Hard to start

hpmaxim

Member
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2003 Mazda Protege5
Sometimes (usually when the car is "cold", ie hasn't been driven in a while), the car requires several seconds of cranking to start. Cranking sounds normal, no codes. It seems like it's just not getting enough gas. Once it starts (and it always does of cranked long enough), it seems completely normal. Thoughts?
 
Do you hear your fuel pump whining? when was the last time you replaced spark plugs, wires, and coils?
 
Probably the fuel pump getting weak and not holding pressure.

I think there is a somewhat common issue with the fuel pump relay socket too.
 
Corphish, I don't hear the fuel pump, ever. I certainly wouldn't be able to hear it over the engine trying to start. I don't remember when I last replaced the plugs, wires and coils. The car has about 138k miles on it, I got it from my father probably 10-15k miles ago. Pretty sure I replaced the plugs, doubt I replaced the wires and coils. I don't know if he ever did.

MrGiggles, I can't remember if I replaced the fuel pump. I replaced the tank, and I'm pretty sure I replaced the integrated filter assembly, but I think its the original pump. If they really do allow fuel or pressure to backflow into the tank when they age, that might explain everything. Bit surprising, you don't hear about check valves failing very often. Do you have more information about the relay socket problem (I think a bad checkvalve, if that's possible, is more consistent with the actual behavior I'm seeing).

pcb, I'd prefer not to get stranded when it doesn't start (if I'm home its not a big deal since I have other cars) -- but if I'm not... well, it'll suck. OTOH, if MrGiggles is right about the fuel pump, a weak check valve isn't going to prevent the car from starting.
 
Check the ignition switch, could be that. Mine was having a similar problem and when I checked the ignition switch (opened up) the metal beads in there were black, not silver how the metal is supposed to look. Once I changed that, it would start like a car with zero miles.
 
... If they really do allow fuel or pressure to backflow into the tank when they age, that might explain everything...

Try putting your key in run position and give it some time to reach full pressure/prime, before cranking the engine over.
 
Okay, pcb, you made your point! What a pain... Now how many of those would not produce any other symptoms or MIL codes? ;) Hrmm, will try the priming idea...
 
If the "priming" thing works, you know exactly what's wrong.

But changing your plugs, wires, pcv valve, air filter and cleaning your MAF are always a good idea...

Don't do it all at once because you won't know what fixed it.
 
... Now how many of those would not produce any other symptoms or MIL codes?...

I could see all of those not popping a code if it doesn't happen enough BUT you would think they would have other symptoms or at least not let you get it started easily all the time ??
 
I tried the priming thing. I literally heard absolutely nothing when I tuned the ignition on. No pump, no nothing. How does the priming work? When you turn on the ignition, does the pump run continuously, or does it run for a few seconds upon turning the ignition on?

I tried starting the car several times today. A couple times it seemed to have trouble starting, most of the time it didn't. Two of those times, I tried priming by turning the ignition on for several seconds, turning it off, and then turning it back on (and repeat a few times). The times I primed, it didn't have trouble, but then it also didn't have trouble a lot of times when I didn't prime.
 
... How does the priming work? ...

I'm just guessing about the priming thing.
But, the fuel pump isn't powered until the key is turned in the ignition.
If you are losing all your fuel pressure it may take some time to bring up the pressure... I don't know if that's half a second or ten ??
Turning the key on and off shouldn't matter unless you lose all your pressure in seconds.

Once the proper pressure is reached, the fuel pump shuts off then is continually turning on and off to maintain proper pressure.

The part I don't get is that the fuel is continuously circulating through the system and back to the fuel tank. The fuel return line is as big as the feed line and I don't know how it ever builds pressure ?? You'd think that at least the pump would have to be on all the time ?
 
... I literally heard absolutely nothing when I tuned the ignition on. No pump, no nothing...

I never hear mine either.. You could probably hear it if you lift up your back seat and remove the cover over the gas tank.
 
I tried the priming thing. I literally heard absolutely nothing when I tuned the ignition on. No pump, no nothing. How does the priming work? When you turn on the ignition, does the pump run continuously, or does it run for a few seconds upon turning the ignition on?

I tried starting the car several times today. A couple times it seemed to have trouble starting, most of the time it didn't. Two of those times, I tried priming by turning the ignition on for several seconds, turning it off, and then turning it back on (and repeat a few times). The times I primed, it didn't have trouble, but then it also didn't have trouble a lot of times when I didn't prime.

The PCM energizes the pump for a second when you first turn the key on to prime the system. It doesn't begin running continually until the engine starts cranking or running.

If fuel pressure drops to zero for some reason, the prime cycle isn't enough to pressurize the system, and the engine won't start until you get enough fuel pressure after cranking for a couple seconds.

Had the same issue on my Ranger, would start fine in the morning, but took some cranking after I let it sit for more than 30 minutes. New pump fixed it, and it was also setting a lean code because fuel pressure was really low.
 
... the prime cycle isn't enough to pressurize the system, and the engine won't start until you get enough fuel pressure after cranking for a couple seconds....

You could Jerry rig a jumper wire to a switch inside the car to get a full prime !!!
I'd be redneck approved !!



(maybe even try it to see if it works, to help diagnose your problem...)
 
Couple comments:

1) It doesn't surprise me that it primes the pump for a few seconds upon turning on the car, but I sure as heck can't hear ANYTHING whatsoever. In fact, I kind of assumed that was the behavior. So when I've been trying to "prime" the system, I turn on the ignition, wait a few seconds, turn it off, turn it back on wait a few seconds, turn it off, etc, maybe 4 times before trying to start. I haven't had a hard start while doing this, but I haven't tried that many times that I'm convinced this is correcting the issue.
2) I'm starting to suspect its not the pump:

On two different occasions, I drove the car, shut the car off for 5-10 minutes and tried to restart it, and it took quite a bit of cranking to start. The car also shuddered quite a bit when cranking, in a very unnatural way. On one occasion, after parking for about 35 minutes, I went to restart it, and it took a bit of cranking. I stopped cranking, and then a couple seconds later tried again, and the car started immediately. I'm going to try to see how repeatable it is.

Still no error codes, I'd think if the fuel pump was weak, I'd be getting some sort of code, like inadequate fuel pressure, or too much long term fuel trim, etc. I think a weak check-valve would be more likely, but if it depressurizes the lines in 5-10 minutes on a "hot" car, then it should ALWAYS be failing when I'm cold starting it, like in the morning or when leaving work.
 
Isn't there a vacuum solenoid under the hood for the fuel pressure regulator?

Also, it definitely sounds like a weak pump. The S10 platform trucks are notorious for having s*** pumps, I've replaced the pump in all 3 I've had. Long cranking, and priming the pump by cycling the key to run a few times got it going before it totally s*** the bed.

Could also be a clogged filter, but that's less likely.
 
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