More problems with the 'burb.... **FOUND IT**

[jonathon]

Well today I started tearing into the Suburban to see if I could find the reason for it's stumbling and hesitation under wide open throttle... I found the following (pics coming later today when the camera gets home):

Dizzy cap had one really rusty terminal on the outside, the inside contacts.. ALL 8 were corroded bad.

Rotor was toast, corroded and burnt looking.

All 8 spark plugs were pretty nasty, looked corroded on the tips.

The other thing I noticed is the shaft that connects to the rotor... the round "plate" underneath the rotor has what appears to be a crack in it, running right through one of the several pins on this plate. Is this normal? It looks very straight and clean, so I'm not sure.


It runs much better, and when cold starts right up and idles smooth(much better than before). It accelerates smoothly under WOT and seems a little more responsive.

The problem I'm having now though is it's dieing.. didn't die at all when I first drove it, but it was cold. When I got it warmed up I rolled up to a stop sign and then it died, after that if I wasn't on the throttle it would die. Did not do this before

What's the problem here?? I need to get this figured out

 

[jonathon]

After letting it cool I started it up.. same thing.

The engine stumbles and sputters like it is running out of fuel unless I hit the gas

It seems the crack is actually on part of the shaft assembly(the flower shaped plate). Do I need to get a new shaft?

 

[GNERGY]

Did you disconnect the battery for a couple minutes to reset the ECM.
Tarey

 

[jonathon]

Did you disconnect the battery for a couple minutes to reset the ECM.
Tarey

Yes, still does the same thing.

I am thinking the culprit is probably wires, ICM, or pickup coil.. no idea though which. I've got the ICM and pickup.. don't want to pull the dizzy but if I have to...

 

[GNERGY]

I would try the new ICM you have. The magnetic coil in the bottom of the dist.on my burb looked like crap. It was rusted and had little pieces of metal stuck to it and I just cleaned it up and mine runs good. So I don't think that it goes bad. I'm not positive though. I'm new to these TBI fueled engines. My other burb had a carb on it.
Tarey

 

[jonathon]

I'm going to check the timing first, then going to put in the ICM. If that fails I guess I'll pull the dizzy and put in the pick up coil I bought

 

[jonathon]

Well I'm 90% sure it's a vacuum leak causing it. There is a loud hissing noise at idle and my brake light came on today and my brakes weren't stopping to well

I traced all the lines I could find and found nothing. I checked all the connections at the TB with a spray bottle as well as the TB gasket and got no where..

I think the leak started sometime between driving from my grandparents and the 3-4 miles down to the bottom of the hill.

Going to take it to a friend's to have him look at it...

 

[dyeager535]

Sounds like maybe your booster is dead...obviously check things out, don't just go replacing.

 

[GNERGY]

I think if you use a propane torch and (not lit of course ) with the gas on anyplace you think there is a vacumn leak the RPM's will increase. Bingo, you found the leak.
Tarey

 

[jonathon]

My friend(he's a mechanic for a GM dealer) found the problem after much poking around

The noise was coming from the dizy, but it was because the magnet had fragged itself(those cracks I posted about earlier? Yeah). His conclusion was that I was driving a time bomb as far as the magnet went, and I was LUCKY to get it home

The magnet slowly broke apart causing the rough idle and WOT problems till it finally disintegrated leaving only half the magnet's points on the shaft. Unfortunately when the the magnet finally let go it took out a couple parts of the distributer(I can't remember what now). The remainder of the magnet was flopping around and bent the posts around the pickup coil out.

This explains the cracks in the top of the shaft I saw and the chunks of metal that fell out when I took the cap off

The good is no vacuum leak, the bad is it needs more parts than I had counted on so my lift gets delayed