I've searched but cannot find the posts that described some cleaning methods for a TPS. Besides electrical contact cleaner, seems like I read someone used a pencil eraser and an oil or wax of some kind after cleaning. Can anyone clarify?

Thanks,

M

I just cleaned mine today with electrical contact cleaner from Radioshack. Seems to have done a good job, as the car isn't stumbling much anymore. There was a lot of junk on the traces that the cleaner took care of. You do have to recalibrate the TPS if you take it off - there is an article on Pelican describing how to do it with an ohmmeter.

Zach

Here's some help for aligning the TP switch. Mount it with the cover off.
Then refer to the pics. Hope that helps.
Click to view attachment
Click to view attachment

You didn't say what year your TPS is, but shouldn't matter too much.

I've renewed about 10 now, 8 of which were still usable after the process. And, my process is a little different than others.

Contact cleaner is good, but rubbing alcohol (which is what contact cleaner is primarily composed of) works well. But, you need a mild abrasive to clean out the groove. I've had really good luck with a Q-tip and Simichrome.

Alignment is simple - follow the aforementioned advice, and you should get a lot more service out of it.

If not, let me know. I'll send you a refurbished one for postage. Doesn't help - trash it. Works - you owe me a part some day. Oh. forgot, talking 1.7/1.8 TPS only.

I do have ONE new one, but that stays with me.
Pat

I'm glad you guys posted this. Just today I started to experience a little hesitation when I first open the throttle. Gonna try some beer uh I mean alchohol first.

Thanks for the offer Pat!

I ended up using DeOxit that I found at Radio Shack. Actually I have a spare that cleaned up pretty good if I'm not happy with how my original turns out. Unfortunately it may be a while before I can test drive. In the process of removing and reinstalling the TPS I have somehow tangled my clutch and throttle cable; I guess due to slack in the throttle cable when I took off the throttle body. Now when I depress the clutch, the throttle cable pulls and is opened full blast (topic in another post). Has this ever happened to you? I'm going to have to find time to pull out the carpet and foot board to get to the access for the tunnel by the pedal and hope I can readily see something snagged; ugh.

M

What engine is this pictured TPS from? The tracks in my switch are not like this ('73 1.7L). In my switch the center track does not widen at a dead spot like in the photo. There is a break in the gold track but it is very high and if I set the TPS there, the switch would be turned backward on the throttle body. Actually, when mine was alligned initially (with 20 audible clicks) the wipers appeared to be at the base of the gold tracks on the circuit board.

M

that's a 2.0 switch.

Got the switch all cleaned up, reinstalled and the car really accelerates more smoothly. Unfortunately the idle is low and hunting and adjusting the ECU knob or mixture screw on the TB has no effect; symptom of maladjusted TPS? I think it was correctly adjusted before I took it off and I tried to reinstall it in the same position but... Guess I better try the method on the Pelican site but I don't own an ohm meter. Is this an expensive unit to buy? What is a good brand and where is the best place to get one? Will it need aligator clips on the ends of the wires?

M

M, an OHM meter is cheap! Get one from radio shack, or sears, or wherever for $15. You really need to have one anyway, for lots of 914 troubleshooting (helps around the house too).

Your idling problem could be associated with your vacuum hoses - how old are they. They can look OK on the outside, but riddled with leaks. If they aren't sound, and the connections are stable, you have "hunting" problems with the idle.

The TPS is such as simple thing to adjust. You've probably done it correctly if it's running that well.

914 fuel injection is sooo simple! So long as you have minot adjustments made, and the vacuum lines working properly, you shouldn't need to touch the TB adjustment.

I think you have some vacuum hoses that need to go.
Pat

I cleaned the contacts in the car without removing the switch. I used rubbing alcohol. It took 15 minutes. I then test drove it. No Hesitation whatsover! Nice free and easy fix.

Pat,

Got a multimeter at Radioshack and the TPS is adjusted correctly. However, the idle adjustment knob on the ECU does nothing. I have been able to adjust my idle up to 900rpm using the airbleed screw (but still hunts a bit). Before I embarked on this TPS cleaning, the ECU knob had big effects on the idle, now nothing. I had a significant idle/hunting problem initially with this car but within the last 6 months all my vacuum hoses have been replaced and a rebuilt MPS installed. It was actually in decent idle and running condition except for occasional "bucking" around 3000rpms. Do the plugs for the TPS ever go bad?

M

If it is hunting you have a vacuum leak or your MPS is bad I believe.

This is the best site out there for D-jet troubleshooting and info:

Brad Ander's D-jet page

Hope this helps,

Jim

Update: idle problem solved but not permanently fixed. The wire going into #17 pin (idle) of the TPS plug has pulled out. To repair I will need to remove the connector from inside the plug and solder the wire back on. Sounds easy enough until you consider the location and size of the plug and I don't want to take out the whole ECU harness to work on it. Temporarily I have used a piece of large gauge wire I had to wedge into the opening of the plug and spliced it to the loose wire with a connector. The larger wire is in there tight enough to make contact so my ECU is back online and I can adjust idle again. Has anyone made wire repairs to this plug without removing the harness from the car and if so, can you offer any tips?

Regarding the hunting, I have indeed replaced all vacuum hoses and the MPS as stated earlier. When I first obtained the car it hunted severely and had to have the ECU knob adjusted full rich. I got it to the point where the hunting was minimal after the AAR warmed up and nonexistant with a solid 950rpm idle once the engine was good and warm. I've had no luck identifying the location of a vacuum leak with spraying carb cleaner in the usual areas but I suspect it may be in the plenum. I can hear a hissing sound down in there when the motor is running. Also, if I cover the opening of the aircleaner with my hand, the idle speeds up. After this TPS fiasco it looks like a took one step up and two back.

M