Triple X

iTrader: (1)

I think my Lambda sensor is on its way out since fitting my Lambda Link module, would people tend to agree from the following symptoms?

When i first start the car in a morning it may take a few minutes for any LED's to light up (apart from the power one) on the Lambda Link.
It then seems ok, LED's going up the scale (quite erratically mind), until after i have been driving the car quite hard and then no LED's light up asthough the heat has caused it to seriously under read. I doubt its underfueling as the knocklink is showing no signs of det. I have pressed the intercooler waterspray a couple of times in a bid to cool the lambda sensor down and then the LED's begin to light up again.

Once the car has been driven hard and then brought to a stop it hunts on idle to the point it nearly stalls, this happens for about 10-20 seconds and then it settles to a smooth idle.

I will be taking it to be put on the select monitor to try and find out for sure but just wanted some opinions please.

Cheers, John

Andy McCord

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TBMeech

John,

Are you running the Link ECU yet or still on std ecu?

AndrewC

Sounds (partially) like normal Lambda behaviour, the std sensor is only narrowband and will under read when hot, however it shouldn't under read so much that the voltage drops below the lowest LED on the Lambda link (about 0.72v IIRC).

Are you sure your MAF is OK - many MY99/00 cars with these symptoms are assumed to have faulty O2 sensors or ICSVs and it turns out to be the MAF.

Try a DVM on the Lambda sensor and see what values you are getting.

Andrew...

Another local Link user eh!

Andy McCord

Toby, johns out & about on the shop floor most of the day, but i can tell you hes still running std ecu, booked in with BRD for this sat m*

TBMeech

Hi Andy,

If he's still on std ecu my suggestion would point to the maf sensor, with my Autometer AFR when my maf was up the spout a few weeks back I had very similar sympthoms to what John has now, I put a new maf in and it cured both the dodgy idle and the afr being all over the shop....

If he's gonna get linked on saturday I wouldnt bother with a new maf as the Link makes it redundant anyway....

Triple X

iTrader: (1)

Cheers Andy.

Toby, like Andy says its booked in this saturday for the Link ECU fitting and mapping, should have been last month if it wasnt for clutch probs.

AndrewC, I changed the MAF sensor only a few month ago just to be on the safe side so for that reason i was thinking of other sensors. If it is the MAF then it will be redundant after saturday anyhow. What sort of voltages should i be looking at from the lambda, about 0.72 at idle? Bit thick when it comes to all the abreviations so what does IIRC and ICSV's mean?

Cheers for the help so far.

Andy McCord

IIRC if i recall correctly

Triple X

iTrader: (1)

I dont know, you office boys. LMAO

AndrewC

At idle the std ecu will be in closed loop mode and will be rocking the mixture around stoich so you won't see a steady voltage.

At WOT (Wide Open Throttle) you should see between 800 and 900mV (closer to 900).

ISCV - Idle Speed Control Valve.

If the MAF failed once, it can fail again!

Andrew...

PS. Checkout the V5 Link manual for more info about O2 sensor voltages.


[Edited by AndrewC - 6/17/2003 3:56:43 PM]

Andy McCord

yeah john, us shiney asses are good for something m8

Triple X

iTrader: (1)

Cheers for the link Andrew. Lots of info to read through.

AndrewC

Did Bob not say that he will be testing you on that document when he fits the Link, he'll only map cars for real enthusiasts you know

Andrew...

Triple X

iTrader: (1)

Shhhhhhhhhhh, ive got him thinking i am an enthusiast and i was hoping to cheat my way through the exam! I just dont know how im going to fit all 46 pages on my arm!!

The latest on the problem is that i fit my old MAF sensor (i only replaced it out of paranoia) and when i started the car and blipped the throttle the car nearly stalled when the revs dropped back down!?
I fit my newer MAF which cured that fault, however it still hunts on idle briefly after the car has been driven a while.

Does the Lambda Link usually take a while to display anything when the car is started cold?

AndrewC

Yes it does because the sensor has to be warm (~300C) before giving realistic readings.

Ask Bob to check it for you on Saturday.

Andrew...

Triple X

iTrader: (1)

Spoke to bob last night, found out he uses a Motec PLM rather than the stock item for mapping but he will check mine out too and replace if neccessary.

Thanx for your input.

Triple X

iTrader: (1)

The latest:

I drove home from work and found that there was no activity on the LED's at all (apart from the power one) so decided to get my DVM out. Started the car and measured the Lambda sensor voltage, got around 0.3v! Took the car out and this lowered to 0.26v when on cruise and went down further still to 0.2v when flooring it.
Still no activity as you would expect from such low readings.

All the voltages were measured at the ecu were i joined the Lambda Link wire.