Technical Injection light lit on specific usage - Diagnostics (lambda, knock sensor)

[Modano]

Hi all,
My wife's 1.8 Marea from 1999 has 235k kms. It is running quite fine (a little bit overconsuming regarding to other similar Mareas in spritmonitor). So far never had any big issues on this one.

The last 4 times she went to work she had the MIL (injection light) up in a motorway hill. This light never lit in the past 7 years (except once during a very heavy rain session).
The light switches off after 20 to 30 seconds.
During the remaining ride, flat highway, and countryside roads, the light never showed up. Same when I tested the car in my garage.

The car, when the light is on, is operating absolutely normally, with no other noise and no performance impact.

It *seems* that the first consumptions numbers are 1.5 liters/100 kms above the previous refills.

I was considering at first a lambda probe that was giving incorrect values in some conditions, but before, I ran a MultiECUscan on the car.

It returned lambda probe and Knock sensors errors.
I would consider that knock sensors failure would have an impact in the car performance and running, while lambda may only introduce a rich mixture and fuel overconsumption..

What is your take on this ?
Thanks

 

[Neverth]

Too much ethanol in fuel?

Faulty knock sensor might cause the ECU to retard ignition a bit to make sure it does not knock (less power for the fuel).
I've had knock sensor errors on the 20v variant, ignored them and just used better fuel or atleast 50/50 mix of 95E10/98 octane.

I'd reset the errors, take battery cable off for an hour and then take couple trips to see if the errors come back.

 

[Modano]

Hi,
thanks for your answer.
I never use E10, but only 95 octane. I may give a try with a 98 tank to check whether it comes back..
Yesterday I changed the fuel filter which was 50k kms old.
Oil, and other filters are less than 6 months old.

I already cleared the errors yesterday. This morning my wife had no issue. Let's continue the tests.

 

[varesecrazy]

I suspect you may have a poor connection / earth somewhere..unless you know for sure where the KEY CODE faults have originated..

clear the codes..and see what happens,
Charlie

 

[Modano]

Sorry, forgot about that.
I have a 1/4, 1.5 failure rate in the immobilizer recognition. This has always been the case since day 1. The code light does not power off when the key is in start position. I have to put it back to stop and forth to start and the light comes off.

I think this is an antenna related issue, all keys including master have the issue.
I can check the earth points , they are well documented in the service guide.

 

[varesecrazy]

Sorry, forgot about that.
I have a 1/4, 1.5 failure rate in the immobilizer recognition. This has always been the case since day 1. The code light does not power off when the key is in start position. I have to put it back to stop and forth to start and the light comes off.

I had a weekend that did that..
it was a relay in the supplement fusebox,
it HAD to click before immob. was deactivated-only did it at warm temps..:bang:

have a LISTEN - to see if you hear a relay..