First, I just want to say that I have been researching and deep-diving old threads on this popular topic for 3-days straight. I have not found a perfect match in symptoms or circumstances, and all my solutions thus far have failed.

I have a 2000 Civic DX (hatch) with a B18C1 swap. I have owned it for about 6 months and bought it exactly how it sits. No AC and no PS. Needless to say it's been hot in the midwest for a few weeks. Since I bought the car, I noticed a quark. On cold starts, it fires instantly and runs like a top. If I drive for more than 10min, run into the store, and come back out, it doesn't start immediately. It either is a long start, or I let it crank for a second or two, turn the key all the way back, and then it starts right up immediately. The other quark is that it has a bit of hesitation right around 5200 RPM. The motor seems a little chocked up. And this persists through VTEC crossover. It had a check engine light when I bought it, the previous owner said it was for an 02 sensor and the bosch replacement he used did not draw enough power to turn off the light. I attributed the hesitation to this and have not replaced the 02 sensor. Since buying it in January I have only put about 1000 miles on it, I don't drive it too much. But it's run very well besides those things mentioned.

On Thursday it was extremely hot and I had a busy day. I ran around town making quite a few stops until going to a family gathering. The car sat for about 2 hours and fired up no problem to make the 30min drive home. I stopped at the store down the street from my house, drove home. I live on a hill and drive up it past my house to turn around so I can angle the right direction into my driveway. At the top of the hill, the car shut off. I cannot for the life of me remember if I was already in Neutral or 2nd, but either way it was at low RPM and just died. I coasted back down the hill, parked on the street, and it hasn't run since.

I start searching and quickly assume it's main relay, based on the heat and symptoms. I let it cool off the whole night, hoping it would enough to start the in AM but it did not. I would start for about 1 second then die again. I could hear the main relay and I disconnected the battery to reset the CEL, so I could test the property light sequence of the relay. It worked properly, but still, I replaced it anyway. It seemed to have been an aftermarket one because the one I got at O-Reilly's had identical markings. The new one did not solve the issue. The battery is also working perfectly.

I could also hear the fuel pump priming perfectly, and believe it to be working well. I check fuel pressure, after the filter, the dangerous way by cracking the banjo bolt and attempting to start. Plenty of fuel sprayed out (there is also almost a full tank). Next, I changed out the ignition switch and when I did, accidentally blew the ignition fuse. I replaced the fuse and with the new switch in place, it's the exact same issue. Next, I disassembled the distributor and pulled out the ignitor to check for obvious wear or any oil. It all looks brand new in there. Finally, I removed the valve cover to inspect the timing belt, it looks great and at TDC on the crank pulley, the cam gears are in perfect line.

My next move is to pull the plugs and inspect them and check for spark in each wire. My hesitation though is that even with 2 plugs bad or 2 bad wires, the car would most likely start and idle, albeit rough. I supposed the igniter or the whole dizzy could be bad, I know aftermarket ones suck, so despite it looking brand new, suppose that could be it. Also, my valve cover and trans grounds are great. Is there anything I am very obviously missing here?? Thanks in advance.

 

Update: I replaced the ICM (ignition control module/igniter) with a replacement unit from AutoZone. It did not solve the problem.

Some additional information. As I mentioned before, I checked the fuel pressure by cracking the banjo bolt on the engine side of the fuel filter. I do have a Gates FP gauge connected to a valve off the same banjo bolt. It reads zero when off and barely 10psi when cranking. Running should show 35-45psi (someone please correct me if I'm wrong) but I am having trouble finding a conclusive answer as to how much pressure should be shown during priming or cranking.

 

Are you getting spark? If not, then your ignition coil probably went out

 

The next thing you need to buy is a multimeter, learn how to use it and start testing sensors before buying any replacements. Don't replace something that ain't broke! There are videos on how to test every sensor. Also, go over all your grounds and battery connections - make sure they are making good clean metal contact. Even the hidden ecu ground on the thermostat housing.
After that, do a thorough check of all the vacuum lines just to be sure it's all in check. No cracks or deterioration.

 

I have not yet checked spark, I know it's stupid to have tried so much else without checking, but I only have one pair of hands. I need someone to crank it while I hold the screwdriver. That being said, I have heard that even if you are getting spark, it could be less than needed to start properly. Also, if it was a wire or plug, I would think it would still start unless all 4 went out together? The coil however was the next easy part I was going to try. Just sick of throwing parts at it.

Yes, thanks, I think you are right. I've never been good with the principles of electronics or circuitry, just have a hard time conceptualizing, but at this point, I need to stop throwing parts at it. These little things add up quick! My valve cover and trans grounds look great, along with my battery connections. They are all nice quality ones from Chase Bays. But I did not check the on the t-housing. I'll do that now. Vacuum lines look healthy as well. Would a bad vacuum line keep it from starting?

 

any video on how to 101 for dummies using multimeter to test car electrical components? thx.

 

Ditto!

 

For anyone following, a user in another thread suggested the Crank Fluctuation Sensor, located next to the crank snout behind the lower timing cover. It was failing, the car should have started up with the sensor unplugged. This however did not work.

I continued looking over the engine bay and attempted to start the car with some easy access sensors unplugged. When I unplugged the Idle Air Control Valve on the back of the intake manifold, the car would start the most consistently that it has in a week. It would struggle, but turn over, begin to idle at ~1000rpm, and die within three seconds. If I even whispered at the throttle while it momentarily idled, it would die instantly.

This does seem like the Idle Air Control Valve may be contributing to the problem, but my symptoms are not very consistent with typical failing IACV symptoms.