LT1 Camaro $EE running 41 degrees of timing at WOT

[96lt4c4]

This is a 383 LT1 that I built for a friend of mine, the motor is probably around 500 horse. Its been hard for us to get together and tune this car right, need a whole day. Anyway, the car has a problem with the knock sensor so I turned it off for now, I know a bad idea . The car has no signs of knock and pulls like a frieght train but jumps to 41 degrees timing at wide open throttle. I have the high load, high RPM areas of the tune set to about 32 degrees. Even is I set the max spark advance to say 35 degrees it still jumps up to 40.

Are there some PE spark adders? I have the latest .xdf and have not found anything.

[EagleMark]

Maybe the ADX is reporting spark advance total and can't show where it is maxed?

When running an aggressive spark table on an engine like this I usually remove the PE spark... sometimes I have found by cafrefully looking at data at WOT the jump in timing was from DFCO or Decel as throttle is lifted. Also something not needed/wanted in a built engine. Also need to watch where WOT data is? 80-90 or 100 MAP? Higher elevations may only be in 80 MAP, so I have max timing the same for last three or four rows.

LT4 knock module is usually the answer to knock noise from a built LT1 engine.

I haven't played with $EE for awhile but will look around later if one of the ideas above didin't find the extra spark.

Spark latency is also an issue. Is the EST/ICM GM? 5 degrees is easily lost or found by changing to Accel or MSD module, even worse with parts store aftermarket.

[96lt4c4]

Maybe the ADX is reporting spark advance total and can't show where it is maxed?

When running an aggressive spark table on an engine like this I usually remove the PE spark... sometimes I have found by cafrefully looking at data at WOT the jump in timing was from DFCO or Decel as throttle is lifted. Also something not needed/wanted in a built engine. Also need to watch where WOT data is? 80-90 or 100 MAP? Higher elevations may only be in 80 MAP, so I have max timing the same for last three or four rows.

LT4 knock module is usually the answer to knock noise from a built LT1 engine.

I haven't played with $EE for awhile but will look around later if one of the ideas above didin't find the extra spark.

Spark latency is also an issue. Is the EST/ICM GM? 5 degrees is easily lost or found by changing to Accel or MSD module, even worse with parts store aftermarket.

Thats the thing I can not find the PE spark table in the latest .xdf that I have downloaded. I do not think that is has been added. Do we have the hack for $EE floating around anywhere? I will ad it in there myself if i had the hack. I will do some more digging.

Like you said in all my $0D tunes I zero out the PE Spark to get a more acurate spark reading while logging the vehicle. Or at least log what is actually in the main spark table. I am logging 41 degrees with this Camaro.

Aww..just thought of something. It has the MSD Optispark that allows you to advance the timing 5 degrees. I do not think that would show up in the log though. The ignition module is stock GM, the only thing changed as far as ignition is the Optispark.

[EagleMark]

I've never seen a hack of LT1 $EE?

I can't find an PE Spark Paremeters either? IIRC I had left Spark Advance tables alone and was fine in WOT high RPM advance? Disabling WOT TPS% was a bad idea as it also killed PE fuel. Pretty sure I have Data Tracing set up for Spark Advance tables in this def to watch.

Not really sure this mask has any more WOT/PE spark either, it's a pretty agressive table to begin with. Really no reason to add spark advance when AFR has increased! So where are you getting an additional 9 degrees of timing from? It's not an MSD distributor with timing adjustments is it?

[96lt4c4]

I've never seen a hack of LT1 $EE?

I can't find an PE Spark Paremeters either? IIRC I had left Spark Advance tables alone and was fine in WOT high RPM advance? Disabling WOT TPS% was a bad idea as it also killed PE fuel. Pretty sure I have Data Tracing set up for Spark Advance tables in this def to watch.

Not really sure this mask has any more WOT/PE spark either, it's a pretty agressive table to begin with. Really no reason to add spark advance when AFR has increased! So where are you getting an additional 9 degrees of timing from? It's not an MSD distributor with timing adjustments is it?

