TPS - quick question

[monda2]

Hi All

I am still having hunting issues (awesome) when the engine is idling it does the usual hunting 1000-2000rpm, if I disconnect the TPS the hunting stops but the idle is still around 2000rpm

Does this mean the TPS stuffed?

Cheers

[monda2]

Also, just doing some research, my exhaust has a rattle in the cat or the muffler, not sure as yet will check - this could cause code 23 couldnt it? I have replaced the knock sensor.

[dougie_504]

What car/engine?

What else have you done to correct the idle problem?

IACV? FITV? Idle screw?

[TbM]

Test the TPS with a multi meter to check it, unplugging it wont really tell you much, im pretty sure if you unplug your tps your ecu wont know what throttle position you have and wouldnt be trying to keep the idle within the correct rpm range ie when your ecu sees 0% throttle its meant to idle.

To fix the hunting issue do what dougie_504 has said and Check/clean the IACV, Check for Vacuum leaks, Clean/readjust the FITV if your engine has one, have the idle screw set as per the factory specs if its been improperly adjusted. o2 sensor can also cause idle problems ive heard.

[monda2]

Hi all

Yes I have cleaned the iacv and replaced it it, which made no difference, no vacuum leaks either, I havnt tried the 02 sensor, if I disconnect it this should stop the hunting? But would obviously throw a code to?

I have also adjusted the tap as per thread on here!
Cheers

[TbM]

What car/engine do you have?............ by adjusted the tap do you mean TPS? disconnecting sensors doesnt tell you if they are faulty, testing them does.

[monda2]

Yeah sorry adjusted tps! I have a b16a obd1 standard ecu, Its in a mini

[TbM]

I think you have a FITV then, so check that, should be a DIY on this site if you search.

EDIT: FITV = Fast Idle Thermo Valve or Fast Idle Thermal Valve, cant remember if its thermo or thermal

[monda2]

I have removed the FITV and blocked it off as I dont really require it, doesnt get cold enough here!

Disconnected the O2 sensor, made no difference except through code 41 as it was unplugged!
Cheers

[TbM]

How did you block off the FITV? or did you just bypass the coolant lines?

[monda2]

yeah made a plate to bolt on using existing holes and bypassed the coolant hoses - just joined them together basically

[TbM]

did you use some sort of sealant or gasket? may be gettin an air leak from the block off plate.

[monda2]

yeah used a gasket sealant, the hunting started6 months ago, I have removed the fitv bout a month ago

[TbM]

Is your throttle plate sealed at closed throttle? Has the Idle screw been set per the Factory specs? how did you check for vacuum leaks?

[monda2]

Yea I Hve chkd the throttle plate is closed as per factory specs, the idle screw has been played with but should b back to factory specs, I sprayed carby cleaner around the vacuum lines and chkd if any fluctuations with idle, nothing found.

[TbM]

your gaskets can leak too so spray around them, also i think you can develop a vacuum leak if your brake booster has a leak so id block off the vacuum hose to the booster and see if that stops the hunting/high idle. another way to test for vac leaks is too block off the ports in the throttle body and/or the whole throttle body to see if the car stalls or maintains idle, ie if you block off the throttle body and your cars still idling you have air gettin in where its not suposed too.

[monda2]

Ok thanks will try some of your suggestions, cheers

[TbM]

No worries mate i hope it helps, idle issues can be tricky to work out.