Bizarre Starting Issue

[SnakeyesTx]

This only happens sometimes, but I've had my car for almost 2 weeks now and this has happened maybe 5 or 6 times. It's rather annoying and I bet the fix would be simple.

Anyway, most of the time I turn the key and it'lll start up within 1 or 2 seconds and everything is fine and normal. Once in a while I try to start it and let go of the key after the typical 1-2 seconds and it doesn't run. Then I have to sit there and crank for a good 8-10 seconds before it starts. Sometimes when that happens it'll "catch" and run about 5 seconds in but it'll idle rough and low speed and die out, but then the next crank it'll start right up in 1 or 2 seconds and everything is fine. The other times it'll take the full 8-10 seconds and then it'll start up and run fine.

Its weird... and its irritating, and kind of embarrassing. A neighbor suggested I clean the fuel pump relay's contacts, but I didn't know which one was the fuel pump relay, so I cleaned them all, and wiggled them to make sure they seated well. That didn't work apparently.

Once I'm running, normal or not, everything is fine, idle's good, runs great, its just that starting thing.

Any ideas? I'm kinda stumped.

[saj3n]

Same problem I have! The mechanic here told me it's called "Vapor Lock". Not sure if that's the case, but I feel your pain. Makes me want to recline the seat until the car starts. :-P I would definitely love to find out what the problem is. It's not the airpump, so I think. My far was just fine until I had the engine replaced, and then the starting problem arose. I did replace the fuel pump when that was first thought to be the issue, before replacing the engine. I only wonder what it could be.

[SnakeyesTx]

Well.... vapor lock is typically a term used in carbureted applications. My jeep had that issue and it was usually caused by heat and the fuel vaporizing too early because it was getting cooked in the bowl. Being fuel injected, I doubt the problem lies there.

It just occurred to me that the crank position sensor acts alot like a pick-up coil, and could cause this, but I'm hoping its something simpler than that.

(I REALLY hope that's not the problem... I cant afford 90-108 bucks for one! X_X )

[ThoreauHD]

Idle Control Valve would be my guess. And I'm not a mechanic.

[saj3n]

Hmm, ive also seen the problem more likely after I've driven the car, let it sit, then come back to it. opposed to a fresh cold start

[BillionPa]

evaporative emissions charcoal canister.

[Ausmpower]

Fuel 'boils' in the fuel rail as it is heat soaked after shutdown. the fuel pump will take a second or two to repressurise the rail with fuel in it's liquid state hence the small amount of extra cranking needed.

A 10 second crank time would concern me.... 5 seconds won't.

If your relays aren't sick and the pump is healthy......Try this during your next hot restart.

1.key to 'on',
2. wait 3 seconds,
3. crank........ I'll bet she fires right up and idles smooth.

The reason is that the fuel pump runs for a few seconds to pressurise the lines when you first switch the ignition on. If you don't pause for a second the pump doesn't have time to pre-prime the system.

Also never touch the gas pedal whilst cranking, the DME will cut the cranking enrichment if there is no closed throttle signal when cranking.

[saj3n]

Ok, I will have to try this today. I'll check back this evening with updates

[Ausmpower]

Ok, I will have to try this today. I'll check back this evening with updates

Any update on this?

[saj3n]

Any update on this?

It seemed to work the first couple times I did it, but i don't think that its a fix as the issue has returned even after leaving the key in ON for 30second - 2 minutes, it will still stutter and take 7 seconds to start up.