I've searched many times, followed advise from the forums, read and read again and still have a problem with my F Engine 1969 FJ40. It is a stock engine with an almost new 32/36 Weber DGAS carb. I live at around 4500 ft.
The problem is that when I set up the ignition timing to a point where the car runs almost ok, It won't start when cold unless I retard the ignition. If I leave the ignition at the point where it starts when cold, the performance is unbearable. Any intermediate point will give me an unstartable car or a poor performance.
I have tried:
1. Changed jettings on the carb using advise from the Weber Carb forum here, got better idle and great performance while only one bbl is open. When I step on the gas there is a flat spot in acceleration and "sputtering" like when condenser is faulty. If I back a little on the pedal, sputtering reduces and the engine starts gaining RPMs slowly. When going uphill, the power is not enough for increasing speed, only on flat roads backing on the pedal a little will increase speed. If I advance the ignition, it starts getting better but never ok even if it's advanced to the point where I get constant pinging under load or retarded to the point where it barely runs. I bought the altitude jetting kit and tried almost all possible combinations. Kept the "least worse" (Right now I have Primary Idle 65, Primary Air 190, Primary Main 135. Secondary Idle 50, Secondary Air 200, secondary main 145.)
2. Rebuilt head, new valves, new valve seats, slight polishing to ensure flattness. This increased power and smoothness of idle and low RPM but no change on high RPM or load. Timing gear was changed in this process. Compression is ok and less than 10mm difference between cylinders.
3. Rebuilt Dizzy (a non-usa vacumm advance). New points and condenser, no change. Electronic ingition, no change. Coil is a high voltage with external resistor.
What can cause a condition where you can't find an ignition timing that works both cold and gives good engine perfomance (Where I live, air temp never gets below 60 - 65)
Please help
. I would hate to change the engine just because I can't get it tuned.
The problem is that when I set up the ignition timing to a point where the car runs almost ok, It won't start when cold unless I retard the ignition. If I leave the ignition at the point where it starts when cold, the performance is unbearable. Any intermediate point will give me an unstartable car or a poor performance.
I have tried:
1. Changed jettings on the carb using advise from the Weber Carb forum here, got better idle and great performance while only one bbl is open. When I step on the gas there is a flat spot in acceleration and "sputtering" like when condenser is faulty. If I back a little on the pedal, sputtering reduces and the engine starts gaining RPMs slowly. When going uphill, the power is not enough for increasing speed, only on flat roads backing on the pedal a little will increase speed. If I advance the ignition, it starts getting better but never ok even if it's advanced to the point where I get constant pinging under load or retarded to the point where it barely runs. I bought the altitude jetting kit and tried almost all possible combinations. Kept the "least worse" (Right now I have Primary Idle 65, Primary Air 190, Primary Main 135. Secondary Idle 50, Secondary Air 200, secondary main 145.)
2. Rebuilt head, new valves, new valve seats, slight polishing to ensure flattness. This increased power and smoothness of idle and low RPM but no change on high RPM or load. Timing gear was changed in this process. Compression is ok and less than 10mm difference between cylinders.
3. Rebuilt Dizzy (a non-usa vacumm advance). New points and condenser, no change. Electronic ingition, no change. Coil is a high voltage with external resistor.
What can cause a condition where you can't find an ignition timing that works both cold and gives good engine perfomance (Where I live, air temp never gets below 60 - 65)
Please help
. I would hate to change the engine just because I can't get it tuned.
