johnster

1986 Trans Am 305 FI TPI w/ large body HEI distributor.

I have the distributor out and shaft removed. Took out 3 screws and lifted out coil, shield and locator star.
Then I removed the C clip retainer at top of shaft.
The casing/holder will not come off the shaft. It is just STUCK. No other visible fasteners. I can't put in the replacement till I get this old housing out. What am I missing?

Any reason it in there so tight? Should use a puller? No one else has this problem.

Help

Rebuildman

Small burr on the bushing above the groove where the C clip came from. Use a file to clean it up?

johnster

Thanks for responding, I'll take another look, but seems clear. I''m thinking it's just seized from heat and age.
I'm going to try heat on housing (again), but I'm pretty sure the inside will heat up almost as fast. Soaked it in some PB blaster overnight.
I'll take the other modules out for room to work, then try some pullers.
I just wanted to make sure there are no other hidden screws, (or some special incantation I should perform).

Since there aren't any vacuum mechs in there, that tab is locked in place with a roll pin, so I'll have to pull that to try and wrench it
back and forth and break it free. I'll definitely post the solution if I find it.

johnster

Woo hoo. I got it out.
I dug out the grease under the C-clip and loaded penetrating oil in there overnight.
Then using a lever I gently pried it up evenly until noticing it had lifted above the C-clip line, and I knew it wasn't seized anymore.
(I didn't want to crack, bend or break it up. I think now it has to be steel.)
Now, underneath is a bunch of goo in the cavity below that I think may be dried up grease that comes up through two holes in the bottom of the housing.
This I believe is a reservoir of grease that migrates to tiny bearing at top of the shaft to lube it.
I'm going to pack that with new (marine) grease, as well as at the top cap (where the rotor screws into) when putting the shaft back in.

If anyone reading this has a comment, I'd love to hear any cautions or advice.
Thanks for reading.

johnster

Bump; on the grease question.
I cannot find any discussion on what is in the reservoir beneath the pickup coil housing. I dug out the old dried up crud which must have been grease that migrates up shaft to the top.
I put sticky (red) marine grease in there; am I on the right track or all wet on this. Shop manual does not mention it other than how to remove and replace it.
All other discussions are about older mechanical models with cam grease and advance weight lubes.

johnster

Bump; on the grease question.
I cannot find any discussion on what is in the reservoir beneath the pickup coil housing. I dug out the old dried up crud which must have been grease that migrates up shaft to the top.
I put sticky (red) marine grease in there; am I on the right track or all wet on this?
Shop manual does not mention it other than how to remove and replace the coil itself.
All other discussions are about older mechanical models with cam grease and advance weight lubes.

RBob

iTrader: (1)

I can't recall where I read this, but my understanding is that it is an oil reservoir to lube the upper bearing/bushing. A thick/heavy foam ring is installed and then saturated with oil. Even the small cap distributors have this arrangement.

Filling with grease is much better then nothing. As it will weep oil.

RBob.

johnster

Thank you RBob.
I think I understand, and have read about the foam ring, which I didn't find anywhere. There was nothing below the housing but the gunk in the little sump, and dried grease was poking through the two holes in the housing.
The cap below the star pointer (under the rotor shelf), had no foam ring or plastic seal as described in 60-70s distributors, this one just sat on the shaft as a simple race arrangement.
I was also thinking this reservoir could be filled with old dried oil that came up past the shaft and collected over 38 years.
Where is the foam ring you are referring to? I can't quite picture what others have described, and have little experience here yet.
I'm worried there was a foam gizmo below the housing that kept oil out of the distributor, but has disintegrated, and my new grease will fly up through those holes and grease everything.
Which would not be good.
Shop manual has all the steps to remove the assembly, but never mentions foam, felt, lube or anything else.

Rebuildman

I have the Delco tube of grease that is called for that goes in the reservoir. I will get a part # off the tube tomorrow.
Some where I have the Delco manual that calls it out.

Rebuildman

I have used thick wheel bearing grease to fill that up also. The old stuff resembles the original as it is a little fibrous.
I might have spoken too soon on the grease I am thinking of, I don't believe I have any. But I will check.

johnster

Okay, so they did fill it with (some type) of grease. I was just guessing, but it made sense.
My only question is now, should I put some sort of felt/foam under those holes, or should they remain wide open (again, no evidence of that, just what looks like dried grease).

