can't get wot timing below 26 degrees

With my turbo setup I'm trying to run less than 26 degrees timing at wot, but no matter what I command it will only go as low as 26 degrees. I got the 2 bar tune from engineermike who had this problem also I believe and is using his ignition box to pull out timing.

I didn't have this problem with my old 1 bar tune, but for some reason this two bar tune has this problem. I've compared tables to my 1 bar tune and nothing is drastically out of what it should be though.

I've copied all the tables from the 2 bar tune into my 1 bar file, but that didn't help.

I'm running open loop and never hitting PE. Minimum spark advance I've set as low as 3 degrees and it will still run 26 degrees at wot.

Under part throttle/idle the timing is normal though.

I've heard of another person other than engineermike having this problem before, but can't remember who it was though. Also I believe Mike had this problem back when he had the 1 bar tune also.

Any suggestions?

You checked the actual "Minimum Spark Advance" table. It has positive values beginning with 4400 RPM, up to 20* at 5200, and 23* at 5600+. Zero those out or put them at your new, appropriate mins. But if you mean you already did that...

Then what about the "Spark Coolant Temp Correction Bias" Constant? It's set to 20* stock. You could try zero'ing that out.

Yep already set the minimum spark advance to as low as 3 degrees, I could try zero though.

The bias is at 20, I've set it to zero. I've also tried putting in negative numbers in the spark correction vs coolant temp tables, but it didn't change anything.

Very strange. Maybe we're dealing with another hidden table. Try emailing TunerCat and ask if they can find something that might be it?

I've seen timing go down to 0* when DFCO is engaged, so it's definitely possible to go under 26. But just not at WOT it would appear... the other weird thing is that the stock tables have some WOT values under 26, obviously, in the lower RPM sections. Are you getting 26* from 1000RPM up? Or just the high-end?

Can you put 0 in all the WOT tables and run WOT starting from 1000rpm then tell us what the timing does?

I agree with sending Tunercat an email, but you might want to start from 1000rpm on up first then relay that info to them.

Does it matter if it's in closed/open loop or MAF/Speed density mode?

I'll show them an email, with my 4000 stall, I don't get to see a whole lot of 100% tps under 3500 or so.

I am only open loop, no maf. I haven't tried putting the wot tables low enough that it kicks in PE yet, still want to try that, just been too busy.

I'll shoot tunercat an email.

Oh yea, I was thinking manual trans. I was thinking you could see something like 1-2 degrees of timing added for ever 500rpm being added automatically, or if there's a wall where it jumps up 5 degrees at some event (like RPM or MAP).

Just curious, about what psi do you start to require 26 and lower timing?

I run PUMP GAS 95% of the time so no reason to try to run high timing and take a chance of hurting the motor for the extra 20 or 30HP.

I usually like to run 16-18 degrees, very conservative and plan on running 11lbs on pump gas then 18lbs on good gas. It should go 135mph through my big stalled auto on 11lbs and pump gas.

Makes sense, When I dyno'd I was at 38degrees total timing! :eek: I was wondering what was normal, I'm at 32 right now, occasionally I get some knock usually only in second gear? so Maybe I'll bring mine down to like 22-24. I did compare timing HP on the Dyno once and saw about ~2hp per degree of timing.. I only compared up to 4 degrees though.

When I do that I'll let you know how it went, or didnt went.

Have any luck figuring this out??? Im having the same issure but I seem to be stuck at 27*.

Im also wondering, If I am showing 3* of knock retard, and showing 27* timing. Is that actual timing or is it 27*-3*= 24*

Datamaster on mine currently shows 14 degrrees with 12 degrees pulled out(knock sensor is pulling max amount, had this problem last year, not sure what is wrong with my knock sensor and havent had time to troubleshoot, just letting it pull it out so I can at least get my timing in the SAFE area). It is trying to command 26 degrees then pulls 12 so I end up with 14 degrees. I did bump it up to 18-19 degrees at wot for right now though.

Datamaster on mine currently shows 14 degrrees with 12 degrees pulled out(knock sensor is pulling max amount, had this problem last year, not sure what is wrong with my knock sensor and havent had time to troubleshoot, just letting it pull it out so I can at least get my timing in the SAFE area). It is trying to command 26 degrees then pulls 12 so I end up with 14 degrees. I did bump it up to 18-19 degrees at wot for right now though.

