Hello, I’ll jump right into it.

It’s a 1987 pickup with a 22r engine.

The other day I drove to the store in the rain. When I came back out and tried to start the truck it cranked over about one revolution and then seemed to bind to a stop. It almost sounded like a weak battery but a little different. I tried again and after a few attempts it started up but ran roughly. I headed straight home (3 miles) and it continued to stall and run worse and worse until I rolled to a stop at the curb in front of my home.

Now it will not start. Sometimes it will crank more than other times. Usually just a few revolutions before the binding stop.

The battery has 12.6 V. The compression in the cylinders is about 180 in all of them.

Here is the big clue:

If I unplug to coil wire then it cranks well. When I plug it back it, it cranks a few times and then gets halted.

Does this should like a timing issue? Could the timing be so far off that the pressure from firing on a piston in the upstroke is halting the engine? Would the next step be to remove the valve cover and look at the timing chain or is there anything else this could be?

Thank you for any advice.

 

Check the distributor cap and rotor. Water can get inside the cap and cause all kinds of mayhem. There should be an o-ring on the base of the distributor cap. Make sure it's in good shape, give it a thin coat of Vaseline or silicone dielectric grease. It makes for a better seal, and the oring lasts much longer.
Same with the wires. Pull both ends off of each wire, and blow dry air into them. Put a dab of silicon dielectric grease in them to prevent this in the future. Ensure the outside of the wires are dry end to end.
Check that the coil and ignitor are dry all the way around. Even a little water between the case and the body can be a problem.
Check the various plugs and connectors, like the one going to the distributor, the wires to the coil, and so forth, are dry inside. Put a dab of silicone dielectric grease in every female half of any plug you happen to open. It will help prevent water from getting in, and corrosion from building up.

Once you're certain everything is dry, try to start it again. If it will, problem solved. Check the timing and idle speed. 5° BTDC with the jumper in the test jack, 12° with it removed. Stop the engine before removing the jumper.

If it won't start yet, keep drying everything in sight. If you have one, an electronics use heatgun on a fairly low heat, or even a hairdryer on low heat, high speed, can work wonders.

Check the fuse block and connectors under the driver's side kick panel. It, and the ECU over on the other side, are known for water intrusion from the roof channels. Check the ECU is dry, and all it's plugs are dry as well. Again, some warm air can do wonders.

That's all I can think of right off. I hope something in all my rambling is some help...
Pat☺

 

Thank you, Pat. I checked it all when I got home today and everything looks dry.

While I had the distributor open I hand cranked the engine to the TDC mark. When the mark on the pulley is at 0 then the rotor in the distributor is pointing at the #4 cylinder (furthest back). Isn’t that 180 degrees from where it is supposed to point, to the #1 cylinder?

I have never had a timing chain jump or skip on me but is that what seems to have happened?

Is it possible for a timing chain slip to make the rotor be off by 180 degrees? Is it an insane idea to rotate the position of the spark plug wires in the distributor cap 180 degrees?

 

The crank turns twice for every rotation of the distributor. If you turn the crank another revolution, it should come around to the number one wire.

When it's there, both #1 valves should be closed.

 

True story from long ago. Back in 1971 I bought my first car, a used 1965 Chevy impala V8. Drove it to college a few days, one rainy day it refused to start when I wanted to go home. Cranked and cranked, fired intermittently but never caught. We towed it to the dealer, they checked it over, charged me $50 (a lot of money for a college student in 1971), and did no good whatsoever. So, we towed it home back to the farm. My dad had a 1968 chevy with the same distributor. We swapped caps and my car immediately started up and ran fine. Put the old cap on and same old problem came back. Looked carefully inside the cap and there were carbon traces burned on the plastic which re-routed the spark to the wrong plug wires. I scraped off the carbon and the car started and ran, but I didn't trust that as a permanent solution. A new cap solved the problem more elegantly.

So, I suspect you have something similar. Moisture inside the cap allows the spark to travel along the plastic incorrectly and the heat carbonizes the plastic creating a mildly conductive carbon trail that the high voltage spark can easily follow. That provides a permanent path redirecting the spark to the wrong place. In your case, probably to the next plug in line, causing it to fire early, resulting in stalling the starter. Even after the cap dries out, the carbon path is still there and the timing problem persists.

