Premium gas needed?????

[gr8tires]

My daughter has a "00 XJ, 4.0, auto with 4x4. With 40,000 miles on it, the thing has developed a "pinging" when accelerating. Not off-roading, but around Charlotte.
Dealer says he checked plugs, timing, etc, and she should go to 89 or higher octane gas. What's up with that???? City fuel economy(she thinks) hasn't changed since she got it 2 years ago with 20,000 miles
Any comments are appreciated.

 

[rattler43]

My 88 4.0 has an anti-knock sensor on it to eliminate ping. Don't know if yours has one or not. It is located on the block behind the exhaust manifold, I think, and is supposed to advance/retard timing to eliminate ping. Might check to see if you have one, as I use the cheapest grade of gas and have had no problems with ping at all. HTH Don

 

[piperRonnie]

Did the dealer actually check the knock sensor?
He may have suggested the 89+ to help 'clean' the injectors etc.
Try regular again but from different stations.

later

 

[89xj]

there is no knock sensor on a 00, only on the renix 87-90. try some gm top end cleaner and higher octane fuel.

 

[gr8tires]

there is no knock sensor on a 00, only on the renix 87-90. try some gm top end cleaner and higher octane fuel.

She put in a tankfull of 93 octane. I'll check the pinging after that is run thru the engine(by Friday), then try some top end cleaning additive.
I still am surprised at the pinging.....
will a blocked cat. converter do this also???
Thanks for everyone's comments. :wow:

 

[pancake]

I always use 89 octane because it idles a little better for some reason. You only have 40k miles though, so I cannot imagine many problems. You could try some concentrated fuel injector cleaner if you want. btw, you cannot adjust timing on your XJ.

Also, how old are plugs, wires, etc?

btw, I have 140k on my '98 XJ.

 

[Eagle]

Injector cleaner won't remove carbon in the cylinders. I second the advice to use GM top engine cleaner. It's not an "additive," though. Unless they've changed it since when I last used it, it's a heavy duty cleaner that you pour into the throttle body with the engine running, until the engine chokes and dies. This floods the cylinders with cleaner. You let it sit there for awhile, then start it again and burn out the crud.

Do not do this procedure in a garage, or if you have open windows downwind of the theater of operations. It creates quite a smoke screen.

 

[gr8tires]

Premium gas??

Thanks for the suggestions. I'll look around for some of the GM Top End cleaning liquid, and try it this weekend.

 

[Wayne Sihler]

If you have the pinging problem after these suggestions have the dealer re-flash the ECU.This will return the ECU to the base line specs.
Wayne

 

[89xj]

Thanks for the suggestions. I'll look around for some of the GM Top End cleaning liquid, and try it this weekend.

go to a gm dealer for it, wont find it at pep boys, advanced auto,etc....

 

[Moto]

That Top end cleaner works pretty good, It is or at least was available at other places, I was able to get some from a friend that worked at Sooner lube, I can't remember off the top of my head where they were buying it from but It worked exactly the same way the GM stuff did, and IIRC was made by the company that makes it for GM. If you are pinging alot, you may want to check out where you are purchasing your fuel from, you may be getting bad Gas, try going to a different brand name gas station and see if that helps, I know that someplaces may put additives in thier fuel during the colder months of the year that could cause an issue.

 

[gr8tires]

:clap: :yelclap:
I installed some of the GM top end cleaner, as directd. Lots of white smoke, and a little more smoke for a mile or so after starting the engine. Two days later, and no pinging!!!
Thnanks everyone for the help.....

That Top end cleaner works pretty good, It is or at least was available at other places, I was able to get some from a friend that worked at Sooner lube, I can't remember off the top of my head where they were buying it from but It worked exactly the same way the GM stuff did, and IIRC was made by the company that makes it for GM. If you are pinging alot, you may want to check out where you are purchasing your fuel from, you may be getting bad Gas, try going to a different brand name gas station and see if that helps, I know that someplaces may put additives in thier fuel during the colder months of the year that could cause an issue.

 

[8700XJS]

Dealer says...she should go to 89 or higher octane gas. What's up with that????

Funny that the owners manual for the 2000 XJ says not to put anything having an Octane rating higher than 87. It goes on to say that it could cause spark knock at higher speeds and this can cause damage to the engine. Also that if this is the case it may not be covered by the new vehicle warranty.

I run 87octane in my '87 and in my '00. I just put Techron in everyonce in a while. I would be interested to hear what others use.

8700XJS

 

[ryurabbit]

Chrysler has top end cleaner as well!

The part number for it is 4318001AB. Its called combustion chamber cleaner. Works great I do it bout every 3000 miles.

Rabbit

 

[Atl XJ]

Injector cleaner won't remove carbon in the cylinders. I second the advice to use GM top engine cleaner. It's not an "additive," though. Unless they've changed it since when I last used it, it's a heavy duty cleaner that you pour into the throttle body with the engine running, until the engine chokes and dies. This floods the cylinders with cleaner. You let it sit there for awhile, then start it again and burn out the crud.

Do not do this procedure in a garage, or if you have open windows downwind of the theater of operations. It creates quite a smoke screen.

I have a lot of city miles (bad traffic miles) on my XJ and its doing the same thing. Is there anything else I need to know about this proceedure? I have heard you need to change your oil afterwards, is this true? I have 85K on my 4.0. :spin3:

 

[ryurabbit]

No oil change required

If it makes you feel better do the service right before you change the oil. This is really only effective once every 3000 miles anyway. Otherwise your just wasting time and $$$$.

Rabbit