TPS Question

[JHylton]

Sometimes on partial grades or under load, the OD kicks in and out. . especially if the throttle is held at a steady spot. If I throttle up, it will shift back into OD. This is an intermittent problem, the dealer last year told me the TPS was acting up and that it cost over 300$ to fix it. Is this something that can be easily repaired/replaced by a reasonably competent shade tree mechanic (me) or is that best left to a pro. Is there an adjustment for this? The Chilton repair manual I have doesn't mention anything about the TPS.

 

[Tippin Spotted Cow]

First try pulling the harness out of the TPS and spraying some electronic cleaner in there. I like the CRC quick dry stuff. Spray it out real good. On a warm day you could make a puddle of that stuff and it'll evaporate in 10 seconds, so don't worry about using too much.



After that, there's an adjustment on the nut underneath the TPS. Check Piers old website for how to adjust that. It's pretty straight forward. Also, make sure you have some preload on the tps when you install it... it should have about 1/8 turn of preload when installed.



If neither of those work, you might me SOL. I believe the part itself was about $300 last time I checked with my dealer. Install is a piece of cake though. Maybe you can find aftermarket or boneyard replacement.



I've heard there is a fix for it that involves installing a noise filter in the signal wire... someone else may have more on that.

 

[JLandry]

... the dealer last year told me the TPS was acting up and that it cost over 300$ to fix it.

Assuming you're talking about a TPS for the 1997-98 model year, the Mopar part number is 4874412 and the cost is "only" $171. 60 from Mopar Parts America online. You can easily replace it yourself.



Regards,



John L.

 

[JLEONARD]

Assuming you're talking about a TPS for the 1997-98 model year,

Very very bad assumption John L. since you are in the first gen section.

 

[JHylton]

Nah... this is a late year model '91... I call it a '91 and 3/4, built in June 91, one of the very last ones of the 91 production run.

 

[cerberusiam]

TPS or speed sensor, either can cause that. Clean both of them with the contact cleaner then check your TPS voltages at rest and across the range of operation. You could have a worn spot in the wiper arm in the TPS.



The last TPS I bought was $125 from Cummins but that was 2 years ago. Not sure what they cost but a dealer will always be higher, waaaayyyyy higher.

 

[JLandry]

Assuming you're talking about a TPS for the 1997-98 model year,

Very very bad assumption John L. since you are in the first gen section.

You're right... my bad.



John L.

 

[JLandry]

I don't have a 93 or earlier Dodge parts catalog to get the actual part number, but in searching an online Mopar parts web site, it looks like a new TPS for an 88-91 would only cost about $50.



John L.

 

[PToombs]

Another option is to replace the TPS with a potentiometer. There are several posts here on doing that. Then you can set it where you want, and it shifts the same everytime. If you want to shift sooner, turn it down, later, turn it up.

 

[JHylton]

Off Topic just a bit, but if you are as old as I am, CRC used to be THE major sponsor for the spring Darlington NASCAR Winston Cup Race... The CRC500. I know this, because I attended several of those events back in the 1970s... .

 

[Tippin Spotted Cow]

I don't have a 93 or earlier Dodge parts catalog to get the actual part number, but in searching an online Mopar parts web site, it looks like a new TPS for an 88-91 would only cost about $50.



John L.

That's gotta be a gasser... the earlier 1st gen diesels tps would be pretty cheap, considering they didnt have o/d... thus no tps... unless it was something to do with cruise control? Someone help me out here.



also 1st gen diesels started in 89, so right there kills the 88-91 thing.

 

[JLandry]

That's gotta be a gasser...

I think you're right. I found this on the Parts.com web site:



THROTTLE POSITION SENSOR, All Models, 5. 9L Diesel, 92-93, List: $373. 00, Your price: $256. 45



For our 2nd gen trucks, we found a $120 Williams throttle sensor kit is a direct replacement for the original, except for needing to replace the connectors supplied on the Williams TPS (a piece of cake). That's what I'm running now... a Williams TPS.



Maybe there's a simple solution like this for the 1st gen trucks?



Can you send me pictures and measurements of the TPS you have now? I'll research it against what Williams sells and see if there's a match.



John L.

 

[JHylton]

John L.

Where does one find this TPS? The Chilton's manual is next to useless in finding this, and were it is located. I did find it in a schematic in the chassis wiring section... but no mention of it anywhere else.

john H.

 

[monkeyman]

I have Timbo's conversion, do a search to find it. Much cheaper and beats the stock one hands down.
Rick

 

[JLandry]

John L.

Where does one find this TPS? The Chilton's manual is next to useless in finding this, and were it is located. I did find it in a schematic in the chassis wiring section... but no mention of it anywhere else.

john H.

John H. ,



I'm probably the last guy to ask because I don't have an early truck (I'm playing in the wrong sandbox), but if my memory serves me correctly, I've seen it on the top of the fuel injection pump just above the end of the throttle linkage.



I searched the web and found the attached pictures which may help.



Also, see this web page:



Recall #605 Diesel Fuel Injection Pump



John L.

 

[BHerring]

What is the easiet way to check for idle and WOT voltage? I really dont want to splice into TPS wires, but will if I must. .



Thanks in Advance and Cheers

 

[JLandry]

What is the easiet way to check for idle and WOT voltage? I really dont want to splice into TPS wires, but will if I must. .



Thanks in Advance and Cheers

"Back probing" the connector at the TPS is likely the easiest way. To back probe a connector, basically you try to stick a multimeter probe, or something like a paper clip (straightened) along the wire where it goes into the connector cavity. The idea is to make contact with the metal inside the connector. If using a paper clip, you would then clip your multimeter lead onto that. Here's an example of back probing:



#ad




If back probing isn't possible (due to the design of the connector), then you can pierce the wires with sharpened multimeter probes.



John L.

 

[cerberusiam]

Back probing is the easiest, but, it has it dangers also. The TPS plug, at least on mine, is pretty well sealed so every time you stick a probe or pin in there you open the avenue for corrosion and moisture where it is hard to clean.



I had enough problems I just cut the middle TPS wire and put spade connectors on it liberally coated with dielectric grease and good tape to seal it. Its another maintenance point but easy to get to and remember.

 

[robbiesworld]

I don't have a 93 or earlier Dodge parts catalog to get the actual part number, but in searching an online Mopar parts web site, it looks like a new TPS for an 88-91 would only cost about $50.



John L.

VERY BAD ASSUMPTION... . LOL I had to do that:-laf