Hey everyone, most of you know for the past several weeks I have been fighting an inconsistant problem with my 79. From bad running, missing, not starting sometimes, to starting right up 10 minutes later then again to poor running.

Well I had looked at everything from fuel delivery to ignition. Come to find out it was the green wire leading from the distributor to the ignition control unit. This wire was bad and it was shorting onto itself causing the motor to stop running. Everytime I would look and test things I would move or displace the wire and it would be fine until the engine ran and vibrated the wire to where it would short out again.

So I replaced the wire, but I had also adjusted other things like mixture and timing. So now the car starts right up and idles perfect. I figured I had cured my problem but when I tryed to rev the motor it will die. As soon as I just barely touch the accelerator the car dies. And I mean just barely crack the throttle. But the car idles perfect!!!! How can this be. Am I missing something here.

I went to check timing but when I pull the vacuum advance line off the motor sputters and dies. I tried to advance and retard the timing and then pull the vacuum advance off and it does the same thing.

I have looked for any vacuum leaks and dont have any. Like I said it starts and idles perfect. I have never had a vacuum advance go bad but I figure you should still be able to rev it up just not get any advance out of it.

So I was wondering if any of you 78 and 79 owners could go out and check your timing with the vacuums connected. I recall doing this and think it was around zero degress (top dead center) with everything still connected. This will give me a baseline to set it at with my lines still connected. Also, for those that know what they are doing with the mixture. If anyone could tell me how many turns counter clockwise it takes to get back to where you cant turn it anymore. If you do do this be carefull because it doesnt take much to screw up your mixture. But if i can get this information again it will get me to a baseline setting.

Thanks

 

Curt,

If I remember correctly, with the vacuum advance on at idle should be +- 5 degrees.

As far as the mixture goes, I only turn that about 1/16". As you know, it's super sensitive. I've never fully turned it one way or another.

How's the MAF? It almost sounds that when you accelerate TOO much air is entering the system causing the engine to die. My .02 cents. Send me mail offline if you have any other questions. I'll try and help out anywhere I can.

 

Curt,

Your problem sounds like too much ignition advance or a too lean fuel mixture. With your engine off and the #1 cylinder at TDC, set your timing so the rotor is directly on the #1 spark plug. If it still dies when rev'd, richen your mixture in small increments as mentioned earlier. I wouldn't adjust from stop to stop since you are close as indicated by the idle.

Dennis

 

This car is kicking my butt.

I double checked timing position last night. Turned car over untill I was at TDC. Looked at cam gears and marks line up. Pulled cap and rotor was at #1. So I know for sure my timing is dead on.

Next, started car and with timing light checked timing with vacuum's still hooked up. It was right at 0 degrees. Kinda thought thats were it was at last time I checked it with vacuum's on.

Now what happens next is odd. I pull the vacuum and the timing moves back retard a bunch. Like off the scale. Now normally the timing would advance a bit with vacuum off.

So I hook vacuum back up and have my girlfriend bring up the revs while im looking at the timing. The revs come up to about 2000 rpm or so and right at that point the timing goes way retard, and i mean way, off the scale retard, and it dies.

What would cause the timing to retard??? Am I missing something. Is there some kind of safety device (rev limiter) on the 79 that could be acting up at 2000 rpm???

Dennis, I have tried what you are saying, with the car idleing, slowly pull the throttle open with one hand and adjust the mixture with the other. I have found precisely by doing this where the car seems to idle the best but it still doesnt allow me to rev the motor.

I am almost 100 percent sure that the problem is that the timing is retarding itself. But why would it do this??

Im almost to the point of trying to find a spare distributor and vacuum advance and swaping them out. Anyone have one laying around and willing to let me try??

I have an extra ignition control unit and it does the exact same thing with it on. So I highly doubt that both boxes could be bad.

Anyone have a phone number of someone that I could talk to about this problem.

Thanks again for your help.

 

If your distributor vacuum advance can has two connections, it sounds as if you have the vacuum lines switched.

On the distributors that have the vacuum retard, one vacuum connection (on the back or inner side of the can) retards the timing when vacuum is applied. This one should have the line attached that has vacuum at idle.

The other connection (on the outer face of the can) advances the timing when vacuum is applied. This one should have the line that has no vacuum at idle, but has vacuum with partially opened throttle.

 

Thanks Wally, I thought I had tried reversing those two somewhere in all of my testing, but I will double check that as well.

Usually when I test my timing I pull both vacuums and plug them, I cant even keep the car running when I do that. It must be some kind of timing issue and I will triple check all positions when I get home tonight.

 

Well, im very happy to say that I have fixed the problem.

And as always Wally P. was right. I had the vacuum advance and the vacuum retard on opposite order. How I did this I have no idea because I had them marked. I guess I just screwed up and its embarrasing. Such a simple mistake could cause such problems. The mixture was also way out of whack which was also messing things up.

All I have to do now is time it and adjust the mixture a bit more and all should be set.

Thanks again everyone and Wally.

 

Geeze-Louise Wally, where does this power of remote diagnosis come from?

I used to have a feeling of great respect, but now I think it's just fear. Be vewy, vewy afraid - Wally's out there <img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" /> .

 

Awesome!

Atleast it didn't cost $$$$