Interesting ping phenomenon.

I've been doing some research and some people who have problems with ping have it when they are lugging their engine and accelerating hard. I got a chance to drive a V6 Mustang a while back and it had pretty bad ping too. It even pinged at full throttle. But mine's weird. Everything's pretty quiet until I climb a hill and I'm running in 3rd. So, I'm not lugging the engine. Pretty soon, the engine will start to ping. What I noticed is that the pinging goes away when I go hard on the throttle. The pinging is virtually GONE when I floor it. I start to back off and it comes back. Running premium fuel does help, but I noticed I've also been getting ping with premium. Hasn't done that before. Guess I got a bad tank of gas or they accidently filled a Premium tank with Regular. So, why would the ping go away with more throttle? That may help the problem, but also give me another problem. Speeding ticket.

I do have a theory, however. I'm running Bosch Platinum sparkplugs. I think I do notice that my engine didn't have ping until I put those plugs in. A set of NGK sparkplugs that are $6.99 each and are MADE for the Van are on their way. I ordered them the other night along with a K&N filter. My guess is that the Bosch spark plugs are running too hot and are being cooled when I increase the throttle enough to introduce more air into the cylinders to cool them off. I could have a problem in the EGR system too. I know the EGR valve is fine because I checked it when I was replacing the headgasket. Could be the "OH SHIT, I BROKE IT VALVE" which would be the BVSV. I haven't tested that, but I should.

I took video a long time ago to give you a basic idea what I'm talking about.

http://kc.cognitivelube.com/VanShit/Ping.avi

The knock isn't going away as you acclerate, its just reaching a frequency that you can no longer hear. Its probably upseting any near by dogs though.

So don't acclerate harder in the thought your making it go away.
I tried that once, on a new motor to. Thought I was getting around the problem, then a ring land crack and I had to tear the motor down to replace one, brand new piston.

Find whats causing the knock, then fix it.

Generaly engine knock is caused by bad timing, bad fuel, or a combination of the two.

When my engine was rebuilt, the cylinder head had to be shaved. In fact, it had to be shaved so much that new push rods had to be custom made so the valves would close. A compression test is showing around 195 PSI. I think that might contribute.

Speaking of timing, here's something I noticed. I have vacuum advanced. There are two vacuum lines going to it on the distributor. I'm guessing the other line is "vacuum retard." I sucked on both lines and noticed one line holds vacuum, from my mouth of course. Then the other line seems to not hold a vacuum. Is this normal or could I have a bad vacuum advance/retard diaphragm? I doubt that timing is an issue though. I've retarded my timing enough to cause hesitation and it still pinged. Right now, I have it adjusted just where I want it so throttle response and mileage is at its best.

You may have a bit too much midrange vac advance. Your wot timing is ok.

When my engine was rebuilt, the cylinder head had to be shaved.


Then get a new head.
I had a similar problem, the idiot who rebuilt it shaved to much off.
I ended up getting a second head, built by a proffesional head builder, which help solve some of the problems.

But if your running to much compresion, i.e. more than the enigne was ever designed to handle, then you are going to have problems with knock, no matter how much you play around with the ignition and fuel mixtures, or change spark plugs.

I remember I was able to use 87 Octane with no problems with the Denso plugs I had in it. Like I said, the NGK plugs are on their way. We'll see if that helps. But I do like the extra power that the higher compression gives me. So I won't go through the hassle of getting a new head.

When my engine was rebuilt, the cylinder head had to be shaved. In fact, it had to be shaved so much that new push rods had to be custom made so the valves would close. A compression test is showing around 195 PSI. I think that might contribute.


uh yah, that'll definitely cause pinging.

Run high octane gas, or get the computer reflashed (buy a programmer that is capable of it, run you roughly $300 or so) or replace the heads.

Just a FYI, although this obviously isn't your problem, I see newer cars ping all the time, and its usually something dumb causing the car to run slightly lean and/or causing the car to miscalculate the engine load. Such as a hose left off on the intake snorkel or a dirty/bad MAF sensor.

Ah well. Just kinda curious. Not too worried about it. I'd probably wouldn't notice the ping if my engine was outside. But since I sit on the engine, I can hear every little sound it makes. So there's probably not going to be any long term effects. Anyway. The sparkplugs that I ordered that the Van is designed to run with will be here Friday. I'll put them in this weekend and go up that mountain I was climbing in the video and see what happens. To make things more interesting, I'll top it off with 87 Octane and find another hill to climb. If the ping's still there, I'll start checking my vacuum advanced system and the vacuum lines and other controls going to the EGR. I also have a timing light. If I can find the damn timing marks, I'll check that too.

When you pulled your plugs out did you see any spots of aluminum or anything on them. If you do check your timing, make sure you are checking base timing. You might have to disconnect a sensor or do the paper clip trick to stop your computer from advancing. But if you have a distributor you just need to disconnect and plug your vacuum advance lines.

I dont know what kind of vehicle you got but 195 psi is pretty avg for a compression test.

how old is the car, carbon deposits tend to build up if you use bad gas, drive light throttle a lot, or have an old car. carbon deposits raise compression and create hot spots which cause ping

I changed the headgasket a couple years ago and I cleaned everything up in the process. I do have a pretty heavy foot, so it never really gets a chance to build up deposits. I run cleaner through the gas tank quite often too. Lately, I've been running fuel from Fred Meyer (Kroger) because it's the cheapest. Once and a while, I'll fuel up with Shell V-Power.

I went and had my Van fueled up at Fred Meyer the other night and told them to put Premium in it. The guy forgot and punched in Regular instead. I noticed the mistake, but didn't say anything. Another guy came up and was like "Let me guess, Premium?" I go "Well, he hit Regular instead." So he went and stopped the pump and finished it off with Premium for me so the octane level doesn't get too much lower. On my way home that night, it'd ping during acceleration at a certain RPM. I decided to experiment and shut the overdrive off and hit the throttle enough to where it'd ping like crazy. It'd even ping at full throttle until it reached a certain RPM.

Then yesterday, I used my mouth as a vacuum tester on my vacuum advanced system on my distributor. It also has a vacuum retard. I sucked on the vacuum advanced line, which connects to the air filter side of the throttle body, and the line stuck to my tongue, which indicates that it can hold a vacuum. I sucked on the vacuum retard line that connects to the side of the brake booster port and it didn't stick to my tongue and wouldn't hold a vacuum. I read on a website that if you have a high idle and you rev the engine a little and quickly release the throttle and your idle goes back down to normal, then there's a problem with the vacuum retard system. I'm thinking I have a vacuum leak there and my distributor will have to be replaced. They're only a couple hundred bucks and I'll consider it soon and see if the ping behavior minimizes.

"Oh good, I see you've got the engine that goes 'PING!!!!' "

-Monty Python