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[wildrover]

My Cherokee is running a bit rough today , and is definatly down on power...Its a 1997 2.5 xj with the vm engine...During a drive today it lacked power , didn,t pull as well as normal , and if it had been a petrol engine i would say it was pinking under load...

When i got home i lifted the bonnet and it seems as though the engine is only running on three and now and then the fourth pot is lighting up....Its like there is a detonation now and then that makes the engine jump , happens every few seconds...   Any ideas folks...?

[tim_aka_tim]

Injection pump? Dirty injector?

Add 100ml of pure acetone to a full tank of fuel to clean the system.

[wildrover]

Just now when i tried it , i was getting a loud rattle now and then that sounded like there were a few loose pushrods flapping about , does this still sound like an injection pump not doing as it should...?

I am out in the middle of nowhere here , so i am relying on the experts here to give me some clues...

I will give the acetone a go though , can.t do any harm to elimenate that possiblility i guess...

[tim_aka_tim]

Yep, a bad pump or injector will clatter like a bastard.

[wildrover]

Thanks mate...I now have some idea which bit to poke with a pointed stick...

[daggie]

also, have a looksee under the rocker cover, could be a push rod jumped out

[wildrover]

I heard of that mentioned before on this forum in relation to Jeep diesal engines , whats the procedure if one of the little tinkers has jumped out of place....?

[Mike Pavelin]

Put it back.

[wildrover]

I had a feeling that might be a solution to the problem...

[Dave69]

undo alternator brace
take off rocker cover
look for displaced push rods
undo the relevant rocker (two nuts) doesn't have to be removed
tighten nuts back up
when all done put rocker cover back on.

repeat when it happens again.


this is down to a lazy hydraulic lifter, possibly caused by a sludge buildup.

there is not alot of a cup to hold the pushrods into place but a 5/16th nut tack welded to the rocker arm stops this happening again.

[wildrover]

Thanks mate...  i shall be having a poke at it tomorow...The old burner is overdue for an oil change , so it might be the sludge causing this problem , i might be as well to give it a flush through as well...

I have heard the vm diesal likes its oil changed pretty often to keep things running ok...

[daggie]

with the tempratures being, so low over there I'd be tempted to put tinner oil in it...........

[Dave69]

it's not a case of the engine likes it's oil to be changed frequently it's a case of preventative maintenance.

[The Smiths]

sounds like push rod

oil change every 6 months or 6K miles

[wildrover]

One day i am going to have myself a heated workshop on this farm...Anyways , despite the cold i went out and removed the rocker cover from my Jeep , and discovered that sure enough one of the pushrods had dropped out of place , and the two nuts holding the rocker arms in place were loose....One of the two pushrods was simple enough to put in place , but the other one did not seem to want to find anything solid to sit on , and kept dropping down untill it rested on what felt like rubber...  Has something broken at the other end , or is it just a matter of persisting till i get it in the right place...?   The project has been abandoned for today , as its getting dark , and i can,t feel my fingers any more....

[Dave69]

pull the pushrod out and compare it to the same one next to it as they should be the same length. depending on where the cam is in relation to the lifter could cause a problem in refitting as the correct position might seem to be a bit tight to fit. the hydraulic lifter has a metal seat for the rod so you might be dropping into a pocket of oil (?). when you pull the rod out is it oily or "dry"

[wildrover]

Both the pushrods are the same length , and both have oil on them after dipping them into position....On the one i am having problems with it is possible to get it to sit on what feels like the correct place , but then it is at an angle , and won,t meet up with the rocker arm , something is stopping it from being moved into the upright position to line up with the rocker arm...Is it possible the bit that the pushrod sits in has moved out of position...?  Would turning the engine over a few times do any good..?

I am sure there is a simple answer to this , but sadly i am too simple to figure it out..!   I am really stuck without any transport out here in the wilds , so will be more than happy to get it rolling again...

I really hope that it does not require further dismantling to get to the cam followers , but if thats what i have to do i will have to bite the bullet...   If the worst comes to the worst , and i can,t fix it , would it do any harm to remove the two pushrods and rocker from that cylinder and drive it on three pots to my mechanic friend ten miles away in town...?

[Dave69]

it might be a case of the hyraulic lifter has moved slightly but these are held in place by a stirrup (sp) bracket clamped in place by the cylinder head so would seem unlikely. the other option might be a worn cam follower wheel which has allowed the lifter to drop and move. This probably isn't an answer just ideas so dont panick.

you could try turning the engine over but have both rods removed from that cylinder. you don't need to start the engine but just enought to allow the cam to rotate and push up on the follower, then refit the rods to see if there is any difference