Electrical/ Ignition help please!
Thread Starter
Melting Slicks
Joined: Mar 2006
Posts: 2,465
Likes: 0
From: Orange Park Fl
Electrical/ Ignition help please!
A while back I posted that I had an intermittent ignition problem on my '81. The tach needle starts jumping irradically and the engine misses. I got two possiblie reasons: a bad TPS and a bad magnetic pick up pole peice in the distributor. Well so far I have replaced the TPS, entire distributor assembly (distributor, module, coil, cap and rotor). It has been frustrating to diagnose because it will not do it when I am trying to find the problem. I have disconnected my MSD box and disconnected the computer (running in "limp home" mode; no ignition advance) and the problem still happens. My ignition wiring all looks good and all the connectors are tight and clean. Last night I replaced the spark plug wires and checked the plugs. I didn't think they were the problem, but I had replaced or eliminated everything else I could think of that could cause it.
The problem varies from running fine, to the tach needle jumping about 200 rpms with a slight miss, to the tach jumping wildly about 1,000 rpms and the car studdering badly. I noticed last night after I replaced the plug wires that the headlights seem to flicker with the tach movement (when the tach is jumping, the lights get dimmer and brighter with the movement of the tach.)
I've been battling this for some time now and am at the end of my rope. Someone help please! God bless, Sensei
The problem varies from running fine, to the tach needle jumping about 200 rpms with a slight miss, to the tach jumping wildly about 1,000 rpms and the car studdering badly. I noticed last night after I replaced the plug wires that the headlights seem to flicker with the tach movement (when the tach is jumping, the lights get dimmer and brighter with the movement of the tach.)
I've been battling this for some time now and am at the end of my rope. Someone help please! God bless, Sensei
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Well with the headlights getting in on the act, I would back up the elecrical system from there to wherever it crosses with ignition, Firewall connector, ignition switch, fuse block...
Instructor
Joined: May 2006
Posts: 223
Likes: 1
From: Kennesaw GA
This sounds goofy, but have your alternator tested for spikey output. I had similar issues with my '94 Z71 when the alt was getting ready to die. Noticed it mostly in the guages, but also in the lights.
