Jeff928S4

Had the 1989 S4 in to check for vacuum leaks and/or bad alternator, as I am having looping idle problems and what feels like the gas is cutting in and out at revs below 3500.

Did a smoke test and found no vacuum leaks and the alternator/battery all checked out fine.

I now want to pull the MAF out (disconnect it) to check if it is the possible culprit. It has been mentioned that the MAF is held in the throttle body with a "clip". I know how to get to the MAF and am going to do this tonight, but am a bit worried about this "clip". Any tips on removing this clip so I can disconnect the MAF and see if the car runs better? I'm using minimal tools here, so I need some way of removing the clip with the basic of tools.

Thanks all,

sharkmeister85

I think your's will be the same as my '85. Flat blade screw driver to loosen hose clamp holding rubber MAF boot to bottom of airbox. Same screwdriver (if small enough) can pry the clip off the electrical connector attached to MAF and it's free to remove.
Glenn

Jeff928S4

That's what I wanted to hear. Flat screwdrivers I can work with!

Bill Ball

The MAF is held on the intake rubber boot by a simple hose clamp. You should be able to use a long, thinn flat blade screwdriver to reach the screw, hopefully visible at the base of the MAF from the right side, sighting between the fuel rail cover and intake. You can disable the MAF by just unclipping the electrical connector, though.

Jeff928S4

So, there is no need to actually remove the entire MAF? I can disconnect it while it still sits in the throttle body? I guess I'll know more when I go open it all up.

sharkmeister85

Once I get my lower air cleaner box out of there, the MAF will pull right out of the manifold (held in by nothing more than the rubber o-ring in the manifold) and then I disconnect the electrical plug. Its just easier than trying to disconnect it with the MAF in place.
Glenn

Gretch

pictures

1) MAF in situ

2) MAF on throttle body (not my picture, BTW)

The connector is mounted on the MAF on the drivers side. couple of spring keepers on the side of the connector. You can get to the hose clamp that holds the MAF to the throttle body from the passenger side of the intake manifold, with a loooooong flat bladed screwdriver......see clamp on lower portion of MAF on second picture. Pay no attention to the rubber goose neck on the top of the MAF in the lower picture........not OEM......

word of advice......GO EASY.................You pull the lower rubber connector off of the throttle body and you are gonna HATE YOURSELF.

Jeff928S4

Great stuff!!! Pictures speak a thousand words, in this case, just 4 - "Look at that MAF!!" Heading out to play with it right now. I'll report back with my findings.

A quick question....once the MAF is disconnected, should I put the air box/filter/etc back on and then start it, or just start it as is?

Gretch

For testing purposes, I have run my engine for short periods without the air box on it. the MAF has screens on either end that will keep anything except a bit of dust from being sucked into the engine....
You do, of course mean that you intend to disconnect the MAF from the connector, and then run the engine, NOT that you intend to try and run the engine with the MAF removed, correct.

Jeff928S4

He he, yes. I wouldn't try to fire her up sans MAF. I'm no mechanic, but I summized that open holes into the engine while running is not a good thing.

Gretch

OK, and oh, BTW not that I am an electrician either.........I have no idea if your car will run with the NAF connector unplugged.....I never tried it and never had an interest in knowing.......

bgrabner

Hey Boyeee (nice name BTW ) Can you update this thread with your results? I have an 87 S4 too, and I am concerned my MAF may be contributing to my lack of power...interested in how yours comes out...

Bill

Jeff928S4

No problem Bill - will do.

By the way - I gotta change that name (and get a membership) - it's my old 944 name and the "Boyeee" just doesn't fit a 34-year-old who has never been in the rap group Public Enemy.

UKKid35

Try to get hold of a known good MAF. The effect of an old MAF on performance, idle stability and responsiveness is dramatic. Also check www.JDSPorsche.com for more info.

John Speake

Boyee,
The easiest way to get a MAF out of a 32v is to undo the worm drive clip at the lower end with a 7mm ring spanner.

That way you can slip it over the hex, and it is much easier than trying to keep a screwdriver in the slot.

Sometimes the clip has been positioned so you can't get a screwdriver on it anyway.

Please note that a MAF disconnect is only valid for gross MAF failures, on S4 onwards. When you disconnect a MAF, the ECU goes into "limp home mode" - the car will run, but badly.

Even a badly aged MAF will make the car run somewhat better than "limp home". To properly test a MAF, you need an accurately calibrated flow jig. They have to be within 2% of nominal, or performance/running is affected.

In the section "free stuff" there is the offer of a loaner MAF for fault finding.

Regards,