[LCML] FJ60 Intermittent Stall at Idle

[Jeff Zepp]

I have an issue with my fully smogged 1987 FJ60 where it sometimes will idle just fine and other times will stall when pulling to a stop. We are only talking about full normal operating temperature. I have eliminated the EGR system as a potential cause by disconnecting the line between the vacuum modulator and the EGR valve and capping the line, so the EGR isn't coming on. I also verified that the idle cut solenoid is operating.

Backing up in the story a bit, she used to do fine until I had to do some work to get her through emissions testing. She failed the first try. So I changed out the air filter element, backed the static timing back to stock 7° from the 17° she was at, changed the main jet from 147 to 138, and dumped 4 bottles of Heet into the remaining 5 gallons of fuel, and then she passed with flying colors. She ran like crap though and stalled at idle a lot. After passing, I put the static timing back to the 17° that she was running good at and put the 147 jet back in, filled the tank back up to dilute the methanol. That made her run a lot better, but there is this intermittent stalling issue that is really making her a PITA for my wife to drive her.

It is almost as if the fuel (or timing?) is connected to a LSPV: when you come to an abrupt stop, as in traffic and press the clutch in, she will often stall. If you slow down really gently to your stop, no stall. The idle adjustment mixture screw is set at 3 turns. I tried other settings, both leaner and richer and neither seemed to make any difference. And besides - she used to work just fine before I messed with her to pass emissions. For now the brute force fix is setting the idle too high, around 1200-1400 RPM. Whenever she gets much below 1000 she wants to stall.

There are no obvious vacuum leaks, although I haven't done a thorough test for those. She runs great just driving around. If there is a vacuum leak, it would only be under the circumstance of coming to an abrupt stop and putting the clutch in. I figure there are about 3 or 4 other emissions subsystems which might cause this symptom other than EGR and idle fuel cut solenoid, so I am coming to the almighty List to see if anyone has any suggestions for where to look and what to test. I have good manuals but am kind of looking for a shortcut here.

Thanks and happy cruisin'!

Jeff Zepp
Kittredge CO USA
1971 & 1976 FJ40s, 1978 FJ45, 1987 FJ60
Rising Sun 4WD Club, TLCA #4063
http://rzeppa.org