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kens96

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Job is finished. Removed the top strut mount to get at the TPS. Not a lot of coolant leaks from the bolt with the hole. Placed a shop towel under it on the tranny case and everything stayed dry. Disconnected the batttery and replaced the TPS. Put everything back together. Total time about 1 hr. Performed the re learn procedure (3 diagnostics cycles- bring engine to temp at idle. Put it in Drive to Park with and without AC) Drove the car at 70MPH and above for about a 1/2 hour with and without cruise control. NO MORE SHIFT PROBLEMS! In fact the car shifts smoother between all gears at all speeds and the occasional "fishbite" is gone. I wouldn't have believed that a TPS could cause so much trouble and not throw a code. We'll give it a few more days to make certain the problem is fixed, but for right now, I'm pleased with the results.

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That is fantastic Ken, I would never have thought that was possible! This is a great thread for the board's collective knowledge. I would get back to your tranny guy and tell him about your discovery. Your tranny was dropping out of OD and you knew it. If he was not an honest guy, he might have taken a less knowledgeable person for a ride.

I am impressed. I am also surprised that the TPS issue did not set a code. Look at the codes a TPS can set in ODB 2:

P0120 - TP System Performance

P0121 - TP Sensor Circuit Insufficient Activity

P0122 - Throttle Position (TP) Sensor Circuit Low Voltage

P0123 - Throttle Position (TP) Sensor Circuit High Voltage

P0124 - Throttle Position Sensor 1 Circuit Intermittent

Well congratulations your persistence paid off

I would love to know what Logan thinks of this

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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This has been a very interesting thread.

I have been following it, but not commenting, because I did not have anything constructive to add.

Very strange that the TPS could do that, but with the way the cars are integrated now a days... I reckon just about anything is possible. :D

Glad to see it is probably resolved.

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Comparing the old TPS to the new one, the center part that connects to the shaft on the TB was loose and wiggled a bit where the new one is tight. I think it might not have thrown a code because it was technically working , not going all high or all low, not intermittent, just varying voltage slightly moving around. Just a guess.

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Since this is possible, I am going to request that Bruce put this one in the HOW TO, under Driveability/Fishbite/Dropping OD or something like it. This is an excellent thread and we should not loose it. I would have thought that this would have set a TPS performance (do to a shifting range) or an intermittant (due to spikes or drop offs in readings).

Ken if you have a digital or even analog ohm meter, connect its leads to the TPS, I think there are two connectors or you will need to find the two connectors for the variable rheostat portion and sweep the TPS and see if the reading is smooth. I think both types of ohm meters would produce interesting results but an ANALOG meter might visually show anomolies.

This might be a job for JimD, he is great at performing autopsies on failed equipment and reporting back his findings, you might want to send this TPS to him for further analysis. I would

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Electrical is not my forte, but I gave it a shot.

I did put a meter on it and turning the pot low to high with a pencil and the meter set at 2K I get readings around .655 to 1.458. Looks linear as I turn it but it bounces around looking at 3 significant digits on the meter. Noticed if i wiggle it i can get it to read 1. Just let it sit and there is +/-.004 more or less drifting around.

If Jim D will PM me his address, I would be happy to ship him the part for his feedback.

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Electrical is not my forte, but I gave it a shot.

I did put a meter on it and turning the pot low to high with a pencil and the meter set at 2K I get readings around .655 to 1.458. Looks linear as I turn it but it bounces around looking at 3 significant digits on the meter. Noticed if i wiggle it i can get it to read 1. Just let it sit and there is +/-.004 more or less drifting around.

If Jim D will PM me his address, I would be happy to ship him the part for his feedback.

Interesting, I alerted Jim to this thread, he will stop by at some point, I think you confirmed the problem now why didnt it set a code?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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This is a good one indeed. Great catch!

I had a similar situation back in the 1980's with an Oldsmobile engine that had a TPS potentiometer buried inside the carburetor. The transmission was getting bad information.

But I did not make the leap from that 1980 technology to the Northstar state of the art technology so I couldn't be of any help with a diagnosis.

PM sent.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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I found this in my tranny book, pretty interesting

TPSDescription.jpg

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Declared victory too soon.... trouble came back worse than before. It's at the dealer now. Still no codes. Its cold again today so it could be temperature related. We will see

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4th Servo....

