Running poorly/misfiring, code 33

**JeepsAndGuns** · 03-20-2024

Again, sorry for such long times between posts/updates. Just been really busy between work, life, and other projects.

The alternator was mentioned a couple times in this thread. I had been having a random issue with it off and on for a couple months before the running issue started happening.
I would randomly smell burning rubber. The alt was still charging, but it just seemed like it was taking so much force to spin it, the belt was slipping. Pulley was burnt looking.
Every time I took the belt loose and spun it, it spun freely.
I even took it off and completely disassembled it, cleaned everything and lubed the bushings. No change, it would still slip and burn the belts (this engine uses dual V belts for the alt and compressor).
I ended up putting new belts on it with no change.

Finally I got fed up after working on it trying to find my issue and it decided to randomly do it and I got a face full of belt dust.
I bought a brand new (not reman) acdelco and put that on this past weekend.

No change in the running issue, but I have not had the belt slip yet. The voltage also recovers almost instantly when the radiator fan kicks on now, where before it took it a second.

While I was swapping out the alt, I had the battery disconnected, and I also saw a ground I had overlooked before. I checked and cleaned it. But no change. So all grounds have been checked and cleaned.

It is pretty much back to doing it constantly now. However it is a tiny bit different. It is so light at idle and driving down the driveway at no load, I almost did not think it was doing it. However as soon as I pulled out on the road and put it under a load, it is really noticeable.
When coming down the flat part of my driveway in 2nd gear, it is almost not noticeable, but as I start up the hill to my house, it starts doing it harder.
So it seems to misfire harder the more of a load it is under.

Lets go back to the topic of the distributor pickup. It was mentioned to change out the pickup AND the distributor shaft (with the reluctor wheel on it).
What was the reasoning behind that? It is just a toothed steel wheel is it not?
When I swapped to the 7 pin HEI distributor, I bought a aftermarket hei dist for the AMC engine, but it is made for a carb and had vac/mechanical advance. Strangely, the top is separate from the shaft/lower housing. I think it was so they could make the same top and lots of different shafts.
I bought a used complete 7 pin large cap distributor off ebay, and then chucked it up in my lathe and basically made a new top for the aftermarket distributor. The 7 pin module would not fit the aftermarket distributor and there was no way to make it fit (if you had saw it, you would know why).
Since the shafts were different lengths, I pressed the fuel injection reluctor wheel/rotor mount off the gm shaft and put it on the aftermarket amc shaft. I put a small tac weld to hold it in place.
Like mentioned in this thread, it has been flawless for years.
Can this reluctor actually go bad?

I am about ready to rip it all out and start completely over. However, if I was to do that, I would swap it over to a 12200411 ecu and get a brand new harness from a company that makes them for swapping LS engines into vehicles.
Strangely, the cam pos sensor would probably pretty easy. But the crank wheel and sensor will be the challenge. Mounting the coils on the valve covers should not be too hard either.

**MO LS Noobie** · 03-20-2024

Yes the reluctor can go bad, it gets magnetized and throws things into a tizzy. Since you have a two-part housing could be spark be cross firing between two different spark plug terminals, i.e. is the part that holds the distributor cap timed right to the reluctor position? Just shooting in the dark here.

**JeepsAndGuns** · 4 Weeks Ago

Interesting.
Could a magnetized reluctor cause the issue I am having? And could it cause them intermittently?

It is kinda hard to describe how I rebuilt the distributor. But pretty much the whole top part is original GM 7 pin. This includes the pin that holds the pickup in pace for proper timing to the posts in the distributor cap.
Not sure if I would be able to get a good enough picture to without it without completely disassembling it.

I do actually have a spare reluctor, as when I originally built it, I actually bought two complete (used) distributors off ebay to use for parts.
I pressed the reluctor off both of the gm shafts since they are the wrong length. One is in the distributor now, the other I kept as a spare.

I am thinking about swapping the reluctors. I will have to disassemble the distributor, cut the spot weld and then press on the new one and spot weld.
But if that would fix it, it would be worth it. I would just hate to go through that and it not do anything.
Only one way to find out.

