My Q45 Wouldn't Crank!

[AlabamaDan]

Yesterday my Q45 didn't want to crank. I parked in Saturday morning in my driveway. Sunday morning it didn't want to crank. I had to just sit there and try and try and try for like 15 mins. I almost ran the battery dead trying to crank it. Finally it did crank after I pumped the gas pedal and held it down. The whole time it was trying to crank I heard this loud buzz from the rear.

Once cranked I had to keep the RPMs up around 2000 to keep it running. I let it run for about 30 mins before shutting it off to build up the battery and see what happened. It ran fine the rest of the day.

This morning it cranked up fine, but ran rough for a min or two.

What happened? I'm not one to ignore this type of thing. I believe it will happen again and next time I might not be so lucky.

Can someone help me?

[911/Q45]

Sounds like it was flooded. Possible leaky injector. Also sometimes happens if it doesn't catch at the first start and you try again more than once, shooting a prime squirt in each time.

[Q451990]

I parked in Saturday morning in my driveway. Sunday morning it didn't want to crank. .... The whole time it was trying to crank I heard this loud buzz from the rear.

How long since the fuel pump was replaced? That's the buzz... Hopefully your pump and controller aren't on the way out. ALSO, you say you parked it in the driveway Saturday morning. How long was the car running between when you started it and turned it off when you parked it there. It's not uncommon for owners to have a flooded engine after moving the car a short distance and shutting down (especially in cold weather). (e.g. moving get another one out of the garage, etc...)

The injectors send an extra large pulse of fuel to the engine on a cold start-up. The engine needs to run for a while (until warmed up preferably) to burn off that excess fuel.

If it ever floods again, hold the pedal to the floor and keep it there until it starts. Pumping will put even more fuel in the cylinders. The ECU knows not to add more fuel when it's floored before starting.

Heath

[AlabamaDan]

I backed it out of the garage Saturday morning and it sat there for until Monday morning. It only ran for about 30 seconds when I backed it out.I don't know if the fuel pump has ever been changed. I'd have to venture a guess of no.

Flooded eh? I didn't think cars without a carb flooded. I guess that's why it didn't cross my mind. Now that you mention it, the car did act like it was flooded... Wierd? I've never had that happen and this is my fourth Infiniti.

Do y'all think that's all it was? Is there a way to test the fuel pump?

[Q451990]

I'm 95% sure that it was flooded. The G50 Qs and J30s tend to have this issue more often if the number of posts we see are any indication. I've never had the flooding problem on either Q, but I have remote start and use it to warm the car up before it ever moves.

The test for the fuel pump is hearing it. If it's loud enough to hear at idle - especially at a 1/2 tank or less - it's probably on it's way out. They're typically ready for replacement by 80-90K, depending on gas conditions.

Heath