Trent

 

[Missouri Mule]

1. You also have to have the air conditioning on, (to set idle speed) 750 to 800 rpm.

2. Try cleaning TPS (throttle position sensor).

3. Check coolant level and oil level.

4. You need an adjustable boost elbow or non-wastegated turbo. The stock wastgate opens up some where between 20 and 24 psi.

 

[Vaughn MacKenzie]

Lonestar:

180 and 175-pump engines crank longer before firing than the 215. I found this out when I replaced my 215 with a 175 pump on the '96. My '98 hits about 10-12 compressions before it fires.

Sounds like the vacuum modulator in the transmission might be bad. I would call a transmission shop you trust and ask them about it, or give DTT or Goerend a try.

On the blowby are you pushing oil out around all your gaskets? Are you using oil? Leaving large drips on the driveway? If not I wouldn't worry about the blowby.

On your boost also make sure all the clamps are tight, then check the first boot leaving the turbo to make sure it's not cut or torn. These tend to rub on the inside of the fender and become torn.

Vaughn

 

[Lonestar]

Thanks for all the tips and help. I have tried to check for boost leaks, and cant find anything definite, but sometimes they hide well.



Vaughn, all my prior 12valves were 215pump'd trucks, so if the 180pump takes longer to fire, that would explain.



My Blow by tube is occassionally leaving a puddle of oil, but the truck really isn't using any to speak of. The previous owner had a complete check of the motor before he sold it, and it appears that everything checked out great according to the cummins tech that did the work.



One other thing I am noticing is fairly high egts at cruise. Typically, I am seeing about 5psi of boost, and 800*+ at 65mph. That sounds high to me, I was expecting the boost to be slightly higher, but the temps I thought would be in the 600's.



Thanks again, I'll get some time to make some changes this weekend.



Corey

 

[blacksheepdiesel]

Corey,

With those egt's I would agree you have a boost leak somewhere. After checking the boots and clamps and finding nothing it is time to test the intercooler.

Godspeed,
Trent

 

[CogginsP]

Not to insult your intelligence lonestar, but on your original post you said you are only making 23 PSI. Have you disabled your wastegate? I think your plate kit came with an adjustable boost elbow, you can adjust your gate with that or just plug it off like i did.

 

[Lonestar]

Well, I bought the truck just like it sits about 1 month ago. I have already found several things that were not as I would do them. The boost gauge is attached to a "T" fitting in the line that goes from the boost elbow to the wastegate. Therefore, the reading would be skued by an adjustable fitting anyway. So my first correction will be to relocate the boost fitting to the intake manifold.



Thanks again for the tips. I'm going to check all my hoses, clamps, and intercooler for leaks.



Does anything in the transmission function via vaccum lines? I am thinking if the transmission isn't performing right, and I have excessive blow, it could be due to the vaccum pump continually venting into the crankcase and causing excessive pressure?



Corey

 

[arthr31]

hey there, I don't know the answer exactly to your question, but you might find it here. http://www.fixinrams.com/ This fine fellow has a lot of information about the vacuum pump, what breaks, what's effected, etc. I hope this helps.

 

[Missouri Mule]

Lonestar, No your transmission does not use vacuum to operate. So no vacuum lines run to it.

But your transfer case should have vacuum lines running to it (on top of case).

 

[Lonestar]

Okay, thanks guys. I'm going to dive into it this week and see if I can start to get everything straightened out.



Corey

 

[DieselDoghouse]

On your long crank - don't forget to check fuel prime - if your fuel prime is dropping when shut down that also will require a longer crank to rebuild pressure to fire. Check your rubber lines for leaks OR siphoning air!!

 

[Bart]

Thanks for all the tips and help. I have tried to check for boost leaks, and cant find anything definite, but sometimes they hide well.



Vaughn, all my prior 12valves were 215pump'd trucks, so if the 180pump takes longer to fire, that would explain.



My Blow by tube is occassionally leaving a puddle of oil, but the truck really isn't using any to speak of. The previous owner had a complete check of the motor before he sold it, and it appears that everything checked out great according to the cummins tech that did the work.



One other thing I am noticing is fairly high egts at cruise. Typically, I am seeing about 5psi of boost, and 800*+ at 65mph. That sounds high to me, I was expecting the boost to be slightly higher, but the temps I thought would be in the 600's.



Thanks again, I'll get some time to make some changes this weekend.



Corey

Corey, I have almost the same exact setup and readings. Mid 20s psi on a hard push (full throttle) and then only for a short period of time. Temps will range around 1100-1200 on that hard push. Cruise temps are down some between 600-800, depending on the terrain with about 5 psi. The #6 fpp is centered. I did lower egts a little by cleaning the K&N filter. I have a new filter system on the way. I'm picking up a use ATS arc flow elbow tonight after work. I'm beginning to wonder if I too don't have an intercooler problem. Is there a way to test the intercooler? I've checked all my hoses and they are tight and no damaged hoses. I did pickup a lot more power after moving the star wheel from 10 clicks to 25 clicks. I don't know if that info will help you any. Good Luck and I'll be watching this to pick up more info as guys post it. You may want to go to the towing/haul section and read a thread I started titled "Why can my buddies' Ford eat my Dodge's lunch" There's lots of ideas there. The post # is 183538

Later.

 

[Bart]

I took the Dodge over to a place here in Victorville, Ca called "Commerial Engine Service". The service manage took a look at it and in no time told me what my problems were. First there was a bolt missing from the intake manifold plate. Second, the gasket was bad, and third it was loosing it's lift pump. The lift pump will make it run hot. I've already replaced the gasket and that improved thing a lot. I have a pony pump that he recommended coming from Idaho. He did this all in about 5 minutes. The truck runs like a scualed cat,now and temps are down. It is still popping due to the lift pump that should be here Monday. If you have any issues with yours I'd recommend talking to him. He had a 12 valve and sure misses it.

 

[tgrfan2]

I love my 98 too, but beware of driving a new 07. 5 68rfe like I did yesterday. A friend just got his this week and it is something special. I hope I feel better when he reports the fuel mileage.

 

[Lonestar]

I was just checking in on this thread today, and Bart, I do believe that we have the exact same problem. I found a missing bolt in my intake, and I am going to go ahead and replace the gasket. I also have a feeling that I have a lift pump going south. I am glad that you are having good luck getting things resolved. I installed a 3KGSK today, and repaired some leaky seals on the motor. I do love the truck, and with the 3K kit, it allow me to use the power for longer. I did open a whole new can of worms though of course.



KEEP ON TRUCKIN'

Lonestar