General H/G fail = Lambda fail??

[ian grant]

Hi guys.....

I'm still getting this slight hesitation when I blip the throttle from rest??

Ive replaced the MAP sensor (and hose) and both coil packs, along with new EON 2 plugs and Magnacor leads. Also, very recent Oil and Filter change (100 miles) and brand new air filter.

Could it be the Lambda??? The H/G failed and was recently replaced, so I imagine that at some point during its failure there would have been an 'amount' of coolant being pushed through the exhaust and presumably over the Lambda - so could this have damaged it in some way??

As far as I know, the lambda was replaced a couple of years ago, but I suspect it may be a 3rd party type and not an OEM?

('96 Sporting - 49k mles)

Thanks,

 

[chaos]

Could it be the Lambda??? The H/G failed and was recently replaced, so I imagine that at some point during its failure there would have been an 'amount' of coolant being pushed through the exhaust and presumably over the Lambda - so could this have damaged it in some way??

Yep, it's very possible.

 

[rallycinq]

Yep, it's very possible.

However, only if it happens when warm, not cold.

Cheers

D

 

[ronnieronson]

sorry to dig up an old thread here - but 2 questions:

* Would a faulty lambda cause a hunting idle?
* Should a lambda fault show up as a dtc / ecu light coming on?

(Background to this is h/g, cambelt & bearing, plugs, leads, map, oil change).

... don't know if it's normal but with the induction kit off I can hear a hissing coming from the opening on the butterfly?

 

[levemircento]

* Would a faulty lambda cause a hunting idle?
* Should a lambda fault show up as a dtc / ecu light coming on?

(Background to this is h/g, cambelt & bearing, plugs, leads, map, oil change).

... don't know if it's normal but with the induction kit off I can hear a hissing coming from the opening on the butterfly?

I had to replace my lambda last year and I am sure it was causing the engine to hunt.

It didnt show up the ecu warning light

If you can hear a hissing from near the spi, check the vac hoses arent leaking, if one of them is, then its possible that could cause the hunting too.

 

[fingers99]

If it does it from cold, it isn't the lambda.

Some hiss (intake honk) is normal, but try and work out where it's coming from.

If hot and cold it'll be something associated with the MAP (or an intake leak). Is this MPI or SPI? If MPI, it can't be a leak on the pipe to the MAP, but may be somewhere else on the vacuum or intake side.

 

[ronnieronson]

If it does it from cold, it isn't the lambda.

Some hiss (intake honk) is normal, but try and work out where it's coming from.

If hot and cold it'll be something associated with the MAP (or an intake leak). Is this MPI or SPI? If MPI, it can't be a leak on the pipe to the MAP, but may be somewhere else on the vacuum or intake side.

Doesn't do it cold.
The hiss is definately coming from the flappy opening thing on the TB (dunno what it's called- sorry )

It's mpi by the way

Did use some redex the other week which seemed as if it helped for like a day or so - but I think it was my imagination

Didn't do this prior to HG failure by the way

 

[randomizered]

mpi have 2 lambda, and if the first one (the one that is used for fuel calculations) failed, fueling would go out of whack, and the second one would notice that the CAT or fuelling is wrong, and trigger the DTC light....so thats probably ok.

Hissing past the butterfly is not normal on a car with a bypass circuit, as it lets the air past at idle.

What you may hear though is the IAC bleeding air past, which its supposed to do....but if it went bad, it could cause hunting.

How much is the hunting, in regards to rpm...a fwew hundered or a few thousand.

Kristian

 

[ronnieronson]

mpi have 2 lambda, and if the first one (the one that is used for fuel calculations) failed, fueling would go out of whack, and the second one would notice that the CAT or fuelling is wrong, and trigger the DTC light....so thats probably ok.

Hissing past the butterfly is not normal on a car with a bypass circuit, as it lets the air past at idle.

What you may hear though is the IAC bleeding air past, which its supposed to do....but if it went bad, it could cause hunting.

How much is the hunting, in regards to rpm...a fwew hundered or a few thousand.

Kristian

Ahhh that makes sense then - always wondered why mpi had two lambda sensors...
The hunting is about 100 rpm difference either way - but it's hard to tell as she's idling really low once warm.
From cold the car idles at a steady 1000rpm, and is much smoother at idle.