Thanks for any help,
Mike
Maybe there is a cutoff relay that needs power?
When you have the key in start, power goes directly to the pump, when
the key goes to run, the power feeds through a ceramic ballast resistor
on our 88 4.0 engine's pump.
The resistor sits on the drivers side fender out near the rad on our
Cherokee.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Mike
Fuel pump should run all the time once the engine has started. Only exception
is startup where the computer runs the pump to pressurize the fuel rail.
Hard to tell without an ODB-II scanner. Does ignition on-off-on-off-on
blink the check engine lamp... I guess, do you have that circuit hooked up?
In the 93 I would check the fuel pump relay and the ASD relay.
ASD = Automatic ShutDown. When that relay gets old the engine may die.
If the computer is getting bad sensor readings (overheat, no CPS, or Camshaft
position sensor inputs) it probably will shut down.
My inner greasemonkey says you might have a sensor that's not working or not
hooked up properly. I know that if the CPS is faulty the engine will not start,
so that sensor might be fine. Now if the CPS and Camshaft PS (the one in the
distributor) disagree, the engine will shut down, but it will also stumble like hell
before it does. Yours sounds like it's running properly then the computer is
killing it because of a bad sensor input. i.e. the computer thinks your engine
is going to grenade.
Best suggestion I have is check your wiring again. Make a copy of the schematics
your working from and mark each connection off as you check it.
Good luck.
It could be all the other things like the ballast resistor or a relay,
even a plugged filter rather than the pump itself, but the fuel
pressure sounds like a good place to start since that's the end result
of all of them.
--
Will Honea <who...@codenet.net>
Slap a pressure gauge on it. R-12 Low side gauge works fine.
Look for about 32PSI at all times. With the vac line off
the regulator it should go up to about 41.
Thanks a lot for the help guys.
Mike
yep. :)
> The only thing I can respond on with a certainty is the fuel pressure
> with the switch on before being started sits at 40psi, during the 5-10
> second running period it fluctuates between 34-35psi.
That's within spec.
Hope you find what's b0rked.
--
Will Honea <who...@codenet.net>