Engine/Transmission (1998.5 - 2002) TST evidence

[Ncostello]

Well, my story gets longer. Still trying to solve that poor idle quality I'm having. I was luckey enough to have a member PM me about some evidence I found while putting dielectric grease on all of my connections. I was told the truck was always stock and it sure looked it. However...



I noticed two wires red/green and black/tan had been tampered with. The red/green up by the firewall and the black/tan down on the VP harness. It appears after reading the TST instructions, it at one time had a TST module hooked up to it. The red/green still had the scotchlock on it. I also noticed that the steel pipe coming off the intercooler up to the air horn had a brass fitting on it which looked like to me a place to measure boost pressure, but no hose or wire on it. Maybe thats normal but the wires obviously are not.



Now, if a person had installed a TST unit, and then removed it, could they have not done something right to cause my fueling problems? Or could the TST have caused the VP-44 to self-destruct slowly and cause poor idle (timing). I dont think the overall engine has been hurt from this, but something is amiss. I also know that the lift pump was bad when I bought it. I replaced that and the CKP sensor right off the bat bacause of a "check engine" light was on. It was cleared by Dodge after the CKP was fixed (scan said CKP was bad which is how I knew).



The black/tan wire had about half the copper strands cut on it but still had contact. Could this be the ground and maybe it just needs soldered to make better connection. Where else should I check for problems if any were caused by wiring or ???



Sad thing is, I found a Dodge dealer with good Cummins techs who were going to help me under warranty Monday with my problem. Now, when they see that, I'm going to have egg on my face and be left on my own, plus miss a days work just to have that happen.



I suppose I'd better get ready to pay for whatever is wrong myself. I'm getting smarter by the minute. Ya know, 03's dont look too bad right now.

 

[Steve St.Laurent]

If they hooked up a TST fueling box to that wire I would think it could possibly cause a problem - because that's not where it should be hooked up!! AFAIK all the major fueling boxes hook to the pump wire that isn't a part of the harness. There's two wires about an inch and a half in length that come out of the VP44 and right back into it - that's where they hook up (there's no connectors on those wires - you can't remove or replace them).

Here's a good article written by Blue chip on why VP44's fail and specifically discusses fueling boxes and their effect on the VP44 - http://www.bluechipdiesel.com/Bosch-VP44.htm .

 

[catoiler]

Great link Steve! being new to the 24 v it was good reading.

 

[jwilliams3]

Nice article Steve,

Everyone should read that.



--Justin

 

[Ncostello]

The instructions for the TST box are found at http://www.tstproducts.com/PMInstr3.htm .



Step 10 describes hooking the "ground" from the TST Harness to this black/tan wire. The other connection at the pump hooks to one of the other two independent wires on the pump that controls the fuel selonoid (wire closest to the cyl head). I did not check this wire yet for signs of tampering cause I was not looking to put any dielectric grease on them. But I will check them today. I dont have the truck with me now.



The red/green wire up on the firewall is where TST gets its fused key on 12V power from. This wire also goes to the VP-44 I think, cause the VP-44 plug in harness did have one wire the same color. Maybe this is also where the VP-44 gets its 12V power from. I dont know.



I do know that the black/tan wire had maybe more than half of the copper strands inside the insulation cut from the scotchlock connector. I held this wire tightly and wrapped blacktape around it for the time being until I can do a permanent fix. It did seem to idle OK intermittently now but not all the time. Maybe this ground had been compromised to the point of causing my trouble.



The red/green wire looked unharmed and intact when I removed the scotchlock that was still on it, but still should have a permanent repair I think.



I really need to check the two wires on the VP-44 that control the fuel selonoid, the MAP sensor connection (maybe replace the whole sensor or check it), and look at the turbo housing to see what the deal is there on the boost control elbow. I dont know it the TST is still on there or not. Maybe the stock elbow will help if I need one on there.



I believe two things. This truck had a TST module on it at one time. The person who took it off maybe didn't return it to stock and this may be causing me my problem (wiring cuts, boost elbow, MAP sensor)



The only hopeful thing I see from the article Steve is that they say if the VP dont fail after installing this module, its probably good for a long time. Which may mean my VP is still good, but needs some attention to the wiring and other things.



I also found two small holes drilled under the ashtray about 1. 5" apart from eachother. Looks like this may have been a mount place for the module to keep a close eye on the yellow and green lights on it.



