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CO sky high

Hello people back for some help after i thought i had solved my problem. (If thats ok)

I have a 1994 Escort 1.4i (CVH type)

It failed the MOT on emmissions.

Lambda was at 0.67 CO was at 12.57 HC was at 669ppm

At the weekend i stripped the head down, cleaned the lot out, re-ground the valves in, changed the oil, plugs, ect etc. re took it for the MOT and everything was slightly higher except Lambda wich was slightly lower.

Took it back home and noticed the plugs were really badly covered in soot.

I then went to halfords and bought a Gunson ECU tester, this throw up 2 errors a 24 and 25, which 24 is Throttle positioning sensor and 25 is Vane air flow meter.

Can these just be simply changed? does anybody know if i could easily test these, as i dont want to spend £160 at Ford to find its not these. I tested the TPS with a meter and was getting between 1.04 and 4.98 ohms as i moved from full throttle to normal.

Thanks for any help in advance

Ta Si

Reply to
Simon Green
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Which wires are the voltage, does this run its earth from the Chassis or form one of the wires?

Cheers Si

Reply to
Simon Green

Please don't top post, it makes it harder to respond. :-))

All wires on the ATS and TPS go back to the ECU

On the ATS one will be an earth, one will be the signal return. Not sure of the colours.

On the TPS one will be 5v supply one earth, one signal.

Regards, Graham L

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Reply to
Graham

Is it likly the TPS could go faulty or is it more likely that its giving me this error code because its something else?

Ta Si

Reply to
Simon Green

It is possible to get spurious codes. Always worth clearing the codes, drive a couple of miles and then see what has come back.

Remember the codes are pointing to a component circuit not necessarily the component itself. So a fault code for the TPS could be either the TPS or the wireing between the TPS and the ECU. (or even an ECU fault or ECU earth problem.)

Check the ouptuts of the sensors.

Regards, Graham L

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Reply to
Graham

Hi Graham,

I`ve meter the voltages out on a Digital meter set at upto 20V, here are the readings:-

With the Engine Running:-

Red to Earth on Normal throttle is 4.85 Red to Earth at 3500RPM is 4.85 Green to Earth on Normal throttle is 5.10 Reen to Earth at 3500RPM is 5.16 Yellow to Earth on Normal throttle is 0.06 Yellow to Earth at 3500RPM is 0.11

With the Engine Off (Just the Ihnition on):-

Red to Earth on Normal throttle is 4.87 Red to Earth at Full Throttle is 5.02 Green to Earth on Normal throttle is 5.07 Reen to Earth at Full Throttle is 5.07 Yellow to Earth on Normal throttle is 0.04 Yellow to Earth at Full Throttle is 0.4

Thanks Again Cheers Si

Reply to
Simon Green

On Fri, 29 Aug 2003 18:50:48 +0100, "Simon Green" wrote: L

Ok, the above shows that the earth point to the TPS (supplied by the ECU - yellow wire) is OK as it is nearly zero volts.

The Green wire is the supply voltage to the TPS 5v - Fine.

The Red wire is the signal to the ECU. At throttle closed it should be about 0.7 v and at WOT around 4.5 v BINGO you have a faulty TPS. All the figures are too high.

Basically the ECU is being told that you have your foot to the floor ALL THE TIME.

Regards, Graham

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Reply to
Graham

TPS- pin 1 signal to ecu (0.9v to 4.5v WOT) pin 2 5v pin 3 0volts or earth.

Tim..

Reply to
Tim..

TPS is easy to fit, just make sure the TPS lever is actuated by the throttle lever. When hot and ticking over the volts out should be between 0.8 v and 0.6v

IIRC the ATS is located on the air filter housing.

Regards, Graham

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Reply to
Graham

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