Stumbling 1974 2.0...It's finally fixed. Post 63., Thanks to everyone who weighed in, embarrassing reason posted below... |
|
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. |
|
Stumbling 1974 2.0...It's finally fixed. Post 63., Thanks to everyone who weighed in, embarrassing reason posted below... |
rhodyguy |
Aug 26 2019, 02:34 PM
Post
#21
|
Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,042 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
Is your tps calibrated with an ohm meter?
|
orthobiz |
Aug 26 2019, 02:36 PM
Post
#22
|
Senior Member Group: Members Posts: 1,754 Joined: 8-January 07 From: Cadillac, Michigan Member No.: 7,438 Region Association: Upper MidWest |
The car had horrible vapor lock and it was eliminated with a new fuel pump last year, so the change was a while ago. Never stumbled before.
As far as what was done right before: I installed LED lights from Spoke and for a few minutes had the ignition turned on while I was testing it. Maybe I fried my points? But I looked in the distributor and it doesn't look like points, there are two newish wires coming out from a thing where the points used to be (years ago when I did my own tuneups). I am somewhat lost so I apologize for the murky descriptions. Paul QUOTE I've read here that low pressure can be the culprit, but would doubt it in my case. Why? Unless you’ve verified the correct pressure, it’s a possibility. Did the car ever not exhibit the stumbling behavior? If yes, when did it start, and what was done to the car right before? Did it begin after the fuel pump was moved? Have you checked for a kinked fuel line? |
orthobiz |
Aug 26 2019, 02:39 PM
Post
#23
|
Senior Member Group: Members Posts: 1,754 Joined: 8-January 07 From: Cadillac, Michigan Member No.: 7,438 Region Association: Upper MidWest |
I did not check it. However, with the ignition on, when I move the accelerator cable, I hear what must be the 20 clicks, all regularly spaced. Maybe the TPS went out of calibration? Could that be why the car stumbles with or without it?
Hmmm....maybe just install the new TPS, I already have it. Paul Is your tips calibrated with an ohm meter? |
rjames |
Aug 26 2019, 05:36 PM
Post
#24
|
I'm made of metal Group: Members Posts: 3,876 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
I did not check it. However, with the ignition on, when I move the accelerator cable, I hear what must be the 20 clicks, all regularly spaced. Maybe the TPS went out of calibration? Could that be why the car stumbles with or without it? Hmmm....maybe just install the new TPS, I already have it. Paul Is your tips calibrated with an ohm meter? New or old, TPS’s require calibration. Calibrate the on you gave and see if that changes anything, although I doubt it will. Sounds like you don’t have points anymore, depending on what they were replaced with, it may be possible to fry them if you leave the ignition on. That said, if they were fried, I would expect the car wouldn’t even start. Someone else can chime in on that. So... you’ve been offered several suggestions, why not actually try some of them and report back? |
orthobiz |
Aug 26 2019, 06:26 PM
Post
#25
|
Senior Member Group: Members Posts: 1,754 Joined: 8-January 07 From: Cadillac, Michigan Member No.: 7,438 Region Association: Upper MidWest |
Update: spoke with my mechanic, the car has Pertronix ignition, hence the lack of points. My daytime job is interfering with car matters but I will look into this more carefully this week, appreciate all the input.
But I still wonder, if the car runs poorly with the TPS connected AND disconnected, does that eliminate the TPS as a potential cause? Paul |
orthobiz |
Aug 26 2019, 07:06 PM
Post
#26
|
Senior Member Group: Members Posts: 1,754 Joined: 8-January 07 From: Cadillac, Michigan Member No.: 7,438 Region Association: Upper MidWest |
In reading about the Pertronix, which is what I have, they caution against leaving the ignition on without running the car and this is EXACTLY what I did when I installed my LED rear lights.
So, I'm gonna get a replacement AND if it fixes it, so be it. And if it doesn't, I'll have a spare! Will report back... Paul Thanks to everyone who chimed in including Mark 914rubber who thought "electrical" and rjames who asked what I did just before this behavior began. |
Sm914650 |
Aug 26 2019, 07:12 PM
Post
#27
|
Member Group: Members Posts: 84 Joined: 15-October 18 From: Sf Bay Area Member No.: 22,573 Region Association: Northern California |
Im also having a bucking issue with a 73 1.7.