I'll do a through check on all this stuff this weekend and try to hide all my work with new loom, good solder jobs and high quality shrink tubing. Maybe I wont need a dealer after all but theres no way I'm gonna hold my breath.

 

[Steve St.Laurent]

Sorry, your right. That's a change, their older harnesses had a round terminal on the end of the ground wire and you simply put it under a bolt to ground it to the engine. I'll have to call Mark to ask why they changed that. I prefer not to use scotch locks as much as possible. If they used that new harness then they also probably used the grabber that they sell to connect it to the fuel solenoid wire - you'll have to look pretty closely for that.

 

[Steve St.Laurent]

Just got off the phone with TST and they changed that because they had a problem with 2001+ trucks having the ground go to chassis ground causing an intermittent miss and also having problems with the road relay product not counting mileage. By moving that ground to the harness which is a computer ground they fixed the problem. It wasn't a problem on the earlier trucks like mine.

 

[Steve St.Laurent]

Also, you can tell easily if the map sensor part of the harness is still there. It's about a 4" long bundle of wires with a female plug on one end and a male plug on the other end. It goes inline between the factory harness and the map sensor. So if your factory harness is going straight into the map sensor your fine there. The boost elbow from TST will have a black set screw in it which allows you to adjust the elbow. You can go to a hardware store and get a 90 degree elbow and a barb (completely open) and replace the elbow and that will take it back to stock. I'd say it's possible that the compromised ground could be your problem. I had a bit of an intermittent miss because of about half the wires being cut at the scotch lock connection to the pump solenoid wire on my truck. I soldered the connection there and the problem went away completely. Good luck, hopefully you've found the source of the problem.



BTW, TST said that they switch to that new harness about 6 months ago, so he didn't have the box on there for very long.

 

[Ncostello]

My lunchtime findings...

The stock boost elbow is on there, but with a non-stock clamp. The other end still has the OEM clamp. OK here.



The MAP is hooked up as original. OK there. Unless maybe the MAP sensor is bad, but that may be a seperate issue altogether but certainly worth looking into I suppose.



I looked at the two black wires intergral with the VP and fueling selonoid. No real damage it looks like but the protective sheath has been pulled back and there is evidence that some kind of connection had made an impression in the insulation coating on the one closest to the cyl head. Must have been a Grabber connection??? What are they???



I forgot to check for a cut in the grommet through the firewall where the harness passes. But I'd bet its there.



Whoever removed this knew what they were doing. This was no rookie. (I kinda feel like a detective now looking for evidence). hehe. I do remember the previous owner telling me his dad had a truck almost identical to the one I bought. Bet his dad is running a TST module right now. I think calling him back would be useless. Maybe he thought modifications were bigger pistons or some permanent mods. Funny thing is though, he didn't touch the exhaust, or at least there are no marks from wrenches on any of the bolts. I figured he would have at least tried to free up some power there.



Steve St. Laurent, would TST have told users of the old ground design to switch their ground to this newly created wire position if they were having problems? Just thinking if it was on there long time ago, maybe he switched it.



I'm long winded today, sorry. Um... I guess I'll just do my best to fix what I can on the wiring. Then see how it does. If it works great! If it dont... well, I sure am learning alot and fast. Then I can let Dodge diagnose it and hope they don't start asking me questions. Cause then I start forgetting things all of a sudden.

I'll post my results soon. I think I'm gonna call TST. I've got a few questions of my own.



Wait!!! Maybe if I hook one back up my troubles will be over!!??

 

[TowPro]

Did you buy this truck used from a dealer? I would point out this "wire crunch" to them and say "you sold me a truck that had been modified" Stick it back in there face for a change. If they say "how do we know you did not do this?" tell them "Well you could read TDR and see all the questions I been asking to figure out what these wire marks were from"



It would not be the first time they read TDR. One guy I recall got denied warrantee coverage for a head gasket based on what the Dodge boys read right here. Since then I have read about lots of head gaskets going bad!



You know the dealer looks for this stuff as soon as you pull into the shop (if its warrantee), they even give the techs "lessons" on how to look for mods that have been removed. My local Stealer guy said "its easy to tell, look for the velcro on the fuse cover (VA), finger prints on the pump connector (again VA), aftermarket clamps on the waist gate hose, finger prints on MAP sensor, wire marks on pump, Etc" He also said "When a truck comes in with gauges, it gives me even more reason to look for signs of mods that have been removed".

