Minor Irritating Start Up Issue-Opinions please

[kayger12]

Your fuel pump could be going. Check pressure at the rail.

This. Just went through similar set of symptoms with my wife's car.

[echo46]

Do I have to buy a fuel pressure guage to measure the pressure at the rail. Kayger-what ultimately was the problem with your wife's car. If the fuel pump is on its way out shouldn't I be at least stalling when driving or does it tend to deteriorate and weaken over time? This is driving me crazy. I am also leaning towards fuel pump but have read that when the fuel pump is failling the car tends to stal, my car is not stalling, just rough idle and weak start on warm start up.

[kayger12]

Do I have to buy a fuel pressure guage to measure the pressure at the rail. Kayger-what ultimately was the problem with your wife's car. If the fuel pump is on its way out shouldn't I be at least stalling when driving or does it tend to deteriorate and weaken over time? This is driving me crazy. I am also leaning towards fuel pump but have read that when the fuel pump is failling the car tends to stal, my car is not stalling, just rough idle and weak start on warm start up.

So here's the story: My wife's car would always start and idle when cold no problem. Occasionally (usually after driving for a while and then stopping and shutting her off), she would fail to turn over. If she did turn over, she would run rough. If I let her sit for about a half an hour, though, she would eventually turn over and run fine.

This happened intermittently for over a year before total failure. Sometimes it wouldn't happen again for several months.

I changed the fuel filter in March of this year hoping that was the issue (even enough there were only 20k miles on the old one). Then last week, after not doing it for almost 6 months it did again- but this time it wouldn't start at all, even a day later.

I suspected fuel pump, mechanic confirmed same. $650 later, she's right as rain.

Apparently when my wife would run the tank down low (which I never do on the ZHP for this reason), the pump would overheat and not function well until it cooled off. At least that's how the mechanic explained it to me.

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[echo46]

Very interesting. THe only thing is I also never allow the tank to go below 1/4. Tonight I will test voltage at the pump, see if pump is functioning when key is turned to Position2 and look into testing pressure at the rail.

[kayger12]

Very interesting. THe only thing is I also never allow the tank to go below 1/4. Tonight I will test voltage at the pump, see if pump is functioning when key is turned to Position2 and look into testing pressure at the rail.

Forgot to mention, the reason I settled on fuel pump was because I could no longer hear it priming when I turned the key to the equivalent of the #2 position in our cars.

As for running the tank down, I believe that only accelerates failure, so I'm guessing you could still have a failure even though you are good about not running it down.

Curious to see what you find tonight.

Keep us in the loop.

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[echo46]

Will do. Thanks for your help.

[echo46]

Back seat is out, took it for a long ride, by the way I love driving this friggin monster, fuel pump seems just fine. Leaky fuel injector?

[kayger12]

Back seat is out, took it for a long ride, by the way I love driving this friggin monster, fuel pump seems just fine. Leaky fuel injector?

Are you discounting the fuel pump based on the voltage?


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[echo46]

Well yes and also seemed to be functioning--ie hearing the whirling motor. However, it did change sounds as it was working. You don't think I'm out of the woods with the pump? Actually, I was kinda hoping it was the pump as that is a fairly simple fix. The car drives strongl after it is started. I'm still frustratingly perplexed. I may just change the pump and see what hAppens.

[kayger12]

I'm just spit-balling.

Sometimes when pumps are on the way out they initially work, but their performance degrades as the pump heats up. It's the fact that your symptoms appear when warmed up but not cold that have me still thinking fuel pump.

Not convinced that the pump is good just based on voltage or hearing it- that just tells me it's ok when cold at start up- but I'm not sure how else to know for sure without replacing it.

That being said, I'd hate to see you spend the time and money changing out a pump for no reason.


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