lurk520

Hello, I just recently purchased an 02 Grand Cherokee with the 4.0. It seems like it either starts too fast (instantaneously) when I turn the key, or it starts too slow 3-4 seconds of cranking, very inconsistent. But it does start every time. Any body experience this problem before???

Bustedback

Sounds pretty normal if you ask me.

lurk520

Lol, I guess if that's what classifies as normal in the realm of 4.0's. My 93 XJ 4.0 had a weird start to it as well. But none of the other vehicles I've ever driven have had such inconsistent funky starts. I'm talking sometimes when I fire up the WJ it starts so fast it almost doesn't crank at all, it's like turn the key and BAM it's on, then other times it sounds a little weak and takes longer than normal. And when I say 3-4 seconds I mean 1 Mississippi 2 Mississippi etc.....A normal start should take about 1-2 seconds and sound clean and crisp.

Bustedback

Is the first start of the day long? Any different when hot or cold?

lurk520

Nothing to do with ambient temp. Seems to do the long crank when it's sat for maybe an hour or more. It's intermittent though and I haven't had it very long so I'm not completely sure. I am noticing if when I cycle the key to ON and only wait like 1 second to start it then it doesn't seem to long crank, as opposed to cycling the key to ON and waiting 5 seconds. But the quick start it does, doesn't seem normal either. I am kinda wondering if it's the fuel pressure regulator.

lurk520

Ok, now why is it when I search on the Auto Zone web site for a regulator only performance ones come up?

tuneman

its the regulator so try this to check it After lettingf it sit for more then an hour turn the key on and wait 2 or 3 seconds before cranking if it starts right up then the reg is weak and just to let you know when it does start easy for you its because the gas didnt bleed out of the line yet

Bustedback

The regulator is on the fuel pump, if you're going go that far you might as well replace the whole fuel pump module.

lurk520

what an awesome design! Looks like it's going to be funny starting for a long time! Or is there an access panel in the cab to pull the pump?

tuneman

no access point but just leave the key on for a couple of seconds before cranking and problem solved. its a common problem

lurk520

No Tuneman, actually if I leave the key on then the long crank happens. Cycling the key on a couple times "poor mans prime" doesn't work either. If I turn the key to on and only wait 1 second then it DOES NOT long crank. But the issue is also there that it starts too quick sometimes.

lurk520

Well to cap off this thread I ended up taking it in to the dealership I purchased it from because I have a 60 day warranty. They ended up putting a new factory fuel pump and filter in it, which apparently had a restriction in it. So far it seems to be starting normally. I guess there was also a service bulletin to install a shield on injector #3 to prevent a vapor lock issue, so they took care of that too. Glad I bought from a reputable dealership instead of some janky used car lot.

lurk520

So it appears there is still some kind of issue here.....For some reason it only happens during one part of the day....I usually get off work and 2 or 3 o'clcock, I drive home and reverse into my front yard...front of vehicle faces East...Sun is in the western sky blazing...it's hot here in Tucson...when I go to leave some where a few hours later it starts funny...It cranks, the engine goes to kick over but it just dies, then I crank it again and it long cranks and starts. Has happened about 4 times now and only does it during this part of the day. Maybe something to do with the sun beating on the back of the vehicle where the fuel tank is. Vapor lock issue

Evil Bender

This may or may not be a factor but, I had a wierd starting issue that cleaned up after I refreshed my chasis ground and added an extra block to chasis ground wire.

lurk520

This damn thing still isn't starting right. I don't think it's a ground issue, the engine bay is spotless, probably steam cleaned. Seems more like an air/fuel issue. So since a new fuel pump was installed, does that mean the regulator is new too?