About 2 month ago the car would only start when cold out side-car from VA
Now in Florida and the problem is the worst
No codes ever set prior and data looks fine except ST fuel trim adding 25%-meaning lean when it does get to idle
Problem has always been When it is above 60 deg car cranks long time -stalls and dies out on start up continually and when it will idle,it ,bogs on accel like starving for fuel-new pump and fuel regulator,dist,maf,o2 plugs.PCV wires,injectors and did not correct.EGR not open or major val leak.
Fuel pressure and drop ok and dead head pressure to 80 psi pinching off fuel line still no start. Tryed this to get all the gas in the rail so it must not be a volume issue.Spray with fuel into intake-runs ok until you stop that.
Takes almost half hour to get running then ok until it sits overnight.
Found tsb for valves and compression is good-160 psi.
Did top cyl cleaning anyway.
.
IAC working ok.
Whats up as this has been going on for 2 months.
If i disconnect maf starts better.(sets code and OL mode )
What am I missing
think it is PCM signal to injectors-but scan data looks ok.
PS has Calif emissions
THX

 

It could be the PCM itself. After all it is an aged car. I would get a used PCM, or have a mechanic try a known good pcm before shelling out more dollars.

 

Another thought: the intake manifold gasket may be leaking and leak less so when the engine is warm. Try an enrichment tool around the engine: a propane bottle with a rubber hose for example.

 

thanks for the though but i did that - also early on had a guy smoke test it for leaks and ck for vac leaks also

 

Two thoughts (re: guesses):
1) When my 3 was acting as you described it turned out to be a check valve in the evap fuel system that was stuck open. No code... the second time.
2) EGR inlet tube clogged w/carbon, and/or vacuum lines are on backward?
I had a friend who's Accord acted like this until he reversed the vacuum hoses. Problem solved.

 

You have a long list of things you already tested and fixed. I did not see 2 items: Air Intake Temperature Sensor and Engine Coolant Temperature Sensor.
Of course their failing should trigger a code, but it still may be worth checking since the trouble appears to be temperature related.

 

Good thoughts and I would still check these two sensors. Sensors will not always set a code when failing! If the sensor is in its working range but way off for the current running needs of the engine, it won't set a code.

A good example is a recent ECT sensor I just replaced on a customers vehicle. It was cranking a long time when first started in the morning and wouldn't come up on fast idle. The rest of the day it would start fine! So, the customer left it overnight and the next morning I hooked up our monitor and the ECT wasn't reading the current ambient temperature of the coolant correctly. The current temp. at that time was 10C in the morning and ECT was spec'ng out at about 50C. You see, the ECT wasn't out of its working range but it left the ECM to believe the engine was warm already and no code was ever set!

As a final test to confirm a bad ECT sensor, I unplugged the sensor connector and placed a 10K ohm resistor across the connector terminals (to simulate -40C for this particular vehicle) and started the car. Car fired very quickly and came up on fast idle. I replaced the ECT and all was good.

**Caution - don't run the vehicle for more than 30 seconds with a resistor in the ECT's place as it will be running very rich and could damage a catalytic convertor**

Cheers! and hope this helps.