My FJ40 has been backfiring for over a year now, it is stuck at my parents house. Here's a summary of what has happened so far:
Truck ran fine, but then had problems starting. I replaced the fuel filter (filter was full of debris) and all was well for another few weeks. I only drove it short distances but it ran fine. Shortly thereafter it began backfiring when under load. I drove it to Yakima, 150 miles from where I live, over the mountains. It stumbled but it made it. I tried to check the timing but the light would not come on, tested it on 2 other cars and it worked fine. In that last 12 months I've done this:
Removed and rebuilt the weber carb - no change
Installed new fuel pump and replaced all the rubber fuel lines, cleaned out the hard line from pump to carb - no change
Replaced weber with trollhole carb - no change
Removed stock distributor/crane fireball ignition that was all screwed up, just floating around loosely inside the distributor with new DUI HEI unit - no change
New plugs
New fuel filter
Lashed valves, followed instructions I found here somewhere but added .002 since I can't get the engine hot - no change
Today I tried to remove the thermostat housing, because the temp sending unit shows I'm overheating in only a few seconds, but the bolts are frozen. The timing light worked sporadically with the old distributor in and I set it as close to the bb as I could at idle. When I installed the DUI I was hoping the light would work, but no difference there and I don't understand why my timing light won't work on my FJ40 when it works on 2 other cars I've tried it on. I also noticed it will start and run decently when cold for about 30 seconds to 1 minute, then it starts to get rough, backfire and die. Could the thermostat cause this, can I overheat in only 30 seconds? I also noticed it was making a high pitched squeek while idling, not constant but every once in a while, I thought this might be the water pump but when I removed the fan and belt the pump nose didn't feel like it had too much play in it. So my question is, what haven't I thought of? What do I do next? From going over all this again, I'm wondering if I should hook up a small gas can in front of my pump to rule out fuel delivery, let me know what you think, I'm running out of ideas.
Truck ran fine, but then had problems starting. I replaced the fuel filter (filter was full of debris) and all was well for another few weeks. I only drove it short distances but it ran fine. Shortly thereafter it began backfiring when under load. I drove it to Yakima, 150 miles from where I live, over the mountains. It stumbled but it made it. I tried to check the timing but the light would not come on, tested it on 2 other cars and it worked fine. In that last 12 months I've done this:
Removed and rebuilt the weber carb - no change
Installed new fuel pump and replaced all the rubber fuel lines, cleaned out the hard line from pump to carb - no change
Replaced weber with trollhole carb - no change
Removed stock distributor/crane fireball ignition that was all screwed up, just floating around loosely inside the distributor with new DUI HEI unit - no change
New plugs
New fuel filter
Lashed valves, followed instructions I found here somewhere but added .002 since I can't get the engine hot - no change
Today I tried to remove the thermostat housing, because the temp sending unit shows I'm overheating in only a few seconds, but the bolts are frozen. The timing light worked sporadically with the old distributor in and I set it as close to the bb as I could at idle. When I installed the DUI I was hoping the light would work, but no difference there and I don't understand why my timing light won't work on my FJ40 when it works on 2 other cars I've tried it on. I also noticed it will start and run decently when cold for about 30 seconds to 1 minute, then it starts to get rough, backfire and die. Could the thermostat cause this, can I overheat in only 30 seconds? I also noticed it was making a high pitched squeek while idling, not constant but every once in a while, I thought this might be the water pump but when I removed the fan and belt the pump nose didn't feel like it had too much play in it. So my question is, what haven't I thought of? What do I do next? From going over all this again, I'm wondering if I should hook up a small gas can in front of my pump to rule out fuel delivery, let me know what you think, I'm running out of ideas.