99 grand cherokee larado flooding problem during cold startup attempt

[Guest]

1999 grand cherokee 4.0 4wd auto 180k

for the last year every now and then during crank up, my 4.0 would kick over just enough to disengage the starter gear from the flywheel, then I have to start cranking again and would run rough for 10-15 sec. after a long crank and finally starting.

it wasnt a bad problem until saturday, when i went to start it up, did the same thing as described above except this time when I started cranking again to start it I could smell fuel. so now its flooding, needs about 30-45 minutes to dry out before it will start. Then when it does start after flooding/drying out, I have to feather the pedal fairly long to keep the engine running and finally get the idle smooth.

it does start, usually starts best with the throttle part way down. However it starts fine after initial start. but leave it for a couple hours and the trouble is back.

thought it was plugs fouling (o'reillys hooked obd checker to it a couple months ago and it indicated "multiple mis-fires on cyl 5 & 6)
so I changed plugs (all the plugs were wet), same thing, changed cam position sensor (on top of distributor shaft), didnt fix the problem either.

I did turn the key on and allow the fuel pump to pump up and turn off before cranking up this AM. It did start without having to depress the accelerator, but it was still running rough after initial fire up today.

any wisdom would be greatly appreciated!!
Thanks,

Steve
call if you care to 8 1 6-616-4501

[audioguy1]

Fuel pressure regulator? Sounds like its letting too much fuel through. Im no mechanic though

[reward_1000]

It sounds as if the o-rings in the fuel pump are leaking down. There are o-rings that go around the internals in the pump that will cause for long crank times due to fuel psi. bleeding off. It will act like a flood out to some people but it is acutually running lean. Jeep used to offer a kit to reseal the fuel pump, I have not done one in years because if it is out you may as well replace it with the mileage that is most likely on it.

[Guest]

Just checked fuel pressure at the fuel rail port

before starting (or trying to start it) with cycling the key a couple times 45-47#

finally got it started: while running 45-47#

while reving the engine: 45-47#

after turning off the engine 45-47#

after 7 minutes after shutting down the engine the pressure was around 44-45#
after roughly 35minutes it was around 20#

O'reillys said the intec pump is supposto be around 80-85psi with key switch on only.
While engine is running pressure supposto be around 45-50psi

from the looks of it as reward1000 suggested its likely a fuel pump.
any other thoughts guys?

thanks

[reward_1000]

That 80-85 psi would be if you were to dead head the pump not with the key on engine off. Your other prssures are good also per my books. Is the check engine light on? It sounds as if an 02 sensor is running lean causing for the car to richen up even though it is not needed. This will not set a code sometimes. The way to test is best with an engine scanner that can read the o2 sensors. You would need to look at all of the o2 sensors and see what they are reading, look for any of the precat o2 sensors to be really slow to move or stuck at a voltage. I will give you a call tonight.

[Guest]

As it turned out it was the crank positioning sensor. Somewhat difficult to get to, used about 2.5 feet of 1/4 drive extension from below. Had to remove the transmission cable bracket to allow me to position the extensions proper on the sensor bolt, but everything worked out well.

Now 7 months later my mileage has dropped from 19.1 to 17.3 (based on the on board computer overhead console readout) and I get an occasional "stumble" while idling, not horrible but noticable.
So I'm thinking it may be going out again