when I was struggling to get my truck through emissions this fall I set my idle a little high, around 950 rpm, and I hadn't really gotten a chance to set it back down to 650, so I went in and started the lean drop method again after checking the timing. I am using the tach on my timing light and it moves around a bit, so it is kind of hard to do. I am also using a vacuum gauge, but I started to get a little movement of the needle when it is idling that low. I'll post the videos below and I guess my question is how much movement in the vacuum needle is ok. I had always read that it should be pretty steady, but I'm having a hard time fine tuning idle at 650. Here are the relevant specs:
Rebuilt motor with about 500 miles on it.
Just recently adjusted the valves cold, but planning on giving it another go
The cam is not stock, it is a very mild cam that the shop recommended
I'm at 6500 feet elevation, so I think my readings of around 17-18 on the vacuum gauge are pretty good
I can't find any vacuum leaks as of yet.
Vacuum taken off the brake booster
Here is the vacuum at 850 rpm.
Here is the Idle on my tach around 650 rpm.
Rebuilt motor with about 500 miles on it.
Just recently adjusted the valves cold, but planning on giving it another go
The cam is not stock, it is a very mild cam that the shop recommended
I'm at 6500 feet elevation, so I think my readings of around 17-18 on the vacuum gauge are pretty good
I can't find any vacuum leaks as of yet.
Vacuum taken off the brake booster
Here is the vacuum at 850 rpm.
Here is the Idle on my tach around 650 rpm.