Porsche Repair: troube shooting 1986 944 automatic, air flow meter, fuel line hose

Question
Hi Dave, all of the hoses checked out fine and the intake manifold was checked by spraying brake cleaner near the intake and the head where they bolt together. Everyting checked out OK. Sure could use those bench test air flow meter specs if you have them. Thanks for the help offered so far.

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Followup To
Question -
Hi Dave, all of a sudden my 944 (1986 automatic) began stalling whenever you touch the gas pedal. The car starts and idles fine but get near the gas pedal and it dies immediately. Have you heard of a problem like this before? A friend mentioned bench testing the air flow meter. Do you have access to the specs? What else would you try checking? Thanks in advance for any information or ideas. Nancy     
Answer -
Hi Nancy...

Yes, I do have the air flow specs, but I'm not sure I'd check there first.

I'd begin by looking for a vaccum leak in the fuel injection system or at the intake manifold as it attaches to the engine block.

If you can readily tell the difference from a vacuum hose and a fuel line hose, then here's what to do first:

1.  Depressurize the fuel injection system by  removing the fuel pump fuse, which should be #2 on the auxillary panel under the left side of the instrument panel.   Start the car and let it run until it dies from fuel starvation.  Remove the gas tank  cap.  These precautions are necessary in case you mistakenly mess with a real fuel line.

2.  Identify every hose that you believe is a vacuum hose and remove each one, one at a time.  If the hoses are the ones that came with the car, replace every one of them...or you'll do this drill again and again and again.

3.  As you remove the vacuum lines examine each hose for a break or a tear...or possibly a loose hose clamp.  When you find it, say AHAA!  Then keep replacing all those hoses.

4.  When you're done replacing hoses,  replace the gas cap and the fuel pump fuse and restart the car...it'll take a minute to repressurize the fuel system  since the fuel lines will be empty at first.  Try the gas pedal in gear and off you'll go.  Say AHAA!

5.  If not, there's another test to check the intake manifold...but I'd rather cover that later.  I'd suggest you work on your vacuum hoses and when you're done, give me some feedback as to whether you found the problem.

Use the follow-up feature of All-experts to re-contact me.

Thanks,

Dave

PS...In the meantime, since you'll be at the auto parts store anyway...buying lots of hose by the yard...pick-up the following:

"Porsche 944 Automotive Repair Manual", published by Haynes in '87 and 1990.  It's their product # 1027".  If your auto parts store doesn't carry Haynes, find another auto parts store.  If they try to charge you more than $20 for the manual, leave it in the store.

There are both new and good used manuals on the internet for sale at great prices.  My wife knows the name of a site she always starts with whenever I say "honey, I need another Haynes manual".  I think it's Bookseller.com.  Anyway, the idea is to not overspend for this manual.  But when you read it, you'll see why it'll be the handiest tool in your Poprsche 944 toolbox.  Trust me.

Answer
Nancy,

The info you're looking for is in the new Haynes manual you're picking up...pg.103.

Air flow sensor check:

Non-turbo engine...voltage between terminal 9 and ground = 8 or more volts

Turbo engine...voltage between terminal 3 and ground = 5 volts

Non-turbo...voltage between terminal 7 and ground:
with sensor door closed = 150-250 millivolts
with sensor door open = 8 or more volts

Turbo...voltage between terminal 2 and ground:
with sensor door closed = 250 to 260 millivolts
with sensor door open = 4.6 volts

Have fun.

Dave