Okay, so I noticed today that at excelleration onto the highway, I am getting a pinging sound as if the timing advance may not be working. What should I be checking first. This is the only problem, doesn't misfire or run rough and no problems starting. My plan is to check my plugs, cap and rotor. The plugs, wires, cap and rotor have only about 5k on them. I recently looked at he air cleaner and that is still looking like new.

Thanks for the help.

 

check for codes first

 

I have no check engine light but, I will check for codes tomorrow. I do have a scan tool.

 

Pinging can indicate a carbon problem on the top end.

What I usually try for this is a quick and dirty 1 time experiment. Next time you fill up with gas, instead of using 87, fill with premium 92. Or 89 if 92 isn't available.

If using a higher octane fixes the pinging, you have a top end carbon problem.

 

What grade fuel are you running? Did you check the knock sensor?

 

Also buy a can of seafoam and run it through the tank. This does wonders. An induction cleaning would be the best.

 

I run the regular 87 octane. Where is the knock sensor and how do I check it? As my sig says, I have a 98 sport.

Thanks again for all the AWESOME help. This site is GREAT

 

No knock sensor on a 98.

If you run 87, as I mentioned, try some 92. That one simple experiment can tell you so much.

 

Well I checked the engine codes with my scan tool and I have not codes at all. I will get a can of seafoam and put it in the tank. Any other ideas to clean out the top end carbon problem?

 

a pinging sound would indicate predetonation, not carbon deposits in your top end, sounds like your timing or timing advance are a little off to me.

and don't just dump a full can of seafoam in your gas tank, 1/3 of it should get sucked into your intake(use the vacuum hose going from the brake booster to your intake manifold) 1/3 should go in your oil(change it within 500 miles of this) and the last third should go in your gas tank, just putting the whole can in your tank will pretty much only clean your fuel system. read the directions on the can people.

 

I might be wrong, but I thought that carbon deposits can raise compression by decreasing the chamber volume. In addition, carbon deposits can create hot spots contributing to detonation.

 

that would have to be more carbon than I've ever seen in a motor to noticeably decrease cyl size. carbon deposits can create heat as well, and a hot engine will also be much more likely to have predetonation. sucking seafoam into your intake and letting it sit for 10-15min like the can says should remove almost all carbon deposits though. after doing rebuilds on motors that have been seafoamed and not, there's an amazing difference

 

I will give the seafoam a try.
Thanks again for all the help.

 

always glad to help another jeeper

 

Carbon can absolutely create pinging.

And seafoaming is de-carbonizing the top end..........