I have had my 1985 for over 20 years now and have struggled with the roller test. The first thing I would confirm is if the valves are properly adjusted. Beyond a seriously malfunctioning smog component this has been my biggest issue over the years...
Guessing it is part of the emissions system. There are a few functions that can leak vacuum at certain engine temperatures, they connect to the two BSVC valves. The hardest thing to test is the EGR as you can not confirm its not leaking without removing it but you test the rest of the system.
So after some testing and a week of using the search function I came across my 9 year old post, might be useful:
https://forum.ih8mud.com/threads/california-60-smog-high-co-low-no-no-o2.823664/
My ASV valve is bad but that should not make a difference for the test. My pump barely registers...
@DieselFJ Full disclosure I have never tried the test method that I posted, but something I have thought of a few years ago. Just got bit by disabling the ERG so still trying to figure out how to best pass the test, preserve stock components, and have the best drivability.
You would think I...
Here is what I put together to check if my smog pump was performing per spec, pretty easy to confirm it operating as designed through the bypass. Some irrigation pipe and a gauge. If it is up to speed then start going through the FSM checklist or just bypass to pass the test...
I did consider installing some stainless screen material between the cooler and the valve but got worried it would clog up, will either run it or at least on a regular basis.. The days are numbered for passing the California treadmill test with a 2f.
For what its worth I have been chasing this for years. I just failed yesterday for high CO @ 25mph and the O2 was 0. I have a pretty fresh rebuild, good compression, and more or less everything in working order. Looking back I think my AI quit working a few smog cycles ago but the good motor...
@OSS , how right you are. I have only had the egr engaged for testing for the better part of the last few decades. I had suffered from the classic acceleration flat spot the egr valve vacuum hose disable fixed it. I am now down the rabbit hole of if the EGR function is ever needed for the...
Ok, changing the title again and finally found the problem. Amazing this simple machine can get the best of me so many times. So I cleaned everything up, checked for flat and square then reassembled. Started it up and it basically ran like before. I had to hole 1900 rpm to keep it running...
I was just chasing what I thought was a vacuum leak and it turned out to be out of adjustment valves, worth the check before you start pulling a bunch of stuff apart...
So here is the update and the lesson I needed to learn again. I found the "cold spec" for the valve clearances and ended up adjusting all of them. Most of the intake valves were pretty close but the exhaust valves were all very tight. 4,5,6 were the worst in that order with #1 not far behind...
Sorry, should have said that better. The adjustment was just tight enough there was no play in the rocker arm. I found a "cold spec" for the valves and ended up loosening them all a bit but the back three exhaust valves were the worst. I may try another compression check to see if it made a...
I will add some more to this. I pulled the carb, intake and exhaust manifold. No real surprises but could have been tighter on most of the bolts. I am sure this is some of the vacuum leak. The low compression is what worries me the most so I decided to check the valves even though they are...
Thanks OSS. I forgot to mention that I had at least cycled the EGR with a hand vacuum pump and can hear it click when released. Just about every smog component has been replaced / refurbished in the last 50k.
I have had my 85 FJ60 for 24 years and have gone through just about everything in that time, suspension, engine rebuild, 5 speed, body work... It was time for California smog again and for the last few years the truck has not gotten a lot of use so I went through the usual checklist of timing...
I bought one and ended up sticking it in the trash, very poor quality and all the bends were kinked. I ended up having a local shop make one and it is much nicer.