Engine/Transmission (1998.5 - 2002) transmission Shifting/Hunting Solutions

[DLausche]

Be Cautioned...

Mine needs some sort of fix too. I've been reading them all. Part of one of the solutions does not sit well with me and I believe it could be a source of another (potentially expensive!) problem. The ATS solution details taping the ground between the ECM and APPS and wiring this directly to the battery ground. This is a really bad idea that *could* fry your ECM under the wrong conditions. The scenario is what could happen *if* your battery to engine block ground cable is bad. Maybe the ground cable is dirty or corroded??? Maybe that could be part of the hunting problem??? If the large gauge battery ground is somehow not connected or there is a bad connection, then the path of least resistance for the battery negative to the engine *could* be the new ground wire you taped directly into the ECM. I do not know how much current the ground circuit on the ECM is designed to handle. I suspect it is significantly less than the starter or heater grid draws. Low likelihood of this happening? ... Yes, but it is possible. My thought is never wire any engine mounted electronics component directly to the battery negative. Doing so is asking for electronics things to be fried in the case you have a less than ideal battery ground cable or connection. Check out the same instructions from Suncoast. They say to wire the ground to the dash. They have good reason behind their instructions to wire it to the dash ground when it would be a lot simpler just to run it to the battery negative.

-Deon

 

[SMcGrady]

Good point... I think I might redo my ground...

 

[JoeCanuck]

All you would have to do is use a chassis ground instead of the battery ground.

 

[DLausche]

All you would have to do is use a chassis ground instead of the battery ground.

Well - not really. I believe the only factory ground path between the engine block and the chassis (frame or body) is via the big negative battery ground cable(s). If you ground the ECM to the body sheetmetal (fender or whatever) and the main ground connection at the engine block were to be less than ideal, then the new ground you've provided could still be the path of least resistance and could conceivably result in significant current draw through the ECM, possibly frying it.



The way I determine where to ground an electronic component is to consider what other devices it is or will be interconnected to and then ground the new electronic device to the same ground as what it is interconnected with. For example, an electronic device interconnected to the ECM is best to be grounded to the engine block. Something interconnected to the PCM would be best grounded to the fender or firewall (I think the PCM has a ground connection there). A good example of an aftermarket add-in electronic device is the Edge Comp. It is mounted in the cab so we don't normally think of it as an engine mounted electronic component. Well, it is connected almost exclusively to the engine mounted ECM and other engine mounted sensor(s) (MAP, etc). Note that the manufacturers design of the Comp wiring harness is such that it is made to be grounded to the engine block. I am quite sure that Edge designed the Comp wiring harness specifically like this for a reason - to eliminate the possibility of alternate ground paths to the engine block. I am only using the Comp wiring harness to illustrate the point of proper grounding location. When adding wiring such as a ground wire, the same considerations should be made for proper ground location so as not to provide even the possibility of alternate negative potential paths to the engine block.



I'll add that under all normal conditions what I am saying here really does not matter all that much. The only time the ground location is of great significance is under a condition where the battery to engine block ground cable is less than ideal.



-Deon

 

[Floyd4runner]

thanks for this thread and prople like all ya'll.

 

[magaliasram]

This is the link I used to fix my hunting problem. The noise filter here is cheap and worked for me 100%. A friend of mine and I both put this filter on and both trucks have been running perfectly since. Good solid upshifts at very predictable RPMs it is amazing. Pretty extensive article at this site. Dodge Ram Cummins 24V Truck Converter Clutch Cycling Repair.

 

[texascowboy572]

Mine needs some sort of fix too. I've been reading them all. Part of one of the solutions does not sit well with me and I believe it could be a source of another (potentially expensive!) problem. The ATS solution details taping the ground between the ECM and APPS and wiring this directly to the battery ground. This is a really bad idea that *could* fry your ECM under the wrong conditions. The scenario is what could happen *if* your battery to engine block ground cable is bad. Maybe the ground cable is dirty or corroded??? Maybe that could be part of the hunting problem??? If the large gauge battery ground is somehow not connected or there is a bad connection, then the path of least resistance for the battery negative to the engine *could* be the new ground wire you taped directly into the ECM. I do not know how much current the ground circuit on the ECM is designed to handle. I suspect it is significantly less than the starter or heater grid draws. Low likelihood of this happening? ... Yes, but it is possible. My thought is never wire any engine mounted electronics component directly to the battery negative. Doing so is asking for electronics things to be fried in the case you have a less than ideal battery ground cable or connection. Check out the same instructions from Suncoast. They say to wire the ground to the dash. They have good reason behind their instructions to wire it to the dash ground when it would be a lot simpler just to run it to the battery negative.



-Deon

I'm fixing to tackle this hunting / TCC lock / unlock issue on a friends truck and I agree completely with the potential ground issue here, for added protection wouldn't a 2. 5A minifuse take care of the above issue on the new ground ckt without affecting the function of the new ground to the APPS / PCM?

 

[Floyd4runner]

try this

I ordered that $12 filter from Novain. While I was waiting on it to arive in the next day or so I cought myself under the hood charging the AC. I was shaking the can and noticed the wires laying on top of my altenator the wires had to have been rubbed at least half way through could not believe they had not arced across it and blew apart. Well any way got my black tape out and went to town. My truck has never hunted again before you had to push the overdrive button and have your foot in it just to get up to speed. Can some one else try this to see if sam$e results or it was just a coincidence for me.

 

[Moe]

I got the fix from the TDR. Simply unhook both batterys and wait. Reconnect both batts. Problem solved. Seems the computer learns this hunting problem over time and all I had to do was erase its learning curve by disconnect. Now the author of this fix I cant remember, but he said the computer might relearn the hunt problem. I can always disc and reconnect for nothing.

 

[DLausche]

I'm fixing to tackle this hunting / TCC lock / unlock issue on a friends truck and I agree completely with the potential ground issue here, for added protection wouldn't a 2. 5A minifuse take care of the above issue on the new ground ckt without affecting the function of the new ground to the APPS / PCM?

Yea, I think the fuse idea is better than doing it to the battery straight. The fuse would likely blow before the ECM in case it was the least resistance path. I think the best bet is to just ground the APPS/ECM directly to the engine block with a known good connection.



I haven't decided what to do with mine yet but it needs something. The ATS lockup controller I have kinda counters the urgency to get this fixed. I do have a 2-3 hunting issue once in a while which I believe is the same issue so some warm day this spring it will get fixed one way or another.

 

[DLausche]

Another thought I'll throw out here... Does anyone think it would help to remove the large positive wire from the engine harness and wire the alternator output directly to the passenger side battery? I think it is a 140 amp fuse in the fuse box and maybe a high end audiophile type inline fuse could be used between the alternator output and the battery in place of the fuse box fuse. My thought for rerouting this wire is that *if* the alternator is creating a lot of noise in it's output, then maybe the proximity of this high-current wire to the delicate APPS and ECM circuitry is somehow inducing noise in the circuits where it can cause problems. Wiring it to the passenger side battery would isolate the noisy alternator output both physically and somewhat electrically from the rest of the electrical system. The batteries would then be connected between the alternator output and the electrical system and the batteries act in a way like large capacitors to smooth out electrical pulses and spikes, etc.



Looking for others thoughts if this might have any effect - or maybe it has already been tried before?

 

[3grumpy]

where is the ground under the dash? Why can't you use the battery grd or the grd strap under the hood by the firewall. I know there is a reason. I'm too old to crawl under the dash. Any ideas, Thanks Chuck