Hard starting car after 1/2 tank

[FDSpirit]

I posted this on Honda Tech, but I'll probably get a faster response with you guys.

The car has always done this. As soon as the needle dips below the half tank mark on the gas gauge, the car takes a little more effort to turn on. But today the weather was much colder. It had a half tank. I turned the car and it took a little longer to start as usual. Then, it shook and cut off. I made sure I didn't leave the car in 1st. It was in neutral. I started the car back up and it started the same way but didn't cut off. Now it RUNS fine even if its on less than half a tank. It's just that it doesn't start immediately like it would if it were full 3/4 full or 1/2. Its never just died(cold weather on top of this?). I'm thinking I need a fuel filter? I gave the car a tune up with the exception of the filter. I bought some gas line anti-freeze to see if it helps any. I prime the fuel pump and I can hear it still doing its job. Any ideas?

[theholycow]

I prime the fuel pump and I can hear it still doing its job.

Are you saying you prime it before you even try to crank? If so, it's pretty severe.

Could be the fuel pump, or maybe just the pump has a sock that's clogged near the bottom.

I think it's a pretty common problem, I know I've seen it posted a few times but I don't remember the resolution.

[FDSpirit]

I just turned my car to check to see if there was a problem. I don't do it all the time. Maybe I have my words mixed up. What I did was I turned the key to the ACC position and I could hear a buzz. Like I said, I just did this as a troubleshooting thing.

[theholycow]

Try turning it to "on" for a couple seconds, listening for the fuel pump to stop, before turning it to "start". If it doesn't produce the symptom when you do that, it's definitely lack of fuel pressure before starting.

[FDSpirit]

I think I meant the "on" position like you just said. So if I turn it to on and I dont hear the buzz, its a lack of pressure? I'll be going out for lunch, so I'll check and report back. Thanks a lot.
*update*: turned to "on" position. Heard the buzz, then it went off. Car started fine. But this also probably happened because I have a full tank of gas.

[theholycow]

If you don't hear the buzz, your fuel pump is dead.

If you hear the buzz and, after waiting for the buzz to stop, the car starts properly...then you have a fuel pressure problem. (Assuming that you're doing it when you expect the symptom to rear its ugly head - i.e. when low on gas).

The buzz is the sound of the pump repressurizing the fuel system. It should already have pressure anyway, making it pointless to repressurize; if it doesn't have that pressure then it will crank but not fire, as you described. Letting it pressurize before cranking is a good way to diagnose that.

[FDSpirit]

Ok cool. Thanks. One of the members on Honda Tech said its a common issue discussed for my Civic's generation . I'll change the filter anyways . So I guess for now just keep the tank above half?

[theholycow]

What's the fix you have to do if you don't want to tolerate keeping your tank topped off?

[FDSpirit]

He never said. I need to go back to the site and ask. As long as I don't let my tank get too low, I'm good. But I'd really just like to eliminate it.

[watkins]

Hondas do not prime. The fuel pump does not turn on until the key has been turned to the START position.

[Rope-Pusher]

Fuel pump output increases when you give it more head.

[theholycow]

Hondas do not prime. The fuel pump does not turn on until the key has been turned to the START position.

I've learned something new today. Is there another relatively easy way to diagnose fuel system pressure failure? Maybe a fuel pump test jumper you can feed power to?

Fuel pump output increases when you give it more head.

[FDSpirit]

No word on a fix yet, but no problems after filling up. But like I said, it's a commonly discussed issue among my generation of Civics. Honda Tech's search feature isn't the best, so its gonna take some time to browse through the site and actually find something.

[watkins]

Hondas do not prime. The fuel pump does not turn on until the key has been turned to the START position.

I've learned something new today. Is there another relatively easy way to diagnose fuel system pressure failure? Maybe a fuel pump test jumper you can feed power to?

I dont know offhand. My friend with a '98 Civic is having similar hard start issues. Ill ask him what hes done.

[Rope-Pusher]

Hondas do not prime. The fuel pump does not turn on until the key has been turned to the START position.

I've learned something new today. Is there another relatively easy way to diagnose fuel system pressure failure? Maybe a fuel pump test jumper you can feed power to?

I dont know offhand. My friend with a '98 Civic is having similar hard start issues. Ill ask him what hes done.

I bet he gave it more head!