Rebuildman

Originally the well was full of grease, then a thin plastic washer was pushed over the grease to seal it off from the points or moveable pickup coil. On top of the plastic washer was the felt washer soaked in oil. Then the moveable advance plate went on top.
Now you don't have the moveable plate, the grease is still needed for upper bushing lube. I don't remember if the later housing will take the plastic seal, but it's easy to see if it will. You also made no mention of finding an old one sooooo??
As far as the felt washer goes, if you have no plastic seal the felt washer will keep the grease in its place.
There should be two holes in the upper bushing that the grease will seep through, make sure they are clear.

johnster

I am not seeing any holes in the bushing. The housing presses on to the upper bushing fairly tightly, (remember the old one was almost seized on there till I pried it off.
The only path up to the race would be between the housing and the bushing it presses onto, then past the C-clip around the top of the bushing that holds the housing down. The top race of the rotor shaft sits directly on top of that.

I think the new coil is completely enclosed in plastic now, maybe that will keep the grease in place, but not sure how that worked before as the wires were routed out the bottom (I think, at least the new one is that way).

Sorry if I seem thick, but maybe we are talking about different parts. I wish there were tech notes on how this version goes together, but there just isn't anything out there, or in the factory manual.

Tom 400 CFI

Are we sure that gunk isn't just "dried up" engine oil? The shaft has a spiral groove cut in it, to move engine oil up the shaft to lubricate it. The engineering of that isn't likely to be SO perfect that oil makes it to the top....but none spills out. This is no Polsha! Designing such a lube strategy, it's likely that they'd design it so as to err on the side of excessive/leakage, rather than insufficient and bushing galling or seizure. I'd think the gunk is just the small amount of oil that's leaked out the top of the housing/bushing, and dried up/got baked over years of driving.

johnster

Thank you yes, I think that is one of the possibilities considered. With all the discussions I've read lately on the iNet, with added grease in some of these older systems, it seems like this model should have that too. I'm starting to lean toward your idea as more probable; being a place to store old gunk that gathers.

When I took it apart, I had a bear of a time getting the shaft out, as the dried gunk on it seized it in place after only moving a couple inches. The same thing with the pickup housing; also stuck, and required penetrating fluid to break it free.

Some discussions led me to believe the oil couldn't make it that far up, and the grease was there to climb up to the top bushing on its own. But since the shop manual never mentions it makes me think that's not true either. The rod is smooth w/out any channels for it to migrate, but not so tight that oil would be blocked either. Does look like the shaft has paths maybe.

I bought this car in 1990 as a second owner, so I'm pretty sure it's never been touched. I started working mostly as a restoration project a few years ago because it just got old. Intake rebuild, timing gears/chain old and sloppy, fuel rail, injectors, crumbling sensors so old, that just touching them caused them to break. Unavailable parts like egr sensor just increased the fun. Car was running so nicely after sorting out all these issues that I was surprised by unexplained stalling when slowing to idle while driving, and completely warmed up, that led me to give the distributor this "rebuild".

Now I'm thinking I should take my new grease out, and run it dry, leaving room for old oil buildup like you say. No evidence of felt washers, plastic seals etc. also point that direction.

I am going to pop the coil housing out again and look for anything I might have missed as far as a migration path past the bushing to make sure nothing is clogged. I didn't want to crack that open again as it was tedious to get the interference of the pole piece centered. (I had to take it apart to get it in there, and don't fancy doing that again.)

The inside of the housing the oil would have to migrate past the bushing looks like "refiling" for lack of a better term. Maybe the oil moves through there when very hot.

Then, I'll just grease the top cap and put it all together and see how it works.

Forgive the long response, but I wanted to show where I was coming from and how I got here. I just started thinking about it, and wasn't convinced it was correct, which could lead to catastrophic failure.

johnster

Update; I finally found in Electrical section of Serv Man; "Oil resevoir under pickup coil lubes top of shaft." No mention to fill it with anything, must fill itself. No felt washers etc.
No spiral oil path, but 5 channels at top of shaft-hole to allow oil mist migration I suspect.

Now:
I have it back in there, and starts, runs fine, idles down after cold start, runs 30 seconds to 2 minutes and then shuts off like a switch.

I inserted the following into a Youtube discussion with a fellow on progress:

1986 Pontiac T/A w 305 FI . Fuel pressure is 36-42 when running, up to 42 when stalling, just a glitch upward upon stall. New ICM, pickup coil. Runs, idles down after cold start injector swithches off. Revs fine, smoothly, settles, runs, then just shuts off like a switch. .. ADD: It used to just start and shut off before new pickup coil change.

Timing is 6 btc base with bypass unhooked per spec. Noticed a slight jump once when timing, but resolved before next stall. Cannot run long enough to troubleshoot. Looking at Electronic Spark Control; checking ECM charts for clues. Bypass no longer sets a trouble code when disconnected as it should. Checking on possible driver damage to ECM with maf/maf pwr/ fuel relay logic, and found possible ECM fail at spark control input to ESC Module (Module unplugged) input is less than 2 volts; not good according to chart.

