Change Out of TPS
 

I need to change out the TPS on my Variorum 3.6 motor. Unfortunately, the Varioram manifold and other engine parts make access to the back of the motor (where the TPS is located) difficult and cumbersome.

What is the simplest and easiest way to change out the sensor? Lower the engine? Strip off components? Etc? Just looking for some hints to curb my cussing when I attempt to do the work.

Anyone have any suggestions?

Can you post a pic, assuming it is behind of the side of the TB, a partial drop of 4-6"s may be in order. Not sure if the 964 has a shift rod coupler but if it does have something similar. I recommend disconnecting it.

I have that most if not all manufacturers place the damn TPS in the most awkward location and some use straight edge screws, WTF??? an Allen Screw would be much better. Geez.

Are you sure it needs replacing and just not out of range? Do you have the adjustment and ohms specs?

No, not sure that the TPS needs to be replaced; but, it the only and last engine sensor remaining that I have not swapped out while chasing an idle issue. When you remove load on the engine, one expects the engine to drop to idle and stabilize out at the idle speed set by the ECU. Mine does that about half the time. But, on about half of the times when I remove load, the engine drops below normal idle, headed to a stall. Then the ISV appears to catch it, and the engine speed flares a bit and then attempts to return to idle, only to go through the surging cycle again. Eventually, without me adding fuel, the engine usually stalls out. Starts right up and idles perfectly...,.until the next load removal cycle.

The TPS on a 993, supposedly, feeds continuous info to the ECU. Since my TPS is original to the car (18 years old and 110K miles), I am wondering if the carbon track isn't failing right in the idle position, sending a signal that tells the ECU to shut down the fuel on decal.

My indy that was attempting to diagnose my stalling did a voltage test of the TPS and pronounced it as OK. But, I wonder if my situation isn't periodic?

So, I've decided to replace the TPS. Unfortunately, it is mounted on the rear of the engine on the throttle body. And, since my 1998 993 has a Varioram manifold, access to the rear of the engine is limited. So, I'm asking for the easiest way to replace the TPS. Right now, I plan on lowering the engine several inches, and removing the air filter housing and the MAF sensor. But, after doing that, I am not certain that I will be able to "see" the TPS to replace it or to adjust its position.

I just need the wisdom of those of you that have done this job before.

Images of Lumbergh asking me to file my TPS reports on time, yeah, that'd be great, yeaaahhh.../

Sorry, but I fail to see the humor in your reply.

Keep looking!

Ernie, you might try posting this on the 964/993 forum or maybe over on Rennlist. There have to be at least a few DIY types who have done this.