85 pings at 6 degrees timing.
Thread Starter
Instructor
Joined: Apr 2022
Posts: 181
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From: Oregon
85 pings at 6 degrees timing.
I am getting my 85 ready for power tour and had to replace the front crank seal. While in there i did a water pump, hoses, and a new double roller timing set (the original timing set was pretty sloppy - even at only 33,000 miles.
Drove it to the golf course today, and on the way home it was pinging pretty bad under load. Since I did not check the timing after replacing the chain, I checked it when I got home. Still dead on 6 degrees (yes, I know to disconnect the ESC brown wire when setting timing). I had to back it all the way down to 2 degrees to get rid of the pinging. It seems to run great now, but it also seems odd that it can only take 2 deg when so many on here are bumping it up to 8-10 deg for more power.
Would a Hypertech or other chip advance the timing so much that it can only stand a tiny bit of static timing before pinging? I have not pulled the ecm to see if it has been chipped, but the PO did install a K&N, airfoil, and Borla catback. Maybe he chipped it?
Do any of you have a canned tune on a chip that could comment on my timing issue?
Thanks!
Drove it to the golf course today, and on the way home it was pinging pretty bad under load. Since I did not check the timing after replacing the chain, I checked it when I got home. Still dead on 6 degrees (yes, I know to disconnect the ESC brown wire when setting timing). I had to back it all the way down to 2 degrees to get rid of the pinging. It seems to run great now, but it also seems odd that it can only take 2 deg when so many on here are bumping it up to 8-10 deg for more power.
Would a Hypertech or other chip advance the timing so much that it can only stand a tiny bit of static timing before pinging? I have not pulled the ecm to see if it has been chipped, but the PO did install a K&N, airfoil, and Borla catback. Maybe he chipped it?
Do any of you have a canned tune on a chip that could comment on my timing issue?
Thanks!
Thread Starter
Instructor
Joined: Apr 2022
Posts: 181
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From: Oregon
I read about the egr system last night. If I understand correctly, it shuts off at full throttle. I am only getting spark knock at high load, high throttle when the engine is hot. There were no codes stored in the ecm.
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
The shelf hyper chip does advance timing curves, but I don't recall hearing that it advanced to that level. If he somehow customed it, maybe, but thats pretty bad to advance where your base can't be set at 6. EGR isnt doing **** here.
I'd have to confirm again the TDC and timing marks.
I'd have to confirm again the TDC and timing marks.
Thread Starter
Instructor
Joined: Apr 2022
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From: Oregon
The timing cover is original and has the original timing tab. The balancer has less than 3000 miles on it, and I used these to set TDC when installing the new timing set. Timing chain was installed straight up at 0 degrees. Dot to dot lined up and when I reinstalled the balancer it was still at 0 degrees.
Melting Slicks
Joined: Aug 2003
Posts: 3,407
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From: Lakeville MI
Fuel quality? Elevation?
Audible knock is concerning. It is an indication that the knock sensor and knock retard system may be malfunctioning. When this occurs, the ecm will try and force it to knock by adding timing under high load conditions. If it never detects any knock it will eventually set a dtc (code 43), however the forced knock test itself can be destructive. Audible knock should be a rare occurrence with knock retard functioning as intended.
Audible knock is concerning. It is an indication that the knock sensor and knock retard system may be malfunctioning. When this occurs, the ecm will try and force it to knock by adding timing under high load conditions. If it never detects any knock it will eventually set a dtc (code 43), however the forced knock test itself can be destructive. Audible knock should be a rare occurrence with knock retard functioning as intended.
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Thread Starter
Instructor
Joined: Apr 2022
Posts: 181
Likes: 118
From: Oregon
Fuel quality? Elevation?
Audible knock is concerning. It is an indication that the knock sensor and knock retard system may be malfunctioning. When this occurs, the ecm will try and force it to knock by adding timing under high load conditions. If it never detects any knock it will eventually set a dtc (code 43), however the forced knock test itself can be destructive. Audible knock should be a rare occurrence with knock retard functioning as intended.
Audible knock is concerning. It is an indication that the knock sensor and knock retard system may be malfunctioning. When this occurs, the ecm will try and force it to knock by adding timing under high load conditions. If it never detects any knock it will eventually set a dtc (code 43), however the forced knock test itself can be destructive. Audible knock should be a rare occurrence with knock retard functioning as intended.
I did wonder why it was knocking since it has a knock sensor. I replaced that last year as a PM item. The connector broke and I have it held on with a zip tie. I will put it back up on the lift this afternoon and check that connection. Anyone know where to get that connector quickly? I am headed out on my road trip Wed morning.
