Knock Retard confusing this TBI Illiterate. LOL!

**trlrider** · 05-19-2021

Trying to figure out why my PCM is pulling timing from idle start and on!
The attached .xdl file was not focused on any particular driving, in fact the first couple of minutes the truck was not even running.
As soon as I started it it showed 23.2 Knock Retard up to as much as 25.8.

Or is the knock retard a false flag. I have read this forum and others till my eyes were dead and cannot find a good explanation of what is happening.

Only changes to the .bin have been cutting off the EGR. Have not played with the timing or fuel due to the knock retard question.

Base timing is 0 (confirmed balancer is zero'd with the cam)
vehicle: 1993 K1500 Suburban 350 SBC (head and cam profile similar to the originals '70's LT1) with a TBI that was native to the truck.
Trans: 4L60E (1993 type) with 3.42 gears.
Sadly I did not have the ability to log the original engine before it was pulled from the truck due to very low oil pressure.

Any hints would be appreciated. .bin/.xdf/.adx/.xdl attached.

**1BadAction** · 05-20-2021

Are you sure the below parameter was saved to the tune when you were datalogging? It looks like what happens when this is not done, but you may need to change the ADX to match, I'm not sure on that part.

Screenshot 2021-05-19 161151.jpg

**1BadAction** · 05-20-2021

However, looking at your knock counts, it wasn't out of hand at all, so it's not REAL KR, it's just a display or logging error.

**trlrider** · 05-20-2021

Originally Posted by 1BadAction

Are you sure the below parameter was saved to the tune when you were datalogging? It looks like what happens when this is not done, but you may need to change the ADX to match, I'm not sure on that part.

Screenshot 2021-05-19 161151.jpg

Thanks for the reply! Yes, double checked by closing the .bin file and reopening after making that change.
Tried another $E6 .adx file straight from TunerPro website, still shows the high counts.
Have not find anything in the documentation to indicate a change is required in the .adx to go from voltage to actual KR.

**trlrider** · 05-20-2021

Originally Posted by 1BadAction

However, looking at your knock counts, it wasn't out of hand at all, so it's not REAL KR, it's just a display or logging error.

Kinda what I am hoping is a logging error of some sort, but looking at others post and logging data, that number should be zero or close to it and not red. That is the part I am attempting to understand currently.
Maybe that is the problem eh, I am trying to understand it.

Add: What I am gathering, is no matter what value I put in L51FE, despite what the .adx says, I am still getting a voltage reading there instead of actual knock retard in degrees, and the flag/alarm value is set extremely low.
Noticed looking at the Spark Advance (Open Throttle) MAP vs. Tachometer vs. Spark Advance history table, it also appears to be showing a value other then degrees!

**stew86MCSS396** · 05-21-2021

Had to dig back to June 2019 when working on friend's S10 using $E6 and I'm going to agree what 1BadAction suggested is the problem. I had 3 xdls saved and ran every one with either adx in post #1. 2 of 3 had the 20 odd knock retard. Going back to each bin 2 of 3 did not have the L51FE changes whereas 1 did. I looked at the bin post #1 and it does have the correct value at L51FE. Maybe do a double check that you have the correct bin loaded to the PROM and give it another whirl.

http://www.gearhead-efi.com/Fuel-Inj...nock-retard-no

**trlrider** · 05-21-2021

Originally Posted by stew86MCSS396

Had to dig back to June 2019 when working on friend's S10 using $E6 and I'm going to agree what 1BadAction suggested is the problem. I had 3 xdls saved and ran every one with either adx in post #1. 2 of 3 had the 20 odd knock retard. Going back to each bin 2 of 3 did not have the L51FE changes whereas 1 did. I looked at the bin post #1 and it does have the correct value at L51FE. Maybe do a double check that you have the correct bin loaded to the PROM and give it another whirl.

http://www.gearhead-efi.com/Fuel-Inj...nock-retard-no

Morning stew86MCS396!

Read the thread you supplied! Interesting, and see that others have the same anomaly in the knock retard.

The PCM, .memcal, .bin, sensors and TBI are native to the truck since before the engine swap.

Sadly as stated before I did not have the ability to datalog the original tired swirl port tbi engine before pulling it from the truck. The old TBI engine would induce ping/knock under moderate to hard acceleration that was audible. Not a big fan of the 3.42 gearing in this thing for the most part.

The only component electrical wise not native to the truck is a modified big cap HEI distributor in place of the divorced coil that is native to a TBI. Advance is locked out and it has a Speedway Motors advance mechanism in place of the vacuum canister. The module is the original to the truck mounted remote on a large heat sink. After reading the supplied thread, I do now believe that is not adding to the problem.

In the post you supplied, Eagle Mark mentioned over tightening the knock sensor. That thought did come to mind as it was a bear to remove from the old block. I have a new AC Delco sensor in route but it will not be here until mid-week next week. Those are getting hard to find and may order another one for a spare.

Next change I get I will remove the G1 Memcal adapter and run it with the Memcal straight and see if the knock counts/knock retard are still running the same as with the adapter.

I am running out of time to test and tune this unit. We leave for 4-H Shooting Sports Nationals in right at a month from now and our son has competitions scheduled every weekend up until we leave. Plus making sure all the maintenance is done and ready for the truck we are taking to Nationals.

More then likely I am overthinking this and just need to start working on timing and fuel that works well with this engine, head, intake combination and start enjoying the journey again.

Thanks for all the input. Anymore thoughts or suggestions are greatly appreciated.

Louis

**stew86MCSS396** · 05-22-2021

Further digging...playing back your xdl in "data list views" /sensors, you'll see "battery voltage" in the "general" section ~13.x volts. After "knock retard" bin change, what you should see is "battery voltage" reading "0." Subsequently, "knock retard" should read "0" too unless you're really experiencing knock.

**trlrider** · 05-22-2021

Originally Posted by stew86MCSS396

Further digging...playing back your xdl in "data list views" /sensors, you'll see "battery voltage" in the "general" section ~13.x volts. After "knock retard" bin change, what you should see is "battery voltage" reading "0." Subsequently, "knock retard" should read "0" too unless you're really experiencing knock.

Received! Thanks for the input.
Maybe there is something up with the .adx file that is not playing nice with the .bin.
Will have to research deeper when the time presents itself again.

When time allows I am going to plug my spare PCM, a '7427 into the truck that uses a $OD .bin, using the correct .xdl and .adl for that and see if it logs the same way.
My new knock sensor should be here on Tuesday, but between work and our sons competition and practice schedule getting ready for Nationals, will have to squeeze it in.

Louis

**stew86MCSS396** · 05-22-2021

What you quoted me^^^I'm hoping you're not getting confused that if you make/save bin changes at L51FE, will fix your old datalogs bc it will NOT! You need to go out for another drive w bin changes on the PROM and give it another whirl.

**trlrider** · 05-23-2021

Originally Posted by stew86MCSS396

What you quoted me^^^I'm hoping you're not getting confused that if you make/save bin changes at L51FE, will fix your old datalogs bc it will NOT! You need to go out for another drive w bin changes on the PROM and give it another whirl.

No, I am aware of that. I data log large tractor/trucks as part of my daily work.