tuggspeedman55

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lawsoncl

Welcome aboard.

Hearing the fuel pump after key-on is normal. It will turn off after a few seconds if you don't crank the engine, and then start again as soon as the computer sees the engine crank again. As for the poor mileage, my first guess would be O2 sensor since you didn't mention it. You'll have to do some troubleshooting to narrow it down. It could be bad temp sensor - the one for the computer is on the block under the intake and exhaust manifolds. Bad thermostat and it's not actually warming up. Could even be he put the wrong injectors in.

My advice is to start learning some basic automotive skills. The older Renix era Cherokees are fairly easy to work on, and most testing can be down with a basic multi-meter. Also update your profile so we know what year, engine, trans you have when you post.

cruiser54

Here ya go. Let's get started on familiarizing you with your Jeep and eliminating some known issues.

go to my website www.cruiser54.com.

Complete Tips 1,3,4, and 5 right off the bat.
Check and make sure the intake manifold bolts aren't loose. Very common.
Give us a pic of your engine bay so we can see if the PO monkeyed with stuff.

Saudade

Just to double check, how much fuel does the tank take? XJ's came with 2 sizes of tanks. One is 20 US Gal (75 Liters) and 13.5 US gal (50 Liters). Normally. the 4.0L engine gets the larger tank but I've seen some low spec models get the smaller tank. Also, was this originally sold in Canada or "imported" from the US? Is it manual or automatic?

As for horsepower, and XJ is no dragster. The '90 specs out at 177 hp when new. Yours will have a bit less these days. That's not a lot of ponies to move a 3200 lbs + vehicle.

Current gas formulation is no help either. My '88 gets about 10-11 MPG just driving around locally. On most trips, it barely gets up to temp before I arrive. It goes up to 15-16 if I take a long trip on the highway (which I rarely do these days). I have about 210K miles.

As mentioned by the others, the previous owner may have messed with a few things that need to get sorted that could impact your fuel economy as well as other systems.

tuggspeedman55

Thanks for everyone who responded I really appreciate the help.

The gas tank is 20 gallons as far as I know. it’s a Cherokee, automatic. Fairly certain car was originally purchased in canada. there have only been two owners and the last guy said he got it from his neighbour.

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cruiser54

Tank size means NOTHING!!!!!

You fill the tank and record the odometer reading.
At next fill-up record the mileage.
How many miles have you driven since last fill?
Take the miles driven and divide that number by the number of gallons used and you get MPG. Only way to do it.

And, you can waste tons of money on sensor replacement when the only reason they're not reading correctly is they have a bad ground.
do the Tips, manifold fasteners, plugs cap and rotor first along with ignition wires.

tuggspeedman55

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cruiser54

Looks pretty much unmolested.

lawsoncl

The vacuum line to the fuel pressure regulator looks a bit hokey. Make sure that's not leaking where it's taped up. That the normal angle for the oil filter on a 90?

I don't think I've ever seen a brake booster that rusty. Not even the piece of crap DeadJeeps sent me that had actual rust holes in it.

cruiser54

Oil filter is okay.

Root Moose

It's a Canadian Jeep. Sticker on the drivers side firewall has "Chrysler Canada" on it. Also, OP, the dash is metric right? Canada switched to metric in 1977 (78?) so all Canadian market XJs will have metric gauges.

Root Moose

Download the service manuals. They have sensor testing procedures in them.

tuggspeedman55

Yes it’s all metric and I use metric since I’m in canada, I just used imperial in my post because I know most people here are american

awg

get a vacuum gauge on it

old fashioned tech may very well show up certain issues, especially a vacuum leak

very cheap, google it