Car running like crap, 4 days before Hershey Options

[saigon71]

You need to check the voltage at coil terminal #15 and maybe at pin 1 of the white 4 pin FI harness plug on the relay board. High resistance somewhere will reduce voltage to the consumers. I would plug another ignition switch into the harness and see if the problem goes away.

Thanks Ed. 13.7V on terminal 15 of the coil. Which pin is pin 1 on the white 4 pin FI harness?

Heading out to swap out the ignition switch.

[saigon71]

I swapped out the ignition switch with a new one. Still acting the same. (IMG:style_emoticons/default/headbang.gif)

[Spoke]

Where are you measuring the 13.6V and 12.5V when running? At what RPM are you at? If 12.5V is at the battery, you have an issue. Also what is the voltage at the coil?

With the engine running at high idle like 2k, measure all 3 pins of the VR with respect to chassis ground. Not the engine but the chassis. D+ should be 13.5V, DF should be 6-10V and D- should be less than 0.5V. All voltages DC. Don't disconnect anything; just jam the DMM probe into the connector to the VR.

Damn this is frustrating. (IMG:style_emoticons/default/headbang.gif)

I discovered I had an adjustable voltage regulator and bumped up the voltage slightly.

Still battling this problem. I installed a reman "Carquest" alternator from NAPA. Things got better, but the car still bucks when I drive it with the lights on.

Spoke: I measured the voltages as you suggested with the new alternator at 2000 RPM. These are my readings:

D+: 14.5V
DF: 3.2V
D-: negative 62 millivolts

Does the low reading at DF indicate I got a bad rebuilt alternator?

All those numbers look good especially the 14.5V on D+ and 62mv on D-. That D- reading is basically testing the grounding of the alternator. You should be seeing 14.5V or near it on the battery as well.

Was this with lights on or off?

[Spoke]

BTW, what voltage do you have at the coil with ground referenced to the engine case?

[saigon71]

Does the tach bounce or jump when this happens? Sometimes that could signal ineffective burn or ignition issues.

Tach remains steady when it acts up.

[saigon71]

BTW, what voltage do you have at the coil with ground referenced to the engine case?

13.7 on coil terminal 15, 7.7 on coil terminal 1, referenced to the engine case.

[saigon71]

Update:

I've swapped out the distributor cap and points, I've swapped out all 4 injectors with known good ones. Replaced the ignition condensor. Ran a new battery ground strap from the negative terminal to the side of the engine bay. Tried a replacement voltage regulator. Swapped out the relay board with a known good one.

I just re-tested fuel pressure - it is 30PSI at idle, 29PSI at 4000 RPM.

Nothing has changed.

I'm still driving the car. She's missing now without the lights on sometimes. However, it is always much worse when I turn the lights on. The hesitation seems to be more prevalent at higher RPM.

Bump for some fresh ideas. (IMG:style_emoticons/default/icon_bump.gif)

Man this sucks, it's prime driving season.

[mepstein]

Because of what I went through I’m still guessing electrical. I would pull every connector and spray with contact cleaner. Mine got better when I switched out the coil. I did the switch with other stuff but I have a spare if you want to try.

I had a friend help me go through the dizzy at the same time it started running right. I had already changed out all the fuel lines, filter, rebuilt the ingectors and checked the fuel pressure. I switched out the engine harness but it made no difference.

[oakdalecurtis]

My 76 2.0 Djet would miss intermittently for years, couldn't find the problem, not for lack of trying. I finally pulled the dizzy and slid out the fuel injection points underneath it. Well well well. The points on one side had a piece of plastic debris behind them which would slide around and jam up the points, only intermittently. Maybe check your injector points. This problem would not have any relationship to lights on or power use however.......

[saigon71]

My 76 2.0 Djet would miss intermittently for years, couldn't find the problem, not for lack of trying. I finally pulled the dizzy and slid out the fuel injection points underneath it. Well well well. The points on one side had a piece of plastic debris behind them which would slide around and jam up the points, only intermittently. Maybe check your injector points. This problem would not have any relationship to lights on or power use however.......

Thanks for the response. I've swapped out the trigger points with no change to the problem.

[dralf]

I have finally started working on a similar running issue with my 1975 that still has D jet injection. My engine would actually die while driving, I could restart it, and if the REVs were above 4000 RPM it would continue to run and die if the RPMs dropped. I does not do this all the time but is a scary situation on the interstate. My previous posts regarding this issue have suggested I replace the coil, some of the wiring harness, check grounding and points. Reading this post makes me wonder if I do not have an alternator / power to the coil issue. I am going to use some of the suggestions and checks from this post to look at my car for source of my problem.

[JmuRiz]

Just a shot in the dark, how's the fuel filter (how old/dirty/clean etc)?

[904svo]

Just a WAG, check all the red leads on the battery connector you might have one of
the red wire with broken strands causing a intermittent problem.

[saigon71]

Duplicate post - oops. (IMG:style_emoticons/default/dry.gif)

[saigon71]

I THINK (and hope) that I found what is causing the problem. I've gotten in contact with Odyssey about a warranty on this new battery.

This thread shows what is going on:

http://www.914world.com/bbs2/index.php?showtopic=338054

The video on post 5 shows the whole battery post moving.

[VaccaRabite]

Its a weird problem, and I would assume that the post would cause all sorts of other issues, but the timeline matches. Do you have another known good battery you can swap in? If not swing by and grab one.

Zach

[saigon71]

Its a weird problem, and I would assume that the post would cause all sorts of other issues, but the timeline matches. Do you have another known good battery you can swap in? If not swing by and grab one.

Zach

Thanks Zach. I'm in the warranty process with Odyssey. They said it could take 7-10 days until I get my new batttery. I may run down to your place if I get time to test this bad battery theory. Plus, I've got some parts from Mark for you.

Youre right, the timeline fits. The problem definately gets worse under electrical load.

[Big Len]

One weird problem Bob. It's a new one for me.

[saigon71]

I wanted to get plenty of driving in to make sure the problem was fixed before reporting back.

The loose battery post was the problem. Odyssey was great to work with to get a new replacement under warranty.

Relieved that it's fixed but frustrated that it took so long to figure out.

On the bright side - my alternator was on the verge of failure, so swapping that out probably saved me a future break down.

Thanks for all the help.

Back on the road (confidently). (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif) (IMG:style_emoticons/default/driving.gif)

Bob

[mepstein]

(IMG:style_emoticons/default/beerchug.gif)