yellowline

How full is the gas tank? I'm wondering if you have ice in your lines, especially with recent temps. My car acts the same way in winter if you don't keep the tank full.

A can of Drygas couldn't hurt.

iloveporsches

It would have been nearly full both times. It takes me a little less than half a tank to get home. I'll then fill up when I leave on Sunday or Monday.

Both days were extremely cold, though. High for December 4th was 26, high on Monday might have been 2 or 3. However, I was able to drive without incident back home for winter break, all during winter break, and back home on last Friday.

jgleano

my problem similar to this one got fixed. I simply changed my fuel filter.

hderr

"iloveporsches" Check your fuel pressure regulator per Clark's. It's a simple procedure that only takes a couple of minutes. That's my guess.

gtroth

I have been chasing this exact problem for years. Here's my thread:

944S cuts out when very cold

So far this year it has occured at 3.2°F, 10.4°F, but not 13.3°F (today), which is typical. Car must be warm and air cold for it to happen. Runs absolutely beautifully otherwise.

New for this year is O2 sensor, no help.

I am suspecting the AFM since I've ruled out most everything else I can think of, but it measures normal electrically, at least while I'm measuring it (flap voltage and thermistor resistance). And I'm somewhat convinced that the DME has decided to cut back on the fuel when it cuts out. Interesting to note that when it's acting up, I can put the car in neutral or press the clutch and it will easily rev to 5K~6K rpms no problem.

iloveporsches

It was the AFM.

My roommate just happened to be going down to Sebring the following weekend with Midwest Eurosport Racing for a PCA race. He crews for them sometimes. Anyway, he picked their mechanics' brains and they thought it was either AFM or TPS. I picked up both off of todd944 a few weeks ago, but it's been snowing and below freezing for weeks here, so today was the first chance I had to get out and work on the car.

The first thing I did was test the old AFM on the car, as per Clark's Garage. Found a dead spot around 400mV where the voltage dropped to zero. I swapped in the replacement and tested that and found it to be in good working order. Just drove the car for several hours and it drove great.

944Turbo413

Hey i know this is a very old thread but it wont let me post my own thread because i had to start a new account cuz i forgot my old one. Anyways, me and my dad picked up a 87 Guards Red 951 for $4350 with 130k for a project track day car. The car blew a head gasket about 4k miles ago and had everything done on the car to get it back to spec (over $5 grand worth of work and i have receipts) but then was sitting for like 4 years barely driven. It has extensive records and receipts of the work done and is in nice shape.

Anyways when we took the car for a drive a few times we discovered that the car has good power in 1st and 2nd gear full throttle and boosts correctly but then at higher loads in higher gears (3rd and 4th) WOT conditions every time it will cut out. Ive been doing alot of research and it seems like according to everyone talking on the net and clarks garage it is the DME or KLR computer going into overboost protection mode and cutting fuel (sound right)? I checked all the vacuum lines but they all seem ok but the bypass valve might need replacing(need to do a few more tests). Anyways ive heard soooo many different diagnoses like wastegate problems, faulty computers, fuel pressure reg, vacuum lines, tps, afm. We were thinking since we want to track the car we could do a replacement AFM kit for more power and solve the problem. Im not a Porsche expert by any means and im just trying to learn more about turbo systems. What else should I test and how? Anyways any help would be greatly appreciated! Thanks!