Seems to happen the most around 2-3k rpm as well, but it happens lower/higher as well. Seems to happen more often when car is warm, and when driving on rough roads. Drove it from SF to Santa Cruz a week ago and a 3-4 times during ride down hwy1, would start bucking, and then stall out while driving. Pull over 15min while flooded. If anyone can pinpoint from that im all ears otherwise ill take the advice already listed. |
rjames |
Aug 26 2019, 07:52 PM
Post
#28
|
I'm made of metal Group: Members Posts: 3,876 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
Im also having a bucking issue with a 73 1.7. Seems to happen the most around 2-3k rpm as well, but it happens lower/higher as well. Seems to happen more often when car is warm, and when driving on rough roads. Drove it from SF to Santa Cruz a week ago and a 3-4 times during ride down hwy1, would start bucking, and then stall out while driving. Pull over 15min while flooded. If anyone can pinpoint from that im all ears otherwise ill take the advice already listed. Start a new thread of your own and add more details. (Ex: FI or carbs? When did the issue start happening, etc.) and people will help. |
orthobiz |
Sep 7 2019, 12:59 PM
Post
#29
|
Senior Member Group: Members Posts: 1,754 Joined: 8-January 07 From: Cadillac, Michigan Member No.: 7,438 Region Association: Upper MidWest |
rjames had me thinking...the last thing I did was mess with my wonderful LED taillights, turning the ignition, working the blinker, running back to look.
Turns out I burnt up the Pertronix, put a new one in and...problem solved! Of course, I first had to order the wrong unit, send it back, get the right one, yaddayaddayadda. Also, Mark 914rubber sent me a PM saying it sounded electrical, that helped as did everyone else who posted. So, if I want to check the taillights, I will leave the car running or disconnect the ignition at the coil. And I'll probably put a spare Pertronix in my travel tool bag, along with some crimp on wire connectors. Thanks again, everybody, love this site! Paul |
JeffBowlsby |
Sep 7 2019, 03:03 PM
Post
#30
|
914 Wiring Harnesses Group: Members Posts: 8,439 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
So one has to wonder if the Pertronix is truly an 'upgrade' with all of this fiasco. Same goes for the LED lights.
(IMG:style_emoticons/default/idea.gif) |
FlacaProductions |
Sep 7 2019, 03:44 PM
Post
#31
|
Senior Member Group: Members Posts: 1,523 Joined: 24-November 17 From: LA Member No.: 21,628 Region Association: Southern California |
LEDs are most certainly an upgrade. I don't think that's even a debate.
Petronix? Dunno....I don't run it so I can't comment. |
ndfrigi |
Sep 7 2019, 03:55 PM
Post
#32
|
Advanced Member Group: Members Posts: 2,925 Joined: 21-August 11 From: Orange County Member No.: 13,474 Region Association: Southern California |
here is what I posted also on other thread:
here is my experienced with pertronix, bought my 1st 914 75 1.8 FI last 2011. The car last registration was 2003 and been sitting for 8 years as non-op. So 2011 since I bought it, did nothing with the dizzy except just look at the inside and it is clean, so I didn’t bother changing anything except replace spark plugs and wire for the ignition system and fix all fuel lines and installed SS tunnel lines and other needs to be restored since it was a non-op for 8 years. I was able to drive the car for more than 4 years until the pertronix failed. Installed old contacts points just to test and it did run again. And since I also have a used pertronix from my stash of dizzy, grab that pertronix and installed it and it run well again even not knowing the condition of that pertronix. Sold the car last 2017 with same pertronix. So meaning, as long you have the right or proper installation, pertronix should be better than contact point. link below is the other thread regarding pertronix. http://www.914world.com/bbs2/index.php?sho...52909&st=20 |
Tbrown4x4 |
Sep 7 2019, 04:41 PM
Post
#33
|
Senior Member Group: Members Posts: 699 Joined: 13-May 14 From: Port Orchard, WA Member No.: 17,338 Region Association: None |
I hope this is contributing to the thread and not a hijack.
I was aware of everyone's concerns about leaving the ignition on and damaging the pertronix. I installed a 2 pin weatherpack connector in the distributor wiring. Now I can disconnect the pertronix module from the car any time I need to keep the ignition on for an extended period of time. Also handy for swapping distributors on the side of the road if necessary. |
orthobiz |
Sep 7 2019, 05:36 PM
Post
#34
|
Senior Member Group: Members Posts: 1,754 Joined: 8-January 07 From: Cadillac, Michigan Member No.: 7,438 Region Association: Upper MidWest |
So one has to wonder if the Pertronix is truly an 'upgrade' with all of this fiasco. Same goes for the LED lights. (IMG:style_emoticons/default/idea.gif) For visibility the taillights are terrific. And from what I understand it's possible to burn out the standard points with the ignition on as well. The Pertronix is easy to adjust, especially for someone like me with limited mechanical abilities! Paul |
rhodyguy |
Sep 7 2019, 06:05 PM
Post
#35
|
Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,042 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
Check the lights with the engine running. (IMG:style_emoticons/default/smile.gif)
|
orthobiz |
Sep 8 2019, 12:59 PM
Post
#36
|
Senior Member Group: Members Posts: 1,754 Joined: 8-January 07 From: Cadillac, Michigan Member No.: 7,438 Region Association: Upper MidWest |
Thanks for being patient with me everybody. I replaced the Pertronix yesterday and all was fine...until today. Stumbling is as bad as it ever was. I'm fixated on disconnecting the TPS to see if it cures the problem but alas, disconnecting the TPS makes it worse. It is hesitating, maybe a bit better with hard acceleration, but irregular especially under 3000 RPM. Not improved by warming up the engine.
