Cold Start Issue 914-4, Admitting I'm stuck and asking for help Options

[Blue Lightning]

Car: 1976 2.0, FI

Background: bought in November last year. I am least the 4th owner. Drove a couple times, then plugged up the fuel filter (? no fuel pressure when the fuel pump was running, but see note below on replacing the fuel pressure regulator), so spent a couple months with the gas tank out and replacing the fuel lines, pump (and yes, filter). Read a lot in the meantime, so corrected vacuum line issues (vac advance was connected, replaced all the lines that didn't already look new, added hose clamps). But where the car started and ran well last year, I can't get it to happily start any longer. While cranking, it will skip and catch. After a few minutes of cranking (and skipping and catching) it will finally start and run fine for a few minutes but only idle around 1000 rpm (until the AAR warms up the rest of the way?), then dies. Starter fluid has no effect, so guessing it is running rich? Pulling the air hose off the cold start injector while running causes the idle to increase to maybe 1400 rpm (but with hunting, as you might expect with that big leak). There are a lot of threads on what to look for when the engine is running lean, but few on it running rich.

Some things I have checked:
- AAR works (https://youtu.be/YmO1ZCLDB7g)
- Compression is good (130-140 psi cold)
- Replaced the MPS last weekend with new one from autoatlanta, after finding the previous one would not hold a vacuum
- Replaced fuel pressure regulator after finding it bad (yes, I've been told these never go bad, but this one would not hold any pressure). Fuel pressure set to ~29 psi.
- Timing is good (~27 degrees at 3500 rpm with vac retard disconnected)
- Vac retard mechanism is working (checked with vacuum pump)
- Spark on all 4 cylinders (checked by timing light)
- Smoke tested the intake...only leaks now are the bearings on the throttle plate
- CHT reads 2k at cold, ~250ohms at warm/hot (at splice connector)
- Plugs look okay (see attached)
- Fuel injectors are all spitting fuel (checked into bottles...all about the same) and have new seals
- idle adjust screw has some control, but I cannot get the idle above 1000 rpm with it
- valves adjusted back in December (my first time, but the car runs so I assume I didn't do too bad of a job?)

I'm at a loss of what to try next. (IMG:style_emoticons/default/hissyfit.gif) I'd like to consider myself fairly good with cars (we have a 1966 Mustang, as well as a Mazda RX-8 that I have kept running for >20 years), but I'm about ready to throw in the towel and have the 914 towed to someone smarter than me!

Thoughts?

[emerygt350]

Here is a video of mine at cold start this morning. You can see how the vacuum starts and where it is after a minute and a half. The video starts maybe 5 seconds after I started the car. Didn't think of it till I started otherwise I would have recorded that for you too.
https://www.youtube.com/shorts/-owQvPa68sc
Don't mind the wonky AFR, it takes forever for that thing to kick on.

Here is where all the needles are after my 1 mile commute to work.

[Blue Lightning]

Here is a video of mine at cold start this morning. You can see how the vacuum starts and where it is after a minute and a half. The video starts maybe 5 seconds after I started the car. Didn't think of it till I started otherwise I would have recorded that for you too.
https://www.youtube.com/shorts/-owQvPa68sc
Don't mind the wonky AFR, it takes forever for that thing to kick on.

Here is where all the needles are after my 1 mile commute to work.

Do you have a deceleration valve in your car still? Reading https://members.rennlist.com/pbanders/DJetP...tm#troubleshoot in the Deceleration Valve section, it seems like this should limit the vacuum to ~17 psi?

[emerygt350]

Here is a video of mine at cold start this morning. You can see how the vacuum starts and where it is after a minute and a half. The video starts maybe 5 seconds after I started the car. Didn't think of it till I started otherwise I would have recorded that for you too.
https://www.youtube.com/shorts/-owQvPa68sc
Don't mind the wonky AFR, it takes forever for that thing to kick on.

Here is where all the needles are after my 1 mile commute to work.

Do you have a deceleration valve in your car still? Reading https://members.rennlist.com/pbanders/DJetP...tm#troubleshoot in the Deceleration Valve section, it seems like this should limit the vacuum to ~17 psi?

That would cause my idle to skyrocket. My engine produces 'extra special' amounts of vacuum. My decel keeps my vacuum below 23 on overrun and that is about all it does. The decel shouldn't be setting idle vacuum, it would only function as an AAR. Why is my vacuum so high? No clue (freshly rebuilt, larger displacement, very careful tuning and timing)... However, not many people run vacuum gauges on their dash so how many other 2056s with my compression ratio and a stock cam are also at these low pressures? Hard to know. Made tuning the MPS fun.


OP: Did you check the compression after the valve adjustment?

I prefer (just personal choice) the crusty method of valve adjustment. No need to look at the flywheel or get out from under the car.
Have one wheel on the car, block the other wheel from moving, and put it in 5th gear. Rotate the wheel until a valve (let's say the one closest to the driver is completely compressed. When it is you know the opposite valve (closest to the passenger) is completely loose. Set that loose valves lash. Rinse and repeat all the way around. No guessing about what cylinder is at what stroke etc. Just methodical and no getting up and down. What clearances did you use? And just a thought, are you sure you have flat tappets? Stranger things have happened.

[Blue Lightning]

Did you check the compression after the valve adjustment?

I prefer (just personal choice) the crusty method of valve adjustment. No need to look at the flywheel or get out from under the car.
Have one wheel on the car, block the other wheel from moving, and put it in 5th gear. Rotate the wheel until a valve (let's say the one closest to the driver is completely compressed. When it is you know the opposite valve (closest to the passenger) is completely loose. Set that loose valves lash. Rinse and repeat all the way around. No guessing about what cylinder is at what stroke etc. Just methodical and no getting up and down. What clearances did you use? And just a thought, are you sure you have flat tappets? Stranger things have happened.

No haven't checked compression again after adjustment. I added a compression check to my list after the valve adjustment this weekend.

The valve adjustment method you did is similar to mine, except I look at the TDC and 180-degree marks on the flywheel while under the car. No need to get out from under the car, as long as you check the distributor before you start!

[emerygt350]

Did you check the compression after the valve adjustment?

I prefer (just personal choice) the crusty method of valve adjustment. No need to look at the flywheel or get out from under the car.
Have one wheel on the car, block the other wheel from moving, and put it in 5th gear. Rotate the wheel until a valve (let's say the one closest to the driver is completely compressed. When it is you know the opposite valve (closest to the passenger) is completely loose. Set that loose valves lash. Rinse and repeat all the way around. No guessing about what cylinder is at what stroke etc. Just methodical and no getting up and down. What clearances did you use? And just a thought, are you sure you have flat tappets? Stranger things have happened.

No haven't checked compression again after adjustment. I added a compression check to my list after the valve adjustment this weekend.

The valve adjustment method you did is similar to mine, except I look at the TDC and 180-degree marks on the flywheel while under the car. No need to get out from under the car, as long as you check the distributor before you start!

I would do the compression check next.

And you are certain no one upgraded your car to hydraulic lifters?