Would Anybody Agree?

[Mi16Lemans 0]

Hello.

 

I'm quite new here but as you may of read, I bought a P1 mi16x4 last week from a very popular online auction site.

 

it was advertised as having a missfire up untill about 2500 rpm.

 

well it isn't so much a missfire more like it only just about mannages not to cut out compleatly but get it past 2-3K then it flys along and doesn't miss a beat.

 

nobody on hear seemed to have anyideas on what it may be, so I've done some searching around and cam accross another site where some guy posted a thread giving the same kind of symptons as I'm having. people replied with make sure your plugs are new etc etc, others said to check the air meter/stepper motor on the inlet plenium and mine is fine and all the plugs and leads etc are new..

 

one post said it may be down to the O2/Lambda sensor - and my car even though its a 'G' 1990 has a cat and the post went on to say that the lambda sensor has a massive part in controlling the fuel mixture at low revs BUT DOES NOTHING AT HIGHER REVS.... is this true.?? can anybody verify this as from memory the sensor deffinatly doesn't look in any way new or am I very likely to be wasting the best part of about £50.???

 

for what it worth, most websites which sell them tell you that they only have a life if 50,000 miles or so and need to be changed to maintain good idel and avoid hessitation on quick acceleration..

 

..anybody...?

[KRISKARRERA 2 1 Cars]

Well, lambda sensors always are neglected and if the engine hasn't been running right it'll be nicely sooted up by now anyway.

I'm intrigued by your car though, something just doesn't add up about it having a cat and lambda on a UK 4x4 mi, and especially at G reg.

[ryan13961345402285 1]

Have to agree that something is strange about that setup. I have old Autocar and Motor magazines here that list the 4x4 as being able to run on Leaded petrol only (at least in 1989)

[Jer309GTi 3]

It could well be possible that the lambda sensor is at fault. I remember when I had a bad connection on the sensor on my 309, it overfuelled and ran like a bag of crap, but from what I remember I think it ran ok when giving it a bootfull.

 

I can't remember if you said, but does the engine management light come on when the car is missfiring/cutting out?

 

Have you priced up a new sensor? If they are not that dear and you have the cash spare you may as well fit a new one. If it doesn't do the trick at least you have a nice shiny new sensor, and you have eliminated the sensor as a cause.

[Mi16Lemans 0]

The K light has come on sometimes but not every time. As you sa ya new sensor is only abot the £50 mark so its no majoer loss if it turns out not to be that, but yes, give it a 'bootfull' and it becomes a proper Mi

[Jer309GTi 3]

Have you tried reading the faults? Think it is described somewhere on here how to do it. If you don't have any joy then I would whack on a new sensor.

[JamesLeMans831345402285 0]

Have you diconnected the lambda? Car should run on as ecu resorts to a default value, which is not great long term but if the misfire stops then you know the lambda is at fault? I've not tried this on a XU engine but it should be right. I have read a lot of similar threads when trying to work out a similar issue with a TU (pants) engine on a 106, would be rough from idle up to about 2.5k and then go fine. Have you had a compression test done?

Edited June 22, 2007 by JamesLeMans83

[Mi16Lemans 0]

Well everybody.. it wasn't the Lambda sensor although it has made a very slight difference..

 

..When the engine is cold the problem isn't nowhere neer as bad as it is when its hot, after I replaced the Lambda, I reconnected the battery and I thought that the problem was fixed, let it sit turning over for a short while (it wasn't perfect though) switched the engine off, packed my things away, started the car again and it wasn't really any better..!!

 

Does the fact that the problem gets worse when the engine is hot make any sense to anybody.?

 

...by the way, if I disconnect the sensor, the problem get slightly worse..