I did NOT leave the ignition on so I should not have fried my Pertronix BUT maybe I should go back to points/condenser?? Paul |
porschetub |
Sep 8 2019, 02:26 PM
Post
#37
|
Advanced Member Group: Members Posts: 4,695 Joined: 25-July 15 From: New Zealand Member No.: 18,995 Region Association: None |
Did you replace with Ignitor 1 ?,I've never burnt one out but many say the Ignitor 2 has no issue with leaving the ignition on.
You are running the correct coil with your Pertronix right ?,I only use their matching (impedance) coils just to be sure. |
orthobiz |
Sep 8 2019, 02:31 PM
Post
#38
|
Senior Member Group: Members Posts: 1,754 Joined: 8-January 07 From: Cadillac, Michigan Member No.: 7,438 Region Association: Upper MidWest |
Ignitor 2 BUT I am using a Bosch Blue Coil. I've read that people have run blue coils without issue.
And it seemed to run OK yesterday and now is up to the old shenanigans, so I'm not certain if the coil should be the source. It definitely seems electrical. There is a test of resistance in the installation manual for the Pertronix that I did not follow. Maybe I need to revisit my installation. Ugh! Paul Did you replace with Ignitor 1 ?,I've never burnt one out but many say the Ignitor 2 has no issue with leaving the ignition on. You are running the correct coil with your Pertronix right ?,I only use their matching (impedance) coils just to be sure. |
porschetub |
Sep 9 2019, 01:40 PM
Post
#39
|
Advanced Member Group: Members Posts: 4,695 Joined: 25-July 15 From: New Zealand Member No.: 18,995 Region Association: None |
Ignitor 2 BUT I am using a Bosch Blue Coil. I've read that people have run blue coils without issue. And it seemed to run OK yesterday and now is up to the old shenanigans, so I'm not certain if the coil should be the source. It definitely seems electrical. There is a test of resistance in the installation manual for the Pertronix that I did not follow. Maybe I need to revisit my installation. Ugh! Paul Did you replace with Ignitor 1 ?,I've never burnt one out but many say the Ignitor 2 has no issue with leaving the ignition on. You are running the correct coil with your Pertronix right ?,I only use their matching (impedance) coils just to be sure. I've run Bosch blue coils with Ignitor I on two engines,zero issues ,I don't remember the resistance of them but I know there is a difference with Ignitor 2. Just dug out my instruction sheet for Ignitor 2,noted the following; minimum voltage 8V, coil 0.45 ohms or greater, "Warning DO NOT USE WITH SOLID CORE SPARK PLUG WIRES". I'am sure you read all that but probably worth doing the voltage test ,oh and the coil I have is Pertronix 0.6ohm which I didn't use as I'am running a matching transformer coil with my Permatune. Good luck. |
orthobiz |
Sep 11 2019, 01:53 PM
Post
#40
|
Senior Member Group: Members Posts: 1,754 Joined: 8-January 07 From: Cadillac, Michigan Member No.: 7,438 Region Association: Upper MidWest |
Thanks but I think I'm just not having any luck with this gremlin and may seek additional hands on help!
Paul Ignitor 2 BUT I am using a Bosch Blue Coil. I've read that people have run blue coils without issue. And it seemed to run OK yesterday and now is up to the old shenanigans, so I'm not certain if the coil should be the source. It definitely seems electrical. There is a test of resistance in the installation manual for the Pertronix that I did not follow. Maybe I need to revisit my installation. Ugh! Paul Did you replace with Ignitor 1 ?,I've never burnt one out but many say the Ignitor 2 has no issue with leaving the ignition on. You are running the correct coil with your Pertronix right ?,I only use their matching (impedance) coils just to be sure. I've run Bosch blue coils with Ignitor I on two engines,zero issues ,I don't remember the resistance of them but I know there is a difference with Ignitor 2. Just dug out my instruction sheet for Ignitor 2,noted the following; minimum voltage 8V, coil 0.45 ohms or greater, "Warning DO NOT USE WITH SOLID CORE SPARK PLUG WIRES". I'am sure you read all that but probably worth doing the voltage test ,oh and the coil I have is Pertronix 0.6ohm which I didn't use as I'am running a matching transformer coil with my Permatune. Good luck. |
Lo-Fi Version | Time is now: 29th March 2024 - 07:59 AM |
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 ... |