944 is down....again

"K-Roll-PorscheTamer" (k-roll390) 08/25/2015 at 15:05 • Filed to: 944Lyfe

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Mark that 4 times within a month the car has broke down on me(It doesn’t really bother me the number of times, rather the frequency and timing). Went for a 3-mile run, mowed the lawn, washed the car, and got ready for class and into the car, only to turn the key, and only hear the sound of the engine crank. At least this time it was in my driveway and not somewhere else, and I think I know what caused this...

When I changed out my speed and reference sensors, instead of going with the original proven Bosch sensors, I only had the money for the “cheaper” BMW-used sensors. I was forewarned that they last a lot less than the Bosch sensors and it is unknown how long they last, as each set is different. I went with them anyways. and the fact that I’m getting no tach bounce points to this being a potential cause.

They did last me maybe 100 miles though? But if that is indeed the cause, I won’t be able to go to the Euro-only car show I’d been planning on going to for the last 2 months....Oh well. When I get home in about 4 hours after class, I’ll see if the car will fire up at all. It’s gonna be another night to relieve stress with fattening Chinese takeout.

If there’s any solace in this, it wasn’t my Fezza gloves that caused this, damn Bimmer sensors... -_-

Party-vi > K-Roll-PorscheTamer 08/25/2015 at 15:12

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I can’t imagine a sensor would be inoperable after only 100 miles. Possibly something is disconnected or maybe a new issue altogether?

K-Roll-PorscheTamer > Party-vi 08/25/2015 at 15:13

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It is possible. But the symptoms I’m seeing are exactly the same as the last time it broke down. No tach bounce is an immediate cause of a failed speed sensor. I haven’t read anything else that could cause it. I’ll check for spark later, but I can’t think of another cause.

SnapUndersteer, Italian Spiderman > K-Roll-PorscheTamer 08/25/2015 at 15:16

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Get a better car. It’s not the sensor’s BMW branding that’s the problem.

Get a Suzuki Every Joy Pop Turbo

K-Roll-PorscheTamer > SnapUndersteer, Italian Spiderman 08/25/2015 at 15:21

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Sam > K-Roll-PorscheTamer 08/25/2015 at 15:24

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I’ll trade you my 924. It leaks oil and the interior lights don’t work, but it’s had nothing major go wrong in several thousand miles (I think I’ve put about 6k on it).

K-Roll-PorscheTamer > Sam 08/25/2015 at 15:28

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I put 4k on mine before this, so I’d say I was doing pretty good. And the previous owner who only drove the car 5,000 miles before me had no problems either. So 9k miles without a problem is pretty damn good.

DogonCrook > K-Roll-PorscheTamer 08/25/2015 at 15:30

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It’s a hall sensor so unless it’s a defect, those shouldn’t fail that easily. Physically speaking it’s one of the most robust sensors made. A stray piece of metal sticking to one will interfere with it’s signal though so a blast of air is worth a shot or if you can reach it wipe it off and the trigger wheel.

Tohru > SnapUndersteer, Italian Spiderman 08/25/2015 at 15:30

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What a troll post. The Renault Twingo is a superior choice.

With-a-G is back to not having anything written after his username > K-Roll-PorscheTamer 08/25/2015 at 15:32

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Perhaps you should reconsider your user name?

Tohru > K-Roll-PorscheTamer 08/25/2015 at 15:33

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“9k without problems is pretty damn good” - that sounds like Stockholm Syndrome, man. I put 30k on my 94 Probe with no faults.

PS9 > K-Roll-PorscheTamer 08/25/2015 at 15:34

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Ls1 swap. Keep the 944 looks and ditch the 944 reliability with some added speed for good measure.

K-Roll-PorscheTamer > With-a-G is back to not having anything written after his username 08/25/2015 at 15:35

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To...?

K-Roll-PorscheTamer > Tohru 08/25/2015 at 15:37

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Compared to the 911, which broke down within 300 miles on two occasions over the last two years, The 944 is doing much better I think?

Stockholm syndrome is a real thing though....(._.)

