gordy07

My 00STi has an annoying problem where once the engine is warm,say after 10 mins driving if i pull up at lights the revs drop right down and sometimes it actually cuts out.

It is also using alot more vpower than usual like 40miles for £20! mixed driving but virtually no boost being used.(Kids in the car)

The Idle Control Valve has been taken off and cleaned but seems to have made no difference

Could it be a fault MAF because it seems to be smoking more than usual which i would of thought meant it could be running rich?

Any help appreciated as usual

joz8968

iTrader: (13)

Normally the CTS (about £30) is at fault when these symptoms show. Do a fault code diagnosti check using the wires under the steer. col....

madscoob

iTrader: (3)

symptoms of 02 sensor , code 32 doesnt always show up light unless cruising at 60-80 . normal everyday use and code wont show up on cel . get the voltages checked on it . should be 0.2-0.9 volts changing all the time on tickover from cold to warm up from memory

gordy07

Thanks lads,so far no lights on dash but i havent checked for fault codes but i will tommorow.Sorry whats the CTS?

madscoob

iTrader: (3)

coolant temp switch . theres 2 of em 1 for gauge 1 for ecu coul also be that or 02 sensor . if the cts if fubared car thinks its cold all the time hence running rich , same with 02 if its firked no signal so ecu just dumps in fuel cos its getting no temp signals so it thinks its cold

gordy07

But would that explain the low idle too?

joz8968

iTrader: (13)

Yeah, the car cutting out or nearly cutting out at low revs when warmed up is a classic CTS (or possibly an O2) issue. As said, it's because the ECU is 'tricked' into overfuelling in a scenario when, obviously, 'extra' fuel is not needed

gordy07

I will check for codes tommorow and let you know,should i warm it up until it starts "playing up" first before reading the codes or will they be stored?

joz8968

iTrader: (13)

If you're happy the ISCV is sorted, then if nothing conclusive comes up with the fault codes, do:-

CTS
O2
MAF

As said, you can test the O2 easily.

And you can also test the MAF, but that'd require someone in the passenger seat checking a voltmeter whilst you go through various repeat boost/load scenarios... But it can be easy to not notice transient abnormal voltage changes (that shouldn't happen if the MAF was okay).

gordy07

I will check codes first and then possibly reverse that order because i have the old MAF off the car which was changed a year ago(just for precaution apparantly)

Thanks for all your help so far

joz8968

iTrader: (13)

Yeah, obviously fit what you already have replacements of first.

Then, if still necessary, fit from the cheapest, etc...

gordy07

Checked tonight an no fault codes being shown

So i guess i could try changing the MAF after its stopped raining!

gordy07

Well i changed the MAF tonight but the problem is still there.It smokes on tickover an stinks of fuel.Do you think i should try and clean the ICV again or start sourcing the CO2 or CTS sensors?

I also noticed the plug that goes into the MAF has a cable coming from it with another 2pin plug which is not connected to anything.Could this be related?

m3dim

iTrader: (1)

Is the car boosting normally?

gordy07

Yeah its boosting perfect!

gordy07

Used the car today and the smell of petrol was even stronger,opened the bonnet and one of the hoses going from the fuel pressure regulator to the injector(i think possibly a return hose,correct me if im wrong)has a small split on it and just at the jubilee clip was leaking fuel.That would count for the smell of petrol but would it affect the idle?