Brun

I've had myine in for a few weeks now and it does it's job from what i can tell. When just tootling around it dances about until i boot it and it shows green
While on my hols last week i regularly was doing 20-30 mile runs. Quite a few times into these runs (10 miles or so) the gauge just appeared static in the red zone and didn't jump into green when booted??? When i came to a 2nd or 3rd gear corner and booted towards the red line the gauge returned to normal.
I was just wondering if anybody else had noticed this behaviour?

Mad Scientist

Just a thought, but mine behaves erratically until the lambda sensor heats up properly. Then all is well! Usually takes about 10 minutes or so.

Brun

Update

Now after only 3 miles it's going static and takes 6500+ rpm to even get near the green zone. Would this point to a possible failing Lambda sensor? or sommat else?
My next step?

I thank you

Brun

I see what your saying Mr Scientist as mine used to act the same, but it now just doesn't
New toys huh?

greasemonkey

Sounds very weird fella. Mine is always straight into the blue when I boot it, no exceptions.

Could be failing lambda sensor, could also be failing MAF sensor, which is worse. Is the car hesitating under boost or not idling properly? If it feels fine, lambda is likelier suspect. Could concievably be dodgy meter wiring installation as well, so that may be first thing to rule out!

What MY is your car, and are the lambda and MAF still original items?

[Edited by greasemonkey - 8/26/2003 3:28:13 PM]

dnb

The ECU takes no notice of the lambda reading at high RPM. Could be a MAF sensor problem. What MY is the car?

dnb

Damned network @ work

Seems that we're in agreement

[Edited by dnb - 8/26/2003 3:32:31 PM]

Brun

MY99
Idle is as steady as you like

greasemonkey

What air filter you using?

If it feels fine under open loop conditions, I'd suspect dodgy lambda sensor ahead of failing MAF sensor, but, like I said, check that wiring first.

Dry joint or bad sensor ground could easily cause this sort of issue, especially given the tiny voltages the meter is measuring.

Brun

K+N 57i i know, i know
The thing that bugs me is that the gauge has been in for only 3 or 4 weeks and things start playing up so i'm hoping a wiring issue is to blame.
Where will the lambda be grounded? or are we talking about the afr ground?

greasemonkey

At least with the K&N you shouldn't be getting oil contamination on the MAF - unless of course you've drowned it in filter oil!

The lambda ground is through the downpipe, turbo and engine itself, so if the earthing here is at all dodgy, misreads could result. A star earthing mod could help in this case.

Do the Autometer gauges have separate power supply and sensor grounds?

Brun

+ve -ve and a wire to hook up to the ECU

greasemonkey

Where did you connect the negative?

Brun

It was connected at some random screw. I've now changed it to the same earth as my knock link. At first it seemed better but as things got warmed up it went static again I'm gonna re solder onto the ECU an take an earth direct from the battery and see how i go. Fingers crossed

greasemonkey

That's a good move. I've got a star earthing system running through my car so this was slightly less of an issue.

A thousand posts, f00k. Been spending far too much time here!

Brun

I've done the above but there's no change
The ECU shows no errors either
What next?
Would an ECU reset show up any issues - ie: it could be handling a half dead sensor as the problem has appeared progressively.

<Brun - clutching at straws >

*Sonic*

HI Brun

When I first fitted my AFR I thought it was playing up, fine upto 4k rpm, then right off the lean scale of engine blowing proportions

A quick trip to Halfords to get a fake (cheap) Lambda Sensor, and that was it, readings are fine now, and backed up by Delta Dash Readings, and the car went like a rocket too

greasemonkey

ECU reset wouldn't necessarily show up the error. If the sensor's still outputting something it won't cause a CEL, although the reset may make the symptoms of a failing sensor more obvious.

To rule out a faulty AFR meter, you could try connecting a digital multimeter between ground and the AFR sensor connection cable from the ECU. Drive the car and see if the readings from the voltmeter correlate to the AFR meter's indications.

The one thing you'll have to bear in mind with this test is that the update frequency of most DVM's is too slow to catch the AFR fluctuating around stoich, although it should be good enough to get a reading on a couple of seconds of WOT.

Brun

Would you believe it After doing a search i came across your 4 page thread *Sonic* and i have just emailed you about it and i come back to my thread and who has posted

Brun

Ooooo Greasemonkey - you are talking technical now
I think i might pay a visit to my friendly dealer to see if the Select can show anything up
Going back to your thread *Sonic*, i did notice one very interesting comment by John Banks with regard the Lambda sensor being "virtually a 30000 mile 3 year consumable"

*Sonic*

Brun

I was going to go on Select Monitor, and the dealer actually advised against it, and said to save my money, as it would only show a 'failed' sensor not a 'failing' sensor

I think in essence John Banks hit the nail right on the head, my car had done 29 k miles, and was in fact 2years 11 months old at the time, so it was failing, another 1k miles & 1 month, and it quite probably would have failed

The cheap halfords one, was a quick (ish) was of telling for sure without spending the 100 quid or so a genuine one costs

Steve

mag6/4

brun must be the muppet that fitted it

Brun

I would of asked you but i figured almost right is closer than no where near

Anyway the latest update :-
There is now not a whole lot of action to the gauge at all. It flicks about a bit for a couple of miles but then sticks on the second LED up from lean in the amber range. If i do a WOT start in 1st, 2nd and third gears it will creap into green but not like it should.
I fear it is a sensor issue after all as the readings are going down hill

Brun

*Sonic* if the select monitor shows a failing sensor as failed then it still needs replacing i guess even though it's only failing. Sooner or later it's gotta go pop.

Damn gauges I think it was you *Sonic* who said "Ignorance is Bliss" Top words

Just a thought! How would a failing Lambda or MAF affect fuel consumption?

[Edited by Brun - 8/26/2003 11:11:38 PM]

greasemonkey

There are exceptions to this rule, but in general a failing MAF sensor will make the engine run lean throughout the rev/power range, while a failing lambda sensor will make it run rich while in closed loop (i.e. low revs/boost) mode, leading to crappy fuel economy no matter how light-footed you are.

If I was in your shoes I'd still put a digital voltmeter between the lambda wire on the ECU loom and ground to confirm that it's not the AFR meter itself that's bust.

If that doesn't reveal anything, or if you don't have a dvm, follow Sonic's lead and get a universal lambda sensor from Halfrauds or similar. Install, reset ECU and see what happens.

Brun

I'm not sure how to do the multi meter and the afr thing as the afr only has lights so i don't know what the dvm should show in relation to the gauge
And due to an unfortunate month involving Defis, deposit on a Tek3 and a Holiday i feel a bit tight about throwing £20 at Halfords in case it's not the answer

[Edited by Brun - 8/26/2003 11:31:22 PM]

greasemonkey

If the lambda is going, you'll probably waste more than £20 in petrol over the next few weeks!

Brun

Ahhhhhhh good point.
I'm going round in circles as i've just come back from wales and managed 30mpg My head hurts.

*Sonic*

Brun

I see you are in West Yorkshire, are you anywhere near Leeds Thursday Evening? as im working up there in the Centre till about 8pm (all being well ) If you want I can bring up Delta Dash, and take it for a quick spin and get some readings off your Lambda & Maf, that way we should know for sure

Basically my AFR stopped reading anything once car was fully warm

If you are round Leeds, then mail me, and we can sort something out

Cheers

Steve

Brun

YHM