QuestionI'll give this a try this weekend. Thanks so much for the input. I was about to try the fuel pump or the reference sensors next. But Iwas just guessing.
Thanks, Greg
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Followup To
Question -
Help!
I have a 1988 924S that used to run great. Now it has developed an intermittent "stop run" in it. The car starts normal and after 3-5 minutes it seems to "stutter" or "gag" very intermittntly. It can run fine for up to 15 minutes without doing this. Usually it is less. It even rarley dies completly. I was driving it the first time it did this and it acted like I turned the key off and then back on real fast. Another time the moter died completly (stereo and lights stayed on) and I coasted to the side of the road. The motor turned over but it did not start with the starter. I almost killed the battery trying to start it. I popped the hood, "talked" to it a bit, pushed some wires around a bit as to look like I knew what I was dong to the people watching, got back in and it fired right up. It stuttered a couple of times in the 3 miles or so home.
I have replaced, the DME relay, ECM, plugs, plug wires, cap and rotor, fuel filter, fuel pressure regulator, and battery.
I have not noticed any fuel leakage, cracked wires, loose connections, or bad vacume lines. I have moved or wiggled every line I could get to as well as have reseated as many connector or fitting that I can see.
It still has this problem. Any Ideas?
Thanks,
Greg
Answer -
Hi Greg.
Don't you just love to stand over your engine and give it words of 'encouragement'...wit you moving around a bit, looking here and there... staring at this and that, putting on a show for your adoring fans? Don't get too full a head...most of them know its only an act 'cause they've done the same thing! We've all done the same thing!
You've done quite a bit of good detective work. The answer is: the air flow sensor. It's the part of the fuel injection system that measures the rate of air rushing into the intake manifold as the cylinders draw, suck, and vacuum all the air they can get into their combustion chambers. I learned about the air flow meter the hard way. Experiencing all the same symptoms as you...the kicker was driving along at 65 on the freeway...and yeah, it feels just like the key was turned off. I had borrowed my brother's BMW and was out-of-town and the independent shop only charged me $550. to replace it. UGH!
Luckily, you can test yours yourself. Basically the sensor reacts and measures its' air flow "door", a metal flap opening wider when more air is being sucked. Sorry to use the technical terms...I'll try to keep this simple. Anyway, sometimes through age and a worn mechanism, but more likely gunk getting in where the door hinges, the door will stick open or closed or both...intermittently. The Haynes Porsche 944 manual has a great couple pages on some electronic testing you can do to see if the readings the sensor is giving off are accurate, but more than likely, the problem is gunk.
Give that a try.
Dave
AnswerGreg,
I hope you find a balky door this weekend. Not that I'm wishing you a problem, I'm hoping my long distance diagnosis will be correct. I'd appreciate some feedback when you're done, or of course, write me with any follow-up questions.
Dave
