moundsostuf

This problem just started about 2 weeks ago and I can’t figure out the cause largely because it is intermittent. Historically I turn the ignition key, the engine cranks and starts immediately.

Now sometimes (not all the time) I turn the ignition key, the engine cranks, but it doesn’t fire. So I turn the ignition to the OFF position and then start the cranking again and it starts right up. Like I said this issue doesn’t happen all the time.

I have tested two things when the engine cranks without firing:
1. There is a spark. How do I know this? I hooked up the timing strobe and it flashes when the engine cranks but it doesn’t fire. My conclusion with this is that the issue is not ignition related.
2. The fuel pump and the master relay work. How do I know this? I can hear the fuel pump running when I turn the ignition switch to the ON position. I hooked up a volt meter to the fuel pump lead under the back seat above the tank. When the engine cranks but doesn’t fire I get 10 volts (I get 13 volts when the starter disengages … I think the starter is sucking a bunch of juice from the battery so that is why I only get 10 volts.) My conclusion is that the master relay and the fuel pump are working fine.

The pattern that I’m finding is this issue generally occurs when I let the car sit for a prolonged period of time (4-8 hours or more). If it sits for only 1/2 hour then it starts right up again. The other thing is when the engine cranks but doesn't fire, if I stop the cranking by turning the ignition switch back to the ON position and then turn it to engage the starter again, it still doesn’t start. But it I stop the cranking and turn the ignition switch all the way to the OFF position and then turn it back to engage the starter, it starts right up.

The Check Engine light is off and there are no stored codes in the ECU.

I can’t find the source of this problem and it is starting to make me crazy. Any suggestions on further troubleshooting would be much appreciated.

StokelesS_g2

May be a leaky fuel injector flooding your pistons when the car is off.

fcm

Check for power at the injectors when cranking and engine does not start.

It sounds like a PGM-FI Main Relay problem, [fuel injector relay]. 94

moundsostuf

Thanks for the suggestions. I checked the main relay again and this time I checked it on the PGM-FI side. To my knowledge the main fuel relay on the 94 accord EX has two relays in the unit: the relay on one side powers the fuel pump (which I check before and it works fine) and the relay on the other side powers the fuel injectors (which I just tested and it showed 12 volts output when the engine cranked but won't start.)

Back to the drawing board...

Oddly enough I was driving just after another hard to start episode and the Check Engine light came on. So I quickly pulled over to the side of the road and checked the code. It was giving me an "8" code which is TDC position sensor. The car started right back up and the Check Engine light disappeared.

I believe the TDC sensor is inside the distributor. Does anyone know if it is possible for the TDC sensor to fail intermittently yet still get a spark out of the distributor when the TDC sensor is in the failed state?

Any other thoughts on what else to check the next time the engine cranks and won't fire?

I hate chasing intermittent problems. It's like chasing a ghost!

fcm

In a word, yes.

All electrical components will fail intermittently first, before failing completely.

And yes, the PGM-FI Main Relay contains two(2) relays, the injector relay that powers the injectors, IGP1 and IGP2 of the ECU along with other engine sensor/valves and the fuel pump relay that powers the fuel pump.

Replace the TDC sensor or the distributor. 94

Big_Eddy

Sure sounds like the main relay to me. Take it out, resolder the relay leads, put it back in and the problem probably won't come back. The problem with the main relay is cracking solder joints around the power leads. Depending on temperature, vibration, bumps, etc., the connection is or is not there. Sometimes the connection is there, but there is too much resistance to provide the current needed to run the fuel pump or injectors. Resoldering will only take a few minutes.

If the problem is still there afterwards - you know it's something else.

user456101

I would guess that your fuel injectors are somewhat clogged. Put some fuel injector cleaner in it, and use good gas like Mobil1 or Shell and drive it on the highway in D3 for 30 minutes out and 30 minutes back. That may clean out the fuel injectors enough that the spray patterns is back to what it should be. Scotty Kilmer, a famous YouTube mechanic has some videos that may be helpful on cleaning fuel injectors and on cars that crank but don't start. I have heard him say that when a car starts from a cold start it takes extra fuel and a problem with either the fuel injectors, fuel filter or fuel pump can cause what you're seeing.

moundsostuf

Thanks for the suggestion. I replaced the main relay about 6-8 years ago. So a few days ago I pulled the main relay and inspected it with a magnifier. I didn't see any cracks in the solder joints. So I reinstalled it and hooked up wires on the output side of both sides of the relay (fuel injector side and fuel pump side) to see the voltage when the engine cranked but would not fire. It was outputting 13-14 volts with the ignition On but not cranking. Then it was outputting about 9-10 volts on both sides while the starter was cranking. I figured this was normal since the starter sucks down a lot of juice from the battery. Finally when the car did start after switching the power completely off at the ignition switch and then engaging the starter again, the voltage moves to 13-14 volts. Does this sound right?

moundsostuf

This is an interesting suggestion. I'll have to get some injector cleaner and dump it in the tank. It can't hurt. The only thing that spooks me is none of the cylinders are firing. This would mean that all 4 injectors are clogged. Strange but maybe possible. I replaced the fuel filter only about 10,000 mile ago. This 22-year old car has only 114,000 miles on it.

Bobnotch

I hate to say it, but this sounds more like a flaky ignition switch to me. I only say that, as 1 time it's working correctly, then it goes intermittant, then works correctly again.