Hard starting, intermittent - Ideas?

[krewzn_along]

Twice in the last three weeks our J30 ('97 with 155K) wouldn't start for my wife or daughter. Turns over fine but doesn't fire up.

With the accelerator floored and long cranking it finally fires and runs rough for a couple minutes, and then smooths out and all is fine. Otherwise it runs great, and fires right up every time.

Any ideas of what might be causing it? Seems like incorrect fuel delivery or ignition.

I think I learned the 'flooring' trick from Audiworld forums when I had an A4. And they reported cars that had trouble starting due to short run times, like when you start it just to move it and shut it off in a minute or two. Anyone experienced this with our cars?

Last major engine maintenance was 50K ago, I had plugs, hoses, and all done when the timing belt was replaced. It gets good highway driving a couple times a week.

TIA

[kbflip02]

when the last time you cleaned your injectors or replaced your fuel filter....definately could be one of those if they havent been maintained

[yodawill2000]

Blowing a ton of black smoke out the back when it finally fires up ??Could be flooded.Don't want to Hydrolock that puppy.

[driverdriver]

J's don't like short trips or trips where the engine hasn't warmed up to operating temp. That could be the source of your flooding issue.

[FunkRider]

Wifes J is having this same problem as of late. I have been away so she took it to the nissan dealership and they told her its an o2 sensor problem and its going to be 700 to replace them?

Sounds like BS to me, o2 sensors rarely have anything to do with start up problems.

[fogged306]

Whats BS is that price for those o2 sensors. I just bought mine and they were less than 150 a pop (these are for the downstream o2's on an OBDII j30) granted thats not that cheap, but its no 700. They are cake to install too. That being said, I agree, I don't see how bad o2 sensors would cause hard start issues.

Like driverdriver said, these j's don't like to be run and shut off before they reach operating temp, This will flood my car almost every time.

[Jakw]

I find it so weird that so many people say their J gets flooded after a short trip. I have never ever had that problem. Mine takes a little longer cranking before it fires up when it's cold outside. I have noticed, however, that if I leave the key in the position before you turn it to start it, it won't start as hard. Does that run the fuel pump? I dunno, that's just what I do.

[misfit6794]

Possibly a bad fuel pressure regulator or as mentioned, a failing or clogged injector.

[elan]

yes it's the pump building the pressure you can actually hear the noise for the first 15 secs or so