Manifold Pressure Sensor MPS and timing, what is the effect on timing? Options

[thompson-mfr]

Ok, I will try and keep this as brief as I can.

I will pose the question before providing the background.

?? What, if any, effect does the MPS have to do with actual timing of the motor??



Now for the reason for my question.

1974 2.0L FI

My MPS (0 280 100 019 adjusted VW T4 unit) randomly stopped working properly even though electrically it checks out and holds vacuum. Maybe an aneroid cell? anyway not sure. I then started trouble shooting thinking it was points, plug wires, etc. ( I replaced to be sure) and readjusted the timing and dwel.

Right after the MPS stopped working I found a good deal on another nice '74 2.0 FI 914. It has a factory MPS correct PN 0280 100 043 and runs perfectly.

So, I thought I would swap MPS's and see if this fixed my problem. It didn't run well.

Thoughts?? I have read Pbanders a bunch of times.

I have included a picture of the new car in hopes there are others like me that like pictures. I only open threads with pictures as I cannot read good (well )just joking). Maybe other people can relate to this.

[Bleyseng]

If you plugged in a stock 043 MPS into a 74 2.0l FI setup and had to adjust it to run then something is wrong with you setup.

Now that you have adjust the MPS by drilling it out you have to use a wide band to get the A/F ratio correct or ship it to someone who has a Waveteck meter and can reset the 043 to spec.
Then fix what ever is wrong with your FI.

[thompson-mfr]

If you plugged in a stock 043 MPS into a 74 2.0l FI setup and had to adjust it to run then something is wrong with you setup.

Now that you have adjust the MPS by drilling it out you have to use a wide band to get the A/F ratio correct or ship it to someone who has a Waveteck meter and can reset the 043 to spec.
Then fix what ever is wrong with your FI.

I did not adjust the 043 MPS. I simply put a good one in my other car and it didn't run well.

I only adjusted the 019 T4 VW MPS unit. I have it running "OK" with the 019 T4 VW MPS. I may get a A/F meter and dial it in more.

I find it very strange the factory 043 MPS does not work well in my car????!!!

[SLITS]

I find it very strange the factory 043 MPS does not work well in my car????!!!

What ECU do you have? To match up, it should be an 052.

[thompson-mfr]

I find it very strange the factory 043 MPS does not work well in my car????!!!

What ECU do you have? To match up, it should be an 052.

I need to double check that. I thought I had double checked that before, but cannot remember. That or the CHT is a possibility.

I have never run a 043 MPS correct to my 2.0L, so don't have that as a reference.