i have a 1994 jeep grand cherokee that has been blowing the engine control fuse every so offten.can figure out why.there no expose wires from what i can see.seems to happen when i acelerate from a stop.or blows it from stop and take off once in awhile.any idea what can cause this?

 

I've seen a bad Fuel Pump cause this in an XJ, before. The kicker was it was a brand new Fuel Pump that caused this problem.

 

thats fuuny you say that because my fuel pump was put in about 2 1/2 yrs ago and now im having this problem.ill look into it any other ideas?

 

SO do i replace the fuel pump even tho its 2-3 yrs old and works or are there other places to look befor i waste $200 on a new fuel pump?

 

Wow! if you are paying $200 for an XJ fuel pump you are getting robbed!!!! $85 at the local Auto Zone here in Oak Harbor, Wa. Even if you paid for me to buy one for and I had to ship it, it would be less than $200. No I haven't personally experienced anything else that could cause this, but a quick look at the wiring schematic could give me some ideas to pass on.

 

Look at the o2 sensor wiring around the exhaust manifold. The wires will rub on the manifold and after a while the insulation will wear off and expose bare wire, and then it will short out when it comes into contact with the manifold. Worth looking at before spending any cash. I doubt the fuel pump is the problem.

 

ILL CHECK THAT.THANKS.im making a list so keep the ideas comeing.

 

my jeep is a 84 jeep grand cherokee ltd.is that a xj like you call it.sorry but im new here and to the lingo.

 

ok i checked the o2 sensor looks good no exposed wires there.but here is what area the fuse blows this is what it says.(eng.contr 20A) ANDthats a small fuse theres a bigger fuse that reads(30A eng.cntrl) but that one hasnt blew just the small one that reads (20a ENG.CONTR)

 

Sorry about Giving you XJ advice when you have a ZJ. I totally missed that. I really doubted your O2 sensor was the problem. That wiring is right out where you would have spotted it arcing and sparking or seen the charred wires easily. I do believe you have a short of some sort causing the fuse to blow. The fuel pump I had cause the fuse to blow, was in fact internally shorted. I quick once over of all the engine wiring harness would be a good way to find the short.

 

I LOOKED AT IT OVER AND OVER AND CANT SEEM TO FIND ANY EXPOSED WIRE THAT WOULD CAUSE IT TO BLOW.

 

I know how you are feeling dude. Chasing down shorts can really be a huge PITA sometimes. What there any wiring messed with on the Jeep just before the fuse started blowing?

 

no.me nor anyone messed with any wireing.my truck staerted to blow fuses but befor that happen there were times that i start it drive some place and try to start it again and it wouldnt start for 20 min or so.now it starts but blow fuses now.hmmm now i wonder if those two things could be related.one stoped and another started. idk where to start now.would the cam position sensor blow a fuse or cause it to not start then start?

 

would a crank shaft sensor cause the engine control fuse to blow? or how about your door sensor?

 

I have seen a 02 sensor do that, BUT there are so many things that can cause it. I suggest starting it, and start yanking and shaking stuff to see if it does it again. Sounds like the motor mounts are weak and there is a stretched wire somewhere, when u get on it hard the motor shifts and pulls and causes a short.