[MCL968]

We had a pretty good thread on MAFs going a while back. It might be worth it to keep a Volvo unit in the glove box next to the spare DMR relay.

 

http://www.968forums.com/topic/11421-mas...ntry114469

 

a couple rebuilders are also listed in the thread.

 

Enjoy!

 

Matt

Partial Post: Please Login or Register to read the full post.

[mti88m3]

We had a pretty good thread on MAFs going a while back. It might be worth it to keep a Volvo unit in the glove box next to the spare DMR relay.

 

http://www.968forums.com/topic/11421-mas...ntry114469

 

a couple rebuilders are also listed in the thread.

 

Enjoy!

 

Matt

 

Good info!  I tried MAF cleaner, and it seems to be the same.  I opened up my DME relay, and it looked a little suspect, so I have a new one on the way.

Partial Post: Please Login or Register to read the full post.

[mti88m3]

I decided to unplug the MAF and take it for a drive.  It's so much more drivable it's ridiculous.  So am I correct in assuming I need to replace the MAF?

Partial Post: Please Login or Register to read the full post.

[ds968]

I decided to unplug the MAF and take it for a drive.  It's so much more drivable it's ridiculous.  So am I correct in assuming I need to replace the MAF?

Wait, what ?!    The car even runs at all without the MAF plugged in , much less, drives better ?!      

Partial Post: Please Login or Register to read the full post.

[mti88m3]

¯\_(ツ)_/¯ I got the idea from that thread MCL968 linked.

Partial Post: Please Login or Register to read the full post.

[Waylander]

that would be a yes, it will munch through fuel, as it will use a default fuel and ignition map.

 

but i think the old thread on MAF's should be updated, this one was about coils

Partial Post: Please Login or Register to read the full post.

[mti88m3]

that would be a yes, it will munch through fuel, as it will use a default fuel and ignition map.

 

but i think the old thread on MAF's should be updated, this one was about coils

 

Makes sense, I've moved my MAF troubles over here: http://www.968forums.com/topic/11421-mas.../?p=181962

Partial Post: Please Login or Register to read the full post.

[MLB]

Hi, just finally reporting back - I swapped out the ignition coil tonite, no change in idle instability

(Bosch, same part #, but made in Brazil, so we'll see if it holds up. Im keeping the original just in case.)

 

And it seems not to matter much if the car is already warmed up. If I come to a stop and let off the gas (clutch depressed or in neutral), the RPMs fall and the engine stalls. Gently lowering RPMs can sometimes allow it to hold Idle where Flash set his chip for the supercharger, which is around 950 rpm. Otherwise, besides a very high oil consumption issue that I will be looking into this summer, the engine runs well.

 

So my next suspect is the ICV, and I seem to recall someone reporting they were able to open er up, clean and reassemble with improved results. Now where did I read that? Was it Waylander, Bulti?

Anyway, it seems the rubber mounting boots are still available so I'll probably get two of those before I remove the thing.

Partial Post: Please Login or Register to read the full post.

[pdxmike]

http://www.968forums.com/topic/8560-idle...-cleaning/

 

You can probably rule in/out the ICV while its in the car by clamping off either of vacuum hoses attached to it with vise grips while the engine is idling cold. If the ICV is working idle should drop significantly and/or the engine should die. If no change cold then no air is going through and it is either not working or clogged.

 

I can't find mention of this in the workshop manual but its standard procedure to quickly check the Aux air regulator on older Bosch systems. I know our DME system works differently from the older AARs (which are either open when cold or closed hot), but the principle when cold should be the same. The engine must run richer cold, and needs more air to idle acceptably during cold-start enrichment - therefore the extra air must come through the ICV. 

 

Also if the ICV is the only problem I would imagine with full throttle it should fire right up after it dies - the ICV wouldn't make a difference at non-idle conditions. If it starts hard with full throttle then its probably something else. 

 

JMO based on a year of chasing idle problems in my digijet Vanagon. I welcome any corrections if this isn't accurate. 

Partial Post: Please Login or Register to read the full post.

[Waylander]

In a 968 the Motronic sorts out the cold fueling,

 

gets its info from the Blue topped temp sensor, and the oil temp sensor, and the MAF for ambient Air temp.

 

The O2 sensor is not used until the engine is out of the cold start map in the ECU

 

the extra fuel is delivered by increasing the length of the on  / off pulse of the injectors.

 

hope that helps explain,

 

the idle is controlled by the ECU and the ICV, and yes they do come apart with a bit of tab bending, mine was leaking masses of air due the the casing O ring being in about 5 bits.

 

replaced that and sealed it up after a full clean out and not had any idle issues at all, sits happily at about 750.

 

having had all sorts of issues with my SLK320 and MAF's, with the fly by wire throttle as well "nightmare"

Partial Post: Please Login or Register to read the full post.

[MLB]

Flash reminded me his SC chip retains factory idle setting of 840 rpm

I will try to remove and clean the ICV this wkend

Partial Post: Please Login or Register to read the full post.

[Bulti]

Very high oil consumption? Hopefully not something serious...

Partial Post: Please Login or Register to read the full post.

[MLB]

Yeah, i will start another thread for this oil consumption. Concerned that original rings are now the weakest link, with the supercharger adding stress to the system.

No cloud of smoke, but others have said you cant always observe that from the drivers seat.

There are no other oil leaks, got those sorted over the past 5 yrs

Partial Post: Please Login or Register to read the full post.