Loss of power above 2000rpm and weird 'Growl' - JeepForum.com

 
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post #1 of 9 Old 04-05-2008, 10:03 AM Thread Starter
medusa1
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Loss of power above 2000rpm and weird 'Growl'

Hi all,

I have a 1996 Grand with the 4 litre straight six engine. A few weeks ago whilst at speed it lost power and would refuse to rev past about 2000, equating to about 30mph (max) - whilst doing this it would also 'kangaroo' and pop through the intake. I cleaned the sensor that is at the top of the throttle body (just behind the air intake) which was heavily carboned up and it appeared to have solved the problem until last night when it started to do it again. This time it righted itself and I was able to get home and yet this morning it has started to do the same thing once again. I absolutely love this car and so need to get it going again - anybody have any ideas?? I have searched the threads here already and a few offer suggestions (o2 sensors??) - but apart from the TPS I don't really get the other acronyms. When it is playing up it will still tick over reliably, but there is a load roar from the air intake (like a valve is shut but should be open??) please help???

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post #2 of 9 Old 04-05-2008, 12:18 PM
WiLieR
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How many km on the jeep? It could be several things but a few pop into my head first: 1) fuel pump issue 2) clogged catalytic converter 3) really bad timing issue

99 WJ Laredo - Mine once again!
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post #3 of 9 Old 04-05-2008, 01:01 PM Thread Starter
medusa1
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it has done 109000 miles. The fault started all on its own - wouldn't that rule out timing issues??? Fuel and cat ideas are interesting......I run it on LPG usually - it can be a bit 'smelly' on petrol - specially in the morning....
cheers for your help.
Incidentally - I have changed dizzy cap, rotor, leads, coil, new battery.....
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post #4 of 9 Old 10-02-2009, 09:18 AM
Pimmy
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Same problem on 2.5TD engine

Hi,

I have the same problem on my GrandCherokee 2.5TD. Above 2000 rpms it looses power. The fuel consumption goes down as well - like I've released the accelerator pedal.

My problem started suddenly after I havent driven the Jeep for a couple of months. Before this happened I have changed the fuel filter only, but this problem appeared a while after that.

Have you managed to resolve yours problem?

thanks,

pimmy
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post #5 of 9 Old 10-02-2009, 10:54 AM
Ronzo54
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clogged or broken (inside) catalytic converter is something to really look at, it will cause power loss and very bad MPG, and it usually happens suddenly
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post #6 of 9 Old 10-02-2009, 11:38 AM
ratmonkey
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Quote:
Originally Posted by medusa1 View Post
it has done 109000 miles. The fault started all on its own - wouldn't that rule out timing issues??? Fuel and cat ideas are interesting......I run it on LPG usually - it can be a bit 'smelly' on petrol - specially in the morning....
cheers for your help.
Incidentally - I have changed dizzy cap, rotor, leads, coil, new battery.....
clogged cat. have someone rev the engine while you feel the exhaust pressure and see what it feels and smells like.

'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.

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post #7 of 9 Old 10-02-2009, 07:36 PM
vansskaterfreek
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ive seen faulty crank sensors cause these issues too

1998 ZJ 5.9L 122k miles - DD, 242 swap, 3.5" RE, 32" BFG M/T, safari rack, roof-mounted lights, custom steel front bumper with hitch reciever, 10k winch :)
2004 WJ 4.7L 107k miles - her daily driver, 2" daystar BB with scorpion shocks.. not too bad! stuffed 265/65/17 General Grabber AT2'S
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post #8 of 9 Old 10-05-2009, 02:54 AM
Pimmy
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The MPG in fact is really good. Nothing has changes in terms of fuel consumption since this problem started appearing.

During acceleration (engine under load) up to 2000 rpms the engine has good power and I see the MPG jumping up. After 2000 rpms the feeling is like I've released the pedal, the fuel consumption starts going down and the Jeep stops accelerating. I can reach higher rpms/speed but it is times slower than before - cant overtake anything basically. Also on the motorway I can eventually reach higher speeds but when an incline comes speed drops until the engine goes down to 2000 rmps and it stays there.

If I rev the engine without any load it reaches 2000 rpm very quickly, but after that it slows down. And again I can reach 4000 rpms - no problem, but after a while.

What should I be looking at from the exhaust when revving the engine? I havent noticed any difference in the colour, or smell of the fumes.

Thanks.
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post #9 of 9 Old 10-05-2009, 07:10 AM
ratmonkey
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could be tps or any of the other intake/fuel sensor systems...gonna need to get it scanned.

'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.

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