so to simplify things it only stalls when the engine is hot and you are at or coming to a complete stop?

 

If spark is good, and tries to start w/ starter fluid, lack of fuel pressure is indicated. This is particularly true since you have fuel pump sound and have replaced fuel pump. Two options; perform a fuel pressure check (fittings are hard to find and kit is probably US$50 or more), or replace fuel filter. Fuel filter requires special crow's foot tool to release underside fuel line connection and is supposedly tough job. I haven't done a fuel filter on my 94EX w/ 220K miles. Pick your poison.

It could be the fuel filter is partially blocked and your fuel pressure is near/below lower end of acceptable pressure. This might cause an intermittent no-start. I know that when fuel pressure is lost, engine stops like a heart attack and won't even hint about starting.

Also as falkore said, it could be a problem w/ the fuel pressure regulator. Pull vacuum reference line to FPR and sniff. If you smell gas the FPR diaphragm is ruptured. However, this is not supposed to disable the car, so seems less likely.

Tough luck to have such a tricky problem. I once had a coil issue on 90EX that also caused much grief and effort. Coil measured marginal but OK when I checked secondary resistance. I had some spark but no start, so I replaced ignitor w/ no help. I had good fuel pressure w/ cracked banjo bolt check. Stumped I measured coil resistance again w/ a more precise VOM, and found it was slightly below limit. New coil and she fired up right away. That's when I found that checking spark w/ a plug against the engine can fool you. When I checked w/ timing light, nothing.

good luck

 

stalling while hot in my experience is from a variety of things. you've ruled out the ign. coil and ignitor it seems. make sure the ignitor terminals are on there nice and tight btw. loose terminals will cause intermittent stalls/no starts.

another common source is the fuel main relay. keep in mind there are two relays in this main relay. one relay is for the fuel pump and the second is for the fuel injectors. this would explain why you have your fuel pump running but the engine won't start. the relay is just two electrical contacts that touch basically. they tend to fail intermittently. check that the injectors are actually getting power on the red/black wire on any injector while it's stalled. it will be a reduced voltage because of the resistor block, which brings me to...

the injector resistor block! it is a big heatsink by the firewall, driver side. this has a resistor for each injector in it. it might have gone bad, anything is possible, and it intermittently opens up when hot. check the resistance between the red wire and each of the black wires in turn both when the problem is occuring and when it's not(why not?
it should be 5ohm to 7ohm. it's a long shot, but i've had four bad door lock actuators at one time before, lol.
also make sure that same red wire is getting battery voltage with the key on during the stalling condition.


as mentioned, a bad ignition switch would cause an intermittent stall but the car would usually start right back up immediately. it's possible it's very bad and may need some time to cooldown before it decides to work again. it's very sensitive to key position. this means when trying to diagnosis this you can usually play/jiggle/etc the key and get the car to stall if your lucky.
you can also take apart the electrical portion of the ignition switch to verify if the terminals are clean or burnt easliy.

another possible cause would be the fuel pressure regulator. if the diaphram in it ruptured it would be leaking liquid fuel right into the intake system. this would cause a problem when hot but not necessarily when the engine is cold. it all depends on the leak. you can check this by pulling off the vacuum line on the regular and checking for fuel leaking out when the engine is running. on some cars i had to feather the vacuum line on it to 'coax' the fuel out, hehe

another possible cause could be the egr system. when cold a malfunctioning egr system might not necessarily causethe engine to run rough. but when hot excessive egr at idle will cause a stall. possible causes are a sticking egr valve or something causing vacuum to activate the egr valve when not needed(bad egr valve control solenoid and vacuum solenoid). this is easily tested on a good running engine but difficult on a stalled engine. the easiest way to test it would require a hand vacuum pump. if you have access to one i'll tell ya how to do that.

 

falkore24 I have not verified injectors because I don't have a tool to do this and hate to spend the money. I bought a used fuel pressure regulator off ebay and installed in during this process. After install is when the amount of time it was down decreased but it also coincided directly with cooler temps so I don't know if I have something on this or not. I will perform tests indicated and see if I smell gas or can coax any out.

HondaTechAV6 Yes. This is exactly right. I can push in the clutch on a very long off ramp when it is hotand it will continue running until I am almost stopped or stopped then it dies. Idle will stay at about 1100 rpm until speed drops under 5-10 mph. I assume this is normal. Regular idle speed is set at 750 rpm.

TexasHonda No fuel pressure check done. I did replace the fuel filter during this process and yes, it was a royal pain.

HondatechAV6 - I will begin the tests you and TexasHonda suggest and post results of those I can figure out.

Thanks to all that are helping. This should be a great thread in the future for those with similar problems.

 

I think HondaTechAV6 is onto something w/ the EGR system. If EGR valve sticks open, it might cause overlean and engine dying w/ hot idle speed. Easy to check also. Disable the EGR (pull vacuum actuation line) and if problem is fixed you know the source is a sticking EGR valve or perhaps intermittent/damaged EGR vacuum solenoid. Note, EGR should be fully closed at idle.

good luck

 

hook up a fuel pressure gauge,if engine starts when you sprayed starter fuid, it sounds to me like a lack of fuel or low fuel pressure .

 

Unhooked the vacuum actuation line on the EGR and it still stalled. Looks like I will need to buy a fuel pressure guage and check that. The biggest problem I am having right now is that when it dies, I literally only have 60-90 seconds of down time to test things before it starts up again. I will also verify power to the injectors when stalled.

 

Unhooking the vacuum actuation line to the EGR should not stall the engine. At idle there should be no vacuum to the EGR valve. This suggests perhaps the EGR valve is sticking open or EGR vacuum switching solenoid is defective/damaged somehow.

good luck

 

Sorry. I should have been clearer. We unhooked the actuation line and it did not make any difference other than the CEL came on. We drove with it unhooked for about 15 minutes and when the car got hot again, it died again. It did not seem to make any difference on whether or not it would die.

 

What is your idle speed cold andwhen fully warmed?

Have you ever cleaned throttle plate/bore, and the Idle Air Control Valve (IACV)?

A blocked IACV and dirty throttle plate could lead to too low idle that would be unstable when coming to a halt from speed.

good luck