**dave w** · 4 Weeks Ago

7 Pin Module, the 8 Pin Module is similar.

The Reluctor / Pickup Coil produce a small AC signal when the distributor shaft is spinning. Perhaps a wobble / harmonic between the Reluctor / Pickup Coil? Perhaps an uneven gap / runout between the Reluctor / Pickup Coil?

HEI.PNG

**MO LS Noobie** · 4 Weeks Ago

Originally Posted by JeepsAndGuns

Interesting.
Could a magnetized reluctor cause the issue I am having? And could it cause them intermittently?

It is kinda hard to describe how I rebuilt the distributor. But pretty much the whole top part is original GM 7 pin. This includes the pin that holds the pickup in pace for proper timing to the posts in the distributor cap.
Not sure if I would be able to get a good enough picture to without it without completely disassembling it.

I do actually have a spare reluctor, as when I originally built it, I actually bought two complete (used) distributors off ebay to use for parts.
I pressed the reluctor off both of the gm shafts since they are the wrong length. One is in the distributor now, the other I kept as a spare.

I am thinking about swapping the reluctors. I will have to disassemble the distributor, cut the spot weld and then press on the new one and spot weld.
But if that would fix it, it would be worth it. I would just hate to go through that and it not do anything.
Only one way to find out.

If you have access to a lab scope, you could "see" the output of the pickup coil

**Sledhead2** · 4 Weeks Ago

would you be able to test the Dizzy on a distributer machine????

**JeepsAndGuns** · 3 Weeks Ago

Originally Posted by MO LS Noobie

If you have access to a lab scope, you could "see" the output of the pickup coil

Sadly I do not have one and do not know anyone with one.

I have been digging around in my storage looking for my old original distributor I had in it before this one. I was tempted to swap it back to this distributor and reinstall the 8 pin module and external coil.
However I have turned it upside down and can not find it anywhere.

**JeepsAndGuns** · 3 Weeks Ago

So on sunday afternoon I had a couple hours to spend some time with it.
I pulled the distributor, removed the shaft, chucked it up in my lathe, cut the tack welds off and knocked the old reluctor wheel off it.
I then cleaned the shaft a little and put the spare reluctor wheel on it and tacked it in place.
I reassembled and inspected. Everything looks normal and I do not see any visible issues.
I got it started and the base timing re set and tried driving it. No real change.
The missfire is so light at idle it is hard to tell it is doing it. It is not until you start driving you can feel it. I tried moving and wiggling the wires and grounds and the ecu connectors and wires and could not get any noticeable change. However I can not do that and drive it.
I was running out of time and took it for another quick drive around the yard and the missfire was cutting in and out.

**mecanicus** · 3 Weeks Ago

Search for somebody with an oscilloscop or have one for yourself. There are cheap ones on te market used or brand new like hantek.With an oscilloscop you may find where the irritation in the current starts. Old school garages have them too.I do not think its a mechanical problem like a broken valve spring.You would have found it already.

**Sledhead2** · 3 Weeks Ago

I have been watching this post and have some minor thoughts.

Have you taken a water spray bottle and sprayed the harness down? along with plug wires? a little at a time while running while moving the harness around

I have seen plug wires go bad and arc out, but I have also found sensors with hair line cracks that let water in, I also found bad wire harness connectors that way as well.

**JeepsAndGuns** · 2 Weeks Ago

Originally Posted by mecanicus

Search for somebody with an oscilloscop or have one for yourself. There are cheap ones on te market used or brand new like hantek.With an oscilloscop you may find where the irritation in the current starts. Old school garages have them too.I do not think its a mechanical problem like a broken valve spring.You would have found it already.

I am not opposed to buying a o-scope if a decent one can be had for a reasonable price.

Anyone have any recommendations?

**mecanicus** · 2 Weeks Ago

Like already mentioned, if you have a laptop have a look for the hantek1008 or the picoscop 2204 A .The hantek is a 8 channel one while the picoscope has only two channels. Both are about 150 bucks and work pretty well for us nechanics. If you download the picosoftware first, you may see a lot of examples what to measure on a car. Of course you may buy one at a much higher price and become an electronics. :-)