Porsche Enthusiasts Club Forum

So working through all the faults on my 2.7 1989 944

I noticed the TPS was not clicking when it opened/closed. So removed it and of course it was full of oil from the throttle body. It also moved very roughly but oddly it did click but only when it was fully open!!

I keyed in the correct part numbers for my car and the TPS sensors all "Click" when the throttle is closed (then open as soon as you touch throttle, if you see what I mean). So I made the assumption that the wrong TPS may have been fitted etc

I now have a new TPS and have fitted it following Clark's Garage instructions. So when it closes against the stop, it clicks and as soon as you touch the throttle it clicks again as the thottle opens.

Now the car is reving too high (1600), I can't adjust the idle screw down anymore, and the is engine ocassionally revving up and down at idle!!

Yes, I think I messed it up. It's always the simple jobs!!!!

Any help appreciated!

R

Hello again

The correct TPS for your car should be an on and off switch in theory, as you say. It should click as soon as the throttle moves open, and click again when the throttle returns to fully closed. Shouldn't click any time else. You seem to have this now so this is odd.

It sounds like a previous owner could have bodged something for it to be "working" as it previously was. You are going to have to start checking wires if you are 100% happy you now have the correct, and working, TPS.

Stuart

Hi Stuart,

Thank you for your reply.

I had another go today, definately clicks when throttle closed and open. Also rechecked I hadn't pulled out any vacuum lines.

As before, she runs at 1400 and I cant get the revs down. Then when hot, the engine revs up & down at idle.

When I unplug the TPS connector, she calms down. So I suspect you were right, she has been set up to run somehow without the TPS sensor.

I also noticed the Rev Counter does not bounce when I turn over the car! (She does start on the button though!!).

I think I am in for a painful journey here.

Rachel

Hi Rachel

No tacho bounce normally indicates no signal from the crank sensor which = no start. So this again is strange! I normally see one bounce as it starts cranking.

I'm no electrical expert but it sounds like the TPS is wired back to front to operate with a goosed sensor. Worth tracing into the loom at the plug backwards to look for evidence of interference. Maybe you can reverse any modifications that may have taken place. I don't think the plug can be reversed (can it?) as it's one of those connectors with plastic slots and a metal clip?

Sorry can't help a lot more without seeing it. It does indeed seem a can of worms...........good luck!

Stuart

Thanks Stuart.

I purchased this TPS, as it comes up with the correct TPS replacement number.

https://www.onlinecarparts.co.uk/hella- ... term=link3

Could it be wrong? My car is listed

I haven't ever bought one, and I think the turbo one is different, so my car also fits their "list", which is wrong. So i'm not convinced by their list. For some reason I can't open the Porsche PET catalogue at the moment to check the proper Porsche part number for you, you need that, then cross reference with Bosch part numbers etc. to make sure you have the right thing.

You can call a Porsche centre tomorrow and they will give you the absolute correct Porsche part number to start from.

Stuart

Hi Stuart , had the same problem with Pet recently. Spoke to Ben at Porsche Portsmouth who said the system has been updated. Not sure how , but I can only access by searching for for Porsche V pages . Perhaps someone else has more information .
And I agree to be wary with part numbers comparability as you mention turbo tps is not available but some vendors show it is and compatible which it is not . Not sure on 2.7 .