Took off the cap today to inspect that and the rotor and several things were discovered (PICTURES OF THESE BELOW):

1. Inside of the cap the terminals appeared burnt. The one closest to the floor was burnt severely and under the terminal the plastic of the cap towards the floor has a burn mark that has discolored beige. It appears a small explosion of some sort occurred at the terminal and discolored the plastic directly underneath.
2. In addition oil may have pooled inside the cap about 1mm high. Right under the terminal that is discolored and covering the discolored plastic. It could be that the oil was under the cap and when I pulled the cap off and up the oil went over the rim and fell into the cap. Yes, that's how much oil is on the outside of the cap. It's literally dripping. But if the oil wasn't in the cap I don't understand where this burn mark came from. "Something" occurred here to have created this mark, that's what I'm afraid of.
3. The rotor is also severely burnt and features the same beige discoloration.
4. The piece of metal on the rotor that contacts the spring point on the distributor cap is nearly flat.
5. The spring point on the distributor cap extends out about 5mm. I accidentally pulled on it while cleaning the cap and it slapped back in under spring tension. No damage appears to have occurred.
6. The cap has no carbon tracking and no dust. In fact I was surprised by how clean it looked other than the oil on one side.
7. The inside of the distributor where the engine meets appears to have oil stains on it. In my naive opinion it appears the shaft seal is leaking and oil is entering the distributor. Although the oil leak does not appear severe because the inner components such as the ICM are not covered in oil at all.
8. There is no rust or red dust inside of the cap. The only portion that has a red dusty color is this ring around the shaft (looks like a magnet).
9. For some reason the leak cover that would be inside the cap is missing.
10. The shaft itself has no play. The shaft and its rotor twists slightly along its axis but does not move side to side.
11. The outside was unremarkable but there was severe buildup on the outside of the cap, the side facing the floor. Naturally the oil appears to have seeped out of the cap and pooled under the cap where dust and dirt attached to create caked dirt.

So what did I do?:

1. I cleaned the outside of the cap with degreaser and water. Some water accidentally got into where the plugs would go. I pushed a paper towel inside to soak water and used dust off to blow water out.
2. The inside was cleaned using liberal amounts of brake cleaner.
3. When the cap was clean I left it baking in the 110 degree sun we're having outside for about one minute.
4. I re-installed it and placed all of the plugs in the proper position.

Guess what? It doesn't start. It's strange because it usually starts and especially on a sunny day like this one. I'm thinking I messed something up now. It also sounds like it's going to catch on and startup more than it does when it usually doesn't start. I also heard some kind of mechanical noise under the hood when I was cranking but it could just have been from the engine starting but stopping prematurely.

Sigh.

Maybe it had something to do with how I cleaned it? Maybe I left too much lint inside? Maybe I didn't give it enough time to dry after water got into the spark plug ports?

By continuing to crank it I hope I didn't damage the coil or something. I'm going to try again in a couple of hours. But I'm just glad I got the cap off and it was extremely easy once I found out how I could get to that last bolt that holds the cap on.

Could these observations explain the intermittent no start issue I'm experiencing? On some days I find that it is hard to start or doesn't start at all. On other days it starts up as soon as the key is turned without doing the chugga-chugga-chugga.

So anything you guys want to add? I'm not sure if I should even get the cap and rotor to replace because the oil leaking inside is making me believe I should actually be investing in a new distributor. At the minimum I know I'm replacing something. Either the shaft seal, cap and rotor or the entire distributor itself.

 

So you have a no start/hard start problem. You already inspected/cleaned dist cap and noticed wear. Not sure what the mileage on the car is, and if the cap was replaced before, but it sounds like it's time for a new cap and rotor. You can visually inspect the ignition wires for cracks, abrasion - also measure with an Ohm-meter for resistance. Not sure what the maintenance history on the car is, but you may need a fuel filter as well. You also need to determine where the oil leak is coming from - and replace required gasket/o-ring - again maintenance.

 

Previous owner never did any maintenance.

I have a treat for you guys. Pictures! Finally! Now you can see a "MessAround eye view" of the problem.


Note the pooled oil. Actually the oil pools closest to floor, that would be the side of the cap towards the top of this picture. Since I rotated the cap when I took it off the oil pooled on the other side due to gravity.


Notice the burnt erosion on the rotor contact.


Self-explanatory. Inside of distributor.


Shaft. See any abnormalities here?


After cleaning the oil I see this where the oil was. Burnt erosion.


Same spot above before oil was cleaned.


Rotor contact. I notice some burning I think and it's almost flat. Is this normal? I thought it was supposed to stick up a little?

 

Guess what? Car starts. I made another important discovery. Sometimes when the key is moved to ON the car does not make a whirr and the click never happens. Of course the car isn't going to start up then. This must be the root of the problem. This problem is intermittent so I never thought to check for the whirr and click when the car has trouble starting because the whirr and click happened when the car does start so I assumed it always happens.

