my 1997 zj only has 81,000 miles oon it and sometimes takes a while to turn over but sometimes it starts right up any ideas what i can do to reduce the cranking time..thanks

 

Replace the starter.

 

Ricky, I'm betting what you mean by it takes a long time to start sometimes is that sometimes it cranks a long time before starting and sometimes it cranks just a bit then starts. I had a problem like this once with my 91 XJ 4.0 HO. If the long cranking periods are the first start in the morning or after the Jeep has sat for awhile, I'm betting your One Way Check Valve in the fuel pump is bad. This won't effect how the Jeep runs at all it just causes the long cranking period before starting after the Jeep has sat. What this check valve does it keeps the fuel in the fuel line after shutting the engine off. When it goes bad, everytime you shut the Jeep off the fuel all drains back to the tank over time....causing the long crank period before starting.

 

Is that really the problem? Come on really. Lets do some diagnosing here before you just throw money at it.

Does the cranking speed ever seem to change between the hard starts and the easy starts? If it doesn't IT"S NOT THE STARTER!

My quess is that the fuel rail doesn't have enough pressure in it SOMETIMES when starting. The injectors are the only way your engine is going to get fuel AND if there is not enough pressure the injectors won't open properly to atomize the fuel so the spark plugs can ignite it.
There are several threads here about fuel rail pressures. try searching on that and see if any of the sysmptoms mirror yours.

 

yeah what he said!

 

good luck with that. i had this same problem. was told it was the check valve. so i decided to just replace the whole pump and entire assembly. well it still wouldnt start. so i checked for spark: no spark. ok lets test the coil, coil was bad. replaced the coil. now, after 3 days of throwing parts at it i decided it was time for the jeep to get a flatbed ride over to my mechanics garage... AAA picked it up about 10 minutes ago and im just waiting to hear what was finally the problem. but on the up and up hes installing my adjustable trac bar while its there, and hes going to check on the brake light/hazard problem ive been having as well. sometimes its just better to pay a couple bucks to have some things fixed. i hate that i couldnt figure it out but i only have so much knowledge and equipment. i hope for your sake you figure this out without any snags and without having spent too much moola. good luck

 

Mine did the same thing and I replaced the starter and its been fine since. Sorry it worked for me buddy. No need to get all pissy . Just telling him what worked for me.

 

the motor cranks the same speed hot or cold..i read someone with the similar problem and he said that if you cycle the starter to get the fuel pump on it primes the system and it starts rite up when i do it so i think its the check valve

 

is there a way i can put an inline check valve in so i dont have to put a new fuel pumpo in

 

Ill check with Jamie57

 

can the crank position sensor cause similar symptoms?

 

I sincerely doubt it's the starter, I have to agree, here. Besides, i think they have the Nippondenso starter in there, which is a very reliable and robust piece.

 

yeah thats what mine is doing. after it sits for a day or so it does it or if its in the morning. thanks for the help... is it easy to replace? or should I not really worry about it and deal with the occasional long crank?

 

i found inline check valve but does he gas to out of the supply line or the retyurn line

 

Mine does the same thing. It started happening this July, only once and a while. Two quick turns of the key and it would start like normal. I also found that if I crank it for a second or two it will start just fine too. Same cranking speed so I'm sure it's not the starter. HOWEVER, now that it's getting colder out it starts first time right off the bat. I also found that if I turn the key to "RUN" and let it sit for a few seconds (like while I put my seatbelt on and adjust the radio) it will start up just fine too, without any cranking.