Engine/Transmission (1994 - 1998) TPS update

[shendren]

well, the truck started acting up again. lock/unlock... ... pulled the wires out even further. stopped acting up. then it started again. talked to bill kondolay. bought the noise filter. none of my earlier attempts worked even with capacitors. haven't installed the filter yet. bill suggested before i do, that i take the ground wire at the tps and cut it and wire it directly to the fender wall. i did. not acting up anymore. still have the noise filter. good luck to all with this problem.



btw, i used illflem's method to check the tps voltages and it was easier to just stick a couple of wire strands up into the connector... ... .....



scott

 

[Dave Remillard]

Thanks for passing this information along Scott. I realize this is not a big problem for several Ram owners, but for those of us that have dealt with this appreciate any new ideas. Thanks again.

SS

 

[shendren]

i can't believe that more haven't had this problem... ... . this truck and dodge continually amaze me.....



wonder why my wife's hondas have never had any of these problems?

 

[shendren]

i don't have my service manual with me. i'm out of town. does anyone know if the wires to the tps (power, ground, signal) go anywhere else? i. e. are they dedicated to the tps from the pcm? i will try bill kondolay's noise filter today... ... ... .

 

[BigPapa]

My truck had this problem. I had a new TPS installed @60K ago and haven't had any problems since, knock on wood.

 

[Dave Remillard]

Scott... I believe they are. When DTT did my transmission they tagged onto the signal wire at the PCM for adjusting the TPS as one of the final adjustments before sending me on my way. I'll check when I get home tonight and if no one else has confirmed this, will post what I find.

 

[shendren]

thanks. i will install bill's noise filter tonight.....

 

[Dave Remillard]

Scott... According to the PCM schematic, the only wire the TPS shares with any other componet is the ground. The 5 Volt and the feedback go directly to the PCM. The ground is shared with the following.

water in fuel sensor

intake air temp. sensor

engine speed sensor

vehicle speed sensor

transmission temp. sensor (auto only)

Hope this helps

Just in case you need this info also, the ground at the TPS and PCM is BK/LB, the TPS feedback signal is OR/DB, and the 5V output is VT/WT

Dave

 

[shendren]

dave, thanks for the information. i just wired in kondolay's noise filter. no help... ... .



this problem is maddening !!!!!





i guess i will run a new signal wire outside of the harness tomorrow. anyone have any suggestions?



thanks. scott.

 

[Dave Remillard]

I know this has ben haunting you for what seems like forever, but the only thing I can think to suggest if you haven't done so yet is follow the preliminary steps Kondolay suggested on his write up about the noise filter. You may be frustrated enough about the filter not working, but at this point I can't help believe its some small little oversight like a bad or loose connection. I'm not a specialist on DC stuff, but when I do have to deal with it on my job I need to take on a completely different mind set than with AC electrical. Usually its 24 or 48 V stuff at work, but the slightist things will make life miserable. . Example, I once had a DC power supply that was putting out at a 3% loss. First I didn't think 3% would possibly be the problem, but after changing the power supply and regaining the 3%, problem solved. Good Luck on chasing this down.

 

[Howard Durand]

Scott, Is there a diagram somewhere showing how Bill's filter is connected into the TPS scheme and the components it uses?



By the way, did you cut the ground wire at the TPS or did you just tie a jumper wire between it and ground? If you cut the wire and grounded it, that would change the grounding path which could introduce other problems. I think that leaving the wire intact and grounding both ends would be better.



If I was having as much trouble with mine as you have I think I would find some three conductor shielded cable and completely by-pass the existing wiring harness.

 

[shendren]

thanks, guys... ... .



i cut the ground wire at the tps per kondolay's instructions. tonight i will run a separate signal wire... .....

 

[shendren]

well, tonight i hooked up a dvm in the cab onto the signal and ground wire of the tps at the pcm.



the voltage was jumping about . 1-. 3vdc when the tc was unlocking.....



tomorrow i will run a separate signal wire outside of the harness.....

 

[Dave Remillard]

Scott. . If you find that running that wire seperate works well, I like Howards idea of using a 3 conductor shielded cable. We prefer not to do this, but in certain cases have run 24 v signal in a shielded cable in conduit carrying 480 volt circuits and have gotten away with it.

 

[shendren]

where do you find a 3 conductor shielded cable 18awg?

 

[Howard Durand]

I don't think Radio Shack will be of much help but you might try an automotive sound system installer.

 

[Dave Remillard]

If you have any electrical supply warehouses or electronic supply stores in your area, they should carry it. If you run into a snag, e-mail me with an address and I will send you some for the price of postage. I also believe stores like Home Depot carry it. You could also try online at Radio Shack as they could possibly carry it. Let me know if you need some sent your way. Dave

 

[shendren]

i found 3 conductor shielded. i will hook it up today... ... . thanks for the help. i will post the results (good - i hope)... ... ...



scott.

 

[Howard Durand]

From browsing the different threads on this forum, it seems that the TPS problems occurs frequently but not everyone has them.

Mine has not been much trouble. It did drop out of OD a few times when it was new but that went away.

Some of the time it can be cured by removing the wires from the wiring harness. Scott's troubles seem to be more severe.



On a recent thread posted on this forum, there was a problem involving the alternator. After the alternator was replaced the author noted that his radio was no longer noisy.

I am wondering if we aren't devoting too much attention to the affected circuit instead of trying to identify the source.

Usually a DC circuit is pretty stable and electrically quiet unless unfiltered switching occurs and causes voltage spikes which can be induced into any cable that runs parallel with it.

I don't have an oscilloscope and am probably not smart enough to use one if I did but I'll bet something could be learned by connecting one at various places just to see what is going on.

 

[shendren]

well i replace the signal and power wire out to the tps. ran a separate ground from the tps to the chassis.



then, got in the truck and had no tach, cruise, or anything but 3rd gear.



i called bill kondolay. he thinks i cut the wrong purple/violet wire when replacing the power wire.



so, now that i see that there are 2 (my carelessness), where can i go to see for sure which one is which? what pin does the tps power go into?



thanks.



scott.