hi im new to the cherokee world and my 1991 cherokee is having a hard tim starting. it will always start but takes time. what could the problem be?

thanks..

 

That's normal... it's a jeep thing. They have their little quirks, but they always come through. unless it's a little more severe then the norm...

 

You have a Renix XJ (87-90) By design, the engine is not going to fire until the computer (ECU) gets a signal from the crankshaft position sensor and measures that signal to indicate that 300 rpms while cranking has been met/exceeded.

Somewhat extended crank times should be considered a “characteristic” of your engine, rather than a problem.

You can upgrade the battery and battery cables--at least 4 ga., 2 ga. better--and buy a high-torque starter.

Be sure that all grounds are good. Remove them and freshen them. You cannot tell if the grounds are electrically good by looking at them! Renix vehicles are very sensitive to ground issues.

Other than that, performing basic tune-ups on a regular basis is important, (plugs, wires, cap, rotor, fuel filter)

The above suggestions are things that will help optimize start times on a Renix engine.

 

He has the Chrysler operating system in his 91. Put a fuel pressure guage on the fuel rail, start the engine, shut the engine off and look to see if the fuel pressure drops down when sitting over night.

 

Oops, my mistake. Had Renix on the brain from a previous answer I posted.

The grounds and tuneup advice still stands. And never a bad idea to get a fuel pressure gauge on it as suggested by Bustedback.

 

once i put a fuel pressure gauge on. and comes up low. what are the ways to fix that.?

it has a new starter and fuel filter and fuel pump was done in 2007. it takes about 15 secs to start every time.

thanks for the help guys...

 

I believe that the fuel pressure spec is 31 psi.

You should put a fuel pressure gauge on it after it sits overnight, then have somebody turn the key and watch it to see how long it takes to come up to spec.

You may be bleeding fuel pressure down as the engine sits. It's called "fuel pressure drop". That means a small fuel pressure leak anywhere between the tank and the fuel injectors. The factory service manual outlines the proper testing procedure.

You need to get into that 31 psi range before the engine will start.

If fuel pressure checks out okay, review tuneup hardware (when was last tuneup??) and freshen engine grounds.