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153 Posts
Discussion Starter · #1 ·
It's me again :p - this time a little write up about manifolds


Long, long time ago … in a galaxy far, far away :D … hmmmm … maybe not so far, but on the other end of the world, looking from US - some day I've bought an intake manifold from Grand Cherokee WJ - also assembled during the last 2 years by XJ Cherokee. The idea was to assemble it on my 1991 XJ - it was "lying" and waiting for its time, which finally came last Sunday. Also my exhaust manifold was already very loud and I've decided to replace it with other one /not new but in far, far better condition as mine/
This is what I was planning to install

My leaking injectors should be replaced by this opportunity /for those bought on eBay/

So let's start - for the beginning general view before disassembling

After removing hoses, tubes and air filter with its housing it looks similar to this

Disconnect all of electric /2 or 3 plugs on the throttle body and 1 on intake manifold/, detach cables from throttle body and remove it.

If you only want to replace a gasket under manifolds then there is no need to disassemble fuel rail - it's enough to disconnect 2 fuel lines …

… and disconnect injectors - for that the best way is to have a thin, hard needle for moving its clips aside

But if you want to remove the injectors /for replacing them or intake manifold/ then you have to remove the clips by the fuel rail - these are very simple to dismount - simply move them out and be careful not to lose any of it - these are very important holders of the injectors by the fuel rail

After disconnecting all above the fuel rail can be easily dismounted - 4 screws - but BE CAREFUL for fuel draining out after removing rail from injectors !!

Now is a good time to disassemble the power steering pump, that is attached on a side of the intake manifold and has to be taken off
First goes the serpentine belt - loosen bolts A1 to A4 and then turning /CCW/ of B gives belts a space for removing it from pulley

Now the 2 bolts on the back of the pump - in circle on the following picture …

… and 3 more on the front …

… must be unbolted and the pump with pulley and hoses can be put aside

Without disassembling the pump there is no way for taking out one of the bolts holding a bracket to manifold - all of the bolts for taking bracket out are on the following picture

Intake manifold can now be disassembled from head and taken off from the engine compartment - first of all unplug all of the tubes attached to manifold - remember to attach all of them back later! - then you have to unbolt 8 bolts /4 top and 4 bottom/ - these on top are very good accessible with the wrench like this

These 3 bolts /following picture/ are holding exhaust manifold and should not be unbolted at this moment

As you can see the intake manifold "goes" out without problems

Now I could see how is my exhaust manifold broken and why was my Jeep so loud

After unbolting these 3 bolts that I mentioned above and 2 bolts from flange of exhaust pipe, you can easily remove exhaust manifold from engine compartment


153 Posts
Discussion Starter · #2 ·

The old gasket leaves on the head some material that must be thoroughly cleaned - for dust and other remainders not getting into engine I used some rags put into head intake races

Cleaned …

… and after assembling exhaust manifold with new gasket

Small remark - the gasket looks at first sight symmetrical, but it is VERY important to put it on head with proper side - it should be "manifold side" written on top of the gasket - if is not then proper side for head is completely smooth - manifold side has some cambers around every opening.

If you made all of above only for changing manifold gasket, then you should simply put it all together in reverse order but … nothing goes "standard" by me and just now begins "fun"

Factory standard intake manifold for 4.0 engine is designed pretty bad - has to small capacity and unequal inlet channels - these disadvantages was eliminated in manifold assembled in last 2 years of production of XJ Cherokee and in WJ Grand Cherokee with 4.0 engine - I have bought such a manifold few months ago and it was just about time to put it in my car.

First matching - the place in circle is where the bracket for steering pump should be matched

Unfortunately the bracket from older type of manifold doesn't "want" to match on the newer type - I knew that these parts will not fit plug&play, but didn't realized that this will be so much "artistic metalwork" to adapt the bracket to manifold.

Here is the manifold - cut and grinded - the stud is mounted in a new threaded hole, where it will match the corresponding hole in bracket

Cut, grinded and bored bracket - new hole is there, where will it match to hole in manifold

Further matching - you can see two studs - one in "new" and the other in "old" hole in manifold - below is one more mounting - small metal plate with nut welded on it bolted from rear side /without association please :D/ to other /third/ hole in manifold

View from other perspectives …

… and everything assembled together, ready for "receive" the steering pump

Finally the steering pump, serpentine belt and … as you can see it looks "almost" as from the factory

Now only some nice and easy job with injectors, fuel rail, lpg hoses …

… tubes, throttle body /bored out for 60 mm/, air filter and …

Final effect is delightful :D - especially sound of my Flowmaster without extra sounds from beneath the hood.

153 Posts
Discussion Starter · #4 ·
Any real benefit to doing this? Power increase? Throttle response?
Throttle response was already much better after boring out a throttle body - now is even better - the engine works more smoothly - hope that fuel consumption goes down to "normal" 24-25 Liter lpg / 100km from 30 as it was last few months - but this is not "must" condition because I love my Jeep unconditionally :2thumbsup:
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