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?

[Superhawk996]

Overall I don’t see any glaring red flags in your measurements that explain the starting difficulty.

So I go back to what is being assumed:

Valves adjusted properly - original post made this sound a little less than 100% certain

Static timing? Would like around 7 degrees but I’m assuming since you have proper advance at speed that static timing is very close. But I am wondering how that got set if the engine doesn’t want to start and run well. Static timing is easily confirmed & set with a volt-ohm meter.

Plugs - a bit of cold start carbon fouling is present but overall not terrible. I might start with a new set of plugs just to be 100% sure that isn’t part of the issue. Carbon fouling is insidious - It doesn’t look that bad but can lead to no-spark especially with rich mixture and/or flooded plugs (wet).

Beyond that I’d go back and re-try starting and see if the plugs get wet / flooded leading to the no-start no-run and then work from there.

[Edits below]
Do you have the means to video the start attempts and post to YouTube (which can be embedded or linked here)?

Im thinking about the injectors - you said you did the bottle test and they all flowed similarly - did the spray patterns look reasonable?

[Blue Lightning]

Overall I don’t see any glaring red flags in your measurements that explain the starting difficulty.

So I go back to what is being assumed:

Valves adjusted properly - original post made this sound a little less than 100% certain

Static timing? Would like around 7 degrees but I’m assuming since you have proper advance at speed that static timing is very close. But I am wondering how that got set if the engine doesn’t want to start and run well. Static timing is easily confirmed & set with a volt-ohm meter.

Plugs - a bit of cold start carbon fouling is present but overall not terrible. I might start with a new set of plugs just to be 100% sure that isn’t part of the issue. Carbon fouling is insidious - It doesn’t look that bad but can lead to no-spark especially with rich mixture and/or flooded plugs (wet).

Beyond that I’d go back and re-try starting and see if the plugs get wet / flooded leading to the no-start no-run and then work from there.

[Edits below]
Do you have the means to video the start attempts and post to YouTube (which can be embedded or linked here)?

Im thinking about the injectors - you said you did the bottle test and they all flowed similarly - did the spray patterns look reasonable?

Valve adjustments: my uncertainty is just because this is the first time/car I have done this. I double-checked them all twice(?) after doing them, so am pretty confident, but ??? Oddly all my other cars have hydraulic lifters (or don't have lifters!). If I can get the car started, it will idle (~1k rpm) for a couple minutes before dying, and I can keep it running by holding the throttle open a bit. What would the symptoms of incorrectly adjusted valves be, other than long-term engine damage?

Static timing: I can check this, but when I did get the engine running a week or two ago I put the timing light on it and checked the dynamic timing (3500 rpm, 27 degrees, disconnected vac retard), and it was spot-on still. I checked the vac retard mechanism with a vac pump, and it moves. The timing should be a purely mechanical thing -- other that moving the distributor or moving stuff inside the engine, I don't think there is anything that can cause it to change (well, the vac retard, but for checking the dynamic timing that is).

Checking plugs today during the doesn't-want-to-start phase is high on the list. Need to finish putting the intake runner on the passenger side back in still (removed to access CHT) -- ran out of time last night.

Injectors: I did not look at the spray patterns. My concern at the time was that I might have gotten something into the fuel lines when replacing them that might have plugged one of them, but the bottle testing indicated that they were all flowing. Further down my list is to check them more thoroughly.

Today's debug list:
- Add jumper cables/test ground between battery and chassis & engine
- crank and pull plugs if the engine still doesn't want to start to check for fuel fouling
- Plug cold-start injector fuel line to make sure the cold-start injector isn't causing problems.
- plug the decell valve hoses to make sure this isn't causing problems.
- double-check fuel pressure