Fuel rail and regulator rebuilt. Fuel filter replaced less than 100 miles ago last summer. New intake gaskets; upper/lower, Mass Air Flow sensor. Goes into closed loop, on/off time equal. O2 sensor working. No ecm codes. Computer won't communicate with Actron obd1 interface; and there is a signal present on the serial line. Makes troubleshooting laborious and primitive.

Next steps ideas would be greatly appreciated. Thanks to all.
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OrangeBird

iTrader: (1)

Hi Johnster, I'm not being nit picky here, but I want you to know how the cold start injector operates. Your statement of "Runs, idles down after cold start injector swithches off" gives the impression that you believe the cold start injector is operating as the engine warms up, this is not the case. If you look at the wiring diagram for your engine you'll see that the CSI is only active while the starter is cranking the engine (and the engine is actually cold enough for the "cold start switch" to allow the CSI to operate) and is not in control of the idle as the engine warms up.

The CSI circuit is shown just under the distributor in this diagram, note that the 3A "Crank Fuse" indicates "Hot in Start" .

Tom 400 CFI

Can you put a spark tester on it, run it and when it "shuts off", see if it still sparking as the engine coasts to a stop?

Rebuildman

I have had shutdown problems in the past that were caused by EMI on the distributor control wires. But it would always set a code and turn on the check engine light. So not sure you have this problem, but it is worth thinking about. The fact you don't get a check engine light set when disconnecting the brown wire to set the timing is a big clue. If the four wires going to the distributor have been double checked as secure and connected properly and are not near any high voltage spark plug wires, I would try another ECM if possible.

johnster

Thanks OB, I reread that chart and it is indeed on only during cranking. I thought the 8 seconds on time for that circuit would last into startup, but alas it is only 8 seconds total while cranking, and temp sw is still in play. i.e. Won't need cold start extra gas spurt if cts is warm. (And if ice cold, 8 seconds of extra gas while cranking should be plenty.)

I should have stated it as, "Runs fine, idles down normally from 1000 rpm to about 700 after first starting. Cold start working, as it fires right up. "

Subsequent starts all sound about the same, fires right up, idles down, settles out, runs for awhile, then shuts off like turning the key off.

But at least now I know that the initial higher idle is not a function of the cold start circuit, as I thought.

johnster

Thanks Tom 400 CFI, I'll try that, but there is little coasting as it shuts off like key off, (it's TPI FI). Since I have a 'coil in cap' type distributor, I'll have to put it inline with a spark plug, or use a timing light on a plug wire and watch that.

Tom 400 CFI

Yep. Exactly. Perhaps you could increase the RPM, while it is running, thus extending the coast down time for better observation.

johnster

Thanks for the comments RBMan, and others; I was able to spend time on it last night; here's an update.

The four wire conn at distributor check out and ground is solid. I definitely will run the bypass line issue down and try to set a code by pulling it and following any time outs in trouble charts; I.e. how long does it take to set that code, or if there is a self reset etc. That whole area got me looking at the spark control Module and possible ECM driver damage. It's intermittent, so charts can deceive too as you know.

Meanwhile, I was going through MAF power and burn-off relays and fuel pump relay logic. I found poor connections on the power relay and the fuel pump relay had one too. I took them apart (carefully); coils are all good and work. Contacts were unreliable at best though, so I cleaned them to get good contact at 0.0 to 0.1 ohms. (Before they jumped around from a few ohms to about 60. (Essentially, junk.) Reinstalled to check. Caveat; if the protection resistors are burnt, CEMF spikes could damage the ECM outputs.

Anyhow;
Reset ECM.
Started it, and it stalled right away. I then let the burn-off cycle run its course.
Started it again and it ran fine for about 15-20 minutes! Huge improvement from 30-90 seconds.
Ran fine, although about 800 rpm instead of 700. I then turned the key off for a few minutes.
Started it again, and then it died again. Dang.

Huge thread in TPI talking about these relays, interchangeability and power ratings. They were swapping them around as they are similar, but a bunch of people saw the same rpm changes etc, that finally sound close to my issues. Lots to sort through, for they changed through the years (86-89) with tech advisories to replace values etc.;

And now they are hard to get and not well defined. Great; another can of worms, but I'll track them down. I've have an 82 s-10, and remember looking inside a relay and the contacts were amazingly well made. These things are cheesy by comparison, and their best days are behind them.