I’m a new guy and technologically impaired. I have read a lot of old conversations on this site that were helpful with finding problems concerning my 1991 Acty truck but have not been successful starting a conversation yet. Maybe you could let me know if this conversation is successful and I could pick your brain on possible distributor issues with my truck. I bought my truck about 3 years ago and used it a lot to hunt and camp and cruze around in.....love it. Then it developed a few problems and has been sitting forover a year. I have been all over that thingin different directions, some wrong and a few right. I have narrowed the problemsdown to ignition, the charging system, and a bad thermo valve that steersvacuum to the timing advance. The thermo valve is a no brainer. The charging issue takes a back seat to myignition issue. So here goes. At normal operating temp, cylinder 1 has erraticspark. Plug wires are good, I swappedthem out to check them. I’m down to thedistributor cap, rotor, Ignition control module and whatever else might be deeper into the distributor that I am less familiar with. I figured if the coil was bad, all three plugs and their spark would be affected. So.....at normal operating temperature (issue isn’t as prevalent when truck is cold), what do you think would most likely cause number 1 to have intermittent spark?
Possum, First of all, I gotta say, I love your Dads quote! Welcome! I read your paragraph and let me say, their are no dumb or stupid questions here and this Forum is full of a great group of folks who will try to help! So with that in mind I'm rereading and trying to minimize your problem. Have you checked your timing? Your sure your plug wire that you swapped out is good? Crazier things have happened! I'm doing a lot of thinking out loud here so bare with me! Limestone
Some years ago I had on my 1988 BMW M70 12 cylinder engine such problems, turned out the distributor contacts were oxidized and the rotor had haircracks, see pics here http://e32b12.blogspot.com/search/label/Distributor You could install between distributor and the spark plugs a spark plug tester and then see the sparks with engine running, tester costs abt. $10, something like this from HF https://www.harborfreight.com/in-line-spark-checker-63590.html
Possum; Is the spark erratic at idle or throughout the RPM range? When the engine is cold, you said the problem is not as prevalent; when cold, the choke enriches the mixture. If, when warm, the mixture is too lean, the spark may be there, however there may not be enough charge to ignite in the weakest cylinder. I ran into this - one cylinder wasn't firing because insufficient fuel was entering the carb at low RPM, but that was a fuel filter issue... What gap did you set the spark plugs at? I found ~.034" works well on mine... NGK BKR6E-11 plugs
Yeah limestone, my old man is a real sweetheart! Anyway, the way that I came to the conclusion that cylinder 1 has poor/intermittent/some times no spark was by simply attaching a timing light to each plug wire and simply watching the light. 2 and 3 seemed to be pretty healthy as far as the regularity and strength of the spark. Number 1 was weak and irregular. If I drive it and mash the loud pedal, one cylinder obviously drops out and truck loses power. If I ease out of the rug a bit the missing cylinder comes back. I have looked under the distributor cap and at the rotor. There was a bit of white corrosion on the contacts. I cleaned it up, reinstalled but did not solve the big problem. And no, I have not officially checked the timing with a timing light yet and haven’t checked the gap on the plugs other than by putting an eyeball on them
Possum, Shogun, and Roadster, do bring up some very good points here! I do like testing the spark on Cyl. #1 With the plug tester! That's not all that difficult to do! With that white corrosion in mind. The other point that they brought up is the other Contact points on the distributor, that maybe your getting erratic spark due to that! I've posted several times here on the Forum that after I clean up any thing electrical, I use a light film of Di-Electric Grease! It really does keep rust and corrosion at bay! At least that way you won't have to re visit that same spot down the road! I do Understand that were talking about your Distributor and not a simple electrical connection, that to me, matters a lot. Limestone
Thanks for the replies gentlemen. I’ll check on the timing, make sure the cap is clean once more, and I’m gonna try swapping out a buddies distributor cap to see if that helps rather than throwing expensive parts at it just yet. It’s a slow process around here though with kids and life happening all the time. I’ll be sure to keep you posted on my progress. Thanks again. Keep on trucking!
best would be if you could test with the tester first between ignition coil and distributor, if that is o.k., then between distributor and spark plugs. Then you know exactly which part the problem is. Pics Ignition Coil HONDA Acty 1992 V-HH4 https://autoparts.beforward.jp/detail/Electrical-Parts/Ignition-Coils/PA02119032/
Shogun, You make good sense! If I think about it, it's the #1 plug, and not the others! Isolate the #1 plug and test there like you said! Limestone
less I missed it, did you try swapping plugs around, and wires, if they will reach. just to rule out possibility of a bad plug or wire. if miss moves, its not fuel.
Sure did Bert, I swapped my plug wires with some known good wires from a friend of mine’s truck and the problem still existed, same cylinder. I think I can rule out the plug wires as the problem
then if you've ruled out dist Cap, I would check manifold to head gasket. it has been three years since I had my manifold off, trying to remember where there might be a possible leak, or maybe a crack. I re-read all the post, didn't seen compression test. I know it would not just start acting up, would have come on slowly, if compression is low in 1, but we are still ruling out stuff. best to know for sure. I still like moving plugs from one cylinder to another. only sure way to know it is not a plug. and here's a long shot, are the threads in the head clean? maybe have carbon build up in 1, compression will show that, I'm running out of ideas I'm going to sleep on this. will be watching.
