I bought the plug cleaner years ago on sale and found it in a box, thought I would put it to use.

Some of the plug gaps were wrong in addition to being fouled, so I cleaned and re-gapped them all to .035. It did smooth out the idle and the right side is actually warming up some now, but it still reeks of unburned fuel.

Next I'm going to run a compression check on the other bank.

 

I took a few pics of the rotor button and where it goes on the shaft.


The black lines show how much you can rotate it back and forth.

Where the rotor button goes on the shaft of a new not rusted up shaft end.

Amount of rust on the end of the shaft where the rotor button goes on a 3,900 mile used distributor. Sorry my phone focused on the background and not the foreground.

Back side of standard rotor button and HD/Marine rotor button where it pushes onto the end of the shaft.

When the metal pieces in here get rusty and the end of the shaft gets rusty and that rust expands it make the rotor button very hard to get off.

All original 27k mile 1990 Formula 350 distributor. Notice it doesn't have the copper/brass looking shield on it.

There was a heaping handful of white fluffy corrosion and some green corrosion inside.

You could have ate off this car outside, inside, and underneath. Inside the distributor after 27k miles it looked like came off bottom of ocean floor next to the Titanic.

 

Short trips, heat soak and condensation cause the distributor to get nasty.
the original distributor would have had the shield on it. My guess is someone didn't put it back on after a pickup coil change.
When the pickup coil turns green, or fails an ohm check, replace it.

 

good though. I actually had thst happen years ago. Just a small leak that would flood the engine when I shut it off and make for a hard restarts

 

any chance this has a flat tappit cam and it wiped out a cam lobe?

 

Compression check on front bank results:

#1: 165
#3: 155
​​​​​#5: 165
#7: 175

Had a helper this time so got higher numbers than the rear bank.

 

Not according to the video the OP posted showing the rockers rocking. No flat lobes there.

 

IN the fouled looking plugs pic, it looks like two things are going on:
1. those rear cylinders ARE firing....otherwise there'd be no soot/carbon.
2. It's wicked rich on that side of the engine.

Why's it so rich? The injectors must be firing....or they're stuck open? Or the ground side of the inj harness for the right/rear bank is shorted to ground?

 

ahh I missed the video.

is it possible it just has a bad o2 sensor and fouled out the plugs? I had a old 1 wire o2 make a stock car run horrible at part throttle back in the high school days in my 91 tpi car. it finally threw a code after weeks of wondering why it ran bad till it got pastes 3/4 throttle.

I do like the restricted exhaust idea thou too. but sounds like he ruled that out.


oh and I had one of those plug cleaners forever ago when plugs were still 2$ each but somehow that was still a lot of money. if I remember right they looked clean after using it but still didn't run great. if you have run lean and got that carbon tracing stuff, it can't clean that. I'd save that cleaner till after you find the issue. for now a cheap set of auto light plugs are worth it to rule that out.

I only say auto lite since someone had a spark knock issue in a elb thread years ago and Rbob said try autolites instead of ngk. said a few people had issues with ngk. I don't remember if that fixed the guys issue, but since everything I saw the guy post ended up being right, I just switched my car to them the next time I needed plugs. still keeping my ls stuff either oem for the daily and ngk for the ls3 car.

 

Well...as sofakingdom might say....he didn't really rule it out. He rationalized-ruled it out.

It would be easy to put it at exhaust valve open on one right/rear cylinder, blow shop air into that cyl's plug-hole, and listen for a commensurate amount of air to come out the corresponding tail pipe.

 

I don't know how recent his recent is but if it ain't too long ago maybe he knows it's not clogged up.

I wonder how much raw fuel you can dump down a new cat convertor before it's toasted?

 

The front bank of plugs looked about the same, actually. But I tested the harness and no shorts there.

One reason it's a little rich at startup is that I originally tuned it for a 58mm throttle body, but it was too difficult to drive with that thing and I eventually got a 52mm and replaced it back in 2019.

