Lousailor

I've had this type of intermittent problem before as well. In one instance it was the ignition switch. The plastic portion behind the key-lock part, was cracked where it held the spring, so when driving around the other keys, fob, etc. bouncing around would cause the ignition to cut-out. In another instance it was the actual reference sensors (not the connections). I had checked plugs, wires, cap, rotor, coil, fuel pump, relay - all good. Finally pulled the sensors (easier than I expected), and they were gummed up with grease metal filings. They're magnetic pick-ups, so I guess the gunk from all the years and mileage was interferring with the signal. Cleaned them, and re-installed and no-problems for over a year.

washington951

thats interesting - i just had the head cleaned up and a new HG installed - think that might have loosened some gunk up that might have accumulated on the ref sensors? how did you pull them - i'm going to clarksgarage now...

Eyal 951

Hey, yesterday on a canyon run, my car started stumbling real bad on boost delivery, almost violently. It never died on me though. But since your SOL right now, you might as well check this... I pulled over to take a look whats wrong. I started with the intake/MAF area right away, made sense to me, and Viola, what did I find? The J-pipe connection to the MAF sensor was completly loose and moving around, so under boost, it slide back and opened a tiny bit. I tightened it down with the trusted porsche tool set the car came with, thankg god cause my key wasn't working till i remembered i had the tools! The point is, check all your clamps in the intake area, see if any have loosened?
~Eyal

washington951

eyal - good call again as it recently had head work done...will be able to get back out there tomorrow again...will be checking the speed/ref sensors and looking for vac leaks....

Tom M'Guinn

Washington,

How ofen does it cut out? Everytime you drive? Once every few days? And when? Full boost? Over bumps? Can you reproduce it, or does it just happen whenever it wants?

Does it always start right back up without a problem?
When the car dies, what happens to the gauges? Do they all die too? Some work, some not? What happens to the ARM1?

Did you check that the MAF and TPS connectors were fully seated when the head was done? Also, how old is your ARC2? I know of one that had an intermittent electrical problem. (To confirm that it is getting power, you can drive around with the lights on -- so that the face panel of the ARC2 lights up -- when the car dies, check to see if the ARC2 face panel is still lit up.)

washington951

hey tom,
during the one night when it started acting up, it would do it whenever it wanted. every couple of miles - independent of speed, bumps, throttle position - anything. completely random as far as i can figure. i was trying to figure out a common link, but couldn't see one.

it always starts right back up with no problem. gauges: tach goes straight to the bottom - couldn't really tell with the others. headlights and everything else stayed on and appeared normal. ARM1 was running per normal - not sure what it did when things cut out.

i checked the sensors yesterday and all appeared to be seated just fine. yesterday, i also beat the ARC2 around a bit while driving and idling. and also wiggled the wiring around. no effect.

i'll keep an eye on the panel when it starts acting up again.

one thing that i have thought about: this problem didn't start until AFTER i turned my headlights on - i'm wondering if the bar that connects the two headlight buckets is moving enough to disturb my intake plumbing - specifically, the silicone hose that connects the straight pipes to the intercooler. it s a pretty tight little clearance there and i'm wondering if the bar moves JUUUUST enough to bump the straight pipe connection and cause a crazy little leak. am i crazy?

drove around yesterday with the lights on - city streets, just like when i had the problem before - and could not repeat it.

i HATE intermittent problems!!! thanks for the help!!

Tom M'Guinn

Wash,

Does not sound like a big vacuum leak to me. I've had those hoses pop off before and/or get lose. When that happens, the car usually sputters and runs terrible before dying. If a leak were that bad, it would not likely start right back up without problems. Next time it happens, I'd watch the gauges and ARC2 and ARM1 for clues. Does the speedometer (or voltage gauge) die even though the car is still moving? If it is dying completely and without any sputtering or fussing, then I'd think there is some kind of electrical problem -- ignition switch, bad ref sensor adj or connection, bad solder joint in the DME, bad MAF connection, etc.

washington951

gotcha - of course, i've driven it for the last two days with no drama....my eyes will be wide open if/when it happens again....my uneducated self (based on what great replies i've gotten here) is leaning towards the speed/ref sensors. i agree with you that the vac leak thing wouldn't cause this kind of IMMEDIATE shut down. thanks folks - updates as they warrant....