Hey everyone new to the forum since I just got a Cherokee not long ago and its having some issues. Its a Inline 6 4.0 92 Cherokee I love it but something seems to be wrong with it and I cant figure it out.


It all started when I got off work and went to Walmart (about 20 min drive) after I got what I needed and came back out my Jeep wouldn't turn over but it would crank fine. Came back the next day to try and jump start it and it started right up... Duh phuq? Since then it has been doing the same thing I cant drive it far or it'll just crank but If I Crank it and let it sit for 15 secs it'll slowly start cranking it a few times.


I also noticed when I got it that I was getting about 20ish mpg or maybe I wasn't resetting my miles but one day it dropped down to 12 and has been about 12 mpg since. My gas gauge wont go to full either when I Fill it up, it goes about 7/8ths full or so, I don't remember if it was always like this before the mpg dropped.


I was reading a similar thread and someone said it might be the fuel injector or fuel filter I have no Idea I would really like some suggestions on where to look and what to test.


Any help would be great I use it as a daily driver and cant have it falling apart.


Thanks

 

Fuel filter is relatively easy to replace and is cheap, too. Get a Wix. Routine maintenance, anyway.

Start with the simple things first. Good luck.

BTW, "cranking" and "turning over" is the same thing. Your terminology in your story is confusing. Sounds like what you have is a crank, but intermittent no start/run situation.

 

Thanks! Ive only had less then a years work on my cars trying to learn since I'm living on my own now haha I was asking around and I was told it could also be the spark plugs since I noticed it was spitting out of extra gas from the exhaust I took it to a autozone (I've talked to the manager a few times and he's good with vehicles) gonna check these today I really hope it's nothing to big

 

So update, I switched the spark plugs and it did nothing the old ones sucked anyways.
I noticed the other day excessive gas was coming from the exhaust (which explains why my mpg dropped it's spraying to much gas is my guess) my guess is some how it's using more gas and it's like flooding? That would explain why it has trouble starting right after driving and the low mpg.

Could it be the injectors? Or a bad chip like a o2 sensor? Or what ever controls the gas to oxygen ratio.

 

Hm, MAP "sensor" against the firewall? There's a vacuum line that needs to seat on there properly or it will give an incorrect reading = running rich! Also, check the connector as well - will probably give you trouble if the connector isn't 100% in.

 

^^^ this is a good place to start.

 

So far I've replaced the map sensor and it did nothing. it wasn't getting pressure so I thought it was it but I guess I was wrong. anyways I noticed none of my cluster lights are working (brake, Check engine, abs exc) the gauges and turn signals and all that work fine tho. I checked the fuse and and the bulbs its all fine on those... I know I've seen the brake light on that panel flash a few times but it was brief. I figure I might have a check engine light but since that panel isn't working I can't say for sure.

 

When you checked for codes besides 12 and 55 what else showed up ?

 

Sorry, trying to get experience working on cars so I'm not to sure what you mean by this. You mean codes for check engine light? Talking to my brother earlier and he said it wouldn't show any codes if the check engine instrument panel wasn't working. If I take it to a shop to check for codes do you think it would show any if there were any? (tried Autozone but they only do vehicles 96 and up.

 

You'll have to find a shop that has the scan tool for OBD I vehicles. Not many have them. Ask around.

 

Sounds good ill update Monday when most non autozone shops are open the ones I know are closed on weekends.

 

You also may want to check your fuel pressue, you may have a bad fuel pump. Best of luck, hope you get it fixed

 

Pull the instrument cluster panel off... 4 screws. Pull the Warning light cluster off ... 2 screws. Check to make sure all bulbs are good. Mine were missing and burned out. Once I put new ones in, the Jeep changed it's story.

 

I second that, it sounds like you have one or more leaking injectors. See how long the rail holds pressure after you turn the key off.

 

When keys first turned to run does service/check engine light come on ? If so do this .....http://jeep-xj.info/HowtoECUcodes.htm