Strange MPS issue, Lew's car Options

[914itis]

I am helping Brian with Lew's car. As most of you may know, it is a 2056 with djet.
The car was running fine, he drive it to CT one day and when he came back he noticed that the MPS was hanging. The car starts to run on 3 cylinders with #4 not firing. We checked for spark and injectors they are all fine, but if you remove spark wire #4, it had no effect.

The strange thing is if you elevate the mps about 6 inches up, it's all fine, even that 4th cyl works. All the electrical wires on the unit are fine

(IMG:style_emoticons/default/confused24.gif) ?

Dies the 2056 uses 1.7 or 2.0 MPS?

He would like to make it to Hershey.

[Dave_Darling]

One curious thing that I found--the MPS can be sensitive to shocks and sometimes even to orientation. It is an electro-mechanical device, and the core inside it can be moved by external forces and change the mixture.

I found this out by accident with the engine idling while messing about with the MPS mounting--the sensor fell down onto the engine tin, and the engine hiccupped when it hit. Naturally, I tried it a few more times, and tried jarring it a few other ways. It was most sensitive to being hit on the end.

That part was what led to the realization that the core could be moved relative to the windings by thumping on the MPS body...

--DD

[achman_73_2.0]

One curious thing that I found--the MPS can be sensitive to shocks and sometimes even to orientation. It is an electro-mechanical device, and the core inside it can be moved by external forces and change the mixture.

I found this out by accident with the engine idling while messing about with the MPS mounting--the sensor fell down onto the engine tin, and the engine hiccupped when it hit. Naturally, I tried it a few more times, and tried jarring it a few other ways. It was most sensitive to being hit on the end.

That part was what led to the realization that the core could be moved relative to the windings by thumping on the MPS body...

--DD

Hey Dave

This all started when I came home from a drive to NJ and popped the engine cover and found the MPS laying in the engine compartment on the tin. It had been jury-rig mounted and came off...but the car ran fine. issues started when I remounted correctly. So is the MPS toast?

[Dave_Darling]

This all started when I came home from a drive to NJ and popped the engine cover and found the MPS laying in the engine compartment on the tin. It had been jury-rig mounted and came off...but the car ran fine. issues started when I remounted correctly. So is the MPS toast?

No idea! I don't think the core inside the MPS should be able to get to where it won't move unless the MPS body is in a certain orientation, but it may be possible.

Do you have access to another MPS for testing purposes?

--DD

[914itis]

This all started when I came home from a drive to NJ and popped the engine cover and found the MPS laying in the engine compartment on the tin. It had been jury-rig mounted and came off...but the car ran fine. issues started when I remounted correctly. So is the MPS toast?

No idea! I don't think the core inside the MPS should be able to get to where it won't move unless the MPS body is in a certain orientation, but it may be possible.

Do you have access to another MPS for testing purposes?

--DD

He does not and I only have a few 1.7,s

[achman_73_2.0]

This all started when I came home from a drive to NJ and popped the engine cover and found the MPS laying in the engine compartment on the tin. It had been jury-rig mounted and came off...but the car ran fine. issues started when I remounted correctly. So is the MPS toast?

No idea! I don't think the core inside the MPS should be able to get to where it won't move unless the MPS body is in a certain orientation, but it may be possible.

Do you have access to another MPS for testing purposes?

--DD

He does not and I only have a few 1.7,s

Pretty bummed, but looks like I may be taking the normal car to Hershey. Where can I get a 2056 calibrated MPS?

[worn]

Pretty bummed, but looks like I may be taking the normal car to Hershey. Where can I get a 2056 calibrated MPS?

I went through the recalibration process last summer for my 2056. It is a trial and error process, and I would not attempt it without an air fuel gauge. But now it pulls real strong all the way. I could maybe calibrate one for my engine and send it. I have a webcam though. Not sure how much difference it makes.

There is no way for the MPS to affect the firing of only one cylinder. No way. However, the wiring for the mps, the hoses, the fuel injection, the spark plug wires all conspire to want to be right where the fuel injector wires plug in on the right side. I can easily imagine the MPS dragging one of the FI trigger wires out or out of whack by breaking one. It is a PITA, but the MPS has to be held down. It is like putting your iphone in the engine compartment tied to a string for heavens sake!

I did a lot of inductance graphing and I suspect a 1.7 body can work. Good luck! Let me know if I can help.