Pinging real bad
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Joined: Mar 2024
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Pinging real bad
Hi all, I've been experiencing alot of pinging lately and I have tried alot of things, so far nothing has worked. It's a 89 l98 zf6
I get pinging with anything more than quater throttle, especially after the car is warmed up
Here's what I have done so far
- fuel system cleaner
- increasing octane (first tried a full tank of 93 then after that didn't work added 2 containers of octane booster)
- verified that the mechanical spark timing (6° btdc)
- torqued knock sensor to 14 ft/lbs (working on getting a ac Delco oem part)
- replaced 7 spark plugs (one is blocked by ac but will try to get that out later)
- "steam" cleaning through brake booster line
- valve cleaner down the intake
Theres probably other things im forgetting
None of these have worked, not sure what to do now. It's been suggested to me that I should get an obd1 usb so I can watch spark advance and knock counts while under driving conditions. Where can i find a good obd1 to usb cord?
The spark plugs that I pulled out were covered in carbon grime. So I'm guessing the combustion chambers is too, how can I most effectively clean that?
Any suggestion are welcome, just looking for anything to try. Very interested in finding a ob1 to usb!!
I get pinging with anything more than quater throttle, especially after the car is warmed up
Here's what I have done so far
- fuel system cleaner
- increasing octane (first tried a full tank of 93 then after that didn't work added 2 containers of octane booster)
- verified that the mechanical spark timing (6° btdc)
- torqued knock sensor to 14 ft/lbs (working on getting a ac Delco oem part)
- replaced 7 spark plugs (one is blocked by ac but will try to get that out later)
- "steam" cleaning through brake booster line
- valve cleaner down the intake
Theres probably other things im forgetting
None of these have worked, not sure what to do now. It's been suggested to me that I should get an obd1 usb so I can watch spark advance and knock counts while under driving conditions. Where can i find a good obd1 to usb cord?
The spark plugs that I pulled out were covered in carbon grime. So I'm guessing the combustion chambers is too, how can I most effectively clean that?
Any suggestion are welcome, just looking for anything to try. Very interested in finding a ob1 to usb!!
Melting Slicks
Joined: Apr 2001
Posts: 2,112
Likes: 220
From: Ca.
Take a look at tunercat. They have a software program and cable to scan at a reasonable price.There are bottles of stuff to add to the tank that may help with carbon buildup. Or spray water or seafoam in the intake with it running-
Last edited by drive it; Sep 3, 2024 at 10:01 PM.
Safety Car
Joined: Sep 2001
Posts: 4,157
Likes: 554
From: Glenbeulah Wi
Look at tunerpro they have logging software that comes with their program and you just need to buy a cable.
I suspect your knock sensor is not working but have no information to back that up. If you hear knock but are not seeing knock counts you would have to investigate the knock circuit for issues.
I suspect your knock sensor is not working but have no information to back that up. If you hear knock but are not seeing knock counts you would have to investigate the knock circuit for issues.
Melting Slicks
Joined: Jul 2005
Posts: 2,217
Likes: 302
I'm assuming this engine is all stock...
Since you said you checked the timing, I would also check to make sure the outer ring on the balancer hasn't slipped. What you think may be 6 deg could actually be well over 10-15 deg.
Get a piston stop, put it in the number one spark plug holes and get the engine up to TDC on the #1 cylinder (by hand turning the crank). If you search on "piston stop 350 chevy find TDC" on youtube, I'm sure you'll find dozens of videos on how to do it.
Once you've found TDC, then see where the timing mark is on the damper relative to the marker on the timing cover. They should be aligned with eachother. If they're not, you need to replace the balancer.
Since you said you checked the timing, I would also check to make sure the outer ring on the balancer hasn't slipped. What you think may be 6 deg could actually be well over 10-15 deg.
Get a piston stop, put it in the number one spark plug holes and get the engine up to TDC on the #1 cylinder (by hand turning the crank). If you search on "piston stop 350 chevy find TDC" on youtube, I'm sure you'll find dozens of videos on how to do it.
Once you've found TDC, then see where the timing mark is on the damper relative to the marker on the timing cover. They should be aligned with eachother. If they're not, you need to replace the balancer.
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Look at tunerpro they have logging software that comes with their program and you just need to buy a cable.