Your knock sensor only picks up basically full knock only at WOT? What if it decides to work again and doesnt pull anything out?

It yanks full timing all the time, I just have it tuned so it can't pull timing at part throttle. It's an issue I need to fix after the ltx shootout, I believe a new knock sensor will fix it, or I will be tracking down the wiring. Either way, I don't have time right now to fix it, it's been doing it since the last turbo setup so I doubt it will start working now.

Interesting.

I know this isnt worth posting but I was getting ready to make some WOT runs with Datamaster logging to see what my timing did.. see if I had the same limit around 26 degrees but now my laptop freaks out when I insert the pcmcia card... locks up.. gets real slow...

I was going do to it all week and cant until this is fixed..

Datamaster on mine currently shows 14 degrrees with 12 degrees pulled out(knock sensor is pulling max amount, had this problem last year, not sure what is wrong with my knock sensor and havent had time to troubleshoot, just letting it pull it out so I can at least get my timing in the SAFE area). It is trying to command 26 degrees then pulls 12 so I end up with 14 degrees. I did bump it up to 18-19 degrees at wot for right now though.

Silly question, how do you know whats its commanding vs. what its getting? Im assuming your looking at the logs for what its getting, then searching the table for what it should be commanding?

When you tune the timing you use a map pressure and rpm. If you know you have 100 kpa at 3000 rpm set for 25* and datamaster is showing 28*.


Technically should be comanding 25*

When you tune the timing you use a map pressure and rpm. If you know you have 100 kpa at 3000 rpm set for 25* and datamaster is showing 28*.


Technically should be comanding 25*

Yeah. In my tune i was commanding 24* and datamaster shown as much as 27* with 5* pulled from knock. I set it to 15* commanded and now am gettin 16* (on logs).

There must be another table (hidden?) somewhere that is adding this extra timing. :confused:

I finally made a few WOT runs. Mine does not appear to lock at 26 degrees like some others. I've heard timing is usually off a few from request and datamaster reported.. dont know if it's something demanding the timing increase or if it's the way Datamaster reports it.

To test, my file is set for 20 degrees total timing and 100%TPS at 4400rpm timing is at 23degrees and climbes to 24degrees at 5200rpm and stays at 24 all the way to 6100rpm where I have rev limit set.

There is a hystresis somehere (hidden likely) because my RPM is a bit flucuating around 5200rpm so the first timing step from 23-24 does show up around 5250 at first then the rpm drops back to 5100rpm for a second but timing stays at 24degrees..

Im sure there's a bunch of hidden tables we dont know about so wondering if they vary from year or manual/auto flash. Mine is an original 1995 6 speed flash.

Hope this helps!

I finally made a few WOT runs. Mine does not appear to lock at 26 degrees like some others. I've heard timing is usually off a few from request and datamaster reported.. dont know if it's something demanding the timing increase or if it's the way Datamaster reports it.

To test, my file is set for 20 degrees total timing and 100%TPS at 4400rpm timing is at 23degrees and climbes to 24degrees at 5200rpm and stays at 24 all the way to 6100rpm where I have rev limit set.

There is a hystresis somehere (hidden likely) because my RPM is a bit flucuating around 5200rpm so the first timing step from 23-24 does show up around 5250 at first then the rpm drops back to 5100rpm for a second but timing stays at 24degrees..

Im sure there's a bunch of hidden tables we dont know about so wondering if they vary from year or manual/auto flash. Mine is an original 1995 6 speed flash.

Hope this helps!

I noticed that same hiccup in the rpm. Ill have to go back and look, but I think it happened at 5100. Dont think I looked at the timing though, its when i was trying to get the fuel straightened out.

I noticed that same hiccup in the rpm. Ill have to go back and look, but I think it happened at 5100. Dont think I looked at the timing though, its when i was trying to get the fuel straightened out.

Ok, I'm starting to think timing may be linked to MAP.. increasing MAP means increasing Timing?

Can you guys with this timing problem confirm your running a 2 bar MAP and tune? ACtually it wouldnt matter because a 1bar tune would max at 100kpa which (if it's linked to MAP) then could be what is giving you 26 degrees... makes sense.

I'm only at 70-72kpa /5225rpm when I get the jump... could even be MAP+RPM, or MAP or RPM connected. Right now it seems people with higher boost are seeing higher timing, or people with a 1bar which maxes at 100kpa quick. You could pull off your intake tube and go WOT and see what happens to timing with 0 boost.

