D-Jet Conversion not going as planned., Car starts but will not run. Options

[slapshot]

I am converting back to D-Jet and my car will start but dies right after. It will not rev up applying throttle. I have a 1975 914 2.0. It was running great with Weber 40s prior.

The D-Jet system is from a 1974 2.0. All the parts came in visibly good condition. TPS calibrates good, AAV tested good, Thermo sensor good, air intake temp sensor good, and a new cylinder head temp sensor. The only test that I think is failing is the vacuum test on the MPS. It leaks. Video of testing the MPS.. The MPS has also been rebuilt at some point. The original part # has been removed. There's a good chance it is not calibrated for my car. I have all new vacuum hose and fuel pressure is between 28 and 30.

I don't have any tools to calibrate the MPS. Should I try turning the inner screw on the MPS to see if it helps? Or should I send it to someone to have it rebuild again and recalibrated? If the later do you have any recommendations on who to send it to?

[rjames]

As MJames stated, the MPS is critical.

Yes yours doesn't hold pressure, but it doesn't drop so fast that the car shouldn't at least start and run for a bit, albeit likely with a surging idle.

Did they rebuild the MPS such that you can make adjustments without opening it up?
If it were my car I'd try turning just the inner screw a quarter of a turn clockwise first, and if that didn't work, turn it the same amount the other way. Just keep track of how much you're moving it so you can get it back where it was if need be. Given your description, if the cause is the MPS being out of adjustment, a quarter to half turn one way or the other would either allow the car to idle, or rule out the MPS as the issue.

[slapshot]

As MJames stated, the MPS is critical.

Yes yours doesn't hold pressure, but it doesn't drop so fast that the car shouldn't at least start and run for a bit, albeit likely with a surging idle.

Did they rebuild the MPS such that you can make adjustments without opening it up?
If it were my car I'd try turning just the inner screw a quarter of a turn clockwise first, and if that didn't work, turn it the same amount the other way. Just keep track of how much you're moving it so you can get it back where it was if need be. Given your description, if the cause is the MPS being out of adjustment, a quarter to half turn one way or the other would either allow the car to idle, or rule out the MPS as the issue.

They did. I have access to the inner screw. The outer is marked with paint. I have debated adjusting the inner but will not be doing that until I have verified all injectors are firing and all measurements on the ECU pins are good.

How sensitive is that inner screw? If I move it could it cause damage to the engine?

[rjames]

As MJames stated, the MPS is critical.

Yes yours doesn't hold pressure, but it doesn't drop so fast that the car shouldn't at least start and run for a bit, albeit likely with a surging idle.

Did they rebuild the MPS such that you can make adjustments without opening it up?
If it were my car I'd try turning just the inner screw a quarter of a turn clockwise first, and if that didn't work, turn it the same amount the other way. Just keep track of how much you're moving it so you can get it back where it was if need be. Given your description, if the cause is the MPS being out of adjustment, a quarter to half turn one way or the other would either allow the car to idle, or rule out the MPS as the issue.

They did. I have access to the inner screw. The outer is marked with paint. I have debated adjusting the inner but will not be doing that until I have verified all injectors are firing and all measurements on the ECU pins are good.

How sensitive is that inner screw? If I move it could it cause damage to the engine?

You won't damage the engine. Adjusting the inner screw clockwise will lean out the mixture, counter-clockwise will richen the mixture. It's farily sensitive, which is why I only suggested 1/4-1/2 a turn, but you won't break anything if you go further. Note that you need the Tangerine Racing adjusting tool so that you don't also turn the outer screw that the inner screw sits in (not the outer screw you're talking about which is more commonly referred to as the full-load stop screw).