General Pulsing Idle mk2b

[fingers99]

That's pre-cat. The first one you see, next to the cylinder head. There is no pipework.

I'd be amazed if the idle was suddenly OK, though....................

 

[jmckee4]

So where do I go from here, just change it straight off? Or should I be making other checks before I dive right in?

 

[atom0007]

It's a single spanner job to change. Don't try an adjustable unless you're really desperate.

They're often rusted solid, risk is shearing flange off exhaust, but that would be bad luck.

15 mins all being well, easy.

Get a couple from scrappy.

That trace doesn't look right to me, but there are other reasons for duff readings other than sensor.

Also, there is contradictory info regarding which sensor it is, unplug to be sure.

Pre and post cat are same.

 

[danielb]

Easy to change although if you've got the chance to buy / borrow a lambda socket I suggest you do. I got one to do a 3 cylinder Corsa because the lambda is completely unreachable with spanner. They always come out straight away.
http://www.gendan.co.uk/images/stock/55540.jpg
Dan

 

[jmckee4]

They're often rusted solid, risk is shearing flange off exhaust, but that would be bad luck.

All I have with cars is bad luck

That trace doesn't look right to me, but there are other reasons for duff readings other than sensor.

That graph is for the post-cat. So.... They both need changing?

How much are they new? I'd rather buy something like that new than take the risk of buying a duff s/h one

 

[fingers99]

Shouldn't. One says pre cat, the other says post cat.

The second lambda does little more than test if the cat (and the first lambda) are working correctly. So I's suspect the first one, but look at damage to the cat itself.

How much are they new? About £70 each. Hence, especially if you're not 100% sure what the issue really is, it can maqke sense to try a used one.

 

[atom0007]

I've had 2 go, both post cat.

Easy to get to here with spanner, cheaper than socket.

Like fingers says, go for a second hand one, your diagnosis might be wrong. And you get the practice of taking one off a scrapper for free!

It is quite an easy job.

Can't remember spanner size, fairly big, 22mm?

 

[jmckee4]

Ok, thanks for all the advice so far

Couple of things I'm still unsure on.

The Code says Lambda 1 Above Cat, but the description says After Cat.


Is it possible that the electrical connector could need cleaning or something?
Being that the car had never had the spark plugs changed (or anything else for that matter) until I got it, the lambdas have probably never been changed either

Also, the car has passed emissions on MOT only 2 week ago.

 

[fingers99]

It is odd. You might check with support (for multiecuscan).

Thje electrical connectors are different, IIRC. But a clean up and check won't do any harm.

Plug life may be as little as 20k miles. Lambda life should be way over 70k miles. Beware of generic replacements (all of which camn be very difficult to fit) and especially of cheap generic replacements (which can fail or simply not work). Google will find tests for lambdas. Substitution may throw up interesting results.

Still can't see this as causing a pulsating idle, though.

 

[jmckee4]

I recently read a post by ziggy about pulsing under high electrical demand due to alternator belt slipping.
Coupled with Haynes saying you should check it every 12k miles, plus diagnosis of fault said that the code was flagged due to lambda receiving low voltage.

I noticed this morning that it was pulsing with fans on full, stereo on and rear window heater on. After switching off either the window heater or turning the fans down the pulse was less severe.

How can I tell if my belt is slipping? Do they stretch at all? Is so would tightening the belt fix the problem?

Thanks again

 

[fingers99]

They do stretch/wear, even shreik. Try adjustment.

 

[Ziggy122]

I recently read a post by ziggy about pulsing under high electrical demand due to alternator belt slipping.
Coupled with Haynes saying you should check it every 12k miles, plus diagnosis of fault said that the code was flagged due to lambda receiving low voltage.

I noticed this morning that it was pulsing with fans on full, stereo on and rear window heater on. After switching off either the window heater or turning the fans down the pulse was less severe.

How can I tell if my belt is slipping? Do they stretch at all? Is so would tightening the belt fix the problem?

Thanks again

They do stretch/wear, even shreik. Try adjustment.

Mine had cracked and shined - so i brushed mine up with a wire wheel attachment - it's got me through the winter

You cant always tell if its slipping, but i was letting off a sqeak as it slipped when demand was high

Remove the belt and inspect it

Ziggy

 

[jmckee4]

Thanks Ziggy.

How easy is it to remove? The haynes isn't exactly clear. Do I have to take off the wheel arch liner or can I get to it from above?

Is there any chance I could mess anything up? I'm always cautious about the unknown!

 

[jmckee4]

Thanks Ziggy.

How easy is it to remove? The haynes isn't exactly clear. Do I have to take off the wheel arch liner or can I get to it from above?

Is there any chance I could mess anything up? I'm always cautious about the unknown!

Scratch that. Its just 3 bolts right? Undo those, push it back to tighten belt then re-tighten bolts?

 

[jmckee4]

Quick update: changed the alternator belt tonight (after being given the wrong one) and the car just seems to run smoother and more quietly I think.

Not driven far with it but fingers crossed its fixed it