Honk Honk!.... " yea, I know I am stalled out and blocking the intersection @$$H*L$" Options

[shredtherad]

Hello, hello! The new to me 914 is so rad! Love it... went out for a bit of cruise and about 20+ mins into the drive, while approaching a trafific light ( red ) the car came down to idle and that kept going and poof... stall. It did not start, I blocked the lane and angry SUV's and Tesla's honked at me. I did however get it going again after putting the pedal to the floor while starting and it fired up and drove fine, until... idle at the stop sign. Poof, stall. BUT this time pedal to the floor and fired right up.

Thoughts, where should I begin. I have attached a video of the issue... thanks! Beep Beep.


https://www.youtube.com/watch?v=Mx47LENYFuU

[mgphoto]

First test is simple, get a hand vacuum pump with a gauge, test the MPS, pull 10 to 15 in Hg and see how long it takes to drop.
Sounds like a cracked diaphragm, runs rich when that happens.

[GregAmy]

First test is simple, get a hand vacuum pump with a gauge, test the MPS, pull 10 to 15 in Hg and see how long it takes to drop.
Sounds like a cracked diaphragm, runs rich when that happens.

Was my first thought, since I had similar symptoms with the 2L D-Jet.

If you're running stock D-Jet, and you have more than say, 75-100k miles on the car, you have no evidence that the diaphragm has ever been replaced, then I'd wager a dollar to every donut that your diaphragm needs to be replaced. The MPS was a very clever design for its time but that diaphragm has a life limit before it will absolutely fatigue.

Mine had those, and other symptoms, and it actually passed the vac test! But when Tangerine pulled it apart to rebuild the crack was obvious. And replacing it transformed the way the car drove.

I like D-Jet, I think it's worth saving. Consider sending your MPS to Chris for a new diaphragm, even if it passes a vac test.

http://www.tangerineracing.com/mpsdiaphragm.htm

[shredtherad]

First test is simple, get a hand vacuum pump with a gauge, test the MPS, pull 10 to 15 in Hg and see how long it takes to drop.
Sounds like a cracked diaphragm, runs rich when that happens.

Was my first thought, since I had similar symptoms with the 2L D-Jet.

If you're running stock D-Jet, and you have more than say, 75-100k miles on the car, you have no evidence that the diaphragm has ever been replaced, then I'd wager a dollar to every donut that your diaphragm needs to be replaced. The MPS was a very clever design for its time but that diaphragm has a life limit before it will absolutely fatigue.

Mine had those, and other symptoms, and it actually passed the vac test! But when Tangerine pulled it apart to rebuild the crack was obvious. And replacing it transformed the way the car drove.

I like D-Jet, I think it's worth saving. Consider sending your MPS to Chris for a new diaphragm, even if it passes a vac test.

http://www.tangerineracing.com/mpsdiaphragm.htm

https://youtu.be/3lvTXN7d5-8

This seems like a good video/resource

[Lockwodo]

First test is simple, get a hand vacuum pump with a gauge, test the MPS, pull 10 to 15 in Hg and see how long it takes to drop.
Sounds like a cracked diaphragm, runs rich when that happens.

Was my first thought, since I had similar symptoms with the 2L D-Jet.

If you're running stock D-Jet, and you have more than say, 75-100k miles on the car, you have no evidence that the diaphragm has ever been replaced, then I'd wager a dollar to every donut that your diaphragm needs to be replaced. The MPS was a very clever design for its time but that diaphragm has a life limit before it will absolutely fatigue.

Mine had those, and other symptoms, and it actually passed the vac test! But when Tangerine pulled it apart to rebuild the crack was obvious. And replacing it transformed the way the car drove.

I like D-Jet, I think it's worth saving. Consider sending your MPS to Chris for a new diaphragm, even if it passes a vac test.

http://www.tangerineracing.com/mpsdiaphragm.htm

https://youtu.be/3lvTXN7d5-8

This seems like a good video/resource

Yes, that will show you how to test the vacuum integrity and the primary/secondary coil wiring. For troubleshooting MPS and other 914 problems in general, another good resource is the Tech Notebook: https://bowlsby.net/914/Classic/TechNotebook.htm, see Reference Manual section.