[Nurburgringer]

This weekend I plan on installing the Hughs Engines upgraded plenum plate, intake gaskets and new bolts to hopfully cure the pinging under heavy throttle on my 140,000 mile 5.9.
I just bought it last weekend and haven't bought service manuals yet, so was hoping somebody here could share and tips and tricks learned when doing this.
I'm pretty handy with a wrench, but there are quite a few A/C hoses, throttle cables, etc running pretty much over the intake so taking it off looks to be just a bit tricky.
Couldn't find much about this by searching the archives for "5.9 plenum", and couldn't find the TSB that apparently specifies the optimum torque order for the bolts.

Do I need any special tools that I'll only discover the need for after I've got half the motor strewn about the garage? Is it possible to remove the intake plenum without removing any A/C lines (hope so...)

thanks in advance!

Kurt
Philly
'98 5.9 ZJ

[10achik]

Check the FAQ's at the top of the page, I think there is a write-up on doing this on a 5.2 that might help you out.

Yep, it's post #2 in the FAQ's

[Nurburgringer]

thanks Ken - that didn't come up with the search but I should have looked there. Lots of great info there... now to print of all the hints and then off to Pep Boys at lunch to get a 190F thermostat...

cheers
Kurt

[HighLonesome]

Originally Posted by Nurburgringer

Do I need any special tools that I'll only discover the need for after I've got half the motor strewn about the garage? Is it possible to remove the intake plenum without removing any A/C lines (hope so...)

Yes, move the compressor over to the passenger's side of the engine.

You will need a special tool for the fuel lines. Or you will need to remove the fuel rail and injectors.

[Nurburgringer]

thanks 5 9 - just dropped over $200 at Pep Boys for new coolant hoses, water pump, thermo, sensors (and a nice little air compressor to carry around in the 5.9 .

Of course Sears doesn't sell just a 22mm stubby the FAQ says is needed to remove the EGR valve, so splurged on a really nice Craftsman short adjustable wrench that should do the job. Also a in-lb torque wrench for $69 - might see if Pep Boys rents these casue I'll probably use this once or twice... but I can imagine rental torque wrenches probably aren't calibrated that well...

Stopped in the Jeep dealer to get the throttle body gasket. Just for S&G asked the parts guy how much they got for a NP242 transfer case. He immediately said "You can't put that in your GC.". Offered to email him photos of lots of people with 5.9s who have, but he wouldn't admit that it would work, but said it'd cost around $1500. Silly little man

[Nurburgringer]

thanks for the tips!

Originally Posted by ratmonkey

you don't have an egr system in the 98...it's all computer controlled by the o2 sensors.

are you sure? Both write-ups mention the EGR tube going into the back of the plenum, like this in the FAQ:

"About wrenching on the EGR tube: This was the hardest part by far. A standard length wrench will not fit because of the firewall. I needed to run to the store and buy a stubby 22mm wrench (about 6 inches long) just to be able to get a wrench on the nut. The nut is VERY stubborn and less than 6 inches of leverage crammed into a tight space makes things very difficult."

Earlier this morning I actually looked up "EGR" because I couldn't remember what it stood for:

http://en.wikipedia.org/wiki/Exhaust_gas_recirculation

pretty sure all cars made in the last 2 or 3 decades have an EGR system

Kurt

[ratmonkey]

96+ jeeps do not have an egr. emissions are controlled by the computer on OBDII vehicles.

[Nurburgringer]

Originally Posted by ratmonkey

96+ jeeps do not have an egr. emissions are controlled by the computer on OBDII vehicles.

alrighty then! one less thing to bust my knuckles on!

cheers
Kurt

[HighLonesome]

Originally Posted by Nurburgringer

alrighty then! one less thing to bust my knuckles on!

cheers
Kurt

It's a bear too. Dealer only gasket required where the tube meets the exhaust manifold. Feel lucky.

[Colorado 5.9]

I would recomend a new set of intake manifold bolts from the dealer. The old ones will be stretched & won't torqe to the right specs. You do NOT want to pop any threads on the intake. It can be done way to easy if your not carefull.

Get a good inch lbs torqe wrench & follow the torqe specs to the letter. Oh, I nent number. That includes the thumostat housing bolts.

Don't forget a new thurmostat if no one said it yet.

Also don't forget that little hose & new O-ring off the right side of the water punp along with the larger hose off the top of the w-pump to the intake manifold. Since they are right there & easy to get to replace them.

Keep track of which bolts go where. Use little bagies & lable them. Good luck!!!!

[Texas ZJ1]

I'm going to tackle this when I get home.


Hunter

[Nurburgringer]

thanks CO 5.9 - I did buy a craftsman in-lb tq wrench, and new bolts are on the way with the gasket and al. plenum plate from Hughs Engines.

I see the new water pump has a large gasket for the housing and a small rubber o-ring, this must be what you're referring to.

TXZJ - good luck, let us know how it goes!

Kurt

[Nurburgringer]

Texas - I don't know how yours went, but mine was a success (but took a bit longer than I thought).
Wrote some tips and linked some pics here:
http://www.jeepforum.com/forum/f13/gc-5-9-air-sucking-problem-493177/index2.html

thanks everyone for the advice! The 5.9 breathes fire again

cheers
Kurt

[Texas ZJ1]

Kurt,

I'm in Iraq, it'll be a long time before I get to it.

Hunter

[SoWfPaW]

Quick question I noticed on the stock manifold it says do not torque over 12 ft lbs. All ive heard is measurments in inch lbs Are they referring to the intake bolts?