Went to the MOT today with the cossie and CO reading was 8.6%. Car drives fine. Put the CO back towards the required 3.5% max. and passed the MOT. But the car felt than like it needed more fuel to drive smoothly so I turned the CO screw back.

Before the MOT I put a new TPS, CTS, ATS and map sensor in it. Renewed the oil and plugs (071's). Checked the timing, vacuum and fuel pressure. Done this all because of this high CO problem.

I cant figure out why it has to have a so high CO value at idle to drive smootly.


Its a 1991 4x4 non-cat, msd chip, greens etc.

Anybody got a hint for me what it could be?

 

I did the same with my car for the mot i turned the emmisons down got it though its test then turned it up again.

 

Yes, but it shouldnt be that way, should it?

 

Have you set the tps up properly?Mine was on 8.5% on idle and ran ok but with the tps set correctly it went down to 1.5%

 

MSD closed loop 0.7% Co

 

Base setting is 45 Ohms so that must be ok.

 

HOW DO YOU SET THE TPS?

 

the mot centre i take mine to puts another car through the immissions test so it passes all the time .

 

Well, put the new TPS on the throttle body and adjust it with a multimeter so that the value was about 40 Ohms. Than tightened the two screw and put it all back together. After that I measured the value at the connector at the ECU and it says about 45 Ohms.

What is the correct way in your opinion to do this?

 

To set the throttle pot ,follow this guide.
1) Ensure ignition is OFF.
2) Remove rear of ECU plug cover and insert plug back into ECU.
3) Turn ignition back on (do not start engine)
4) THROTTLE CLOSED:
4x4: Check for DC voltage less than 0.5V between pins 11 and 17.
5) THROTTLE FULLY OPEN:
4x4: Check for DC voltage greater than 4.5V between pins 11 and 17

 

fuel pressure??????

 

What about a 2wd? and what's the 45ohms thing? is that measured at TPS plug? if so which pins? open or closed throttle?

cheers

 

Yes, also done that after the resistant check. Value at closed throttle is 0.2 Volts and at open throttle 4.76 Volts.

 

Like I already wrote, have checked this. At idle with vacuumpipe connected it's 3 Bar.

 

Strange part here is that I have got a service manuel were this is discribed as 'at idle you should have around 0.6 Volts'. But I am not sure its a manual made by Ford.

What I do find interesting is what is matters if the value at idle is more to zero than to the 0.5 Volt. Mines at 0.2 Volts. What differents could this make in the CO adjustment?

 

try your old cts ive had a few which were out of range

 

ours is 8.5 for the time being the brainey 1 says it`s been set up like that to stop it underfueling

still passed mot when he explained why it was high the guy went OK

as we have to get it set up again cos we found a couple of small oil leaks we will do the lot together

 

At the local MOT station I go to that doenst matter. It should be under 3.5 % no matter what. And I also want to find out what it causes.

Had tried 2 old CTS before I bought a new one. all are in range..

 

This is quite interesting, my escort suddenly went up to 8%CO. I have had a new TPS fitted too.

 

Yes, me too. I like to know what values (ohms and voltage) people have at their connector on their ECU that dont have a high CO. Somebody who can tell this?