Yes the MSD allows you to +/-6 degrees. We left it alone when we installed it. Instructions say its set to stock, so i am guessing 0*. We may make a timing pointer and check this thing with my timing light to see what we are getting compared to the log. I found a hack but I do not think it is complete.

I did find that the Min Spark Advance table was set to 37* timing at 6000 RPM and up. I zeroed it out and the timing dropped from 41 to 37* at WOT when the timing table is set to 32*. So somewhere there is still some timing being added in.

[96lt4c4]

Here is the $EE Hack that I found. I do not see any PE spark adder tables in it.

The data tracing does work, but I am having problems getting TP to connect with the adx that I have downloaded from here. I am using an older ads file to log, then loading your adx and playing it back wit the data tracing on. I have not looked into why its not connecting.

[EagleMark]

That's not a hack... it's an old TP V4 xdf.

Don't know what the engine is in? But the connection commands in the ADX may be wrong. Use connections from your old one that works or re arrange what is in newer one.. Acquisition, Edit Definition and look for Engine Connection. The new one has commands for Corvette, Camaro, Caprice and Roadmaster. Lots of stuff going on there with other modules.

Is the EST/ICM also a MSD? Big timing issues have been found with other then GM modules do to Spark Latency settings. Easily the 5 degrees your looking for. Since we are down to 5 degrees and MSD has 6??? What happens when you adjust the other way? If plus and minus 6 well....

I'm all for knowing what timing is actual at timing marks! Hard to do with no timing marks...

Minimum spark is not something normally messed with and 37 is not in a bin I looked at? Not even close. Maybe do a compare to starting bin and see what else has been changed.

Also what MAP reading are you getting at WOT? If not in the 100 column then it will add spark! Look at stock tables. When I do aggresive timing tables I usually use the last three/four columns so WOT max Spark Advance can't be more then I want! This is an issue here at 2500 foot elevation and worse when higher. MAP can also be lower then 100 if air intake is not big enough for engine causing a vacuum when should be none, again adding spark from what you think is MAX.

Post a log and I'll take a look.

[96lt4c4]

That's not a hack... it's an old TP V4 xdf.

Don't know what the engine is in? But the connection commands in the ADX may be wrong. Use connections from your old one that works or re arrange what is in newer one.. Acquisition, Edit Definition and look for Engine Connection. The new one has commands for Corvette, Camaro, Caprice and Roadmaster. Lots of stuff going on there with other modules.

Is the EST/ICM also a MSD? Big timing issues have been found with other then GM modules do to Spark Latency settings. Easily the 5 degrees your looking for. Since we are down to 5 degrees and MSD has 6??? What happens when you adjust the other way? If plus and minus 6 well....

I'm all for knowing what timing is actual at timing marks! Hard to do with no timing marks...

Minimum spark is not something normally messed with and 37 is not in a bin I looked at? Not even close. Maybe do a compare to starting bin and see what else has been changed.

Also what MAP reading are you getting at WOT? If not in the 100 column then it will add spark! Look at stock tables. When I do aggresive timing tables I usually use the last three/four columns so WOT max Spark Advance can't be more then I want! This is an issue here at 2500 foot elevation and worse when higher. MAP can also be lower then 100 if air intake is not big enough for engine causing a vacuum when should be none, again adding spark from what you think is MAX.

Post a log and I'll take a look.

Yeah I saw that too, on the min spark advance, this bin came from PCM Forless, you know since they are so awesome... I thought I had found everything they screwed with but I guess not. I will do a full compare with the difference tool to see what else I find. Something else I noticed yesterday was that at idle the car was showing around 21* timing where in the main table it was showing almost 30*. There is a closed TPS at idle spark table that is only uses at idle. I am going to try and zero that out and force it to use the main spark table.

It is hitting 100 KPA during WOT, going by the data trace.

The car has other issues that you will see in these logs, split BLM's for one and running rich. It also does something at idle for about a minute that forces the IAC wide open and the car surges and trys to die, then it goes away.

