Concerning the wife's 1991.5 4-speed automatic which is her daily driver and has always been driven like a car, with very little towing and not real towing at that.

Everything stock/original so far as we know; we are the second owner and have had it about eight years or so.

Neglect, I know; but, the pan has not been off since we have owned it; the PO had recently changed fluid and made adjustments just prior to our purchasing.


What she explains to me it has been doing the last week or so :

Maybe twice a day, always at speed just between 45-50mph, just cruising along, with no warning that she can detect, the engine will rev-up for a couple seconds, as if it had momentarily went into Neutral.

As soon as she lets off the accelerator, it takes ahold and continues as if nothing were wrong.

Thus far, it has not done this while accelerating, nor at any other speed.

It may go an entire day without doing this and then do it twice or three times the next day.

Fluid level shows just a bit over full and no fluid has ever been added during our ownership.

Considering the evidence given, what seems to be the problem ??


Thanks.

 

You need to check the throttle position sensor. There is a link in the sticky's on how to test and adjust the TPS. The PDR link is bad. The other link works.

Diesel bombers has a better TPS adjustment page.

 

Like he said, TPS. It's worn right at the spot it rides most of the time, and when the wiper loses contact, the computer thinks it's at full throttle. Either off or on the throttle puts it back into the circuit. 2 seconds later, the computer shifts the OD back in.

Stock TPS is bunchabucks. You can put in a manual potentiometer. For light driving, I just replace the tps with 2 resistors. Shifts right at about 40 or so all the time.

I'm working on an adapter plate to mount a gasser TPS ($30) on the original plate. Others have made a replacement mounting plate to put the gasser TPS in. Been waiting for the weather to warm up enough so I can do it without frostbitten fingers.

 

Thanks a bunch for the info and pictures.

I did a quick read about the TPS and, as best I gather, it controls when OD kicks in or out, correct ??

If that be the case, until I get time and parts to correct this, would simply turning OFF the OD switch temporarily cure the problem ??


Thanks.

 

http://www.dnrcustoms.com/zen2/index...products_id=97 go here and order the delete kit work's Like a Charm and real easy to install .takes all of about 20 min's

 

Yes, it'll hold it out of OD. It resets every time you shut down. Not fun or economical to run at road speed with OD locked out.

If the random shift only happens once in awhile, it won't hurt anything.

Cheapest quick fix is the resistors. Fixed shift. This beast has so much torque it don't matter unless yer hooked up to my 12,000 lb. double trailer setup.

Next cheapest is the manual pot. Adjustable to needs.

Third would be rigging a Mopar 5276012 TPS found on a lot of 3.9 and 5.2 liter gas engines from 88 to 90. Third party replacement price is around $30. I'm working on a quickie adapter for that. Others have made a complete adapter plate for it. It's better made, more reliable, and lots cheaper than the stock one. (3rd party, $220 - 240 at Rock Auto) OEM part is made of unobtainium.

4th, easiest and most expensive, get the above OEM TPS install, and adjust it.

hope it helps.

 

I find that these resistors are made in various wattage ratings, such as 1/4W, 1/2W, etc.

Which should I get ??

Thanks.

 

1/4 Watt is plenty big....... Virtually no current thru them.

 

Total heat dissipation of both resistors is about 0.007 watts. Any resistors of the correct value, 1/8, 1/4, 1/2 watt would work just fine.

 

Thanks.

I found 1/4-watt 25 in a bag for $1.49 plus $2.69 S&H; a bag of each should be enough to allow for a few mistakes.

 

Try cleaning it first. Unplug it, unbolt it, and spray some electrical contact cleaner up inside of the housing. It has always worked for me, and it's cheap, quick, and easy. Might at least buy you a little time and keep the wife happy.

 

I've gotten one or two 6 month refreshes out of them with a product called DeOxit. Rat Shack has it, expensive micro cans. Professional size usually available at a guitar center. (They use it on the sound system plugs)

I use the stuff on all the other quirky connectors in the beast.

 

or ham radio outlets

 

Just to be certain, the resistor assembly plugs into the TPS cord in exactly the same orientation as the two pictures, right ??

Thanks.

 

I put together the resistor assembly and got it installed a few days ago.

So far, it seems to have cured the situation.

I found a source for the little crimp-on brass pins, male D-Sub connectors or somesuch; I bought a bag of 100 to get 3; they are a near perfect fit for the TPS plug-connector.

Of course, I soldered everything together.

Many thanks to everyone for their time and information.