A pinging sound only under a load

Tiny
VETTE2112
  • 1990 GMC SUBURBAN
  • 231,000 MILES

I filled up with gas and nw I have a pinging sound and chattering I have changed the fuel filter, new plugs and wires new o2 sensor new distubtor and cap rotor butn it also has a rough idle it has plenty of power

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Thursday, February 16th, 2012 AT 3:25 AM

79 Replies

Tiny
FIXITMR
  • MEMBER

Any CEL have codes read maybe knock sensor malfunction?

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Thursday, February 16th, 2012 AT 3:58 AM
Tiny
VETTE2112
  • MEMBER

Engine light came on for a couple secs thn went back off

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Thursday, February 16th, 2012 AT 4:46 AM
Tiny
FIXITMR
  • MEMBER

Codes are in there even if light is off now.

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Friday, February 17th, 2012 AT 1:16 AM
Tiny
VETTE2112
  • MEMBER

Its new too and still doin it

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Friday, February 17th, 2012 AT 1:50 AM
Tiny
VETTE2112
  • MEMBER

I was told maybe it jump time

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Friday, February 17th, 2012 AT 1:51 AM
Tiny
RASMATAZ
  • MEMBER

Could be your KS not retarding the ignition timing or A stuck closed EGR valve that causing excessive combustion heat to detonate/ping-like a bunch of marbles being thrown into a tin can when engine is under load-

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Friday, February 17th, 2012 AT 1:58 AM
Tiny
VETTE2112
  • MEMBER

It only does it under a load and it has a rough idle I was just maybe clogged convertor im open to anything

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Friday, February 17th, 2012 AT 2:19 AM
Tiny
VETTE2112
  • MEMBER

It takes a litte more time to start in the morning mre than usual

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Friday, February 17th, 2012 AT 2:21 AM
Tiny
RASMATAZ
  • MEMBER

Lets do some troublshooting here instead of describing what's going on with it -do what we have suggested then report back your findings

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Friday, February 17th, 2012 AT 2:25 AM
Tiny
VETTE2112
  • MEMBER

I was told that a egr valve stuck open is bad and closed is good which is you can call my cell at 307-677-1886

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Friday, February 17th, 2012 AT 2:32 AM
Tiny
CCUPDAVE
  • MEMBER

Hello Vette, here is some help for you.
You can check the trouble code(s) your self here is how you do it.
This is the OBD 1 system so you locate the connector plug below the steering wheel at the bottom of the dash and with the key off get a jumper wire or paper clip and jump pin B and A, be careful not to short out any other pins or the ECM will fry. Make sure you have paper and pen so you can write down the codes.
See pics below. After the jumper is in place turn the key to the on position not start and count the check engine flashes on the dash. If this is done right you will see one flash then two flashes. This is normal code 12 You will see this three times then it will start a series of flashes like three flashes then two that is code 32 EGR it will do that three times too if the EGR is acting up. After all codes are played it will go back to code 12 and start over. After you are down turn the key off then remove jumper.
Let us know what you find.

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Friday, February 17th, 2012 AT 3:35 AM
Tiny
VETTE2112
  • MEMBER

K will do it in the mring ty

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Friday, February 17th, 2012 AT 3:55 AM
Tiny
RASMATAZ
  • MEMBER

Stuck open or closed is still no good for me-I've studied the EGR system since it was introduced in 1973

Why are you asking us questions when you're getting advices from others. If you trust them, then stick with them-Do your last suggestion.

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Friday, February 17th, 2012 AT 4:32 AM
Tiny
VETTE2112
  • MEMBER

I will do what you said in the morning im just tryin to get all the info I can im on a fixed income so I hve to do it myself cant affrd a shop

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Friday, February 17th, 2012 AT 4:39 AM
Tiny
VETTE2112
  • MEMBER

It has no codes at all what elese could it be

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Friday, February 17th, 2012 AT 9:18 PM
Tiny
CCUPDAVE
  • MEMBER

I am no super expert, but I do know my way around most early American cars. Are you getting code 12 which shows OBD is working? If not something is wrong.
The next thing I would check is the timing with a timing light. If that checks out ok; note: on some older cars and trucks the timing has to be set by hear because of the engine wear they won t run right if set to specifications, old school stuff then I'd go to the knock sensor. The knock sensor is designed to stop that ping by retarding the timing enough to stop that. It's rare that they go bad but it happens.
Good luck

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Friday, February 17th, 2012 AT 11:25 PM
Tiny
VETTE2112
  • MEMBER

The knock sensor hasnt been hooked up since I have had it almost 9yrs now it started after I filled up with gas would the cat have anything to with it im open to anything its driving me nutts tryin to figure this out I cant get a code reader til tomrrw and I will let u know what I find then I have changed the fuel filter, plugs, wires, complete distubor and cap and rotor buttn, o2 sensor I did notice my crank sensor fuse is not gettin power to it its the fuse box I dnt think that has anything to do with it I dnt know im no mech how can I tell if the egr valve is bad without takin it off

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Friday, February 17th, 2012 AT 11:53 PM
Tiny
VETTE2112
  • MEMBER

It also is a little harder to start when its cold

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Friday, February 17th, 2012 AT 11:54 PM
Tiny
CCUPDAVE
  • MEMBER

Well here is some insight. It doesn't have a crankshaft sensor in this year, that didn't start till 95 or 96.
Now that knock sensor is needed in the system because of low octane fuel, incomplete fuel combustion, which is bad for your motor and emissions. What is happening in your motor is it's getting two firing sequences one too far before tdc "the ping" and another with the spark plug. If this isn t fixed it could burn a hole in the piston or burn the exhaust valve, go easy on this motor until it s fixed.
What you can do in the mean time is adjust the timing by ear under load until the ping goes away. You need two people and it s a little dangerous, the experts here wouldn t tell you to do this. But one person puts the truck in gear and holds the gas peddle down until you hear the ping and turn the distributor ever so little until the ping goes away and runs strong and idles good. This is called timing by ear .
It would be better and safer to hook up the knock sensor so it works like it should
RE: catalytic converter I don t think you have a problem there unless it gets real hot and your exhaust flow is low.
The EGR system is still something to look into if you're still having trouble.
Good luck, and don t hurt your self

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Saturday, February 18th, 2012 AT 12:44 AM
Tiny
VETTE2112
  • MEMBER

Ok what water in the gas will that do it

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Saturday, February 18th, 2012 AT 12:56 AM

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