Hi, This problem is driving me bonkers now!
About 3 months ago had the EM light come on, took it the garage and they couldn't get the machine to comunicate with the car so they manually diagnosed a faulty throttle position sensor as the car sits at around 1300rpm and i have a sort of tick, with a thing where if i put my foot on the acceloator the car is not responsive then all of a sudden you get this big power boost but the car feels like it's lacking overall power. Anyway they changed the throttle position sensor and said that the air control valve wasn't making any difference on the engine running and i didn't need to change it as they couldn't get a new one, the power problem has persisted and even got worse especially in the cold, i spoke to the garage and the diagnosed a faulty rear brake cylinder which i had changed expecting a change in the problems but no such luck, my mobile mechanic took the car to check it out and came back and said the clutch was staying engaged so needed sorting it was fitted 2500 mile ago so i took it back and the pedal was adjusted and both clutch master and slave cylinders were changed as the master was leaking. Anyway this weekend the car has been that bad not really been driveable as it looks like a kangaroo jumping down the road. So called brakedown they said it was either ignition leads or coil pack. I opt'd for the ignition leads(easier to get hold of) Changed them got a fair amount of power back, so noticed a thread on here saying it could be due to the exhaust manifold gasket perished so i had that changed too there were only bits of it left so i did need changing, then i remembered this sensor hadn't been changed and could still be the problem because if it's disconnected the re-connected all the engine noises quiet down, but i doesn't last long after putting your foot on the accelorator, but i does idle lower about 700rpm, i took the sensor out of the throttle body still connected and if i turn the ignition to the on the piston comes out slightly then when i turn the ignition to take the key the piston and spring fly off the sensor, it doesn't seem to go backwards unless you push it back with your fingers. Does this mean this has been my problem all along? I don't really want to be spending more money until i know what it is!
Whats up with it?
Moderators: daewoomofo, Moderators Group
Re: Whats up with it?
Hi
As far as you describe , your problem may be related to the IAC - idle acceleration control. If i read well, you say you removed the IAC sensor from the TBI body, and checked that the valve opens but doesn't close at all, unless you press on with your fingers on the little piston... It refers to a clogged valve or a ECU related problem. Either it was clogged by barnish , either it was clogged by dust... In either case, you should remove all grease/oil/dust from it and try again.
If it doesn't work, please take note if all the wires that go to the IAC are in good condition.
... Did you notice any SERVICE ENGINE SOON light flashing on the instrument cluster ?? If so, you should take your car to a computer scanner to see what the codes are. Maybe it throws a faulty IAC and replacing it is the best way to switch to a normal operating condition on idle.
If , after checking that issues the problem keeps going, then the problem maybe on the ECU itself. ( hope that's not the case), since the ECU governs the IAC and some many others peripherals around the engine.
As far as you describe , your problem may be related to the IAC - idle acceleration control. If i read well, you say you removed the IAC sensor from the TBI body, and checked that the valve opens but doesn't close at all, unless you press on with your fingers on the little piston... It refers to a clogged valve or a ECU related problem. Either it was clogged by barnish , either it was clogged by dust... In either case, you should remove all grease/oil/dust from it and try again.
If it doesn't work, please take note if all the wires that go to the IAC are in good condition.
... Did you notice any SERVICE ENGINE SOON light flashing on the instrument cluster ?? If so, you should take your car to a computer scanner to see what the codes are. Maybe it throws a faulty IAC and replacing it is the best way to switch to a normal operating condition on idle.
If , after checking that issues the problem keeps going, then the problem maybe on the ECU itself. ( hope that's not the case), since the ECU governs the IAC and some many others peripherals around the engine.