 

[Ncostello]

I didn't buy it from a dealer... it was an individual. I understand what your saying Tow Pro but I have no leg to stand on for that fight. The Dodge Boys who took Cummins Inspector 101 are going to have a party under my hood. Its all there, fingerprints, elbow hose clamps, 3M Scotchlock scars. [Hey Diamler-Chrysler. . if you read this search "lift pump" and read the 17 pages of threads like I did and fix your trucks. Treat your Cummins owners like you do the Viper owners. ]



I was "ignorent" during the purchase. If I do it again, I can assure you I will know what to look for better. I must say I have learned so much, I "feel" like an expert. My knowledge is growing like compounding interest. All because of TDR.



Anyway, Mark with TST is super nice, informative, and very interested in his work. He helped me through some of this even though the TST is long gone from this truck. He also provided me with some unrelated insight about 24V trucks that I found very interesting. I would not hesitate to buy his products and follow his advise. Lots of Cummins knowledge there folks.



A little more on my 99. About 9 inches down from the turbo on the downpipe, someone welded a threaded fitting to it. I'm thinking EGT sensor was there. I threaded a plug in it. It was left open. Dumb place for an EGT sensor? Also there is a brass compression fitting threaded into the intercooler pipe coming up to the intake. Again left unplugged and open to the atmosphere. Gotta get this plugged up. Looks like I didn't get the gauges either. I dont think these were the best choices for sensor locations.



Tomorrow I have to take out the MAP sensor and check its condition. Possible culprit here. I'm also gonna fix my wiring. I'll still take it to Dodge and roll the dice. If I'm denied so be it. I'll cross that bridge when I get there. Thats all I can do for now.

 

[Bigsaint]

I may be wrong, but I would think that you would be throwing codes if the MAP sensor was the culprit. Mine was acting up about one year ago, throwing a low voltage code. I originally fixed it (atleast I though I fixed it) with some dielectric grease. When it started to throw codes again after maybe 6 more months, I just replaced the MAP sensor and all is now well.



If you have no luck with DC, the first thing that I would do is take care of that broken ground wire on the pump. Cut both ends clean and solder in a splice of the same gauge wire. Easier said than done, I know there's not alot of room to work by the pump but it's amazing what you can reach when you have to . The green wire with the black stripe is only a 12V source for the TST box, as far as I know. I tapped into the same when I put my TST on. Without looking in the service manual, I have no idea what that wire provides 12V to, but I don't believe it's to the VP44 as there is a relay in the PDC for the injection pump and that wire is running across the hood gasket ??? I'd hazard a guess that, if the lack of a solid 12V source was occuring to your VP44, you would have issues under throttle as well as at idle.



Scott W.

 

[Ncostello]

Bigsaint, when I looked the VP also has the same color wire going into it. Maybe not the same wire, but it is the same color. Actually when I unbolt and move the throttle assy over, the harness unplugs and nicely lifts up near the top of the engine. I couldn't imagine trying to solder it still plugged in. I pretty good but I still hate to solder.



Also, I know the truck acts up at idle. If I turn on the air cond, the load instantly clears up the idle problem. Now, I'm not sure it isn't acting up at say highway crusing. I just cant tell it then. It seems smooth, but I dont have anything to judge it against.



Schied ran what I think was the isolation test on all cylinders and concluded at least three were not getting 100% fueling. This test was conducted at various rpms via computer I believe. They never said my problem was at idle only. So maybe it was at all rpms, so I possibly cant tell by sound and feel at increased rpm. I just notice it at idle. Thanks for all the help.



PS. An expert told me that if the PO ran an oiled air filter (totally possible in this truck) the oil can coat the MAP and junk it up. Thats what I'm gonna be lookin for. But no codes shown for that.

 

[Bigsaint]

Well Neil, I will sure be interested to hear what the root of the problem turned out to be and I'm sorry that you are going through it right now. I know how much it $ucks when the truck isn't running right. My MAP plug didn't have any oily residue on the pressure head, but it sure was covered with soot ( ebrake used for quick warm ups). I kept it and will someday clean it up and put it back in, for a test.



My truck is just the opposite regarding the a/c. Whenever I turn it on, I get a short burst of uneven idle from the step 5 injectors. It does clear right away though.



Scott W.