I suspect your knock sensor is not working but have no information to back that up. If you hear knock but are not seeing knock counts you would have to investigate the knock circuit for issues.
I suspect your knock sensor is not working but have no information to back that up. If you hear knock but are not seeing knock counts you would have to investigate the knock circuit for issues.
Shouldn't be, possbile it's clogged or stuck open/closed. Is there a way to test that?
I'm going to test my fuel pressure soon, another detail that could help. No idea when the fuel filter was last replaced if ever. Or maybe the pump is going out?
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From: Saratoga Springs NY
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Are you sure the noise is not something else? mechanical maybe?
If the plugs had carbon on them after you did the cleaner, thats normal. Just means the cleaner did its job.But if the carbon is that bad, yeah that would cause the pre-ignition.......but anything above 1/4 throttle and you get pinging just dosent sound right.
Does it do it without being under a load? Like just revving in neutral?
If the plugs had carbon on them after you did the cleaner, thats normal. Just means the cleaner did its job.But if the carbon is that bad, yeah that would cause the pre-ignition.......but anything above 1/4 throttle and you get pinging just dosent sound right.
Does it do it without being under a load? Like just revving in neutral?
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Joined: Sep 2001
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From: Glenbeulah Wi
[QUOTE=Ekays;1608141964]I unplugged the knock sensor with no changeon the pinging. It was explained to me that unplugging the knock sensor would force the car to stick to very conservative spark timing since it can't tell if it's knocking or not. That seems like it would eliminate the knock sensor. Not sure though, should've included this in the original post.
This is not how the knock sensor circuit works in these cars, what it does is wait for knock to be heard and if it hears knock it does not set a check engine light for a malfunctioned knock sensor circuit. The car waits for the engine to hit 195 degrees and then the first time you go to WOT it over advances the timing and listens for knock, if it does not hear knock it will pull timing and set the check engine light for failed knock system.
A scanner is really what you need to use to verify knock sensor operation and timing advance.
This is not how the knock sensor circuit works in these cars, what it does is wait for knock to be heard and if it hears knock it does not set a check engine light for a malfunctioned knock sensor circuit. The car waits for the engine to hit 195 degrees and then the first time you go to WOT it over advances the timing and listens for knock, if it does not hear knock it will pull timing and set the check engine light for failed knock system.
A scanner is really what you need to use to verify knock sensor operation and timing advance.
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Joined: Mar 2024
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Are you sure the noise is not something else? mechanical maybe?
If the plugs had carbon on them after you did the cleaner, thats normal. Just means the cleaner did its job.But if the carbon is that bad, yeah that would cause the pre-ignition.......but anything above 1/4 throttle and you get pinging just dosent sound right.
Does it do it without being under a load? Like just revving in neutral?
If the plugs had carbon on them after you did the cleaner, thats normal. Just means the cleaner did its job.But if the carbon is that bad, yeah that would cause the pre-ignition.......but anything above 1/4 throttle and you get pinging just dosent sound right.
Does it do it without being under a load? Like just revving in neutral?
[QUOTE=bjankuski;1608143737]
I unplugged the knock sensor with no changeon the pinging. It was explained to me that unplugging the knock sensor would force the car to stick to very conservative spark timing since it can't tell if it's knocking or not. That seems like it would eliminate the knock sensor. Not sure though, should've included this in the original post.
This is not how the knock sensor circuit works in these cars, what it does is wait for knock to be heard and if it hears knock it does not set a check engine light for a malfunctioned knock sensor circuit. The car waits for the engine to hit 195 degrees and then the first time you go to WOT it over advances the timing and listens for knock, if it does not hear knock it will pull timing and set the check engine light for failed knock system.
A scanner is really what you need to use to verify knock sensor operation and timing advance.
This is not how the knock sensor circuit works in these cars, what it does is wait for knock to be heard and if it hears knock it does not set a check engine light for a malfunctioned knock sensor circuit. The car waits for the engine to hit 195 degrees and then the first time you go to WOT it over advances the timing and listens for knock, if it does not hear knock it will pull timing and set the check engine light for failed knock system.
A scanner is really what you need to use to verify knock sensor operation and timing advance.
I also did a little test on the egr. All the vacuum lines look good (not saying i checked every single line and am 100% sure there's no leaks). I pushed up on the bottom of the egr with a screw driver while the car idled and it died. So that seems like normal egr operation. Could be another part of the egr system that's bad though. I did have a Code 32 awhile back that went away on it's own.
