DLS

I didnīt pass inspection today due to too high lambda at idle (1.04-1.05) and at 2500rpm (1.08-1.11).
The car goes into closed loop during driving and lambda is pending between 1.00-1.02 but not when iīm standig still.

Iīve had this problem for many years now but this is the first time they didnīt let me pass.

iīve looked for vacuum leaks but canīt find any and i have leak tested the exhaust but canīt find any leaks.

The only thing left is if i have a small crack in the headers or crossover pipe thats masked by the heat wraps

if the dme temp sensor only shows 200 ohm when hot can it cause the lean issue?

Iīm out of ideas

divil

Have you checked that the idle switch in the throttle position sensor is working?

Tom M'Guinn

How much vacuum do you have at idle and have you reset the base idle? You mentioned closed loop, so assume you have a factory O2 sensor? (Some countries didn't...)

DLS

* Yes i have a factory O2 sensor (3 years old)

* The Tps is also 3 years old but i will check it again.

* I will try and reset the idle and see whats happens

DLS

I Have put up a plan on what to do

1 - Look for vacuum leaks again when the car is hot.
2 - Test to disconnect the lambda control to see what I get for lambda then.
3 - Measure and check the TPS.
4 - Check the pressure in the fuel pressure regulator without vacuum.
5 - Clean the MAF sensor with cleaning spray.

Tom M'Guinn

0.1 Check how much vacuum you have at idle

What MAF do you have and how are you tuning it? Since installing it, has the car ever run in closed loop at idle?

DLS

My idle vacuum is at 36 cm / Hg.

I have a Bosch HFM5 Maf with custom made chipset by Tomas in sweden.

I measured the TPS and it is ok.
Have also cleaned the maf without any noticeable effect.

However, when I jumper the lambdacontrol to OFF then goes lambda value up idling from 1.03 to 1.05 to 1.16 to 1.20, and at higher rpm the lambda is at 1.20 to 1.24 so it shows that the O2 sensor does what it should and tries to fat on but it seems not enough.

When Iīm cruising with the lambdacontrol OFF the lambda is at around 1.08 to 1.10 and with it ON it manages to settle around 1:00 as it should.

I have run the car warm and sprayed starter fluid everywhere in the engine compartment without result, also plugged in compressed air and sprayed with soapy water without showing any leak anywhere.

So either it's a vacuum leak somewhere that I can not find or there is an error in the map for idle / partial loads.

The only thing I have not checked yet are the fuel pressure regulator

I think i had this problem ever since i switched to e85, canīt really remember i had this problem for so long.