got an 88' cherokee with the 4.0.. it turns over but won't start, i have fuel and spark. it was running fine, i came back from the store, started it and drove about 50' and there i sat.

i replaced the crank sensor. i'm curious if maybe the spark is low or if maybe it jumped time.

i was gonna have someone turn the motor over and try turning the distributor to see if it will start..

is this in the right direction or is there a better approach?

 

do you have injector pulse or just fuel pressure?
if the crank sensor was bad you would have no spark at all
if you have no injector pulse i've seen the hall sensor go bad in the distributer
if your coolant temp sensor went i've seen them not dump enough fuel to run(sensor tells the computer its running at like 300 degrees so hardly any fuel)

 

the only fuel pressure i checked was in the fuel rail.. to check pulse do you unplug an injector?

 

fuel pump

 

fuel pump is turning on

 

take catalytic converter off & start

 

you can take to A muffler shop and do A precat intrusion test

 

Check the fuel pressure with a gauge. The presence of fuel means nothing if it doesn't have the right pressure.

 

The cat won't keep it from starting. Distributor shouldn't move and doesn't do timing. The injectors will fire with the wires on the dizy unplugged. Basics, plugs cap rotor wires, been checked?

And always listen to Cuiser!

 

Good advice. Gotta use a gauge. Many big box parts stores will rent you a gauge if you don't have access to one. You need approximately 31 psi for your engine to fire.

 

thanks fellas, plugs, cap and rotor look so i'll check the fuel pressure

 

Huh?

 

Had the same problem a while back on my 88. Turned out to be the fuel pump relay. It would energize the pump momentarily enough to pressurize the fuel rail but would kick out before the eng could start.