The only proper fix is a new cap, plus fixing the seal that allowed moisture inside in the first place.

Hope this helps. Good luck!

 

That's why I keep parts when I do my spring tune-ups. I've gotten a couple distributor caps with hairline cracks in them from the manufacturer. I just use the previous cap I had on before I got the new one. This way, I always have a set of tune-up parts available that are only a year old.

Sure does sound to me like a bad distributor cap, or rotor, to me. They're cheap. Get a new one and try it. At worst, that's not the trouble, and you have a known-good spare for the next tune up. Always go with OEM wherever possible, and definitely get a new o-ring for it when you get the new cap and rotor. Put a thin layer of Vaseline on it when you install it. Makes them seal better, and last longer, it really does.

As was said before, if the rotor was pointed at #4, you may have the crank 180° out of phase. Rotate it one revolution and see if things line up. Bet they do. You can be certain if the #1 valves are both relaxed. If one is tight, or open, the crank is out. Give it that one rotation.

Good luck to you!
Pat☺

 

I had forgotten about the two revolutions in my eagerness to solve this thing. Thanks for pointing out my mistake.

I removed the valve cover. The timing chain looks ok from the top. I also checked the valve lash. They are all too tight. I had set them back in April when I needed to pass smog. So I am sure they were set to .008” and .012” according to my manual.

I measured them now at:

Intakes .006, .005, .006, .006.

Exhaust .009, .008, .009, .009


I assume that I should correct the valve lash since I have it opened up but I don’t think that will fix it. The fact that it turns over and cranks well when the coil plug is disconnected and when the plug is connected it can barely crank at all before halting seem like the best clue that I have.

I will try replacing the cap and rotor and let you know how that works out.

 

Yeah, definitely set the valve lash correctly, or you could well burn a valve or two. Those are WAY tight. Were you maybe checking them cold, but had set them warm, as you're supposed to? If you're going to check them, you should check them under the same conditions you set them, you know?

Anywho, I wish you the best of luck!
Pat☺

 

I think that I did set them warm and, of course, now I am checking them cold. I would expect that the gap would get smaller when hot so I am not sure how they got so tight. Since I can’t set them warm now, I will set them cold at the .008 and .012 specs and go from there. Along with trying the cap and rotor. That’s on my plan for tomorrow.

 

I adjusted the valves and replaced the cap and rotor but neither made any change. It still had a weak binding crank when the coil plug was attached and a strong crank when the coil plug is disconnected.

When I was replacing the cap I checked the position of the rotor at TDC - 0 mark on the pulley. At this position the rotor was pointing about 1/2” past the #1 cylinder contact. I loosened the distributor nut and rotated it back as far as it could go which was about the 1/2” distance to align the rotor and #1 contact. After doing this I was able to start the truck although it ran roughly and seemed to lack power when I gave it gas. I didn’t try to drive it.

Does this sound like the symptoms of a slipped timing chain? Am I right that at TDC the rotor should be pointing directly at the contact or was it correct to be pointing past it?

 

You are correct. It should point directly at the #1 contact. It's possible the distributor jumped a tooth. Or the timing chain did, but I'd go with the distributor first. You can try pulling it and stabbing it again.
When you go to stab the distributor, turn the rotor to the 12 o'clock position. When you slip it in, it should turn to the #1 position as you do. Make sure the hole for the retaining bolt (adjustment bolt) is as close to the center of it's throw. Make sure, absolutely certain, that the crank is at 0°, and on the #1 cylinder. Remember the 180° situation. If you go to stab the distributor, and it still goes past the #1 contact, it may be the harmonic balance on the crankshaft has slipped a little. They are prone to doing that. The rubber in the middle of them get's old and breaks, allowing the pulleys to slip. Something to check for. You can put a straw down the #1 spark plug hole to verify it's at the tippy-top of it's throw.