Log 2 showes the 41* at WOT
Log 3 showes surging idle
I uploade the current bin too. this is in a 96 Camaro SS running a 95 PCM

[96lt4c4]

Just found that the Spark Correction VS. Map VS. Coolant temp was adding 2* in WOT areas, zeroed that table out. So should be down from 37* to 35*...still wanting 32*. Getting closer.

[EagleMark]

I'll take a look later, very curious.

But now your up to 2 weird things? Maybe a new bin to start?

3 degrees off is splitting hairs, that's well within range of acceptable to me. There's so many adders and subtracters etc... It would be nice to get rid of all of them for built race type engine bin but without a hack an extensive work I'm not sure they could all be found and zerod?

3 degrees? Have you smoothed the spark table? Even if data trace is in cell commanding 32 degrees it's still a calculation of that cell and four surrounding cells and can be easily off 3 degrees.

[96lt4c4]

I'll take a look later, very curious.

But now your up to 2 weird things? Maybe a new bin to start?

3 degrees off is splitting hairs, that's well within range of acceptable to me. There's so many adders and subtracters etc... It would be nice to get rid of all of them for built race type engine bin but without a hack an extensive work I'm not sure they could all be found and zerod?

3 degrees? Have you smoothed the spark table? Even if data trace is in cell commanding 32 degrees it's still a calculation of that cell and four surrounding cells and can be easily off 3 degrees.

I have it set to 32* in enough cells that it should hit 32*. the reason I am so set on finding it is becasue Kieth Black hyperutectic pistons, they say no more than 32* total timing or you can blow the top off the piston. Plus no knock sensor. I may be able to lower the main spark table to 29* now and make it happen. Wont know until i get a chance to log.

Yeah I have thought about starting over may still yet.

[EagleMark]

When I know what the engine is built for I usually shoot for 10% less timing on a street vehicle. There's weather, tempreture and who knows what the fuel really is? I never hurt a motor this way!

Make sure you allow the Cold Spark Bias or Cold Spark table to still be in use. Really helps reduce engine wear. Then only use data from full warmed up engine.

How did you disable Knock system? We are having an issue with code 43 on another LT1 but knock counts can be found with a hammer? PCM is in LHM...

[96lt4c4]

When I know what the engine is built for I usually shoot for 10% less timing on a street vehicle. There's weather, tempreture and who knows what the fuel really is? I never hurt a motor this way!

Make sure you allow the Cold Spark Bias or Cold Spark table to still be in use. Really helps reduce engine wear. Then only use data from full warmed up engine.

How did you disable Knock system? We are having an issue with code 43 on another LT1 but knock counts can be found with a hammer? PCM is in LHM...

Cold spark is still in use.

Just turn off code 43 and zero out all the knock retard tables so it will not pull any timing. You may still show knock counts though.

[EagleMark]

There is a closed TPS at idle spark table that is only uses at idle. I am going to try and zero that out and force it to use the main spark table.

Not sure that will come out well in drivability as it also interfers in DFCO? I've never messed with it other then mactching up idle to main table.

Looking at Log2 and WOT, it sure looks like PE/WOT spark is being added!

Advance looks to be spot on till 4000 RPM then it starts adding as RPM increase. Your MAX timing is also set to 40 in that bin, but still bumped 41 in log.

Try zeroing out Minimum Spark Avance Vs RPM and might find 2 more degrees?

[96lt4c4]

Not sure that will come out well in drivability as it also interfers in DFCO? I've never messed with it other then mactching up idle to main table.

Looking at Log2 and WOT, it sure looks like PE/WOT spark is being added!

Advance looks to be spot on till 4000 RPM then it starts adding as RPM increase. Your MAX timing is also set to 40 in that bin, but still bumped 41 in log.

Try zeroing out Minimum Spark Avance Vs RPM and might find 2 more degrees?

'
Ok, I will set closed throttle spark to same as the main table

I did zero out min spark advance vs RPM, thats when the timing dropped to 37*

I think 2 more degrees is coming from the Spark Correction VS. Map VS. Coolant temp , he is running a 160* F thermostat, so in these temp areas of that table, its addid 2*. So I zeroed that out.