musso2010

Hi guys,

Car has been idling very strange lately, and hunting. Yesterday it cut out a few times on me, strangely only when going round left hand corners??? It starts straight back up again. Its nothing to do with the MAF, i have checked the MAF voltage and its spot on.

I checked fault codes last night on the off chance, i got code 31 - TPS.

I have a spare TPS which i know is good, so i swapped them over. However, I cant seem to set it up properly. If i leave ignition off, the most i get is 3.05v closed. If i turn the ignition on i dont get any readings at all ??? I read somewhere that to set it up you should have the car idling, but if i do that i dont seem to be getting any voltage at all?

Anyway, i fitted the TPS as best i could, no where near the required voltage though... Reset the ecu and on the drive it came up with code 42 - Idle switch...

I know the TPS and Idle switch go hand in hand, so what on earth is going on... Is the IACV buggered, is the TPS set up wrong causing a code 42?

Any help appreciated.

Car is a MY95, and a quick note, if i hold revs at say 3k for a few seconds and release the throttle the revs will dive as if it want to stall.

saiklon

Code 42 is caused by the TPS. It's all you need to adjust to get rid of this code not the IACV.

Are you sure your voltmeter is fine? With ignition off, you shouldn't be getting any voltage at all across the TPS. As per the factory manual you should adjust so as to have 4.2-4.7V with the throttle closed.

About the cutting out, maybe you were low on fuel and it was cutting out because of fuel surge?

saiklon

Code 42 is caused by the TPS. It's all you need to adjust to get rid of this code not the IACV.

Are you sure your voltmeter is fine? With ignition off, you shouldn't be getting any voltage at all across the TPS. As per the factory manual you should adjust so as to have 4.2-4.7V with the throttle closed.

About the cutting out, maybe you were low on fuel and it was cutting out because of fuel surge?

musso2010

Fuel surge was my suspicion but i always thought it only really happened on right hand turns not left? I have had the car eight month and never experienced it before. I might pull the fuel pump out to check the wiring.

The voltmeter is brand new, bought especially for setting the sensor up. But i am getting voltage with ignition off and none with ignition on and engine running?

Just to confirm, what setting do i turn the voltmeter to? Some places i have read say turn it to dc voltage ethers say turn it to resistance.

saiklon

The voltmeter should be set to read DC volts. TPS voltage is 0-5V so choose an appropriate range on the voltmeter. Also check the service manual to make sure you are checking at the correct pins.

Fuel surge is worse around right handers but depending on how the fuel sock fits in the tank, you can have fuel surge even when accelerating. The fuel socks that come with many aftermarket pumps are very small and if you have one of those, fuel surge will happen earlier and in more circumstances.

musso2010

Thanks mate, stupidly enough i had the voltmeter on the wrong setting and was trying to check resistance

The strange thing about the fuel surge is that it has never happened before. I fitted a 255 pump a few months ago, with the std sock... but i remember having problems getting the clip back on. Ill pull the pump in the morning to check the sock is still attached.

Cheers for your help