Melting Slicks
Joined: Aug 2003
Posts: 3,399
Likes: 394
From: Lakeville MI
It should be setting a code 43 due to low voltage or due to no knock counts being detected during the function test, so something strange is going on preventing a code 43 from being set.
The low coolant temp could be a contributing factor.
Some background info:
https://www.corvetteforum.com/forums...post1608093208
What chip is in the car? Perhaps the Code 43 parameters, knock retard and/or spark advance tuning parameters have been tampered with in the chip for some odd reason.
The low coolant temp could be a contributing factor.
Some background info:
https://www.corvetteforum.com/forums...post1608093208
What chip is in the car? Perhaps the Code 43 parameters, knock retard and/or spark advance tuning parameters have been tampered with in the chip for some odd reason.
Last edited by tequilaboy; Sep 5, 2024 at 06:08 PM.
Thread Starter
Advanced
Joined: Mar 2024
Posts: 75
Likes: 24
It should be setting a code 43 due to low voltage or due to no knock counts being detected during the function test, so something strange is going on preventing a code 43 from being set.
The low coolant temp could be a contributing factor.
Some background info:
https://www.corvetteforum.com/forums...post1608093208
What chip is in the car? Perhaps the Code 43 parameters, knock retard and/or spark advance tuning parameters have been tampered with in the chip for some odd reason.
The low coolant temp could be a contributing factor.
Some background info:
https://www.corvetteforum.com/forums...post1608093208
What chip is in the car? Perhaps the Code 43 parameters, knock retard and/or spark advance tuning parameters have been tampered with in the chip for some odd reason.
Melting Slicks
Joined: Aug 2003
Posts: 3,399
Likes: 394
From: Lakeville MI
An aftermarket chip should be visually apparent, a reprogrammed factory memcal is likely missing the label or has a new label over the window on the eprom. Otherwise you can read the prom id with a scan tool, or read the bin with a programmer and compare against a known good bin file. Some aftermarket bins did not bother to change the prom id, so reading prom id alone is not conclusive.
You could try shorting the knock sensor wire to ground in an attempt to force a Code 43 via low voltage. Not exactly sure how the knock circuit will respond to an open circuit. but this method should still fail the function test, so it is strange that you're not getting a Code 43.
ECM input circuits:
You could try shorting the knock sensor wire to ground in an attempt to force a Code 43 via low voltage. Not exactly sure how the knock circuit will respond to an open circuit. but this method should still fail the function test, so it is strange that you're not getting a Code 43.
ECM input circuits:
Racer
Joined: Feb 2024
Posts: 268
Likes: 113
From: New York
What's your fuel pressure under acceleration? Put a fuel pressure gauge on the rail with enough hose so you can run the gauge to the windshield and close the hood and drive it while watching the gauge. You should see 30+ psi at idle and 40 - 50 under load.
Thread Starter
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Joined: Mar 2024
Posts: 75
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An aftermarket chip should be visually apparent, a reprogrammed factory memcal is likely missing the label or has a new label over the window on the eprom. Otherwise you can read the prom id with a scan tool, or read the bin with a programmer and compare against a known good bin file. Some aftermarket bins did not bother to change the prom id, so reading prom id alone is not conclusive.
You could try shorting the knock sensor wire to ground in an attempt to force a Code 43 via low voltage. Not exactly sure how the knock circuit will respond to an open circuit. but this method should still fail the function test, so it is strange that you're not getting a Code 43.
ECM input circuits:
You could try shorting the knock sensor wire to ground in an attempt to force a Code 43 via low voltage. Not exactly sure how the knock circuit will respond to an open circuit. but this method should still fail the function test, so it is strange that you're not getting a Code 43.
ECM input circuits:
About 30 seconds ago I opened the fuel rail test port to do exactly that and about a shot glass worth of fuel spilled out... thats not normal right? Haven't touched it since. The engine is hot and I don't want to mess with it and spill more fuel and then have a fire.
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Racer
Joined: Feb 2024
Posts: 268
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From: New York
Verify proper fuel pressure and initial ignition timing first. If either of those are off, it'll never run right. Also, there are no ECM codes generated for either of those issues.