Race Director
Joined: Apr 2003
Posts: 17,700
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From: moraga ca
First of all, I would put 91 in the thing and drive it. That might make a difference, If your chain, sprocket was warn, your valvetrain could have been retarded letting you get away with cheaper, low octane gas.
Thread Starter
Instructor
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From: Oregon
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
yeah the best current solution if the knock sensor is fine is to put in premium for your trip and take a good look at it when you return from the tour
Thread Starter
Instructor
Joined: Apr 2022
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From: Oregon
I have returned from my trip and dove into this again on Sunday. For the trip, I had the base timing set at 0 deg, and the car ran fine for the entire 6200 miles. I tried different octanes along the way and none seemed to make a difference. When I got back, I replaced the plug on the wire to the knock sensor. I also slightly loosened the sensor, as I have read that if it is too tight it may not read knocks. I then put the timing back to the stock setting of 6 degrees. First test drive had significant knock at high load and high throttle. Kept backing the timing down 2 degrees at a time until the knock went away, which is now back to zero degrees.
Maybe this is a faulty sensor, or I damaged it by overtightening? Unless someone has a better idea - I'm thinking about reinstalling the original sensor and torqueing to spec (anyone know what that is?) and see if that makes a difference.
Maybe this is a faulty sensor, or I damaged it by overtightening? Unless someone has a better idea - I'm thinking about reinstalling the original sensor and torqueing to spec (anyone know what that is?) and see if that makes a difference.
Team Owner
Joined: Aug 2004
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From: Park City Utah
If you have audible pinging at 6*, or 4* or whatever, that has nothing to do w/your knock sensor. It's pinging and I don't think that it should.
Thread Starter
Instructor
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From: Oregon
Team Owner
Joined: Aug 2004
Posts: 21,543
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From: Park City Utah
Once again...if you have audible pinging at such a retarded (perceived) timing setting, the knock sensor is out of the equation. It's not causing the knock. So....what is causing it to knock, at 2, 4, 6* timing?
Thread Starter
Instructor
Joined: Apr 2022
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From: Oregon
You tell me. Is it running right? Does backing off timing to 0, to eliminate audible ping, make sense? Not to me. Sounds like you're "Good to GO!", though.
Once again...if you have audible pinging at such a retarded (perceived) timing setting, the knock sensor is out of the equation. It's not causing the knock. So....what is causing it to knock, at 2, 4, 6* timing?
Once again...if you have audible pinging at such a retarded (perceived) timing setting, the knock sensor is out of the equation. It's not causing the knock. So....what is causing it to knock, at 2, 4, 6* timing?
I could buy a piston stop find TDC - using that to confirm that the timing mark on the balancer is correct, but this problem seemed to appear after replacing the timing set. The balancer was not changed. It is the correct timing set (confirmed) and was installed straight up (triple checked before putting the cover on) . I have probably done this a dozen times on other small block and big block Chevy's. I am certain that it was done correctly. This timing set can also be installed 4 deg. advanced or retarded. If I had somehow messed that up, my timing would not have been exactly the same after the installation as it was before.
Last year, after the balancer was replaced, I experimented with bumping timing up to 8 and 10 degrees as has been suggested many times on this site. My car had some pinging at these settings (87 octane), so I returned it to 6 degrees.
Drifting
Joined: Nov 2018
Posts: 1,771
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From: USA
I know you didn't say anything about touching the distributor, but just for the heck of it, I would pull the cap and see where the rotor is pointing when the timing marks line-up! Reading through all the posts, I kept thinking about the +/- 4° options on the crank gear...it is interesting that before your change, that adding 4° timing for a total of 10° advanced made it ping...now adding 4° timing for a total of 6° makes it ping!!??? My initial thought was you had the crank sprocket on 4° advanced keyway....the results you are getting suggest the crank gear is off. But, like I said, expose the rotor and confirm everything lines-up. I would be testing the distributor components (ignition module, p/u coil) and spark control module IF you were just getting erratic timing...but since this absolutely changed after a timing chain set swap....it has to be something mechanical. Like say for instance, the crank gear got installed 4° advanced and/or the distributor has been possibly installed "off by a tooth" for sometime!? Just brainstorming here, hopefully it sparks some ideas! Good luck👍
Instructor
Joined: Jan 2021
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An 85 shouldnt have any problems on 87. Its only 9:1 compression and not as high strung as the later years. I have zero issues with 87 octane on my 85.