K-Roll-PorscheTamer > PS9 08/25/2015 at 15:38

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But I don’t need the speed. And you don’t even know how much actually goes into such a swap... -_-

Shark-Attack > K-Roll-PorscheTamer 08/25/2015 at 15:39

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Bmw brand sensor? All crank sensors that I know of for similar vintage bmws are OEM Bosch. Are you getting spark?

K-Roll-PorscheTamer > DogonCrook 08/25/2015 at 15:40

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Hall sensor?? I’ll try attempting a clean up of the sensor, but I can’t even clean it without removing it, and I can’t fathom what could have gotten stuck to it so soon. It hasn’t even been a week yet!

K-Roll-PorscheTamer > Shark-Attack 08/25/2015 at 15:41

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I haven’t checked for spark, I’m at school currently, so it’ll have to wait until later. I’d honestly be the happiest if it was something stupid like a spark plug, wires, distributor, or coil ect.

uofime-2 > K-Roll-PorscheTamer 08/25/2015 at 15:43

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K-Roll: Porsche’s bitch

or,

Porsche: K-Roll Tamer

Shark-Attack > K-Roll-PorscheTamer 08/25/2015 at 15:44

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Exactly. Always best to check the easiest things first, just to rule them out. And if your cap and rotor haven’t been changed recently I’d do it anyway just as cheap preventative maintenence. Cheaper than a flatbed ride home at least.

Mr. Ontop, No Strokes, No Smokes...Goes Fast. > PS9 08/25/2015 at 15:44

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I think the LS1 might be more reliable than the Porsche engine..

PS9 > Mr. Ontop, No Strokes, No Smokes...Goes Fast. 08/25/2015 at 15:45

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I didn’t say it wasn’t...

K-Roll-PorscheTamer > uofime-2 08/25/2015 at 15:47

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How about nah

K-Roll-PorscheTamer > Shark-Attack 08/25/2015 at 15:49

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They haven’t been changed, but I was hoping it could wait until storage. That’s when I planned on doing more maintenance when I’m forced to not drive it.

DogonCrook > K-Roll-PorscheTamer 08/25/2015 at 15:54

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Hall effect sensors detect a magnetic field. Usually metal sticking to the magnetized triggers causes misfires because it can’t read a trigger point, and if there is gunk on the sensor and something sticks to it, it won’t read anything. Even a small shaving or fuzz can throw off the reading if it’s right on the sensor. If you can’t reach it or see it though, then I’d eliminate everything else as a possibility first because that sounds like a pain.

Hall sensors are pretty much bulletproof I don’t think brand matters at all, but the wiring I guess could be shoddy.

TractorPillow > K-Roll-PorscheTamer 08/25/2015 at 15:55

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I think the obvious moral of this story is that you shouldn’t go for runs.

SnapUndersteer, Italian Spiderman > K-Roll-PorscheTamer 08/25/2015 at 15:55

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You can the Evey Joy Pop Turbo tamer

K-Roll-PorscheTamer > TractorPillow 08/25/2015 at 16:00

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I don’t understand.

K-Roll-PorscheTamer > DogonCrook 08/25/2015 at 16:01

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Wait, so would water by chance be a potential cause for intermittent failure? or a wet sensor, would that be enough to disrupt the magnetic field?

uofime-2 > K-Roll-PorscheTamer 08/25/2015 at 16:04

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You’re just no fun at all!

DogonCrook > K-Roll-PorscheTamer 08/25/2015 at 16:08

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No, but it could carry the object that interferes and leave it behind I guess.

Mr. Ontop, No Strokes, No Smokes...Goes Fast. > K-Roll-PorscheTamer 08/25/2015 at 16:11

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Oh, K, I found a parts car for you. sounds like you might need one.

http://sandiego.craigslist.org/esd/cto/515648…

Master Cylinder > K-Roll-PorscheTamer 08/25/2015 at 16:13

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Seems unlikely that brand new sensors would crap out already, but we are talking about German electronics here. One thing you might check is the sensor connectors up behind the intake manifold. They tend to be super brittle at this point and you may have a broken one. I broke the cam sensor connector on my S just by bumping it with my hand. New connectors are available, though, and pretty simple to splice into the harness.

