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?

[sholman5]

For quite awhile I had trouble with the idle and up to temperature. During a hot start I had to wfo the throttle body. Would not idle well (surging or hunting) below 1100 rpm. Finally I changed the distributor cap and rotor. Source a good used set of FI trigger points and Bosch blue coil. There was a connector between the cht and wire to the ecu. I thought that it was a shield to keep heat away from the connection. Removed the connector and problem solved. Come to find out it was a 275 ohms resistor, which think only belongs on a 73 2.0. I feel your pain. Hope that you get it all worked out.

[Blue Lightning]

Come to find out it was a 275 ohms resistor, which think only belongs on a 73 2.0. I feel your pain. Hope that you get it all worked out.

I've heard of these. AutoAtlanta sells one which they mark as being for all years: https://www.autoatlanta.com/Porsche-914-Bal...1460610100.html

Supposed to slow down the warmup cycle and help warm-start situations.

I'm sure it will get worked out. Just a matter of whether I can figure it out myself, or need to pay someone else to figure it out (IMG:style_emoticons/default/smile.gif)