fraser9764

iTrader: (3)

My 2wd saff was set up a couple of months ago, but ive just had it in for its MOT and the CO was high at idle.
they were having problems with the emissions tester as it was -12 and everything kept freezing but the one test he managed to get was 7.1%CO, HC was fine.
The only thing ive touched fuel/air related is to adjust the TPS to try and get the idle speed control valve to work properly.
it sill wants to idle at 3k hot or cold with the iscv connected, thats with the TPS setting itself on its spring and 4.96v at the ecu plug (its on PF01 and L6)
at the moment i have the iscv disconnected.
will the TPS have a big effect on the CO reading? and if so, i presume it is a linear error and could be brought back into line with the global CO adjustment pot on the front of the ecu?
thanks
Graham

fraser9764

iTrader: (3)

anyone?

james kiely

iTrader: (5)

was it idling at 3k when you got that co readiing fraser

fraser9764

iTrader: (3)

no, iscv unplugged, had been running for about an hour and a half so properly warmed up, idling at about 900rpm

ECU Monitor Enthusiast

iTrader: (1)

The TPS does not affect CO directly untill over around 80% full throttle depending on chip mapping.

Its a strange problem that the idle valve is actuating when the TPS is set correctly which sounds like you could have a COOLANT SENSOR issue to me.
This could explain the high CO and force the idle valve to open if it thinks its a very cold engine.

One test you can do is to unpluig the TPS and plug the idle valve back in.
The ECU cannot tell the difference between closed throttle and no TPS disconnected so this test will rule out a TPS fault.

You can check the coolant sensor by measuring the resistance at the ecu connector pins 11 and 29 with the ecu removed and ignition off.

I bet you have an open circuit or very high resistance


This should read around 200 to 500 ohms for a normal temperature engine (75 to 90 deg C)
The resistance gets higher as the temperature falls.

fraser9764

iTrader: (3)

I did check the CTS a while ago when i was first playing with it, with the engine cold, i had pretty much the same resistance on the CTS as the air temp sensor. cant remember the value though.
will check again in a few mins and try unplugging the TPS.
thanks.

ECU Monitor Enthusiast

iTrader: (1)

Coolant sensors are a common problems and sometimes dont exhibit any problems until the engine is warm.

Good luck !

fraser9764

iTrader: (3)

well ive just been out and had a look, oh dear
with the engine cold, ecu plug disconnected, i get 7.1k ohms between pins 11 and 29 for the CTS and the 7k ohms between 11 and 31 for the ACT,
however, i found this when i unplugged the ecu


and then pulling back some of the tape on the loom revealed this

fraser9764

iTrader: (3)

The melted pin 1 is earth, i have about 15 ohms to earth from the ecu side of the plug and 11 ohms from the wiring side.

phil_focus

oh oooooo, me spies some wiring grmelins come to bite you in your arse

i take it the plug has melted due to excessive heat and therefore either needs the exsessive resistance sorting or beefier wiring

or

has it been fucked about with in the past with a screw driver do you think?

either way, good luck sorting it mate i'm sure it wont be too difficult.

ECU Monitor Enthusiast

iTrader: (1)

fraser,
the resistance readings are about right for a cold engine and I would expect them to be the same if the engine hasnt run for over 24 hours.

As for the connector.... Ouch !!!

If you need some pins to replace them or a new connector shell, let me know as I am sure I have one you can have (for free of course).

The shell is easily replaced one wire at a time by popping the pins out.

Also, I would examine the ecu pins externally and internally to the PCB as they may have affected internal connections too !

fraser9764

iTrader: (3)

thanks for the offer, might have to take you up on that

ive just pulled the ECU out and popped the covers off, no damage from heat etc. but there is a wire linking the 2 earth pins inside the ecu, soldered to the pins between the case and the PCB
ive checked the resistance from the outside pins to the blobs of solder on the back of the PCB and 0 ohms everywhere.
just a bit confused as to why someone would go to the trouble to solder this wire on?

looks to me like the plug as been pushed on wrong, so only the back of the 'socket' on the plug is touching the ecu pin?

would this melted plug/bad earth have caused the problems? or just lucky i found it?

will try starting it in a min with everything connected and then disconnect the tps.

thanks

ECU Monitor Enthusiast

iTrader: (1)

It does sound like one of the pins in the ecu connector relating to earthing has failed some way in the past and has been bodge fixed.

By joining a wire internally, you only get current up 1 of the 2 pins leading to overheating of one pin as you have seen.

It is fairly unlikely this will cause the CO problem you have at idle but not impossible.

If you want the connector on the ecu replaced, I can do it for you or I can send a new one to you to do yourself if you are confident in soldering PCB's.
(FOC of course)

fraser9764

iTrader: (3)

hmmm very true, so i need a new plug and 2 new pins really, or a change of ecu, was wanting to go L8 and eventually closed loop etc. but dont want to spend the money just yet as i would change from t3 to t34 at the same time.
the soldering is no problem, i wouldnt expect it for free, dont mind paypalling you a few quid for your troubles.

thanks