TPS testing question?, Car is bucking under load |
|
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG.
This site is not affiliated with Porsche in any way. Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners. |
|
TPS testing question?, Car is bucking under load |
Jon H. |
May 25 2016, 10:26 AM
Post
#1
|
Member Group: Members Posts: 237 Joined: 1-July 11 From: Ottawa, Canada Member No.: 13,264 Region Association: Canada |
Hello, I had my 73 2.0l out for its maiden voyage this year and the car was running great. On the way home I stopped at a light and when I took off the car was bucking horribly. I investigated and found the bolt under the plenum that grounds the wires for the TPS and, I think, the injectors had come out. I re-installed it checked the grounds, checked continuity between the ecu and the TPS and all is good. I checked the continuity of the TPS as the throttle is opened and closed and it appears that there are about three position that are open circuit. They are small gaps though, barely having to move the throttle to get continuity again. It this normal? Should there be 'flat' spots as I move the throttle or should there be 100% continuity all the time? I did remove the TPS and have a look and it looks fine. Could an arcing ground have caused the TPS to fail?
Thanks in advance! Jon h. |
BeatNavy |
May 25 2016, 11:12 AM
Post
#2
|
Certified Professional Scapegoat Group: Members Posts: 2,924 Joined: 26-February 14 From: Easton, MD Member No.: 17,042 Region Association: MidAtlantic Region |
Ok, so 17 is the idle pin and you should get continuity to ground only when the throttle is closed. 12 and 21/22 are the trigger points. I need to find that testing procedure. I'm not sure I've seen it here.
If you don't hear the clicks and you otherwise think the TPS isn't damaged, then I guess I would still suspect a FI wiring harness ground issue (you said you reconnected the grounds - did you check continuity, say from that common ground point back to the negative terminal of battery?), a bad harness connection to the ECU, one or more injector connectors not seated properly.... what else? |
Jon H. |
May 25 2016, 11:17 AM
Post
#3
|
Member Group: Members Posts: 237 Joined: 1-July 11 From: Ottawa, Canada Member No.: 13,264 Region Association: Canada |
Ok, so 17 is the idle pin and you should get continuity to ground only when the throttle is closed. 12 and 21/22 are the trigger points. I need to find that testing procedure. I'm not sure I've seen it here. If you don't hear the clicks and you otherwise think the TPS isn't damaged, then I guess I would still suspect a FI wiring harness ground issue (you said you reconnected the grounds - did you check continuity, say from that common ground point back to the negative terminal of battery?), a bad harness connection to the ECU, one or more injector connectors not seated properly.... what else? I checked the injectors and all were seated , I'll double check and grounds. I guess I should try and find out why I don't hear the clicks, that I do know isn't happening. I was focusing on the TPS because the grounding issue and I thought it was a simple fix. .......Sigh. |
Lo-Fi Version | Time is now: 2nd June 2024 - 04:47 PM |
All rights reserved 914World.com © since 2002 |
914World.com is the fastest growing online 914 community! We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ... |