Hi guys. Just got my trooper back together after a long while. While my rust repairs have been holding up pretty good, i can't say the same for the engine, it still runs just as poorly as i remember..
I have tried each and every single thing i can think of, and i'm pretty much out of ideas.
For a start, it idles terribly. On both high and low idle speeds, the RPM constantly dips due to misfiring. (can hear popping from the exhuast) At high idle, it runs with the misfire but doesn't stall due to the high RPM, at low idle, the misfiring often stalls the engine outright.
Recently, it started consistently misfiring over 2500 RPM. After replacing the cap and rotor, it still continued to do so for a while, then subsided, but i still have an extremely poor idle.
It cannot POSSIBLY be a vacuum leak. I have replaced all the lines, including all the fat ones, i have completely torn apart the intake to replace every gasket (and do the '5-tec' mod for serviceability's sake). Unless i somehow made a mistake reinstalling the intake manifold, i just don't think it can even be possible. this problem was the case long before i did the job.
EVAP canister can't be causing a leak internally, either. I've tried pinching the lines to it closed to isolate the issue, and the condition didn't change at all.
If it somehow is a vacuum leak, it'd be injector seals as i didn't replace them. even then, they looked just fine.
On another note, the engine also makes this concerning ticking noise that increases in frequency with RPM. Word has it that the 4ZE1 always has a ticking sound, and that when it runs right it should sound like a sewing machine.
I adjusted the valves a while back, and it didn't seem to help with very much at all. I shot a video of it doing its thing, if it's of any use.
Here's all the information i have about this car.
All my fuel injector and spark plug wires are hooked up correctly.
I have tested the IAC, and it is working just fine.
IAC is mounted in the right direction.
Throttle position ""sensor"" (read: single pole double throw switch) is positioned where it should be. idle contacts have continuity.
All plug leads are reading around the range of 2.5 Kilo-ohms.
Spark plugs are fairly new, however every single one has a uniformly black, sooty tip, as if the engine's running rich all across the board.
Injectors are ticking as they should. although #2 sounds like it has a weaker click than #1.
Service manual says the secondary winding of the ignition coil should measure at 9.4 kilo-ohms, however, mine reads 10.4. (could that cause a weak spark? or is that within manufacturing tolerance?)
I've fiddled with that idle air mixture screw on the back of the throttle body til the cows came home, and it hasn't made a lick of difference. The 'ghostbusters symbol' o-ring on it isn't perished, i don't see any compression set on the edge either.
Ground on the rocker cover is not weak. I ran a wire from the ignition transistor to the intake manifold just to be extra sure.
The car does not smoke, There is no coolant in the oil or oil in the coolant, When my family bought the car 8 years ago the P.O said the engine was rebuilt, whether that means rings and bearings or something more, i don't know. Can't possibly have a bad head gasket.
All valves are adjusted to .008, or 0.2mm.
Exhaust manifold gasket is new.
I welded the crack in the exhaust manifold that was making an alternative annoying ticking noise upon acceleration.
When i had everything apart. I sucked and blew on the vacuum hose that actuates the diaphragm in the fuel pressure regulator, and wasn't able to get any air out of it. Maybe its different when everything's under pressure, though. doubt the human lung can top 60 PSI of fuel pressure, or 17 PSI of vacuum. (don't any of you dare make jokes about ex girlfriends!!!!!)
I'm stumped, guys. The only thing that comes to mind now is taking all those injectors out and bringing them to the local injector shop to be tested. They may very well be original, and this car has 405,000 something kilometres on it.
Any ideas?
I have tried each and every single thing i can think of, and i'm pretty much out of ideas.
For a start, it idles terribly. On both high and low idle speeds, the RPM constantly dips due to misfiring. (can hear popping from the exhuast) At high idle, it runs with the misfire but doesn't stall due to the high RPM, at low idle, the misfiring often stalls the engine outright.
Recently, it started consistently misfiring over 2500 RPM. After replacing the cap and rotor, it still continued to do so for a while, then subsided, but i still have an extremely poor idle.
It cannot POSSIBLY be a vacuum leak. I have replaced all the lines, including all the fat ones, i have completely torn apart the intake to replace every gasket (and do the '5-tec' mod for serviceability's sake). Unless i somehow made a mistake reinstalling the intake manifold, i just don't think it can even be possible. this problem was the case long before i did the job.
EVAP canister can't be causing a leak internally, either. I've tried pinching the lines to it closed to isolate the issue, and the condition didn't change at all.
If it somehow is a vacuum leak, it'd be injector seals as i didn't replace them. even then, they looked just fine.
On another note, the engine also makes this concerning ticking noise that increases in frequency with RPM. Word has it that the 4ZE1 always has a ticking sound, and that when it runs right it should sound like a sewing machine.
I adjusted the valves a while back, and it didn't seem to help with very much at all. I shot a video of it doing its thing, if it's of any use.
Here's all the information i have about this car.
All my fuel injector and spark plug wires are hooked up correctly.
I have tested the IAC, and it is working just fine.
IAC is mounted in the right direction.
Throttle position ""sensor"" (read: single pole double throw switch) is positioned where it should be. idle contacts have continuity.
All plug leads are reading around the range of 2.5 Kilo-ohms.
Spark plugs are fairly new, however every single one has a uniformly black, sooty tip, as if the engine's running rich all across the board.
Injectors are ticking as they should. although #2 sounds like it has a weaker click than #1.
Service manual says the secondary winding of the ignition coil should measure at 9.4 kilo-ohms, however, mine reads 10.4. (could that cause a weak spark? or is that within manufacturing tolerance?)
I've fiddled with that idle air mixture screw on the back of the throttle body til the cows came home, and it hasn't made a lick of difference. The 'ghostbusters symbol' o-ring on it isn't perished, i don't see any compression set on the edge either.
Ground on the rocker cover is not weak. I ran a wire from the ignition transistor to the intake manifold just to be extra sure.
The car does not smoke, There is no coolant in the oil or oil in the coolant, When my family bought the car 8 years ago the P.O said the engine was rebuilt, whether that means rings and bearings or something more, i don't know. Can't possibly have a bad head gasket.
All valves are adjusted to .008, or 0.2mm.
Exhaust manifold gasket is new.
I welded the crack in the exhaust manifold that was making an alternative annoying ticking noise upon acceleration.
When i had everything apart. I sucked and blew on the vacuum hose that actuates the diaphragm in the fuel pressure regulator, and wasn't able to get any air out of it. Maybe its different when everything's under pressure, though. doubt the human lung can top 60 PSI of fuel pressure, or 17 PSI of vacuum. (don't any of you dare make jokes about ex girlfriends!!!!!)
I'm stumped, guys. The only thing that comes to mind now is taking all those injectors out and bringing them to the local injector shop to be tested. They may very well be original, and this car has 405,000 something kilometres on it.
Any ideas?