To address some other questions:
- All-roller valvetrain, so not a cam lobe
- Still runs poorly open-loop, so not an O2 sensor problem

 

do you know how long it took to go from new plug to what the pics shows?


clogged cats might be a thing. one of the guys on a tahoe forum just went thru trying find our why his was running badly. turned out he disconnected the head pipes and it ran perfectly. he ended up replacing the cats. he posted a pic and they look pretty good to me but I guess didn't flow enough.

 

I'll snap a few pics of the inside of my distributor. I thought it looked pretty good considering it's 20+ years old.

 

At most 100 miles. But both cats have been replaced within 100 miles as well.

 

Distributor photos

 

Have you checked the fuel psi regulator vacuum line yet?

 

I think that time is being wasted looking at the distributor. I also think that time is being wasted on a lack of clarity as to the actual problem/symptom. First let's review the distributor and it's function. Functionally, what's the distributor made up of?
*Pick up coil
*ICM ("points")
*cap and rotor

The pick up coil does one thing: It says, "now-now-now-now-now...", to the ICM and/or the ECM. That's it. That's all the thing does. It's the electronic version of the cam lobes, on an older points style distributor. There is only one pick up coil, for 8 cylinders and it can only work, or fail. It may be possible for it to work intermittently, but I've never seen that. What ever the case, due to it's singular function and the "mix up" of the firing order after the fact (done by the order of plug wires connected to the cap), the pick up coil most certainly can NOT discriminate between the left bank and/or the right bank. It can't. So if we truly have a dead right bank, it can't be the p/u coil.

The ICM does one thing: It says, "ground-ground-ground-ground-ground...." to the Ignition coil, by providing a ground to the coil's primary circuit, then opening that ground....it's the electronic version of the points' system's contacts, opening and closing on an older points style distributor. There is only one ICM, for 8 cylinders and it can only work, or fail. It may be possible for it to work intermittently, but whatever the case, due to it's singular function and the "mix up" of the firing order after the fact (done by the order of plug wired connected to the cap) the ICM most certainly can NOT, discriminate between the left bank and/or the right bank. It can't. So if we truly have a dead right bank, it can't be the p/u coil.

None of ^that^ has anything to do with "distribution" of anything, it's incidental to the term "distributor" and those components were mounted IN the distributor (starting in the 1920's or '30's), out of convenience and their location w/in the distributor has nothing to do with "distribution". Those same components could have just as effectively been mounted on the cam, completely remotely (as they are on L31's and LT1's) or where ever. The two parts don't have ANYTHING to do with "Distribution" of spark at all. They're simply signaling or actuating devices. The only two "distribution" devices in the whole engine, are the CAP and the ROTOR. They take a "spark- spark-spark-spark-spark..." and send that to 8 posts/studs where we plug in wires that run to the various 8 cylinders.
Thus, the cap and rotor are the only ignition parts related to the "Distributor" that could discriminate or have an effect on the left bank vs. the right bank. NOW...is it likely that the cap and rotor could or would send a spark to #1 post, NOT the next -#8 post, and not #4 post, but then yes to #3 post, but not to #6 post, but then yes to # 5 & then 7's posts....and then not to #2's post? It's incredibly unlikely.

So in this discussion of the distributor as a potential cause of the PERCIEVED problem of only one bank not running....I think it's wasted time to continue to look at the distributor. Spark plug wires? Plugs? Maybe, sure. Because routing, shorts/burned spots, fouled plugs, etc could cause that symptom. Could. Distributor? Probably not.

Having said all of that, I think that we need to go back and re-assess the "Symptom". It was stated at the beginning that the rear (right) bank wasn't firing.
1. I don't think the engine would idle on it's own (no throttle input) on only 4 cylinders
2. We have compression, valve actuation and we verified spark on the right/rear cylinders.
3. We were later shown pics of sooted plugs from the right/rear bank, so at least some firing has happened in those cylinders.

I think that the OP needs to put new plugs in it....get cheapy plugs for diag purposes if money is an issue....and start over on the assessment of what is REALLY going on with this engine. Let us know the facts of the condition.