Just a couple thoughts. I get so few any more...
Pat☺

 

Do you have water in the cylinders? might be worth pulling the plugs and turn it over a few times. Have someone watch to see if water comes out of the holes when cranking.
And no, I'm not implying rain water got in the cylinder(s).

 

There is no water in the cylinders. I used a paper straw to check the piston position and it came out dry.

I first used the straw to check when the piston in cylinder #1 was at the top of the bore. It aligned perfectly with the TDC mark on the pulley so it looks like the crankshaft and camshaft are still correctly aligned with the chain.

However, when I removed the distributor cap I found that the rotor was actually pointing in the wrong direction (by about 180 degrees to the #4).

This is is confusing to write because I had written earlier that it was pointing to the number 4 when it was at TDC but at that time I was only looking at the rotor and the pulley. Ifter being reminded about the two rotations I never actually checked the rotor position again. I just assumed that I had checked it on the wrong rotation. It turns out that the rotor was actually pointing 180 degrees from where it should.

I pulled the distributor and realigned it as Pat instructed and the truck started and ran. The timing is a little off but it is running in a drivable condition, basically back to normal.

So, the truck is fixed although it may just be temporary until whatever happened causes it to happen again.

The gear on the distributor looked ok. What could be the causes of this? Could it be something inside the distributor? Is the gear in the engine that turns the distributor the most likely culprit? Maybe it’s worn or broke a tooth? I don’t know anything about the harmonic balancer but if the crankshaft is still aligned then can that be ruled out? Any thoughts on what could have caused the distributor shaft to rotate 180 degrees?

 

Yes, it's entirely possible for the drive worm gear to have become worn down, or have a broken tooth. Having said that, had you had the distributor out at any time before all this froo-fraw started? IE dd you pull th distributor for some reason, and once you got it all back together, suddenly this trouble reared it's ugly head? Don't get me wrong, it's entirely possible for this to happen all by itself. But, is it possible you put the distributor in wrong?
I'm not trying to imply anything. Just asking to find how all this happened, you know?

Ok, well, whatever had happened, it's taken care of now. I think the harmonic balancer is fine, from your description.
Set the timing, with the jumper in, idle set to 800-850 RPM, engine warmed up to operating temp, to 5° BTDC. Then stop the engine, pull the jumper and fire it up again. It should be about 12° BTDC, with all other variables near the center point.

I hope things continue to work properly so you can enjoy your truck
If this happens again, yes, the drive gear for the distributor may well be bad. Or the timing chain tensioner, or guide, are too loose, allowing the chain to jump a tooth. There are a few possibilities, to be honest. You'll just have to eliminate them as you come to them, you know?

Wishing you the best of luck.
Pat☺

 

I had never removed the distributor before. I would assume that the camshaft and crankshaft would be out of alignment if the chain had slipped so I guess at this point I will assume it’s the worm gear.


Thank you, Pat, and everyone else for all your help with this. I so appreciate these tech support boards and the people on them like you all who are generous enough to offer their help. I have a few old vehicles that I have managed to maintain with the help of various groups. I myself am not able to ever offer much advice because I usually forget everything shortly after fixing it. But hopefully others will at least be helped by the postings.

 

I am still struggling with my truck. Maybe I should start a new thread because the issue is different but it all stems from the same initial breakdown described above. After resetting the distributor, as I mentioned, the truck started and idled pretty well. I thought that it just needed the timing set so in the last post I said that it was fixed.

I did set the timing and it idled a little better but bogged down on higher rpms. I repaired a vacuum leak at the intake manifold and the idle now is very smooth but it still has no power at higher rpm.

when I increase the throttle I can see gas spitting out the top of the carburetor. From this I am guessing that it is a timing issue? Does this sound right?

The vacuum advance diaphragm is shot but from what I’ve read this only affects the idle. Could it be the distributor? I am not sure where to look anymore so I am writing in to see if I can get some more help.

 

Whelp, I finally confirmed the problem. The timing chain had jumped on the cam sprocket. I should have checked the chain and sprocket alignment in the beginning but I wasn’t aware of the indicators on the sprocket and chain. I’m always learning something new.

Anyway, just wanted to post this conclusion in case someone else runs into a similar thing.