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Is the servo a major or minor repair? Dealer says it's an internal issue not electronic. No codes. Wants to drop the pan to look further. If its solenoids we are looking at $480 -$500 at the dealer. I'm inclined to have the tranny place go get it and have them make it right.

Thoughts?

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Is the servo a major or minor repair? Dealer says it's an internal issue not electronic. No codes. Wants to drop the pan to look further. If its solenoids we are looking at $480 -$500 at the dealer. I'm inclined to have the tranny place go get it and have them make it right.

Thoughts?

Shift solenoids in the bottom pan won't cause that.

The TCC solenoid is in the side pan, if they drop/tilt the carriage and do the TCC solenoid for $500 that would be pretty good.

The servo is VERY easy on the lift, its external, Ill post some info

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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This could be a slipping/worn 4th band too but the first place to look would be the servo piston seal (532), I think that is what Kevin replaced. See the salmon colored note "No Servo Apply".

FourthServoDescription.jpg

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Having it flat bedded to the tranny place. Its in their court.

Cool let us know Ken

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Job is finished. Removed the top strut mount to get at the TPS. Not a lot of coolant leaks from the bolt with the hole. Placed a shop towel under it on the tranny case and everything stayed dry. Disconnected the batttery and replaced the TPS. Put everything back together. Total time about 1 hr. Performed the re learn procedure (3 diagnostics cycles- bring engine to temp at idle. Put it in Drive to Park with and without AC) Drove the car at 70MPH and above for about a 1/2 hour with and without cruise control. NO MORE SHIFT PROBLEMS! In fact the car shifts smoother between all gears at all speeds and the occasional "fishbite" is gone. I wouldn't have believed that a TPS could cause so much trouble and not throw a code. We'll give it a few more days to make certain the problem is fixed, but for right now, I'm pleased with the results.

Your 'old' TPS arrived today. Since you have installed a new piece, would it make any difference to anything if the old one was not useable when I am finished?

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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I made an executive decision and opened it up to satisfy my curiosity.

The TPS sensor you sent to me should work just fine. So now you have a spare.

I will add -- due to the design and construction of the sensor, it must be mounted securely in place in order for the proper voltage to be reported to the PCM.

For the electronically inclined readers, the resistance varies from 580 Ohms at closed throttle to 1,625 Ohms at wide open throttle. Construction is two ribbons of resistive film and the rotating arm is a shorting bar between the two ribbons.

Jim

Drive your car.

Use your cell phone.

CHOOSE ONE !

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Thanks Jim,

No need to send it back. Appreciate the autopsy. The car is with the tranny shop. Hope to hear something tomorrow. Dealer says its not electric but something with the pump going to high pressure just before it drops 4th and OD.

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My case was a damaged seal (that I caused) and that 4th gear was slow to engage at first. After 20 miles, I lost 4th gear altogether. It will be interesting to see what the transmission shop's diagnosis is.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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They want to pull the tranny. Metal in the pan. Car is 14 years old with 157K. This is the second repuild in 42K. Is it worth it? Opinion?

This could have been your fishbite all along. I think you are going to find that the 4th band is shot. If it needs a full rebuild what will they charge you? $2200? We can't see the condition of your car, but it is a 96 at this point. The question is do you want to spend for a good 03/04 at this point putting that $2200 to work. Its up to your finances I suppose Ken

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I would be tempted to put it back together...see if they can adjust it to operate for a short time, while I look for a newer/lower mileage car.

I would rather take the $2000 / $2500 that it will cost to fix that that one, and apply it towards the purchase of a newer one.

I would either sell that one..(with full disclosure to the buyer, of course) or trade it in.

Prices on newer ones are pretty cheap right now.

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Quick question but did you ever get any back firing or stack firing into the intake while it was having problems..? PART or your problem sound familliar but mine never "shifts" back and forth just the tps part. the more gas i give it the more it bogs down... also only up hill with trying to maintain a constant speed.

Cop didn't see it, I didn't do it!

93 STS 225,000 Miles

99 STS 111,000 Miles

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Only time I had the symptoms you describe were with the bad tank of fuel ealy in this post. The OD and 4th gear dropping out the RPM and engine remained strong without any back or stack firing.

The update is the tranny is out and I should have the details on what the damage will be. Will keep you posted.

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