Engine/Transmission (1998.5 - 2002) Stumbling engine with box finally solved

[Steve St.Laurent]

My truck's been driving me nuts for the last six months. I've been having to leave my box off it's been so bad. It would cut in and out - BAD. It acted just like a bad connection at the pump wire. All my connections were soldered and I tried everything I could think of. I talked with Mark @ TST quite a bit trying to solve the problem. I resoldered all my connections, tried a new powermax harness, moved the ground from up by the intake horn to the black/tan ground wire in the injection pump harness, new MAP sensor (boost was going up/down 4 psi at steady throttle with the box off). The truck would drive perfect with the box off but as soon as the box was turned on it was awful. Finally Mark said that he had run into 1 truck where they changed everything fuel system related over about 2 weeks and another shop told them it might be the alternator and that fixed his truck. Today I disconnected my alternator and wala the truck was fixed! So I changed out the alternator and everythings fine now. No other indication of an alternator problem at all. It was easy to troubleshoot by disconnecting the large connection at the back of the alternator and driving the truck on the batteries alone (disconnect the batteries before you mess with that cable). I finally have my truck back!! Oo. I highly doubted it was going to fix it even as I was disconnecting the cables - boy was I happy that it did.

 

[SLightfoot]

Right on Steve!!!

That is fantastic news Steve. I can truly empathize with your situation and the elating feeling it would be to finally nail it down for sure.



I've got a similar gremlin that I'm trying to solve (P1689 code) that is intermittant enough to drive a guy insane. Same deal - not sure if it's the box or not, or if the box is just stressing some component enough to put it into fail mode... who knows...



Well, now you can drive with confidence and happiness!



Shawn

 

[isb360]

Any postmortem diagnosese on why the alternator may have been causing problems with the TST box. That would have been one of my last places to start looking?

 

[wtfd6]

do you think the alt was leaking a/c voltage. i have seen that on some cars causing erattic performance problems. glad to hear you figured it out.


mark

 

[Partyat33]

Great to hear Steve. Those electrical problems can be very hard to find.

 

[SnoKing]

Word of caution, most alterators do not like to run without the battery connected, and will burn up their diodes without the battery load. You should disconnect the field wire. SNOKING

 

[Steve St.Laurent]

Any postmortem diagnosese on why the alternator may have been causing problems with the TST box. That would have been one of my last places to start looking?

It was my last place - after 6 months!! No port mortem yet, I just fixed it yesterday. My guess is a flaky diode allowing AC into the system and that the factory ECM has it's own diodes protecting it which is why it didn't affect performance with the box off.

 

[2-ND TIME]

stumbling engine

Glad to hear that it was fixed. I checked the diodes they were within 0. 048 vdc and the capacitor at 15 Micro farads and meggered the alt at 1000 vdc and it was fine the electrical techs were watching over my shoulder and prompting me so sure that things were good. With the new vp it really runs like ^%$#@@((*&^%$*(^ !!!! even bucks going down a 10 % hill. go figure.

 

[David_VT]

Good job Steve!



Hmmm, I've never been able to use a CB in my CTD due to noise like sparkplug interference. Do you think I was going to walk into my Dodge dealer and tell them that with the old oil burner parked behind me... not...



Guess I'll have to try the alternator disconnect idea. . who knows, maybe. ???



By the way, did you ever go back to any kind of ladder bars? I never put mine back on after the front edge snapped on one. I loved the traction while I had them but the idea of catching that bar while driving kind of took the fun out of it for me... . I still have them somewhere in the barn...

 

[Steve St.Laurent]

I'm still running my ladder bars - about 140k on them now. I do need to replace the end links because they are loose and noisy. I do run safety straps on the front of them so that they couldn't drop down like that.