Running poorly/misfiring, code 33

[MO LS Noobie]

It still seems like there is a wiring or ground issue. Try cleaning battery posts/terminals then put jumper cables from battery negative terminal and the engine block. Also test your PCM powers and grounds (with everything connected) with volt meter back probing PCM connecter and the other lead at the battery.

I have seen flooding from ruptured fuel pressure regulator diaphragm. They can leak fuel through the vacuum line intermittently.

What ignition system are you running? It is possible you are getting multiple injector pulses per cylinder because of a cracked pole piece in distributor. In another forum there are reports of multiple failed distributors causing similar issues. Parts quality has really suffered lately.

[dave w]

I’m wondering if the HEI 8 pin ignition module is the issue?

I’ve helped out on some TBI conversions that significantly benefited switching to the HEI 8 pin ignition module and remote mounted TBI coil.

I’m always suspicious of a salvage yard TBI harness, copper wiring will corrode inside the insulation, especially grounds.

[JeepsAndGuns]

I am running a HEI distributor using a 7 pin module.
I bought a aftermarket HEI distributor for the AMC/Jeep V8. It was for carbed engines and had a 4 pin module.
The pad the module sets on was the wrong shape and size to fit the 7 pin module. But strangely, the top half of the distributor could be removed from the shaft. I figure it was so the company could use the same top of different lower shafts for different engines.
I ended up buying a used distributor from a TPI chevy 350, chucking it up in my lathe and machined it to fit the aftermarket lower housing.
I ended up using the chevy shaft, rotor and top half of the distributor and only using the bottom lower housing of the aftermarket unit.
I am using the pickup coil and 7 pin module from the TPI distributor. I attached the two together using some small bolts. They are all still tight and rock solid. Nothing appears to have moved either.
It sounds kinda hodge podge, but it had been great and completely trouble free for years.

I will unbolt and check all my grounds. The battery posts are good and clean. I use AGM batteries, so no powdery corrosion.

The pickup coil and 7 pin module I swapped were used/junkyard units I kept for spares. They are factory GM parts.
If there is a chance they could be the issue, I do not mind buying new ones, if a QUALITY replacement can be purchased. I do not want some cheap china crap that will give me trouble in a couple months.

[dave w]

I am running a HEI distributor using a 7 pin module.
I bought a aftermarket HEI distributor for the AMC/Jeep V8. It was for carbed engines and had a 4 pin module.
The pad the module sets on was the wrong shape and size to fit the 7 pin module. But strangely, the top half of the distributor could be removed from the shaft. I figure it was so the company could use the same top of different lower shafts for different engines.
I ended up buying a used distributor from a TPI chevy 350, chucking it up in my lathe and machined it to fit the aftermarket lower housing.
I ended up using the chevy shaft, rotor and top half of the distributor and only using the bottom lower housing of the aftermarket unit.
I am using the pickup coil and 7 pin module from the TPI distributor. I attached the two together using some small bolts. They are all still tight and rock solid. Nothing appears to have moved either.
It sounds kinda hodge podge, but it had been great and completely trouble free for years.

I will unbolt and check all my grounds. The battery posts are good and clean. I use AGM batteries, so no powdery corrosion.

The pickup coil and 7 pin module I swapped were used/junkyard units I kept for spares. They are factory GM parts.
If there is a chance they could be the issue, I do not mind buying new ones, if a QUALITY replacement can be purchased. I do not want some cheap china crap that will give me trouble in a couple months.

7 Pin HEI Large Cap with the Ignition Coil in the cap is a very good ignition system.

Possibly the 7 Pin Module is faulty?

Quality parts? No longer available, just cheap and worthless parts.

7 Pin HEI.png

[In-Tech]

Hiya,
Buy Delphi at Rock Auto. Fack AcDelco and all the other crap for sale. The originals were probably from the Philippines. Good luck with that.

[JeepsAndGuns]

It is possible you are getting multiple injector pulses per cylinder because of a cracked pole piece in distributor. In another forum there are reports of multiple failed distributors causing similar issues. Parts quality has really suffered lately.

Can you elaborate on this a little? This is the first I have heard about this. However I have been out of the fuel injection/tuning loop for a few years. Plus I do not work on much anything other than my own stuff, so I do not have much exposure to common issues happening to similar vehicles.
I am a small engine mechanic for a living, so I do not get much exposure to working on cars/trucks.

[MO LS Noobie]

Can you elaborate on this a little? This is the first I have heard about this. However I have been out of the fuel injection/tuning loop for a few years. Plus I do not work on much anything other than my own stuff, so I do not have much exposure to common issues happening to similar vehicles.
I am a small engine mechanic for a living, so I do not get much exposure to working on cars/trucks.

Try this link, it explains it better than I can.
https://members.iatn.net/techmail/vi...ruck&kw=N41588

https://members.iatn.net/techmail/vi...ruck&kw=N41588

This is one of the posts if you have trouble opening it. "I have heard a lot lately about the pickup in the distributor being the cause. The pickup itself or the trigger wheel (for lack of a better term.) Check into that a little deeper if you have not. It can develop a crack or get loose on the distributor and cause these types of problems."

