wrmiles

2002 Coupe, MN6, 161,000 miles, Completely Stock

Has what sure sounds like intermittent light pinging when under load such as going up a hill.

Several peculiar things:

Only happens right around 1500 RPM

Giving it more throttle does not initiate pinging or make it worse.

Seems to happen more/worse at lower altitudes (I live at 5400').

Any ideas or anyone know what is so special about 1500 RPM. I have considered that it may be something else, but it sure sounds like pinging.

FASTFATBOY

Clean the MAF

ZZ06

While I agree with FASTFATBOY, there are some other things that need be mentioned. Have you done a tune up recently on the car? ie. filter, changes, plugs, and wires....Id like to believe some type of maintenance was done seeing the amount of miles ad still running, but has it been done recently?

neutron82

don't lug the engine uphill at 1500rpm for starters... I'm willing to bet the car is not driven hard and rarely (if ever) sees the upper rpm band, you could have excessive carbon buildup on the pistons... if that is the case a good top end cleaning and some spirited driving can clear that up... also use the highest octane gas available in your area if you aren't already doing that

evolmotorsprt

My brother's C5 had that problem and we determined it was carbon buildup. We live at 4800ft, and the cars seem to run pretty rich up here. I've found BG44k works awesome to clean out the carbon. We ran a can through his car and drove the **** out of it. The whole back bumper was black with soot. It solved his pinging problem.

Run a can or two through yours and see if it cures your problem.

JESSTERLSX

My 02 C5Z is having this same issue. I have longtube headers and just assumed that it was noise from the thinner walls of the headers. For starters what is BG44k? I would like to use some to help clean mine out as well. I just bought the car recently and even though it doesn't have high miles I believe it may be carbon build up from not being aired out. I've given it a couple pulls but nothing serious yet. Did you just pour it into the gas tank? Would it be comparable to sea foam? Thanks for the info!

leadfoot4

It's a chemical fuel additive, similar to SeaFoam. You add it to the fuel tank, then give the car an "Italian Tune-Up"..............(get out on the highway and "lean on it" real good, a few times)

neutron82

personally I prefer to do a top end cleaning where you introduce the cleaner through the intake... in my experience that works much better than any additive you can put in your tank and it also works faster, the results are nearly instant

JESSTERLSX

I was just about to mention this. In my fbodies I used one of the vacuum lines, i think it was the PCV line. I don't remember. Was years ago. But I put it in through that with a friend in the car to keep it from dying.

leadfoot4

Yeah, that's the difficult part of doing that with a C-5, because there's no mechanical throttle linkage to modulate the engine speed with.

ZZ06

With a friend in the car, like he mentioned, its all the same. Ive always gone through the brake boost line(which I'm sure that is what he is referring to) with a buddy or my wife to keep it running. I actually just did this for the first time with my stroker and good gosh all mighty did a smoke out my street!!!!

cv67

have a 5.3 in a truck started doing that with similar mileage...had been driving it too easy too long as its getting old so lots of carbon

Italian tuneup did the trick, the cleaners didnt do anything. MAF clean a good suggestion!

romandian

you get ridd of carbon buitld up you spray watter into the engine at wot.

leadfoot4

You going to hold your engine at WOT, while you, or someone else, sprays water into it??







............and yes, I'm familiar with the "water spray technique". but not at WOT!

neutron82

what I like to do is use a really long vacuum hose and route it near the drivers area and put that in the can of seafoam or whatever cleaner you might be using, that way I can control how much cleaner is ingested and modulate the throttle at the same time by myself... if you use the brake booster hose only the back cylinders are going to get the cleaner, I like to use the vacuum port on the side of the intake as well... maybe run half a can through the side of the intake so the front cylinders get some cleaner and then use the other half through the brake booster hose to get the rear cylinders

that's what water/meth kits are for... but your average owner doesn't have one of those already installed... e85 also works great as a cleaner from what I've seen, but again not a ton of people running that either

JESSTERLSX

Hey gang. Car was almost empty today. I put an entire 16oz can of sea foam in the tank and filled it up with 93. Not a lot of smoke or anything. But I aired it out real good with a couple of third gear pulls. Car runs smother and seems to be much more quiet on the engine noise. I put it all in the tank because my gas level sensor is messing up as well so I wanted to see if this would help clear that up. So far so good. It's at about 3/4 of a tank now and it's still working so it looks like I killed two birds with one stone. On the next oil change I might run a can through the intake system via the via the vacuum hoses.

romandian

take your windshield washer hose, put a jet on it and put it in a place the engine will ingest. i prefer distilled water.

Roddy13

what in the fk??? Windshield washer fluid hey? facepalm.

Sounds like a how to for Cavitation.