Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: Barneyboko on May 23, 2012, 02:00:59 PM

Title: lack of grunt
Post by: Barneyboko on May 23, 2012, 02:00:59 PM

Based on my experience with my 3.7 Cherokee, I do not think that my 4.0 Grand Cherokee is pulling quite as well. Any suggestions as to where I should look first ?

Barney

Title: Re: lack of grunt
Post by: IrishCJ6 on May 23, 2012, 02:13:41 PM

How long since its had a service? Check for the obvious airfilter,sparkplugs etc first, even a fuel filter, also you could spray some carb cleaner up the intake manifold into the butterfly valve, you would be amazed at how crudded up these can get and the difference it can make. Also check your oxy sensor in the exhaust, if this is old and tired it can give the computer false info and thus a reduction in power.

Title: Re: lack of grunt
Post by: Jeepjedi on May 23, 2012, 08:59:03 PM

 :iagree: what he said, start simple, try some redex to help clean the injectors too

Title: Re: lack of grunt
Post by: Barneyboko on June 16, 2012, 05:41:35 PM

OK, plugs, air filter, oil and oil filter all changed ............ performance no change !

At first glance I can,t see how to remove the black box part of the air in take that sits directly on top of the throttle body. I was looking for clips or similar, but nothing obvious. Any clues ?

also how do I get to the oxygen sensor, does this sit in the cat.

Barney

Title: Re: lack of grunt
Post by: Panic mechanic! on June 16, 2012, 06:32:42 PM

not sure how you remove the pan above the throttle body usually they are a big jubilee type clamp that you need to loosen to remove it, Oxygen  sensors, you will have possible 2, one in the exhaust manifold and you might have one in the cat but If I remember rightly they only have one.

Title: Re: lack of grunt
Post by: Mike Pavelin on June 17, 2012, 09:02:09 AM

Your 4.0 won't be as spritely as the 3.7. It's a heavy, lardy old thing with an old fashioned transmission. Don't waste your time.

Title: Re: lack of grunt
Post by: Barneyboko on June 17, 2012, 11:04:44 PM

Mine is the first of the WJ, with the Quadra Trac transmission (2000 W). I assumed that this was an advance on the older Cherokee.

My thoughts are that the car is heavier and it has over drive, which is there for mileage purposes but dumbs down the readily available acceleration, which is there, but you need to force it out. significantly my mileage figures are better in the big fella than they were in the in little fella. However I think I enjoyed the driving experience in the little fella better.

Barney