Erratic 944S2 Hesitation Problem Solved!
03-14-2005, 06:54 AM
#1
Rennlist Member
Thread Starter
Erratic 944S2 Hesitation Problem Solved!
For some reason I still can't edit thread titles, so I'm posting a new one on this worthy topic.
For several months, my 944S2 had an erratic hesitation problem that was very annoying. See this thread.
The car would very randomly choke or hesitate under WOT and after a series of new parts, including a recent ignition control module and airflow meter, new plugs, O2 sensor, etc. the problem persisted and I was considering some more basic items like distributor cap, rotor, coil, etc.
However, the fact that the RPMs would not drop at all when the symptoms occured had me thinking that it couldn't be an electrical problem. So I was inclined to try ignition related parts, like the FPR. However, when fellow 'lister fpena944 was having similar issues and posted a thread about it, he replaced the FPR on his S2 but the problem didn't go away either, so I was stumped.
When my S2 first started hesitating several months ago, my first thought was a faulty TPS (throttle position switch), however, the switch would "click" normally and thinking that this was sufficient sign that it was working correctly, I didn't replace it.
I recently asked in another thread whether in fact that "clicking" sound was enough indication of a properly working TPS. Someone correctly pointed out that it could be tested with a voltmeter, and I probably should have done that, but since I already had the new TPS I decided to just replace it anyway.
The main reason I hadn't done so sooner was because I wasn't comfortable removing the throttle body to access the old TPS mounting screws. A few detailed pics posted by Riff (see this thread) quickly made the task less scary (this car is my father's daily driver) and armed with some basic tools including a wonderful 5mm Hazet allen head bit, I got the throttle body out and put in the new TPS, making sure that it clicked with the throttle cable.
After buttoning everything back up, I started the car and drove it like I normally do (lots of WOT
) and I'm really glad to report that the problem is GONE! The car no longer hesitates or chokes under any condition. It just pulls like it's supposed to and the acceleration is clean and uninterrupted.
If your S2 is hesitating, the TPS is definitely worth a try. Follow the numbers in Riff's pics (see thread above) to get the throttle body out, and you're done!
For several months, my 944S2 had an erratic hesitation problem that was very annoying. See this thread.
The car would very randomly choke or hesitate under WOT and after a series of new parts, including a recent ignition control module and airflow meter, new plugs, O2 sensor, etc. the problem persisted and I was considering some more basic items like distributor cap, rotor, coil, etc.
However, the fact that the RPMs would not drop at all when the symptoms occured had me thinking that it couldn't be an electrical problem. So I was inclined to try ignition related parts, like the FPR. However, when fellow 'lister fpena944 was having similar issues and posted a thread about it, he replaced the FPR on his S2 but the problem didn't go away either, so I was stumped.
When my S2 first started hesitating several months ago, my first thought was a faulty TPS (throttle position switch), however, the switch would "click" normally and thinking that this was sufficient sign that it was working correctly, I didn't replace it.
I recently asked in another thread whether in fact that "clicking" sound was enough indication of a properly working TPS. Someone correctly pointed out that it could be tested with a voltmeter, and I probably should have done that, but since I already had the new TPS I decided to just replace it anyway.
The main reason I hadn't done so sooner was because I wasn't comfortable removing the throttle body to access the old TPS mounting screws. A few detailed pics posted by Riff (see this thread) quickly made the task less scary (this car is my father's daily driver) and armed with some basic tools including a wonderful 5mm Hazet allen head bit, I got the throttle body out and put in the new TPS, making sure that it clicked with the throttle cable.
After buttoning everything back up, I started the car and drove it like I normally do (lots of WOT
) and I'm really glad to report that the problem is GONE! The car no longer hesitates or chokes under any condition. It just pulls like it's supposed to and the acceleration is clean and uninterrupted.If your S2 is hesitating, the TPS is definitely worth a try. Follow the numbers in Riff's pics (see thread above) to get the throttle body out, and you're done!
03-14-2005, 09:09 AM
#3
Rennlist Member
Thread Starter
Thanks, Mark. You know, that problem hounded me forever!
My father kept complaining about it and I was reluctant to just randomly replace parts without a proper diagnosis of the problem.
I think the important conclusion to draw from this experience is that a failing TPS can still make a "clicking" sound even though it's on its way out.
I learned this the hard way, but am posting about it here so that others get the "signal through the noise" quicker than I did!
My father kept complaining about it and I was reluctant to just randomly replace parts without a proper diagnosis of the problem.
I think the important conclusion to draw from this experience is that a failing TPS can still make a "clicking" sound even though it's on its way out.
I learned this the hard way, but am posting about it here so that others get the "signal through the noise" quicker than I did!
05-17-2005, 10:34 PM
#7
Three Wheelin'
It's my understanding that the TPS is only used in a WOT state? Correct? I just replaced my AFM (with a used part) hoping to get some performance back - but I still am experiencing some flat response and an intermittant hesitation at WOT around 5-6k rpm.
Could this by TPS? I have not yet done some maintenance stuff - like wires,cap and rotors - but plugs are reltaively fresh.
TIA.
RK
Could this by TPS? I have not yet done some maintenance stuff - like wires,cap and rotors - but plugs are reltaively fresh.
TIA.
RK
