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TonyMac · 06-18-2019, 04:49 PM

1984. Does it have a heat riser installed just after one of the exhaust manifolds? Does it work correctly?

Orgotloth · 06-18-2019, 09:43 PM

So I pulled the coil and it looks like someone welded lines down the side of it. Doesn’t seem normal at all, problem remains. Next step is to open that busted muffler back up

Orgotloth · 06-18-2019, 09:48 PM

I also noticed the engine sounds like it’s breathing when it’s turned off after it stalls sometimes. This is an attempt at capturing the sound (it’s hard to hear but it sounds like breathing.)

https://www.dropbox.com/s/0fx3ptjfnz...%20PM.mov?dl=0

MinntoMich · 06-18-2019, 10:24 PM

Hmmm... Following... Lots of suggestions and I hate to muddy the waters but I'll offer this. Like several others, I was thinking of a ignition problem.

Some parts you have already replaced but I'm wondering if it could be a bad EGR valve?

Forty-nine state or California emissions?

VanDiemen23 · 06-18-2019, 11:34 PM

The breathing sound is just a vacuum reservoir bleeding off.

This is almost always electrical. I've had a ballast resistor crack and be fine when cold then warm up and pull apart, killing the engine until it cooled again. Not saying thats the problem, but cut your losses, buy a complete new dizzy assembly and I bet this problem goes away. They aren't that expensive.

Blown muffler - bad ignition causes gas to build up in muffler and then lights off.....

DocKillmon · 06-19-2019, 12:06 AM

I've worked on these quite a bit. Replace the electronic control module and rotor. These are the only things that go wrong and cause the little engine to backfire. Once the engine gets hot the control module causes all kinds of weird symptoms when they are on the fritz. Good luck and have fun. DOC

Orgotloth · 06-19-2019, 12:17 AM

Quote:

Originally Posted by MinntoMich

Hmmm... Following... Lots of suggestions and I hate to muddy the waters but I'll offer this. Like several others, I was thinking of a ignition problem.

Some parts you have already replaced but I'm wondering if it could be a bad EGR valve?

Forty-nine state or California emissions?

I wired it open, the diaphram wasn’t linked to the valve anymore as the linkage has rusted off. Texas registration, no smog check.

Orgotloth · 06-19-2019, 12:19 AM

There’s also no exhaust crossover, I checked today as I was unhooking my second fuel pump (I haven’t gotten a fuel regulator yet and it’s making the engine run super rich)

speed racer · 06-20-2019, 06:32 AM

The most common problem on a Gm HEI no start is the ignition rotor. It will burn through the center and ground the spark. This is caused by too much resistance in the plugs or plug wires.

Randalpho · 06-20-2019, 07:36 AM

Quote:

Originally Posted by speed racer

The most common problem on a Gm HEI no start is the ignition rotor. It will burn through the center and ground the spark. This is caused by too much resistance in the plugs or plug wires.

This would cause a no start, he is having an issue stalling hot. From the videos it sounds like you have a large vacuum leak, or the EGR valve is stuck open, or secondary throttle plates are stuck open in the carb.

wackymac · 06-20-2019, 07:45 AM

Those welds are stock. They're to tie the laminations of the transformer together.

Orgotloth · 06-20-2019, 04:01 PM

Quote:

Originally Posted by wackymac

Those welds are stock. They're to tie the laminations of the transformer together.

Just looked unnatural, good to know I’m not getting massive arcs in there.

CountryB · 06-20-2019, 05:27 PM

The growling I heard is your starter's Bendix drive slowly returning (dragging) after cranking.

On a carburated engine it's easy to test for a no-fuel condition. Just remove the air cleaner (with engine off) and move the throttle to full open. If fuel squirts out the accelerator pump jets, you have fuel in the carb.

Does the choke work - should be closed at cold start up then be pulled open a little by engine vacuum form the choke pull-off canister as soon as engine starts.

How does it run once it gets started (assuming it does run sometimes).

A clogged exhaust will not show up on first start - it takes some time for the gases to build up enough to choke the engine.

Orgotloth · 06-22-2019, 02:26 PM

Ok, so I’m pretty much out of time for trying to do this myself. Took it to a mechanic, said he’s owned one just like it for years. 45 yrs experience. I’ll let you guys know what it ends up being.