Engine 850: B5234T/2.3/20v/T5: Weird thing happened tonight...

[Geezer]

Hi Guys,

Not sure if this is engine related or electrics but I got in the car after work, and fired it up and it immediately started to rev at 2000 rpm! I thought what the hell and tapped the gas peddle thinking it might be a sticky cable or something, but the revs rose higher to about 2300 rpm.

I switched it off, left it for a few seconds and then restarted it. Straight away it started revving at around 2300 rpm, so with my foot planted hard on the brake pedal I selected reverse and the revs dropped down to normal idle speed.

I backed out of the car park, put her into drive and put my foot on the gas and I got a slight hesitation before it wanted to pick up speed...also got the dreaded lamba sond light on the dash.

I haven't had time to pull any codes, but can anyone give me a quick idea on whats going on?

Thaks in advance Guys.

[Jod T5]

Originally Posted by Geezer

Hi Guys,

Not sure if this is engine related or electrics but I got in the car after work, and fired it up and it immediately started to rev at 2000 rpm! I thought what the hell and tapped the gas peddle thinking it might be a sticky cable or something, but the revs rose higher to about 2300 rpm.

I switched it off, left it for a few seconds and then restarted it. Straight away it started revving at around 2300 rpm, so with my foot planted hard on the brake pedal I selected reverse and the revs dropped down to normal idle speed.

I backed out of the car park, put her into drive and put my foot on the gas and I got a slight hesitation before it wanted to pick up speed...also got the dreaded lamba sond light on the dash.

I haven't had time to pull any codes, but can anyone give me a quick idea on whats going on?

Thaks in advance Guys.

IACV stuck?....
Would be the first place i would look, maybe clean out the throttle housing and cable drum too whilst i was at it...
Cheers
Jod

[Geezer]

Originally Posted by Jod T5

IACV stuck?....
Would be the first place i would look, maybe clean out the throttle housing and cable drum too whilst i was at it...
Cheers
Jod

Thanks Jod for your help...guess I have another job for this weekend.

Hows it going over there??

[Jod T5]

Originally Posted by Geezer

Thanks Jod for your help...guess I have another job for this weekend.

Hows it going over there??

Weather is crap as usual, very few dry weekend for car maintenance...lol
Try pulling a code or two using the guide in the technical section...
good luck
Cheers
Jod

[Geezer]

Ok...I pulled all the codes and got the following:

A1: 1-4-3 "kickdown switch shorted to earth"
A2: 1-4-3 "front knock sensor signal absent or faulty"

I got nothing else from anything, so I'm pretty happy about that!

Anyway, I cleared the codes and got rid of the LS light...brill. Took the car for a blast and got the LS light again!!

Could the LS light really be directly related to the knock sensor or could there be something else to investigate? So...I'm useless with electrickery! Job for an auto sparky or is there something basic I can do to try and isolate\both problems.

Lubed the throttle linkages and everything appears to be fine there at the moment...no surging or over revving etc. I'll see what happens over the next few days/weeks though.

[ShadeTek]

After clearing the codes and going for a spin, check the codes again to see what is causing it to come on. These codes may have been in there for ever if you have never checked or cleared them before. I suspect only one of them is causing you the MIL.

[warthog]

Having changed my Knock Sensors twice in the last 5 years, if one is on the way out you will feel a slight hesitation just before the Lambda light goes on and the fault code either for the front or rear sensor is logged as appropriate. (you can get this hesitation for other reasons as well though.) If the same error codes keeps coming back then it's a fair bet that it's pointing to one cause of your problems.

If you're reasonably happy wielding spanners then changing the knock sensors isn't too difficult. Expect to take a couple of hours as the whole inlet manifold has to come off.

There are two knock sensors - before you remove them note the orientation relative to the engine block as they don't just bolt on but have to be rotationally positioned correctly to work properly. The mounting bolts are only 'nipped up' (20Nm)

As an aside, if the car has more than 100k miles on it and hasn't had the PCV system cleaned or changed then this is the time to do that as well (saves having to remove the inlet manifold again!)

[bb54]

Originally Posted by Geezer

Ok...I pulled all the codes and got the following:

A1: 1-4-3 "kickdown switch shorted to earth"
A2: 1-4-3 "front knock sensor signal absent or faulty"

I got nothing else from anything, so I'm pretty happy about that!

Anyway, I cleared the codes and got rid of the LS light...brill. Took the car for a blast and got the LS light again!!

Could the LS light really be directly related to the knock sensor or could there be something else to investigate? So...I'm useless with electrickery! Job for an auto sparky or is there something basic I can do to try and isolate\both problems.

Lubed the throttle linkages and everything appears to be fine there at the moment...no surging or over revving etc. I'll see what happens over the next few days/weeks though.

hi, just so your better informed.... the "check engine light" isnt a "lambda" fault light.
its a fuel/ignition fault light.
a lambda prob will set it off but so will 20 other probs.

wayne

[Jod T5]

Originally Posted by ShadeTek

These codes may have been in there for ever if you have never checked or cleared them before. I suspect only one of them is causing you the MIL.

I agree, best bet it to delete all the codes and then see what re-appears...
I would also be inclined to check the timing markings (cam V's Crank)...
if one is out this will set the knocksensor off.....
Cheers
Jod