 

Yeah it's not the distributor. It's not going to be happily spinning around and say I think I'll just skip firing 2, 4, 6, and 8. Unless there is some smart, evil, devious bastard that hates your guts out there that removed your distributor and filed down the teeth on the reluctor wheel for cylinders 2, 4, 6, and 8 and put in back in.

I probably got us off track answering the question about the shield rotating around and why it's so hard to pull the rotor button off sometimes.

 

Thanks Tom, I do think we need to focus on the most likely culprits. I've thoroughly cleaned and re-gapped all 8 plugs to 0.035. They have no more than 500 miles on them so replacement would seem unnecessary. It smoothed out the idle some, and there is some warming in the right side exhaust from the rear bank now, albeit more slowly than the left. It still reeks of unburned fuel on the right. But I don't think the whole bank is out anymore.

No indication of fuel in the fuel pressure regulator vac line.

 

could the coil just be weak?

not a tpi car, but I had a old Ford 300 6 at work, in some industrial equipment
it drove us crazy for a while, rebuilt the carb and all. ended up swapping the coil just for the heck of it and bam, ran perfectly. never fouled out a plug again and got all it's power back. it would run but always seemed like it had a leaking accelerator pump and fouled plugs very easily.

 

LOL.....that's funny.

Not to belabor the topic, but there aren't even teeth for those cylinders. There's just teeth. They don't correspond to anything related to the specific cylinders...they just go around and create a signal for the "NOW!", 8 times per revolution.

 

Remember this is a smart, evil, devious bastard. If he times and clocks everything right he can knock out whichever cylinders he wants.

 

Is this how threads die when ideas run out?

 

I think you have a bunch of ideas and things to check still....I was waiting to hear back on the out comes of these tests/checks.

 

I have been unable to identify any smart, evil, devious bastards who would have tampered with the distributor in such a way as to render the rear bank inoperative.

I have already replaced the plug wires, brand new Blue-Streaks from O'Reillys and the plugs are re-gapped and thoroughly cleaned.

 

And? What did the plug gapping and wires accomplish?

 

I still think you need new plugs not just cleaned.

starting to think this one can't be solved. Gremlins?

 

Answered previously here

 

Man...this is one diabolical thread, diag routine and update of the ...."results".

Your link took me to a post by Airwolfe at the beginning of page 2. I saw nothing about the results of new plug wires and cleaned/gapped plugs there or anywhere on page 2. EITHER WAY....why are you bringing up new wires and cleaned up, old plugs, from a post I don't see, from two weeks ago? What's that got to do w/the price of bread?

 

Because you asked.



I've been doing a lot of other restoration work on the car in the meantime.

 

Did I? Let's go back and have a look......

Yeah...no, I didn't ask about plug wires and plugs. I didn't think that I had. Best of luck!

 

Don't know why this got so contentious, but you did ask. Thanks for your insight on it, your commentary has been very helpful. I've got other issues I am addressing on it in the meantime, in case somebody has any other ideas.

 

We must be reading different threads. Not contentions...just the facts don't align. What ever. Good luck working through it. It's a killer car....I'd love to see/hear it running.

 

It looks like it's a problem in the exhaust. I decided to take it out for a drive yesterday and while warming up it was spewing glitter out the right side exhaust and that turned to melted chunks of cat when I revved it. I can hear the hissing of excessive backpressure in there too when I'm trying to accelerate. By the time I'd driven it around for a good half hour or so, the right side was moving normal hot air at normal velocities. I really want it to have cats, and it shouldn't be burning them up so quickly. So there were at least two problems and the exhaust is more a symptom, but I think with all the other fixes I did that it should be cleared up and maybe just needs a little tweak in the code to back off the fuel a bit and try some high-flow cats instead.

 

 

So turned out to be clogged up exhaust by bad cats. Not a rat or mouse nest but could have been.

Until you get you car tuned perfectly I'd put a "Test Pipe" in place of where you want the cats to be. They get ruined very quickly when the AFR is not right.