Hopefully it’s something easy like that!

K-Roll-PorscheTamer > Mr. Ontop, No Strokes, No Smokes...Goes Fast. 08/25/2015 at 16:13

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A parts car across the entire country....

K-Roll-PorscheTamer > Master Cylinder 08/25/2015 at 16:15

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How could they get brittle enough to the point of failure after less than a week though?

K-Roll-PorscheTamer > DogonCrook 08/25/2015 at 16:15

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Hmm...much pondering.

Mr. Ontop, No Strokes, No Smokes...Goes Fast. > K-Roll-PorscheTamer 08/25/2015 at 16:15

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details...details.

K-Roll-PorscheTamer > Mr. Ontop, No Strokes, No Smokes...Goes Fast. 08/25/2015 at 16:19

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Science and stuff

DogonCrook > K-Roll-PorscheTamer 08/25/2015 at 16:22

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Well look up hall effect and sensors, they are pretty simple and you can maybe get an idea if there could be a problem in your situation. But a wiring or ground issue seems more likely offhand as a culprit. Especially since its two failures of a really reliable piece of equipment.

Master Cylinder > K-Roll-PorscheTamer 08/25/2015 at 16:23

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I’m talking about the harness-side connectors that the sensors plug into. They’re super easy to break after 30ish years in a hot 944 engine bay. If the retaining clips are broken, they may have vibrated out enough to become disconnected. Just a possibility.

K-Roll-PorscheTamer > DogonCrook 08/25/2015 at 16:23

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Well the first failure was with the 31 year old original set, so that made sense. This one, on the other hand...

K-Roll-PorscheTamer > Master Cylinder 08/25/2015 at 16:26

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I’ll look into it. :)

Shark-Attack > K-Roll-PorscheTamer 08/25/2015 at 16:27

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Then I would recommend at least taking them off and cleaning the contacts with a wire brush. It’s free, if you can find the time. Just be careful not to cut into the contact itself. Even if it’s not the problem the car will probably run better.

DogonCrook > K-Roll-PorscheTamer 08/25/2015 at 16:29

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Does the first sensor have any visible cracking or damage? They encase them in plastic which is why they are so reliable, but 30 year old plastic is a crapshoot. They do lose their calibration and I’m actually not sure if cars have a calibration routine for them or if in this type of application the drift is even a concern.

K-Roll-PorscheTamer > DogonCrook 08/25/2015 at 16:36

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They’re brand new though, the ones that are currently in the car.

K-Roll-PorscheTamer > Shark-Attack 08/25/2015 at 16:43

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It’s worth a shot.

DogonCrook > K-Roll-PorscheTamer 08/25/2015 at 16:45

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Yeah that’s why I wouldn’t suspect the sensors, the chance is really low. Go over all the wiring and connectors and check your grounds. I’d hit up rennlist to diagnose that circuit for failures other than the sensors themselves.

K-Roll-PorscheTamer > DogonCrook 08/25/2015 at 16:46

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Already on Rennlist and awaiting a response as we speak.

Mr. Ontop, No Strokes, No Smokes...Goes Fast. > K-Roll-PorscheTamer 08/25/2015 at 16:53

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RazoE > K-Roll-PorscheTamer 08/25/2015 at 16:55

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Then go for a carb’d 350. Speed’s not the issue, simplicity is.

K-Roll-PorscheTamer > RazoE 08/25/2015 at 17:02

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350?

RazoE > K-Roll-PorscheTamer 08/25/2015 at 18:06

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“Chevy” 350. I use quotes because there are crate engines made up entirely of aftermarket parts. It’s a 5.7L V8 that’s been shoved into everything from Scion xBs to Ferrari 360 Modenas.

Edit: proof

wiffleballtony > K-Roll-PorscheTamer 08/25/2015 at 18:27

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I think I’d like to see the story of your Porsche told through the medium of interpretive dance. Or maybe Greek theatre.

K-Roll-PorscheTamer > wiffleballtony 08/25/2015 at 19:29

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I wonder what they’d say knowing that I just fixed it.....again.