Firebird

Bought a '97 cherokee xj recently. Every thing in good order
BUT No power when driving. Manual Transmission 2.5 diesel turbo.
In first gear will rev to 3or4 1000 and speedo will go to 20 mph
same in 2nd and 3rd with a slight increase in speed. 4th will slowly bring it to
60mph.
Looses power on hills and speed and revs will drop.

Have removed and cleaned MAP. Checked exhaust for blockage
have done FULL SERVICE Filters etc.
Brought it to a main dealer for diagnostic. they found no fault codes
but said the "filter for Turbo was damaged and needed replacing. I have
purchased one and am awaiting delivery but in meantime swapped minewith one from other Jeep -- NO DIFFERENCE-- also bypassed same filter ---NO DIFFERENCE --.
EGR Valve seems to be in working order.
Have checked every thing I can think of.Jeep acts like it has a LIMITER
attached.
I am loosing all hope of finding fault -- what can I find if the main dealer
isn't able to.
I am hopeful that some of you down to earth/hands on CHEROKEE
enthusiasts will be able to help

CodeXJ

Do you know if the turbo is building boost? No boost leaks?

Firebird

No boost leaks in Turbo.Everything seems to be working but I am not sure of
technical specifications. I thought it was a sensor originally but now???.
The Turbo doesn't seem to be pulling in but the erg valve seems to be working -- as I've said everything seems to be working but I cant figure out whats holding it back. Its like something is working but not up to its tech.spec.By the way thanks for the quick response

Willys55

The three major factors on power loss.

Restriction in the air charger/cooler

stuck waste gate

lack of oil to turbo causing bearing failure

OrangeXJ

I don't know much about your engine but turbo charged engines I deal with have a waste gate this makes sure you don't over boost the engine. It is set at a certain pressure where it will open and bypass boost back into the exhaust instead if the intake. Maybe your engine has something similar to this and it's not working properly.

Firebird

Thanks for input.
Willys55 --There doesnt seem to be any air restrictions
I will check for the stuck waste gate and the oil issue and post results

ORANGE XJ I will check the waste gate --Is there any way to check the set
pressures on this to see if its working within parameters

Question: has any one ever heard of " a swirl valve actuator " if so what is it and where would it be situated

OrangeXJ

I don't know how to check the set point. You should invest in a repair manual like Haynes or Chilton. If there is a way to test it those manuals should say how.

superj

did you blow the headgasket out? is it pressurizing the radiator? does it overheat?

00jeepXJ

Firebird... it's mostly likely a dead turbo. To check this all you need to do is really listen. If you can't really hear the turbo spool then you need to see if you can reach into the compressor side of the turbo NOT RUNNING!, and see if you can move the shaft. It should move only a little, to not really at all. Maybe 2mm to 3mm but don't quote me on that spec. If you can move it around a lot you have a failing main shaft bearing... If you can't even move it at all or it is really stiff then you have a failed turbo.
If your turbo is not the cause then take a look at your exhaust manifold and look for cracks in it or loose bolts. The other end of the spectrem you might just have a blown intake boot on the boost side or on the intake side and that would cause you to loose power. Hope this helps.

Firebird

Really off the wall with this one. Have been in numerous garages and a main dealership. Have checked everything from filters to turbo--no fault codes showing---have checked everything suggested by you all.
Last checked was the Turbo and gate valve --OK. Fuel pump checked and nothing visibly wrong .

Firebird

Just a few questions

Would a faulty crank position sensor cause issue without showing fault

should there be a vacuum sphere on this year and model of cherokee
(seen something online about some models having one mounted behind front bumper?)

would the engine breather filter (I think its called this--- its a filter housing about the size of a beer can mounted at the back of the engine bay connected to the air system) would this being dirty or blocked cause my problem and if so do I replace whole thing or is there a filter inside??

Materials cost a fortune over here and I have spent about 2000euro trying to get this Jeep in shape. I dont want to spend more unnecessary cash without having a more concrete lead on the problem. I am convinced it something only a jeep enthusiast will solve as I have a good menchanic who has given up on it and it is only the second car in his 20yr career he hasn't been able to identify the problem with.
Also if some one could give me a lead on getting engine diagrams
and/or pictures of the engine in question I would be grateful.

There also doesn't seem to be any Oxygen sensors that I CAN LOCATE?

CAEMI

The motor just is tired out. Have your shop compression test it.

Or...not enough fuel flow. Check the filter, pump, return line for blockage, etc., etc. All the boost in the world won't help if there is no juice.

O2 sensors will be in the exhaust flow path somewhere. Crawl underneath with a flashlight and follow the exhaust system from manifold to tailpipe.

See if the system is plugged. We used to stuff potatoes in tailpipes as a prank. Not sure if it really did anything because we never saw somebody try to start the car with the spud up the pipe but it was common wisdom when I was 12.

Codes are way overrated. So are some mechanics. Find another mechanic, another dealer.

OK...I'm out of bullets.

JimiT

I'm no mechanic, but are you sure that the MAF sensor is working correctly?

I have a tdi Seat Toledo and after getting a new clutch fitted the mechanic didn't reconnect the sensor. I thought he had killed my car, it wouldn't rev and had no power. Also this didn't bring up any warning lights.

Just a thought as it is an easy/cheap thing to fix.