I resurrected a 1979 fj40 after sitting for 20 years. All emissions equipment intact. Fully rebuilt carb, new fuel tank and fuel filters.
Its first tank of gas everything worked/ran flawless. I set the timing yesterday and went for a drive afterword. Ran great until I ran out of gas, had a buddy bring me gas, no big deal. Driving back to the shop I noticed it would stall at stop signs. Had to keep my foot in the gas to keep from stalling, also slight hesitation when accelerating from low RPM's.
Back at the shop and it will barely idles, eventually stalls out. Unhook the idle cut off solenoid, and it clearly won't run at low RPM's. I determine idle cut off solenoid is not the issue. Hook up vacuum guage which shows poor vacuum, pull choke knob and vacuum is better but still weak. Next I remove air cleaner and spray starter fluid near intake manifold. There is clearly an RPM increases when sprayed near #2 and #4 cylinder on base of intake manifold. Also very slight increase when sprayed a base of carb.
These vacuum leaks are surprising to me because I had both manifolds off, new hardware, gaskets and proper torque on everything. Not to mention the truck ran flawless the prior week.
Here is where I get really puzzled. Since I had the air cleaner off I squirt a liberal amount of carb cleaner down the carb. Start it up and it seams to run better, do it again and it runs even better. It's almost back to the point before I started having an issue. Still stalls at idle but much better than before the carb cleaner trick. Drive it home tonight with the choke ever so slightly out to keep it from stalling and performed great.
Any thoughts as to what could be going on here? The more I think about it I am starting lean more toward a carb issue, the carb cleaner made a big difference. Also, I am second guessing the vacuum leak test using starting fluid. The starting fluid could be getting sucked up somewhere along the air rail causing the increase in idle. I am pretty sure those air rail tubes are not totally air tight.
Eventually my plan is to do a full desmog and go with a sniper. At this point I'd just like to establish a good baseline of everything working/running as it should prior to any mods.
Any help or advice is appreciated.
Its first tank of gas everything worked/ran flawless. I set the timing yesterday and went for a drive afterword. Ran great until I ran out of gas, had a buddy bring me gas, no big deal. Driving back to the shop I noticed it would stall at stop signs. Had to keep my foot in the gas to keep from stalling, also slight hesitation when accelerating from low RPM's.
Back at the shop and it will barely idles, eventually stalls out. Unhook the idle cut off solenoid, and it clearly won't run at low RPM's. I determine idle cut off solenoid is not the issue. Hook up vacuum guage which shows poor vacuum, pull choke knob and vacuum is better but still weak. Next I remove air cleaner and spray starter fluid near intake manifold. There is clearly an RPM increases when sprayed near #2 and #4 cylinder on base of intake manifold. Also very slight increase when sprayed a base of carb.
These vacuum leaks are surprising to me because I had both manifolds off, new hardware, gaskets and proper torque on everything. Not to mention the truck ran flawless the prior week.
Here is where I get really puzzled. Since I had the air cleaner off I squirt a liberal amount of carb cleaner down the carb. Start it up and it seams to run better, do it again and it runs even better. It's almost back to the point before I started having an issue. Still stalls at idle but much better than before the carb cleaner trick. Drive it home tonight with the choke ever so slightly out to keep it from stalling and performed great.
Any thoughts as to what could be going on here? The more I think about it I am starting lean more toward a carb issue, the carb cleaner made a big difference. Also, I am second guessing the vacuum leak test using starting fluid. The starting fluid could be getting sucked up somewhere along the air rail causing the increase in idle. I am pretty sure those air rail tubes are not totally air tight.
Eventually my plan is to do a full desmog and go with a sniper. At this point I'd just like to establish a good baseline of everything working/running as it should prior to any mods.
Any help or advice is appreciated.
