91 Civic Si - Engine turning, but not starting
 

Hey all,

My friend and I bought a 91 Civic Si - drove it home, drove it around that night. A week later, we go to turn the engine - and you can hear the engine turn over - but it's just not starting.

This is a list of stuff we tried to no avail.

1. Filled it with more gas (it was sitting near empty but NOT empty)
2. Tried jumping it
3. Pulled out the spark plug wiring - tested each one as we started the car and the plugs were sparking for each cylinder
4. replaced the ECU
5. replaced the main relay

So it isn't the starter motor. it's not the battery. Any other suggestions?

Could the distributor not be giving enough voltage? or is that unlikely?

The issue here is that the car was running just fine a week before, and now it's not - so we're pretty baffled.

Thanks for any help you guys might be able to give!!

An engine requires three things to run: fuel, ignition, and compression.

It's not likely compression has failed completely in that time, so you have two things to check.

You've already tested for spark and that's working, so that leaves fuel: you can disconnect the plugs, crank the engine over a bit, then pull a couple plugs out and see if they're wet - if they are, that's a good indication you're getting fuel; if they're dry, then fuel is probably your issue.

When you first turn on the key, you should hear the fuel pump start up - you'll hear a brief buzz from the back of the car, around the gas tank (probably on the fuel filler side). If you don't get that, it could be a failed fuel pump, main relay, or even blown fuse.

If you do, it's possible you have a clogged fuel filter. Depending on the model, it may be inside the tank... I know some Civics require lowering the tank to access it. You can check for fuel flow by disconnecting the fuel link from the throttle body, putting it into a jar or some kind of container, and turning the key on - the fuel pump should fire up enough to give you a little squirt.

If you're getting flow there, it could be the injector(s) - check the wiring from the ECU, make sure it's solidly connected.

Beyond that, you get into trickier things like fuel mixture, spark and valve timing, and so on... a snapped timing belt is always possible, although if you're getting spark on all cylinders, that indicates the distributor is turning, and since it's driven off the end of the camshaft, that would suggest the timing belt is okay.

you can also try another alternator if you haven't already :)

as soundy noted, i'd check if it's a fuel issue. if you don't hear the fuel pump going while the key is turned to "on", give the gas tank a few light taps with a hammer while trying to start the car

The alternator has nothing to do with it not starting.

thanks so much guys. My buddy's cousin who's a mechanic took a look at the car and apparently our distributor harness plug was just slightly loose. Damn, we feel like idiots. But it didn't even click into place, he just played with it a bit to check and the car started right up.

Thanks so much for the help guys!!!

Just wondering how you got spark when you did number three if the distributor harness was loose?

Btw - great advice by soundy.

Harness was probably intermittent and contacted enough to give them a couple sparks when they were testing, making it look as if ignition was okay.

ya - I think that's what it was... we saw the sparks so we figured that there wasn't an issue with the Distributor and didn't bother checking the plugs.

thanks guys!