Car is having some fun with me
11-10-2018, 09:30 PM
#1
Drifting
Thread Starter
Car is having some fun with me
Over the past year, I have undertaken significant "maintenance". It's been quite the experience! Lots of hard work and newfound knowledge, I wrapped up recently by licking the last of the little issues--a cold start hesitation, seemingly cured by cleaning & re-positioning AFM inards.
Ah yes, all done now. Time to enjoy another ten years of carefree pleasure driving this fine beast.
Then, a little stumble on the way home from work. No big deal--lasted a second or two. Mentioned it in a post, couple of comments, fun times.
Last night, driving to a highly anticipated staff outing in a nearby city, in the middle of packed three-lane rush hour, the highway on-ramp in the near distance and a set of traffic lights just before it, my renewed 951 dies approaching the lights.
Momentum brings me to the red light. A thousand cars behind me, the cold wet drizzle keeping us all inside, nothing but blurry lights in the darkness. My headlamps disappear replaced by the flashing yellows. I crank once, twice. Holding up the long line of cars behind--nothing like it folks, can't wait. Then, just as the light turns green, it fires up--as if nothing had happened.
Funny.
I tear away with newfound pride. Look at my awesome Porsche take off folks! I was just kidding!
Not daring to get on the highway, I close the gap and put the heavy traffic line back in order. Stop and go never felt better. Running perfect! Then, dead.
This time I'm still moving and the first crank fires it up again. Back to normal. I bet no one noticed.
A mile later, I feel a little stumbling and pull into a gas station. Safe. I can sit here all night. I almost do.
Popping the hood, it's idling perfect. What a nice looking engine compartment: all tidy and newly re-assembled hoses, wires. Everything tight. Lots of new parts! She's a beauty. Wiggling this and pulling that, no change. Sitting in the light drizzle, I wonder at this fine automobile. Then it stalls.
Just like that.
I walk around, get in, and it fires right up. Didn't touch a thing. I play this game for half an hour. Then, I guess it's game over: it idles solid for 5 straight minutes. I close it up and go on my way.
Not one more incident all night long. I enjoy my big social event and drive home on the highway. It's now past midnite. I back up into my spot and park, admiring the smooth idle, and shut 'er down. Goodnight friend.
Jerk better smarten up.
--------------
PS: if anyone has ever had a night or day like this, please tell me it's the fuel pump so I can replace that and for sure be done now. LOL
Ah yes, all done now. Time to enjoy another ten years of carefree pleasure driving this fine beast.
Then, a little stumble on the way home from work. No big deal--lasted a second or two. Mentioned it in a post, couple of comments, fun times.
Last night, driving to a highly anticipated staff outing in a nearby city, in the middle of packed three-lane rush hour, the highway on-ramp in the near distance and a set of traffic lights just before it, my renewed 951 dies approaching the lights.
Momentum brings me to the red light. A thousand cars behind me, the cold wet drizzle keeping us all inside, nothing but blurry lights in the darkness. My headlamps disappear replaced by the flashing yellows. I crank once, twice. Holding up the long line of cars behind--nothing like it folks, can't wait. Then, just as the light turns green, it fires up--as if nothing had happened.
Funny.
I tear away with newfound pride. Look at my awesome Porsche take off folks! I was just kidding!
Not daring to get on the highway, I close the gap and put the heavy traffic line back in order. Stop and go never felt better. Running perfect! Then, dead.
This time I'm still moving and the first crank fires it up again. Back to normal. I bet no one noticed.
A mile later, I feel a little stumbling and pull into a gas station. Safe. I can sit here all night. I almost do.
Popping the hood, it's idling perfect. What a nice looking engine compartment: all tidy and newly re-assembled hoses, wires. Everything tight. Lots of new parts! She's a beauty. Wiggling this and pulling that, no change. Sitting in the light drizzle, I wonder at this fine automobile. Then it stalls.
Just like that.
I walk around, get in, and it fires right up. Didn't touch a thing. I play this game for half an hour. Then, I guess it's game over: it idles solid for 5 straight minutes. I close it up and go on my way.
Not one more incident all night long. I enjoy my big social event and drive home on the highway. It's now past midnite. I back up into my spot and park, admiring the smooth idle, and shut 'er down. Goodnight friend.
Jerk better smarten up.