"also ran onto one that exhibited similar symptoms that ended up being a faulty coil that was leaking voltage out of the coil wire tower over to the primary wire connector. I saw a loss of signal from the module accompanied with a marked increase of system voltage due to HEI voltage leaking into the primary circuit."

[JeepsAndGuns]

Try this link, it explains it better than I can.
https://members.iatn.net/techmail/vi...ruck&kw=N41588

https://members.iatn.net/techmail/vi...ruck&kw=N41588

This is one of the posts if you have trouble opening it. "I have heard a lot lately about the pickup in the distributor being the cause. The pickup itself or the trigger wheel (for lack of a better term.) Check into that a little deeper if you have not. It can develop a crack or get loose on the distributor and cause these types of problems."

"also ran onto one that exhibited similar symptoms that ended up being a faulty coil that was leaking voltage out of the coil wire tower over to the primary wire connector. I saw a loss of signal from the module accompanied with a marked increase of system voltage due to HEI voltage leaking into the primary circuit."

It will not let me read it without logging in.

[JeepsAndGuns]

It is possible you are getting multiple injector pulses per cylinder because of a cracked pole piece in distributor.

I did not really think much of it when I saw it, as I thought it was either just me, or the spark tester.
But when I had the spark tester hooked up, and I was cranking it with the bypass unplugged to see if it was sparking, I swear it almost looked like it double sparked a couple times.
It is a inline spark tester that has a light bulb inside it that flashes. Normally you see the flash, but a couple times, it almost looked like two super fast flashes at one time.

So is it possible we might be onto something here?
You say possible multiple injector pulses, so if it is seeing a extra erroneous pulse, it will pulse the injectors again?


Now I am almost wanting to think I fixed one issue and created another.
I think the original missfiring might have been the pickup coil, that I swapped out for a used one I had, and the used one has a different issue.
Ever since I swapped them, I have not had the missfiring, but I can not set base timing and it's running rich. I am thinking the reason I can not set base timing is it is running too rich and floods.

I'm going to order up a new pickup coil and see what that does.
Looks like my choices that I can find are either wells or standard motor products. Either one of those brands any better than the other?

[MO LS Noobie]

I prefer Standard over Wells but all parts are a crap shoot lately, with so many counterfits from China.

PM me for log in info for the other site.

[JeepsAndGuns]

So looking up the pickup coils for TPI V8's, apparently there are two different ones.
There is a LX324, listed for a camaro, and a LX320 for the corvette. (both standard motor products part numbers)
They both look identical other than the color of the connector. The camaro is yellow while the corvette is black.
The part numbers for the distributors are also different, but they look the same.
Any idea what the difference could be?
The yellow camaro connector fits lots of chevy and gmc, while the black corvette connector fits lots of buick olds, and pontiac

I am pretty sure I am using the yellow connector pickup coil (camaro). I will have to pull the cap back off and double check.

[dave w]

So looking up the pickup coils for TPI V8's, apparently there are two different ones.
There is a LX324, listed for a camaro, and a LX320 for the corvette. (both standard motor products part numbers)
They both look identical other than the color of the connector. The camaro is yellow while the corvette is black.
The part numbers for the distributors are also different, but they look the same.
Any idea what the difference could be?
The yellow camaro connector fits lots of chevy and gmc, while the black corvette connector fits lots of buick olds, and pontiac

I am pretty sure I am using the yellow connector pickup coil (camaro). I will have to pull the cap back off and double check.

I'm thinking the large cap HEI with the coil in the distributor cap is for the Corvette. (7 pin module)

I'm thinking the externally mounted coil using the small cap HIE is for the Camaro. (8 pin module)

[MO LS Noobie]

HEI also had 2 different coils, different color wire to coil itself. Don't forget the coil grounding strap (top of coil under thin plastic cover).

[JeepsAndGuns]

Looking up the parts on rockauto, a 1985 camaro with the 305 tpi V8, and a 1985 corvette with a 350 tpi V8, they both show a large cap HEI distributor and they both look identical, but have different part numbers.

The pickup coils look identical but have different part numbers.
Camaro: https://www.rockauto.com/en/moreinfo...t=7176&jsn=595
Corvette: https://www.rockauto.com/en/moreinfo...t=7176&jsn=599

The coils (both large cap hei coils) look identical, but have different part numbers. The corvette has a red and yellow wire, while the camaro has a red and white.
Camaro: https://www.rockauto.com/en/moreinfo...t=7060&jsn=497
Corvette: https://www.rockauto.com/en/moreinfo...t=7060&jsn=558

The 7 pin module is the same part number.


Ok, doing a little more digging, I found reference to different ignition coils and that they need to be matched to the pickup coil. He says the coils function the same, but the polarity is reversed on the two, so the pickup and coil have to match.
https://www.chevelles.com/threads/he...rence.1089204/

I think I am just going to have to pick one (either camaro or corvette) and order both the pickup and the ignition coil, just so I know they are both matched, as right now it is a mix of junkyard parts.
The pickup I pulled out had the yellow connector and I am pretty sure the distributor came from a camaro. So I think I am going to pick that.
And yes, I do have the ground strap in place. I specifically remember putting it back in there.