What causes pinging?

TBI machines like 89 o-tang even with stock timing. I personally run mine a bit advanced for some seat-o-the-pants HP, and I run 89 exclusively. However when I had stock timing the truck ran MUCH better on 89, it would sputter & stall on 87. I would check your timing. Disconnect the timing advance wire (brown wire that goes to the dizzy) and check that your engine is at 0*. If it isn't that...

GMC Gremlin

Where any codes set? If the knock sensor is working, it tells the computer "Hey we got spark knock" the computer then backs the ignition timing off, spark knock, or ping goes away . Other problems could be the pistons are carboned up, exhaust valves are carboned up, or the wrong heat range of plug is in the engine. I've run regular when the wallet was thin, and while the power dropped like a rock, and the gas mileage a bit as well, I didn't have problem with ping. I prefer high test myself. I cant provide any scientific evidence its better. The idea behind high octane is it doesn't ping/knock with higher compression engines and/or allows more ignition advance. So logic says the ECM can allow more advance if the octane used is higher, which translates to more power, which translates to increase in mpg. I do know by the seat of my pants, the truck runs better on it, and gets better gas mileage. Last tank good mix of highway city averaged 20 mpg. My idea of highway is 75-80 mph. Not too shabby for a '91 S-10 Blazer 4.3 that hit 207,000 miles today. Whitelightning

Also if the ECM *can't* detect a knock, it will set a code. The ECM at highway speeds will advance the timing until it detects spark knock and then back off again. If it continues to advance and doesn't detect knock it will "assume" the knock sensor is bad and set a code.

GMC Gremlin

Could be any one of several things. Contaminated fuel, improperly controlled timing for whatever reason, etc.. And if you haven't pinged on reg (87) you won't all of a sudden need it. See if you got a code.

I had this on my 89 s10 and it was the air filter was dirty and had a hole in it.

. . =3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D (Sounds=A0like=A0a=A0Porsche) asked:

(quest. #1) What causes pinging?

Took my 87 Chevy pickup (4.3 ltr) up a steep hill today and man she pinged heavy all the way. Hadn't really noticed it too much before just the odd time.

(quest. #2) I shouldn't need premium gas for it should I? Dave

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

Answers to the quiz:

1) most often this symptom is due to improper maintenance... (improper=3D neglected)

2) no, you shouldn't.

Answer to the questions you didn't ask:

1) given the symtpoms, most likely carbon buildup inside the combustion chamber.

2) change the plugs...start using Chevron gas for the next couple of months and see if that hill still causes you a problem.

~:~ MarshMonster ~:~

Thanks for all the tips guys. I've put some premium in it for now.

Note to MarshMonster... We don't have a Cheveron gas station in Canada where I am (Alberta) so I checked the web and decided Shell has a pretty good premium fuel... more than five times the minimum amount of cleaning agents required by government standards.

GMC Gremlin and Whitelightning... No codes were set. For sure she is carboned up (black smoke) but I thought I blew it all out last summer.

Also last summer the cat was plugged solid... since been taken care of. That took awhile to figure out... she wouldn't shift out of 2nd. A vacuum gauge showed not enough vacuum to let the tranny shift. The truck would leave a red light no problem but then would just fall on its face. After a couple of mechanics looked at it and couldn't figure it out (still had to pay them) I found one that diagnosed and fixed the problem in 15 minutes (the cat being plugged up).

The pickup has less than 60,000 miles on it. It was an old 'City owned truck' that I picked up at 'City' auction. Should have been well maintained but I'm wondering about that now. For sure she was washed all the time... I had her painted and there was zero rust.

I think the valve guide seals are gone... puff of blue on the morning start up. That seems to be getting less as time goes on (I've put about 5000 miles on it since I got it). She does use oil tho and when I add some there is a bit of sludge I can see in the valve cover... more often oil changes for awhile I guess.

The truck might have sat for a year or so before they decided to auction it off. Being green I figured I was going to get a trouble free almost new truck (60K miles). Oh well I quite like it.

Dave

Black smoke isnt carboned up sign, but rather running way rich

Running way rich can cause cat to plug up.

Minimal maintainece done with the cheapest products available.

Machinery never likes to sit idle, and then doesnt like to go back to work afterwards. sitting that long could lead to problems with the fuel regulater, which could explain the plugged cat and the black smoke. I am not a fan of snake oils. But I hve three favorites that sometimes work. First is Marvel Mystery Oil. A half quart added to the crank engine run for

30 minutes easy, and then change, will help clean the engine but not as harsh as the solvant based "engine flushes" that are hard on seals, will sometimes bring a stuck lifter back to life, squirt some in a cylinder over night through the spark plug holes can sometimes ungum stuck rings (works well on dodge v-6 (the mitsibishi shit motor that likes to gum rings up). Best air tool lube I know of. And if you hunt around they have a kit that feeds a tiny bit into the engine via an orficed vaccumm tube set up that works super on pre-emessions cars. Helps keep the valves from buring due to the lack of lead in the gas. Berrymans Total Fuel System Cleaner, comes in a metal can shaped like a beer bottle. One can to 10-15 gallons of gas. Does a good job of cleaning injectors, and cleaning carbon build up off of piston tops. Dont spill any on the paint. And finally TransMedic, which is by SolderSeal. This stuff has not one drop of stop leak in it. It is a band and clutch conditionor, and will also help free up sticky valves.

Whitelightning

>

lean air/fuel mixture, over advanced ignition timing, excessive carbon build up in the combustion chamber or on top of the piston, defective engine controls........................ too many fuel additives

Sea Foam is another. Great in the fuel, but dynamite in the crankcase. The hubby used it many times in the relics he finds. It gets lifters quieted down, and just cleans things up. The last project was a 1939 Chev, original, sat for 10 years. Used Sea Foam in the fuel and in the crankcase. Changed oil twice (500 miles) and it is quiet and no more smoke.

add to the list: overheating,

add to list, faulty knock sensor

Hi, Your pinging problem is caused by bad detonation. Octane ratings signify the atom structure of the gas. The higher the octane rating the simpler and more efficient the structure is. That's why higher octane runs smoother. Retarding your timing (runs hotter, but reduces pinging) or running your engine cooler will eliminate this also. Enriching your mixture will also help. The pinging is basically like a little hammer hitting the tops of the pistons. I wasted both pistons on my Sportster from excessive pinging. If it continues you will most likely break or melt your pistons. This in not a joke, but water injection will fix your problem. Edelbrock makes a water injection system that's called vara-jection. It's an electronically controlled water injection system. It squirts water into your intake and atomizes your fuel better. It also gives you a denser charge which creates horse power as well as clean your engine insides. It also improves gas mileage. I ran one on a turbo charged Kawasaki and it ran great. My bike would start pinging badly at

155 mph. The water > Took my 87 Chevy pickup (4.3 ltr) up a steep hill today and man she pinged

Add to list... Poorly seating exhaust valves (heat conduction to head is decreased, exhaust valves can get hot enough to cause detonation of fuel:air mixture).