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1990 Camry 3SFE Auto, engine rebuilt with about 67k miles on it, bored next size over from STD.
I’ve been noticing some weird ignition system issues lately, right now some slight misfiring at higher rpm’s, regardless of engine load, seems to run fine at idle. Apart from that the engine also pings pretty bad pulling hills and definitely has very noticeably less power on hotter days which might be normal.
In the recent past I replaced the distributor cap because it cracked badly on the outside near the coil contact in the cap, also replaced the rotor. Shortly after that in the span of about 15-20 minutes the engine gradually began to stumble and then it died and I had a no spark issue. I popped in a spare distributor that I carry in the trunk and drove home. In the original distributor I found that one magnetic pickup had come apart, so I replaced the pickups with another spare set I had and set the air gaps, still no spark. I spent hours trying to figure out why I had no spark on the original distributor and seemingly isolated it to the rotor, this is the first time I’ve ever had a rotor cause a no spark issue, could not see anything wrong with it and assumed it was somehow shorting on the distributor shaft, replaced it and had car up and running again.
Fast forward to today with the slight misfiring, I pulled all the plugs; #3 and #4 physically look different than #1 and #2 which you can see in pics, I think there may be separate issues which I will save for another post. Performed compression test with engine hot and throttle valve wide open, all cylinders range between 200-205psi (see note 1 at end). I popped distributor cap off to inspect all the contacts and then I noticed something I’ve never seen before and tried to take pics illustrating what I’m seeing which I hope you can see clearly; pins #2 and #3 show that spark has been occurring late as the carbon buildup is off to the side of the pin, instead of dead center in relation to the center pin for the coil, like with pins #1 and #4. I’m thinking this must be a mechanical issue related to the distributor and not something like with the igniter, but I’m struggling to understand what could be causing this, or how this could possibly be the magnetic pickups (see note 2 at end).
View attachment 433399
View attachment 433397
View attachment 433393
View attachment 433392
1990 Camry 3SFE Auto, engine rebuilt with about 67k miles on it, bored next size over from STD.
I’ve been noticing some weird ignition system issues lately, right now some slight misfiring at higher rpm’s, regardless of engine load, seems to run fine at idle. Apart from that the engine also pings pretty bad pulling hills and definitely has very noticeably less power on hotter days which might be normal.
In the recent past I replaced the distributor cap because it cracked badly on the outside near the coil contact in the cap, also replaced the rotor. Shortly after that in the span of about 15-20 minutes the engine gradually began to stumble and then it died and I had a no spark issue. I popped in a spare distributor that I carry in the trunk and drove home. In the original distributor I found that one magnetic pickup had come apart, so I replaced the pickups with another spare set I had and set the air gaps, still no spark. I spent hours trying to figure out why I had no spark on the original distributor and seemingly isolated it to the rotor, this is the first time I’ve ever had a rotor cause a no spark issue, could not see anything wrong with it and assumed it was somehow shorting on the distributor shaft, replaced it and had car up and running again.
Fast forward to today with the slight misfiring, I pulled all the plugs; #3 and #4 physically look different than #1 and #2 which you can see in pics, I think there may be separate issues which I will save for another post. Performed compression test with engine hot and throttle valve wide open, all cylinders range between 200-205psi (see note 1 at end). I popped distributor cap off to inspect all the contacts and then I noticed something I’ve never seen before and tried to take pics illustrating what I’m seeing which I hope you can see clearly; pins #2 and #3 show that spark has been occurring late as the carbon buildup is off to the side of the pin, instead of dead center in relation to the center pin for the coil, like with pins #1 and #4. I’m thinking this must be a mechanical issue related to the distributor and not something like with the igniter, but I’m struggling to understand what could be causing this, or how this could possibly be the magnetic pickups (see note 2 at end).
- Note 1 - These readings seem to be a bit higher than factory specs, I’ve been running regular grade fuel (87 octane), maybe this engine actually needs to run on mid grade (89 octane) to compensate for the higher than normal compression so it doesn’t ping as much?
- Note 2 - When I replaced the magnetic pickups, the manual actually states to replace the distributor housing and not the pickups and it also states to use non-ferrous feeler gauges. I’ve replaced the pickups before, but I definitely let the pickups touch the teeth on the tone wheels and I mistakenly used my steel feeler gauges which is boneheaded of me because I have a set of non-ferrous feeler gauges. I was almost thinking that I may have actually screwed up the magnetization between the magnetic pickups and the tone wheels on the distributor shaft, like slightly magnetizing the teeth on the tone wheels which could lead to a weak signal during operation, especially during higher rpm’s. Does anyone know if this is the reason for not replacing the pickups and using non-ferrous feeler gauges or if this is even possible? I can’t see any other reason why it’s so crucial in this case.
