OK Carb gurus.... HELP!

ok. So much for it being something (obvious) that I did during the belt service...

Just checked the cam alignment marks again. They are "right on". Exactly where they were before the service, and exactly where they were after the belt change.

To be a problem on the whole rear bank, then, it HAS to be something with the ignition system, right?

I just can't imagine all 4 plug wires, or all 4 extenders on the rear bank going bad at the same time... and at, just coincidentally, the same time I changed the belts...

Could a condenser cause this problem? They were recently replaced (w/in the last few months). What about a coil?

The only thing left is to pull the distributor (again) and have it run on a machine....

Thoughts?

 

Just found that the ign wire from the coil to the distributor was showing about 4000 ohms resistance. New wire 900ohms resistance. Thought FOR SURE that was it. No luck.

STILL popping on all four rear cylinders on heavy accleration.

Is it possible that the one bad coil wire caused ALL FOUR other ign wires on that bank to go bad? Or the condenser? or the whole coil?

I rechecked the timing and watched the progression of the distributors on both the front and rear banks. They are identical. I thought I might have had some weights that were sticking... Nope.... But I AM getting an occasional shock throught the base of the distributor when tightening/loosening the bottom bolt on the distributor base.

I think something in there is shorting out. Possible a loose connection on the points?

 

Is the MSD coil "plug & play"? Or do I have to change anything else out?

ie points, plugs etc... Also what part number? Thanks!

 

ok, thanks guys! Unfortunately this will have to wait for a few days. I have to go to work until Sunday afternoon :-( Gotta make some money to pay for my hobby...

I pulled the distributor to make sure nothing was loose are arcing inside the distributor. While re-timing, I got the *&%^ shocked outta me! I think the insulation or the wires may be breaking down? But definitely getting arcing across/ around the distributor even at idle. I am sure this is only worse under load and is probably at the root of my problem.

Does this sound like wires to anyone else??

 

I was only home for 36 hours last week, so not a lot of time to troubleshoot...

I checked the points, and they were good..
Replaced the condenser; no luck
Replaced the coil; still popping.

I ordered new plug wires and will pick them up tomorrow on my way home to see if that does it...

The plug extenders LOOKED ok. We'll see, I guess.

One other question though. After doing more research, I keep seeing that other folks are getting an idle flow on the carbs of about 3.5-4kg/h when sync'ed. When I sync mine they are around 6-7kg/h... Is this a problem?

 

(last post didn't seem to go, so here goes again!)

I was only home for 36 hours last week, so not much time to troubleshoot.

I replaced the condenser; didn't help the popping on the rear bank.
I replaced the coil; no luck either.
I checked the plug extenders; they seemed fine.... (this may be next replacement item...)
I had to order new wires and will pick them up tomorrow on the way home to try that...

One other thought: After doing more research, it seems that others are getting a flow of 3.5-4kg/h on their carbs when sync'ed. Mine was at 6-7kg/h after sync'ed (at 1000rpm). Does this seem off? Could this be at the root of the problem?

 

already replaced the cap....

 

Glad to hear someone else is getting these numbers. I was beginning to think it may be some elusive vacuum leak I am missing... It still may be...

Thanks for the advice. I still haven't re-jetted, as I was going with some previous advice that if it was running before, it is something I did. After I get it going smooth, I can re-jet. I have heard that if you go up one step in the mains, then you should probably go down 3 steps on the air-corrector (if there is no problem with the top-end dying away). So your numbers sound right on! Of course you know this because you have gotten that set up to work in so many other cars! Thanks again for your jet set-up numbers!

Cheers,

Max

 

I think I discovered the culprit! I found a plug extender w/ infinite resistance... My theory is that under load, this was arcing everywhere and causing misfiring across the entire bank of cylinders. I am taking a trip to my favorite parts store tomorrow and hopefully that will be it!

On the bright side of things, I have a nice parts bin built up of ignition parts and carburetor rebuild kits for that day when something else happens!

Maybe I can pick up some new jets while I am at the parts store.....

I'll let you know how it goes tomorrow!