I had a truck that would do the same thing I had to hold the throttle open until it completely warmed up then it would run fine. If I let it sit for a couple weeks. I believe it had moisture in the distributor

 

At least for this car, not likely - it's in Nevada. In the summer. In a drought year. One thing safe to rule out is any moisture-related issues

 

If this is the case, the next 3 things I would check are:

1) Ignition coil. you said you got spark, but make sure it is not retarded.

2) Throttle position sensor

3) Idle control valve ( I doubt this is it because pushing the gas peddle should override any ICV problem.

On another note: Do you have an EGR valve? It would be a problem if it was stuck open.

Again, if you have not cleaned the throttle body with B-12 or another throttle body cleaner, try this first.

 

check the timing. if the belt is worn, if is possible it could have jumped a tooth.

 

Was able to test the TPS - numbers are to spec, no weak spots. Fuel pressure kit borrowed from OReilly doesn't have the correct fitting so I'm fabbing one and will try again. Haven't checked timing further yet. Meantime, got an FSM off ebay and they start their diagnostics at the ECM. No way for me to test it so I'm thinking used from ebay. Any thoughts - or reliable sources, for that matter? As stated in op, dash display is by the book - CEL for a couple of seconds but no codes, even with the test plug jumped.

BTW, you guys have been a big help so far. Haven't solved the problem yet, but I appreciate the company

 

Adding starting fluid points towards a fuel problem to me. Pull the vacuum hose from the pressure regulator and check that it doesn't have a strong gas smell.

I would not start throwing parts at this (like an ECU).

Measure the fuel pressure. I had a writeup on how to make an adapter for the rail. Let me try to find it.

 

https://www.hondaaccordforum.com/for...a-gauge-17408/

 

Got a pressure reading: A sustained 10 lbs while the pump is running rather than recommended 30-40 range. FSM said low pressure is a regulator issue, so I swapped in a new one and have the same pressure. Very odd thing is that I got the car running for awhile and held the revs at a smooth 2-3k long enough to reach op temps. Also idled. Hasn't done either for a month. And then it sputtered and stumbled and went back to Square One.

Still feels like fuel delivery. Can the pump cause system pressure loss like this? Manuals make it sound like it either works or doesn't.

 

A restricted fuel filter could cause low fuel pressure. Were you measuring fuel pressure w/ engine running? I assume not since this is a no-start problem.

If not, you may need to measure fuel pressure w/ pump running continuously to get correct pressure. Pump only runs 2-3 secs then cuts off. To bypass you would need to jury rig a main fuel relay which is a pain to reach/release.

Suggest replacing fuel filter before replacing fuel pump. It's a bit of a job but less than replacing the fuel pump. See bushougoma video on youtube about replacing fuel filter, very good video.

good luck

 

Filter replacement was where I started and symptoms have remained consistent throughout. Made the pressure gauge adapter with a 1/4" air tool nipple re-cut to 12x1.25 threads to fit the fuel rail test port and added a section of fuel injection hose to connect with gauge fittings. http://contentinfo.autozone.com/znet...19322/image/3/

Multiple tests showed 10# for the couple of seconds the pump runs, then bleed-down to nearly zero, then back to 10# with engine running. It's like it's hemorrhaging pressure internally - not leaking visibly. FSM shows a relief valve inside the pump though. If that didn't seal properly, seems like the system would never reach pressure. But why no code?