Now I know there's a main relay problem of some sort. After turning it back to OFF and back to ON several times the whirr occurred as well as the click. Turned to START and the car started up fine albeit a little rough.

Fuel pump or main relay? Also noticed that today is a devilishly hot day, the interior is baking hot. It's so hot the air inside hurts your lungs when you breathe it in. This makes me suspect main relay. But would a main relay issue not cause the whirr to occur? If it communicates with the fuel pump I would think so.

Anyway that's for another time and place. I'll pull the main relay and look for crack joints or something. I'd like to keep this thread on track for the distributor.

 

Yes, main relay.

 

Your symptoms could also be a failing ignition switch assy. This will produce intermittent action. Notice when you turn the keyswitch to On, whether you have Check Engine Light and Alt light come on for 2-3 secs and CEL goes off w/ fuel pump.

If the lights don't come on when you have no clicks and no fuel pump, this suggests ignition switch assy. If they do come on, the MFR is likely.

good luck

 

Nope, the lights always come on and go off even if the fuel pump does not whirr and the click that follows the whirr does not happen.

I actually did some naive tests for ignition switch failure like shaking the key lightly in the lock cylinder and turning to START and quickly letting go to let it snap back and observe the lights on the dash to see if they all go out. I'm pleased to report that the lights did not go out.

When this issue occurs where the fuel pump does not whirr and the click does not occur afterwards the lights always come on including CEL. Regardless of whether fuel pump whirrs for two or so seconds and the click happens afterwards the CEL goes out. In other words the lights always behave normally. If I had seen an abnormal behavior with the lights that would have been a dead giveaway to me but the lights were always normal. It's the whirr and the click which I never thought to check for because I have to actually hear them.

Now I actually have to pull the MFR out but I don't have a 10mm deep socket. I'm either going to have to buy one (probably not), find a wrench or get it out while leaving the case attached to the car. Already removed the Cruise Control Unit but can't get the 10mm holding the MFR on to the car removed. I also noticed that while other diagrams state there is a 10mm bolt and a 10mm nut holding the MFR on my car only has a 10mm bolt. The nut is missing but the bolt the nut screws on to is there. Maybe this led to its failure because it wasn't properly secured?

Also about the distributor does anyone think it's leaking internally? I might actually go the shaft seal route if that's the case and I can get away with buying a new distributor. It just seems like such a waste to get rid of the OEM ICM that's in there if everything else works.

 

Yes, you have a leak. Hard to say how bad. You'll have to weigh the cost of replacing the seal (time, tools, parts, ect) vs a new to you distributor (new from a store, bone yard)

 

The MFR on 90-93 is not too bad to remove, but you do need to remove 10mm bolt holding the bracket in place. I don't remember any nut at all.

Others have simply pulled the MFR base from the case leaving the case hanging. This sounds easy, but releasing the tabs which retian the base to the case is not easy either.

Installing a new seal in the distributor is not a terrible job, but a bit tedious. Rebuilt distributors are available for < $100. You will spend $15-$25 rebuilding, and still might have problems. You decide.

good luck

 

Took the thing out, checked the solder joints and no cracked solder joints I can see. At least not as evident as the ones in the pictures I've seen. I think I can see a faint circle that shines in the light and on one of those joints that has the pin sticking up I see a rough circle around the tip of the joint where the pin meets the solder but not at the bottom where the solder meets board which appears to be the more common breakage point.

In any case these two look really small. It's also worth mentioning that today it was really hot and the fuel pump wouldn't whirr nor would the click occur afterwards, again a no-start day. Except today was much worse, I must have turned it to OFF and ON fifteen times with no change. After I pulled the MFR out, looked at it for a good half an hour and put it back on, turned the key to ON and guess what? Fuel pump whirrs, click happens and car starts.

At this point I'm not sure what's going on. My hypothesis is that the MFR solder joints are indeed broken and having it inside to cool allowed it to recover such that when I put it in the car afterwards it worked.

1. Is it possible for the actual components in the MFR to fail? I'm not talking about the solder joints but the actual components such as resistors. Maybe this thing is dead or dying internally and can't be repaired? I'm trying to come up with an explanation as to why I don't see any broken solder joints.

2. Is there anyway I can bench test this thing with a multimeter without applying voltage? I'm seeing these bench test routines but they involve putting voltage and I have no idea how to do that without having this thing connected to the car battery with the cover of the MFR off. I'm afraid of shorting something out with MFR cover off.

3. Would a dead or dying battery or low voltage cause the main relay to act as if it's failing? I'm wondering if maybe this three year old battery might be the problem? Starter cranks fine though and car starts often which leads me to believe it is NOT the problem. Anyway I can test the battery with multimeter?