Hey all, currently trying to find a fault where engine runs a bit rough between 1500-2000 RPM, mostly under load, when I back off, or when travelling at a speed where the engine speed is between those ranges. It is also worse in 4x4 low, and in reverse, where it shudders the car.
It has got better, but that's because most of the parts I have changed have had a problem also. I bought the car recently and it looked like it wasn't used much, but was recently rego'd. When I changed the oil filter, it had a 6 year old date on it and had km's written which were within 5000k. I am in Australia.
Best way to describe the issue is the engine shakes, almost like a damaged mount. (I fixed these)
When I first bought it the fuel level was low, so put 98 octane with an injector clean in the tank. I then replaced the leads, spark plugs, oil, oil filter, fuel filter, and PCV valve, as I accidentally broke it. I also replaces the fuel regulator as the previous owner had done a dodgy silcone repair on it as they said it was leaking.
The issue continued. A mechanic checked and the mounts were bad, so I replaced the the engine mounts and trans mount at the same time. This improved the issue but still was happening.
I have since had the fuel injectors cleaned and restored, with tests passed, have replaced the fuel filter again, as the first time the fuel was a bit dirty on the pump side, noting that the fuel is now clean. I have also replaced the distributor cap, rotor button, ignition leads, spark plugs, ignition coil, and have taken off the throttle body, cleaned the air control valve with isopropyl alcohol, and checked for vacuum leaks.
It has to be something engine-related, as it occurs at the engine RPM in any gear; it is not road speed. Also, accelerating hard doesn't cause the issue. It also has the rough running if I rev it sometimes in P or N.
I have started testing different modules.
MAP sensor has correct voltage as per manual, and seems to hold vacuum, but I need to get a one way pump to build up vacuum properly.
I don't think it is the idle control valve as the issue happens off idle between 1500-2000 rpm
TPS with throttle closed measures 0.7 volts, and wide open throttle is 3.8 volts, not sure if this is right or not, manual said closed should be higher than 0.2 and wide open throttle should be less than 4.8. Seems to go up smoothly, although I have a digital multimeter.
Havent checked crank angle sensor, but the symptoms for that seem to be cutting out, or hard to strat.
Have disconnected fuel pressure regulator to have it wide open, to see if the issue changes, but made no different.
Timing looks ok when checked
Engine isn't noisy other than misfire. After replacing what I have it is almost un-noticable, but I know its there, and in reverse its worse. What could this be? suggestions
It has got better, but that's because most of the parts I have changed have had a problem also. I bought the car recently and it looked like it wasn't used much, but was recently rego'd. When I changed the oil filter, it had a 6 year old date on it and had km's written which were within 5000k. I am in Australia.
Best way to describe the issue is the engine shakes, almost like a damaged mount. (I fixed these)
When I first bought it the fuel level was low, so put 98 octane with an injector clean in the tank. I then replaced the leads, spark plugs, oil, oil filter, fuel filter, and PCV valve, as I accidentally broke it. I also replaces the fuel regulator as the previous owner had done a dodgy silcone repair on it as they said it was leaking.
The issue continued. A mechanic checked and the mounts were bad, so I replaced the the engine mounts and trans mount at the same time. This improved the issue but still was happening.
I have since had the fuel injectors cleaned and restored, with tests passed, have replaced the fuel filter again, as the first time the fuel was a bit dirty on the pump side, noting that the fuel is now clean. I have also replaced the distributor cap, rotor button, ignition leads, spark plugs, ignition coil, and have taken off the throttle body, cleaned the air control valve with isopropyl alcohol, and checked for vacuum leaks.
It has to be something engine-related, as it occurs at the engine RPM in any gear; it is not road speed. Also, accelerating hard doesn't cause the issue. It also has the rough running if I rev it sometimes in P or N.
I have started testing different modules.
MAP sensor has correct voltage as per manual, and seems to hold vacuum, but I need to get a one way pump to build up vacuum properly.
I don't think it is the idle control valve as the issue happens off idle between 1500-2000 rpm
TPS with throttle closed measures 0.7 volts, and wide open throttle is 3.8 volts, not sure if this is right or not, manual said closed should be higher than 0.2 and wide open throttle should be less than 4.8. Seems to go up smoothly, although I have a digital multimeter.
Havent checked crank angle sensor, but the symptoms for that seem to be cutting out, or hard to strat.
Have disconnected fuel pressure regulator to have it wide open, to see if the issue changes, but made no different.
Timing looks ok when checked
Engine isn't noisy other than misfire. After replacing what I have it is almost un-noticable, but I know its there, and in reverse its worse. What could this be? suggestions
