anyone on here know WJ engines?

[boardmanMJ]

i have the opportunity to buy a 2001 grand cherokee limited black exterior on black interior with a 2inch lift and 31s, no rust at all and 125,000 on the clock for next to nothing. the motor quit starting about 3 weeks ago and now its just sitting at a friends house. it cranks but no start. its also the 4.7 v8. now I'm only familiar with 4.0l and 5.2l, does anyone have any idea on what it could be?

 

 

Josh

[Unglar]

On my '99 Burban it was as simple as the coil wire being corroded.

[jimoshel]

Insufficient data. Perform the usual is it getting fuel, fire routine. Report back.

[boardmanMJ]

this sounds like a stupid question but how would i check to see if its getting fuel? the only way i could think of would be to have someone turn the key to on and check to see if the fuel pump kicks on. and i didnt pay attention when i went to look at it, but if my knowledge is correct it is distributorless. this new fangled 4.7l technology is beyond me.

 

 

Josh

[dasbulliwagen]

Cam and crank sensors could be the culprit, or if it isnt getting fuel are the most likely problems. Ive never done a fuel pump in one so I really don't think that would be your problem. Ive done several of the sensors though. The cam sensor is on the right side cylinder head toward the front bottom. The crank sensor is down on the side of the block, I'm thinking near the starter. If its a bad cam sensor unplug it then try to start it, and youll know its that sensor, but that won't help you with the crank sensor... we usually replace them together weather it needs both or not. There should be a schrader valve on the fuel rail, take the cap off and push the center in, if you get a little squirt of fuel, you likely have fuel pressure. Its a decent engine, but nowhere near the reliability of the 4.0. And they sound great with flowmasters on them! Good luck and keep us updated!

[kro10000]

Shoot some ether or gas down the TB, if it fires then it is a fuel issue, if it doesnt than it is a spark, or other computer related issue

[Eagle]

i have the opportunity to buy a 2001 grand cherokee limited black exterior on black interior with a 2inch lift and 31s, no rust at all and 125,000 on the clock for next to nothing. the motor quit starting about 3 weeks ago and now its just sitting at a friends house. it cranks but no start. its also the 4.7 v8. now I'm only familiar with 4.0l and 5.2l, does anyone have any idea on what it could be?

 

 

Josh

I briefly had a '99 WJ with the 4.7. When the engine died, the problem was a failed cam (NOT crank, I do know the difference) position sensor.

[boardmanMJ]

so i went to go look at it again yesterday and i had my girlfriend try to start it while i had my head under the hood and i herd a big psssshhhhhh coming from the right side of the engine bay. my first thought was a blown headgasget as it sounded like it was loosing compression but no matter how many times after we cranked it it never made the psssshhhhhh noise again. my shop is not very far from where the jeep is and i asked if i could leave a deposit and borrow the jeep to run a few tests on it and he said no. still at his asking price, i would still be comfortable buying it, in worst case scenario buying a junkyard motor for $1500, and have a really nice WJ with a lift and new tires for still under blue book value. any thoughts?

 

 

Josh

[pilotblake]

I have had a G.C. 4.7 for about 6-7 years now and it is a snappy little motor. I have the quieter magnaflow muffler and it sounds nice and throaty. My only issue started about 7,000 miles ago. When you first start it up it chatters for a minute or two unless you rev it up(which makes it go away faster) and then goes away.

[Automan2164]

so i went to go look at it again yesterday and i had my girlfriend try to start it while i had my head under the hood and i herd a big psssshhhhhh coming from the right side of the engine bay. my first thought was a blown headgasget as it sounded like it was loosing compression but no matter how many times after we cranked it it never made the psssshhhhhh noise again. my shop is not very far from where the jeep is and i asked if i could leave a deposit and borrow the jeep to run a few tests on it and he said no. still at his asking price, i would still be comfortable buying it, in worst case scenario buying a junkyard motor for $1500, and have a really nice WJ with a lift and new tires for still under blue book value. any thoughts?

 

 

Josh

 

Wouldn't be to hard to run a compression and cylinder leak down test before hand.

 

Have access to an osilliscope?

Rob L.

[Yesterday's Danish]

I have had a G.C. 4.7 for about 6-7 years now and it is a snappy little motor. I have the quieter magnaflow muffler and it sounds nice and throaty. My only issue started about 7,000 miles ago. When you first start it up it chatters for a minute or two unless you rev it up(which makes it go away faster) and then goes away.

 

Running a Fram oil filter?

[pilotblake]

No I have tried several different brands of filter with no change, even different weights of oil.

[sinkrun]

Maybe pay someone from the shop you use to go with to look at it maybe take a scan tool?

[jpdocdave]

definitely check compression before you buy. those engines have tiny oil passages, and there's a screen in front of the timing chain passages. they have a lot of them getting clogged up, starving the timing chain, or other areas for oil, and causing cam damage, or the timing chain breaks apart.

 

replacing the motor on that is not fun, and the motors are not cheap. they are really nice jeeps though. just keep in mind they have an internal oiling problem, but that is easily avoided by on time oil changes. but for those that consistantly go 5k and more, they are prone to failure.