Electric Gremlins, Engine runs fine, until I turn on lights |
|
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. |
|
Electric Gremlins, Engine runs fine, until I turn on lights |
Carlitos Way |
Oct 25 2004, 10:55 AM
Post
#1
|
I did it MY WAY Group: Members Posts: 1,337 Joined: 14-September 04 From: Simi Valley, CA Member No.: 2,757 Region Association: Southern California |
I've got a strange problem that I'm trying to trace. When I start the engine, it runs fine. However, if I try to start it with the headlights on (which I know is not a good idea, but it happened once while testing electrical stuff) then the engine won't start. Then, if I turn on the blinkers the car ends up surging and missing with the "beat" of the blinkers.
Any thoughts/suggestions? I HATE electrical problems!!!! (IMG:style_emoticons/default/ar15.gif) |
dlo914 |
Oct 25 2004, 02:31 PM
Post
#2
|
Whatchu' lookin' at?!?! Group: Members Posts: 3,432 Joined: 6-September 04 From: San Gabriel, CA Member No.: 2,697 |
(IMG:style_emoticons/default/agree.gif) electrical problems get the (IMG:style_emoticons/default/finger.gif) BIRDIE!!!
|
sanman |
Oct 25 2004, 02:57 PM
Post
#3
|
Leaving California Group: Members Posts: 341 Joined: 17-June 04 From: Houston, TX Member No.: 2,219 Region Association: None |
alternator, battery or voltage reg. check the charging system. that is where I would Start
|
mudfoot76 |
Oct 25 2004, 03:10 PM
Post
#4
|
Currently teenerless :-( Group: Members Posts: 946 Joined: 18-March 04 From: Carmel, IN Member No.: 1,814 Region Association: None |
My car had similar problems. For these problems, a new alternator was the solution. But it wasn't the only problem <_<
|
F4i |
Oct 25 2004, 03:13 PM
Post
#5
|
914 DOG! Group: Benefactors Posts: 482 Joined: 22-December 03 From: AB Canada Member No.: 1,460 |
I have a thought on this. I have not tried it yet. I set the fuel px. with the car at idle with no lights on 14v. I have noticed that at idle with lights on the voltage is lower 12v. It goes back up to 14 with some revs. My guess is that the fuel px. is ok at 14v but goes lower when down to 12v. If one sets the fuel px with the lights on it may help. Just theory at this point though. good luck
|
lapuwali |
Oct 25 2004, 03:34 PM
Post
#6
|
Not another one! Group: Benefactors Posts: 4,526 Joined: 1-March 04 From: San Mateo, CA Member No.: 1,743 |
If the system voltage drops to 12v with the lights on at any engine speed above a "too low" idle (like 500rpm), then the alternator or (more likely) the regulator are suspect. It may just be the ground connections (as in the alternator isn't well bolted to the engine). The function of the regulator is to keep system voltage at 13-14v all the time, regardless of alternator output. It's also possible it's just the connections between the alternator and the regulator. Clean all of the connections, and if the problem doesn't go away, replace the regulator.
What's a "fuel px", btw? 99% of electrical problems are just problems with bad connections, and 99% of those are bad ground connections, which are typically not protected with rubber shields or insulation like +12 connections usually are. As a result, these connections corrode (often invisibly), and stop working, or only work intermittently. The other 99% of electrical problems are caused by previous owners bodging things together. The last 99% are charging system problems (battery/alternator/regulator). |
F4i |
Oct 27 2004, 09:16 PM
Post
#7
|
914 DOG! Group: Benefactors Posts: 482 Joined: 22-December 03 From: AB Canada Member No.: 1,460 |
Sorry, my shorthand, fuel px = fuel pressure
|
bperry |
Oct 27 2004, 10:24 PM
Post
#8
|
Lurker Group: Members Posts: 477 Joined: 16-February 04 From: Dallas, Tx Member No.: 1,661 |
Years ago, I had a funky problem kind of like this. I think mine
was much worse. In my case the car went into horible idle and bucking as soon as the headlights were turned on. After a few on/off cycles of turning the lights on/off and seeing the problem come and go, I got smoke coming from under the dash. Nothing like an electrical fire to get your heart going..... The next morning after I traced everything down, the problem was actually quite simple. A light in the Tach had popped out of its socket and the center post connection (which goes hot when the lights are turned on) was touching the case of the gauge and shorting to ground. Amazing that something so freaky and simple caused such a wierd problem and ended up buring up a few wires. Still not sure why fuses didn't blow but they didn't. Just something else to look/check for. --- bill |
Carl |
Oct 27 2004, 10:38 PM
Post
#9
|
Ummm ... what? Group: Members Posts: 781 Joined: 17-January 03 From: San Jose, CA Member No.: 163 Region Association: Northern California |
I had a similar problem in my 6. Idle was ok as long as no other electrical load was applied then the engine stumbled badly when even the brake pedal was pressed causing the tail lights to be lit. This was identified when the tach went wild with the engine at idle and the brake pedal pressed but settled when the brake pedal was released.
Tracing the signal line for the tach led to the cd ignition module. Replacing it solved the problem. It seems that at idle the voltage drop from the brake lights being lit caused the cd module to be unstable. Good luck, Carl |
Lo-Fi Version | Time is now: 10th June 2024 - 04:51 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 ... |