I've a 1997 Cherokee Diesel (2.5 VM), It pulls and drives very well up to about 2000 - 2500RPM then runs out of steam immediately.

It has had a service recently with both fuel and air filters and has also had a replacement Mass Air Flow sensor in an attempt to solve the problem. This has made no difference.

I've driven it in 3rd gear hard and managed to get the performance to improve and it would then rev ok to 3500rpm and beyond etc, but once left for a few days seems to slump back to the original problem.

Has anyone seen this problem before? Any ideas what can be the problem?

Thanks.

 

sounds like a erg valve problem but i might be wrong

 

when did it start doing it... before a service ? after a service? gradually got worse ?

Double check all fuel lines for cracks.. sounds like it might be getting some air in... check conections on filters...

but def sounds like it might be suckin air in the fuel supply...

 

As far as I know it has been doing it for a while. Unfortunately it was my brother-in-law who bought it, not knowing that it had this problem. He had it serviced to see if that made it any better, but made no difference, the garage then thought about the MAF sensor, so changed that, and still no better.

I will have a look at the fuel lines this weekend for him, although as i said before the jeep perfoms perfectly and pulls very well, it is only when it reaches 2000-2500rpm that the problem occurs. I was thinking maybe an exhaust restriction to start with, but that would surely show up as a problem at low revs too.

 

Just keep in mind that diesels are usually Governed ~3500rpm. So, around 2500 youre getting out of the power range.

Im not sure if these diesels have one, but try bleeding the fuel rail with the bleed port pointing uphill to get any air out. I would also check the lift pump and injection pump (once again, if these diesels have one).
Are these turbo diesels? If so, do you have a boost gauge? What is the boost like at ~2500rpm, when you say it "drops off"? Maybe its a wastegate/boost problem (if they have one)..
I know this is more questions then answers, but we dont know a whole lot about the diesels in the US. They didnt sell very many here.

 

Bingo...it also may be a governor issue....Sounds like when you drove it in third, somehow the governor was overridden...I would check the original specs in the owner's manual to see where it is actually governed. Like Defiance said, diesels are typically governed about 3500 rpm and so it shouldn't have revved above 3500 rpm.

 

did you put bigger tires on it?

 

most probably the pilot injector has died, bad news as it costs 400 euro... check its internal resistance, should be 110 ohm, if ok then check airflow sensor good luck

 

BTW if the pilot injector is MUCHHH cheaper in the US, let me know, I need one! Cheers

 

Hi
If it Is not yet fixed diesel bob can fix it as he did mine with the same problem that I ran for years with (just blaming the VM engine after reading so many bad reports)it only required a modified gasket, Now no smoke and all the smooth power you never thought the engine had, the transformation is almost unbelievable especially as I tow a 1500kgs caravan

 

Small diesels have a power peak around 4000 rpm so it should not run out of power so soon. My VW diesel red-lined at 4700 rpm. Does it use a variable geometry turbo? The vanes can get carboned up if you don't rev it out much and they won't move enough to produce boost at high engine rpm. I tried to floor my VW on a regular basis to clear out the carbon. After long highway trips it would smoke like a semi the first time I would rev it out. I miss that part.

 

uhh... this thread is like 7 months old and the guy hasnt been on in about that long, no point in really bringing it back from the dead.
If you guys have a question about your jeep, post a new thread.