--------------
PS: if anyone has ever had a night or day like this, please tell me it's the fuel pump so I can replace that and for sure be done now. LOL
11-10-2018, 10:14 PM
#2
Sounds like maybe vacuum leak or dme relay. I dont know that is odd.
Maybe pull dme out and blow dust out of the holes in fuse box and put it back in? I would say swap with another but I have even had issues with doing that. Make sure you buy the 120.00 relay and not the 30.00 one cuz the latter ones flake out
My old 924 did this to me for a couple days. I would get out and wiggle this and that on the engine and all seemed ok. Then get in and it fired right up. I finally removed that big circular rubber air flow piece on top of the engine to inspect it and sure enough there was a hairline crack in it underneath.
Believe it or not I stuck hot glue on it from a hot glue gun and ten years later its working fine. Glue is still there. Now I know what to do when it randomly dies again. Have some duct tape in the door pocket for just the occasion. At least I know that will get me home when it happens.
before you go chasing expensive parts maybe check vacuum lines and rubber air hose thingys first or just wiggle that dme relay.
Maybe pull dme out and blow dust out of the holes in fuse box and put it back in? I would say swap with another but I have even had issues with doing that. Make sure you buy the 120.00 relay and not the 30.00 one cuz the latter ones flake out
My old 924 did this to me for a couple days. I would get out and wiggle this and that on the engine and all seemed ok. Then get in and it fired right up. I finally removed that big circular rubber air flow piece on top of the engine to inspect it and sure enough there was a hairline crack in it underneath.
Believe it or not I stuck hot glue on it from a hot glue gun and ten years later its working fine. Glue is still there. Now I know what to do when it randomly dies again. Have some duct tape in the door pocket for just the occasion. At least I know that will get me home when it happens.
before you go chasing expensive parts maybe check vacuum lines and rubber air hose thingys first or just wiggle that dme relay.
11-11-2018, 12:43 AM
#3
My guess would be a failing reference sensor or speed sensor. Been there, done that, 2 restarts and then nothing. When it died and failed to fire did you have tach bounce while cranking.?
11-11-2018, 08:55 AM
#4
Drifting
Thread Starter
I haven't considered DME relay--in fact, I have the three-wire jumper in the armrest ready to go. Things you forget in times of trouble! At next stall, I'll sub the jumper in and see. I wonder how long I can drive with that jumper as a test trial?
I'm showing good vacuum on the dash gauge: at idle it's a hair under the first line, the normal reading so far as I've observed. I didn't pay attention to the tach bounce--another weird oversight
Speed & reference sensors are both new and while idling, wiggling the connections doesn't upset anything.
Nice glue story
I'm showing good vacuum on the dash gauge: at idle it's a hair under the first line, the normal reading so far as I've observed. I didn't pay attention to the tach bounce--another weird oversight
Speed & reference sensors are both new and while idling, wiggling the connections doesn't upset anything.
Nice glue story
11-11-2018, 03:30 PM
#6
Drifting
Avoid the URO brand. they're crap and are commonly bad out of the box. get an OEM or Stribel. Have you considered there may be junk in the gas tank that blocks the line and then falls away until you're running and then floats up into the screen again?
11-11-2018, 03:34 PM
#7
Drifting
Thread Starter
Trending Topics
11-11-2018, 03:36 PM
#8
Drifting
Thread Starter
No, I haven't considered that. What is this junk you speak of? To check for it, can I just remove that plate in the trunk?
11-11-2018, 04:16 PM
#10
Pro
Can add my “been there” story. Very similar behavior from my 86 951. Intermittent stop and eventual restart eventually deteriorated into no start condition. Had tach bounce that would indicate S/R sensors were good, but over the course of trouble shooting ended up replacing them with new anyway.
My culprit turned out to be a failed DME. Replaced with the modernized F9T, and all is well.
Good luck! These things never really fix themselves, and will eventually leave you stranded somewhere. I’d limit my travel radius.
My culprit turned out to be a failed DME. Replaced with the modernized F9T, and all is well.
Good luck! These things never really fix themselves, and will eventually leave you stranded somewhere. I’d limit my travel radius.
11-11-2018, 04:54 PM
#11
Drifting
Thread Starter
It's my daily driver ten years now! 100k US miles relatively trouble free; stranded only once with a failed fuel pump.
Until last winter. Now I'm a Rennlist "addict" lol
I guess I'm hitting the life expectancy of all the parts--remarkably designed to begin failing at the same time
My daring plan is to keep driving until it won't quickly re-start. Then, sub in my DME jumper. Hopefully not in the middle of the highway. If it starts, replace relay. If it doesn't, call for tow and emerg day off, replace fuel pump.
