My 99 Civic has started having hot start issues. I've had another car that had the standard main relay problem, but with that happened it was painfully obvious (fuel pump didn't turn on).

I've been reading old threads and tegger.com for an hour trying to find a straight answer if a possible failure mode of the main relay is for the fuel pump to still prime, but the car to not start (injectors not firing?)


The actual issue is a hot start attempt will sometimes just leave me cranking over and over, and eventually it'll catch and run very rough for a few seconds, and then jump up to ~2500 RPM for a while. Driving for a minute or stabbing the gas a few times will bring it back down to a normal, healthy sounding idle.

It's beginning to make me suspect that it's nothing to do with the main relay and that it's just an ignition problem, but so far testing the coil and igniter yields nothing out of the ordinary, and I haven't managed to make the problem happen at home yet when I have somebody to crank the car while I run around trying to listen to clicks or whatever else.

 

Sounds like a bad igniter or possibly coil as you say trouble when starting while HOT (more likely igniter). does your tach go crazy after a certain RPM ?

 

When the car is running right, the tach is fine.
I haven't paid enough attention to the tach when I'm trying to start the car when it's being difficult yet, but I HAVE noticed that when I get the car started and it's running very rough/shuddering at first, the tach usually sits on the peg (although it's entirely possible that the car is just sputtering around below the range of the tach I suppose).

CEL operates normally in time with the fuel pump priming, and I haven't noticed if it comes on during cranking or not.

The car hasn't ever stalled once started, it's only an issue while starting. Seems like a weird failure for an igniter to only be an issue starting, and then just function normally once the car is running.
I'll check the igniter again and see what I come up with.