Changed O2 Sensor But Still Issues

[Stevoo]

I have just replace O2 sensor due to error code on ecu. my range mileage was 173 on a full tank, after replacing O2 sensor this morning it now showing at 358. So all good but the car still wont rev passed 3000rpm! i have reset ecu and scanned for any new errors but at a lost. car will rev upto redline when stationary.

 

I had coil packs and plugs replace begining of the year. As their no errors on ecu has anyone got any ideas?

 

its a 1997 2.3 auto 89k miles.

 

Thanks.

[sepulchrave]

This is starting to sound more like a gearbox ECU or fuel supply issue, does the car kickdown ok and what happens when it gets to 3000 rpm? If it just runs out of puff then I suspect a fuel delivery issue, if the gearbox just keeps changing gear at 3000 then runs out of gears or won't rev when you kickdown then it may be a gearbox problem.

[Stevoo]

gear box will kick down and car will rev but as it hits 3000rpm its holding back and trying to carry on reving but cant. i suppose like a full load going up a hill really.

ive tried manual gear mode and car still cant rev passed 3krpm.

could it be the TPS sensor? or cam sensor?

[sepulchrave]

Dodgy TPS or Cam sensor would definitely show up in fault memory. Fuel pump relay may be marginal, ignition amplifier (is it separate?), are you definitely getting full throttle?

[Stevoo]

i replaced fuel pump realay not long ago as it started to burn out.

 

i cant confirm if the throttle is actually openning 100% but with my code reader on idle my throttle is at 16%, ill try and get a mate to come with me and see if it hits 100% on full throttle.

 

is the tps sensor easy to replace? also is throttle cable or fly by wire?

[andy22]

Stevoo,

I have the same model as you and am experiencing rough idling. I changed a number of things, spark plugs, HT leads, Coil pack, Idle speed control valve and checked for hose splits. I unpluged the Lambda sensor and started the engine but didn't notice any difference in the idling. I will be changing the Lambda sensor next as it is suspect and it did cure your idling problem.

 

Why don't I check the ECM error codes your probably asking, well Fords quoted

[Stevoo]

Hi andy, ive done all the things you have had done too. even a split breather pipe.

My code reader was from ebay. search for u381 in ebay(

[sepulchrave]

Yes, the Cat or one of the silencer boxes may have collapsed. You can check which by removing bits and driving up the road, start with the back box obviously!

[Stevoo]

Yes, the Cat or one of the silencer boxes may have collapsed. You can check which by removing bits and driving up the road, start with the back box obviously!

 

Not a job im keen to do lol, if its my cat, im sure its part of the mainfold? as i have the unit that blows air into mainfold to warm cat up. so whole lot needs to come out?

[sepulchrave]

Errrr, you don't need to remove the cat if you've eliminated the back box and the middle box from your enquiries because it'll be the only thing left!

 

Sounds obvious when you lay it out logically!

[seatkid]

You have checked/changed the air filter of course?

 

Has this car got a MAF sensor?

 

After changing the O2 sensor did you disconnect the battery for 2-3 minutes to make sure all the ECU maps are reset? (Remembering the radio code will be lost when battery disconnected...)

Edited July 31, 2008 by seatkid

[Stevoo]

You have checked/changed the air filter of course?

 

Has this car got a MAF sensor?

 

After changing the O2 sensor did you disconnect the battery for 2-3 minutes to make sure all the ECU maps are reset? (Remembering the radio code will be lost when battery disconnected...)

 

 

Yer i unplugged battery for about 30 mins and bridge the power cables together. i also reset the ecu with my obd tool. MAF sensor is working fine, ive unplugged it and car sounds like a v6 and has no power. i did give it a clean few months back.

[Steve P]

Stevoo - did you get to the bottom of this problem?

 

The tickover on my 2.3 is a little rough - both when running on petrol or lpg. I'm getting a whole 20 mpg - even on a run! It runs fine through the rev range and pulls well but I suspect it's running a bit rich.

 

It scraped through the emissions tests a month ago but I think we were just lucky- we had to go back for a retest and whilst I found a collapsed breather pipe I wasn't there when it was retested - I wonder if they actually checked it?

 

I don't think it's a failed coil pack cos when one of them goes you can really tell - I've replaced a few in the 8 years we've had the gal.

 

I'm going to get me a fault code reader and will probably end up changing the lambda probe - although it is only about two years old.

 

Any thoughts?

 

Thanks

Steve

[Steve P]

Stevoo - no need for you to reply - found one of your other posts - I see that you found the culprit was the MAF sensor.

 

I don't THINK that this i the problem with ours because it runs well throughout the whole rev range - it's just a little lumpy at idle (only just noticeable). HOWEVER - I recall that many years ago we used to get about 30 mpg on a run and then a few years ago it fell to about 22 mpg on a run.

 

I believe that the MAF sensors on the petrols tend to be very reliable - must admit I've never unplugged it to see if it makes any difference.

 

Do any of the OBD 2 readers which do LIVE DATA give a MAF readout? I was thinking of the U581 or the u381 (anybody know what the difference is other than

[Stevoo]

Hey mate yes the u381 gives the air pressure of the MAF but not the volts. the u581 works like the u381 But does cars with canbus ecu and modern diesels.

 

I wish i had got the u581 as i could plug it into my work van lol.

[Steve P]

Thanks - think you mean "air flow" - because that's what they measure?

 

Anyway I've ordered me a U581 - should be good for friends and familly as well then if it reads more.

 

I'll update when I get it and have had chance to plug it in!

 

Cheers

Steve

[Steve P]

Well - got me my U581 and found the problem - dicky connection at the MAF!! Plugged the code reader in and got a fault code that the MAF voltage was low! With the engine running I could see that the MAF read out did not change - should go up with revs.

 

Rooted round under the bonnet - reseated the connector - problem fixed.

 

Steve

[Stevoo]

well done mate, them tools are worth buying eh?