Livin' on the edge in Ontario, CAN
Until last winter. Now I'm a Rennlist "addict" lol
I guess I'm hitting the life expectancy of all the parts--remarkably designed to begin failing at the same time
My daring plan is to keep driving until it won't quickly re-start. Then, sub in my DME jumper. Hopefully not in the middle of the highway. If it starts, replace relay. If it doesn't, call for tow and emerg day off, replace fuel pump.
Livin' on the edge in Ontario, CAN
11-11-2018, 05:18 PM
#12
Nordschleife Master
"Standard" failure is just that."
But it can fail in a way that it works when it's cold, but running the current through it heats it up, when it then fails.
I had a standard 53 relay do that recently. Worked just fine, for a little bit. Then dead.
I was taught a long time ago to carry a spare DME relay. It's not a big deal to change it out.
If nothing else, you can swap a new one in and see what happens.
11-11-2018, 09:01 PM
#13
Drifting
Thread Starter
Nice list.. thanks! The other one that interests me is Bad Ignition Switch. It does seem a little on the loose side, and I've been dangling a group of heavy keys on there for a long time. But, I can't replicate the stall or stumble by jiggling the key.
The DME relay thing still seems a little fishy: before the total stall, it hesitated a few times while driving for a very short time without cutting out--feels like going over a small set of pavement rumble strips. The relay would simply fail outright, not partly cut out and try and 'hang on' and go back to perfect the rest of a drive, no?
Either way, it has to be something that is perfectly fine then, even while idling & without the car moving or me touching anything, it cuts out. Then back to good. Again, without moving a thing other than the ignition switch (and depressing the clutch pedal which I do instinctively at every start). And it stays perfect again irrespective of the operating temperature for a long time. I'd say this rules out movement as the cause, so nothing like loose connection and I agree vac leak or broken part outright probably not that intermittent independent of any operating conditions.
Unless I'm missing something, this means electrical like a switch or pump. It really reminds me of a fuel pump going, though this one is only about six years old.
Once an engine is running, it tends to stay running, and in all my car experiences, I've only been halted in full stride by FPs. And, I haven't been good to this one: I'm in the habit of always waiting till it's near empty before filling up, tracking my gas mileage. Bad Dan.
(Earlier this year, I worked on the ref & speed sensors so much that I have to rule them out for my sanity!)
Next two days, I'm away on a trip, so the 951 will be sitting. The real-time running diagnostics will have to resume Wednesday. DME Jumper is ready and even formed into the right shape for the side-of-road plug in
The DME relay thing still seems a little fishy: before the total stall, it hesitated a few times while driving for a very short time without cutting out--feels like going over a small set of pavement rumble strips. The relay would simply fail outright, not partly cut out and try and 'hang on' and go back to perfect the rest of a drive, no?
Either way, it has to be something that is perfectly fine then, even while idling & without the car moving or me touching anything, it cuts out. Then back to good. Again, without moving a thing other than the ignition switch (and depressing the clutch pedal which I do instinctively at every start). And it stays perfect again irrespective of the operating temperature for a long time. I'd say this rules out movement as the cause, so nothing like loose connection and I agree vac leak or broken part outright probably not that intermittent independent of any operating conditions.
Unless I'm missing something, this means electrical like a switch or pump. It really reminds me of a fuel pump going, though this one is only about six years old.
Once an engine is running, it tends to stay running, and in all my car experiences, I've only been halted in full stride by FPs. And, I haven't been good to this one: I'm in the habit of always waiting till it's near empty before filling up, tracking my gas mileage. Bad Dan.
(Earlier this year, I worked on the ref & speed sensors so much that I have to rule them out for my sanity!)
Next two days, I'm away on a trip, so the 951 will be sitting. The real-time running diagnostics will have to resume Wednesday. DME Jumper is ready and even formed into the right shape for the side-of-road plug in
11-11-2018, 09:10 PM
#14
Drifting
Thread Starter
That's just it: it *does* re-start, though after a brief pause. And, after a number of stalls and re-starts, runs like a champ without incident the rest of nigh--like nothing ever happened. Imagine staring at your running engine and watch it suddenly hiccup and stall. Then you fire it up and it runs just fine all night long, going over bumpy roads, fully warmed up...