If there is a connection and we described it very good we could get TUnercats or LT1 Edit to search the code and come up with a new table!

Next time my tuning laptop is booted up i will look at some of my old logs.

Im pretty sure I have my timing set to 25* but I am actually seeing 29* on datamaster by 6000 rpm.

I still havent bought my 2 bar map. I am 1 bar, speed density, open loop for now.

Im pretty sure I have my timing set to 25* but I am actually seeing 29* on datamaster by 6000 rpm.

I still havent bought my 2 bar map. I am 1 bar, speed density, open loop for now.

yea, I see higher than requested timing as well but it does go lower than 26.

I ran another WOT run with even lower timing than in the first table.

First run I set timing to 20 in ALL wot tables, and results:
4400rpm at 23 degrees,
5200rpm at 24 degrees
6100rpm at 24 degrees where I have rev limit set.

Second run I set timing to 15 in ALL wot tables, and results:
4400-5000rpm at 18 degrees,
5000-5800rpm at 20-22 degrees
5700-5900 22-23 degrees where I have rev limit set.

So, still.. it is lower but seems to be increasing.. need to change or remove boost to determine if it's MAP related.

EDIT -
I just realized my min spark advance in this test above was stock at 15@4800, 17@5200, 18@5600, 19@6000+... to this explains the reason why 15 and 20 timing settings end up close to the same timing above...

11.21 at 121 on 5lbs in 1st and 2nd, 7lbs in 3rd....10.80 at 127.8 on 8lbs in 1st, 11.5lbs in 2nd/3rd....

1982z28with18s, you should be able to tell us if it's MAP related since you run variable psi depending what gear your in. Run your 2 bar tune @ WOT through the gears, let us know if each gear gives the same timing retard at say 4000, 4500, 5000, 5500, and 6000 rpm. If it does give the same timing in all gears regardless of pressure then the MAP theory is out the door and it could be linked to RPM.

BTW you might want to enter 15 degrees in all the WOT tables just to make it easier to see what's happening.

I've had it set at 8 degrees before, still got 26 degrees at all rpm's anywhere from 4lbs up to 14lbs, always the same 26 degrees of timing.

I did put the 1 bar tune back in it yesterday and got exactly 16 degrees like it is supposed to be.

I've had it set at 8 degrees before, still got 26 degrees at all rpm's anywhere from 4lbs up to 14lbs, always the same 26 degrees of timing.

I did put the 1 bar tune back in it yesterday and got exactly 16 degrees like it is supposed to be.


In previous posts you mentioned trying the stock 1 bar and timing was still not right. You must have a corrupt LT1 file.

I had a file suddenly stop reporting speed... did everything.. finally reverted back to an old file and everything worked normal.

I suggest take that working 1 bar and transfer tables.. there's no reason timing should report differently unless the file is corrupt.

I've had it set at 8 degrees before, still got 26 degrees at all rpm's anywhere from 4lbs up to 14lbs, always the same 26 degrees of timing.

I did put the 1 bar tune back in it yesterday and got exactly 16 degrees like it is supposed to be.

Can you post a datamaster file for download? Id like to compare to mine. I can post mine if your interested. Your happenings are indeed strange.

What if I send you my lt1 file? is it anywhere near the same setup?


BTW, I went all the way down to 15 for timing and was getting 18-23 reported in datamaster. Far from what you are seeing (constant 26 degrees all the time in WOT).

Something is definately wrong with your file.

Could the iat vs timing tables be throwing you guys off? for some reason i remember that these tables were only avaliable in lt1edit and not tunercat. This could be that "hidden table" you guys were speaking of.

P.s. i started my turbo build this weekend. Im running 60 lb mototrons could anyone suggest a good constant to start with? i was thinking 20-25lb for my 2 bar sd. has anyone wired in their wideband analog output to both inputs for 02 sensors? vemaster needs o2 feedback to work am i correct? my thinking was why not use the wideband for both o2's and assume the motor should be fueled the same for each bank.

I was wondering if lt1edit had a iat timing table as I don't believe tunercats does. Can anybody confirm this?

:yes: A friend of mine has lt1edit he said the table was there. So im gonna open my tune in lt1edit. Zero the table out, then proceed using tunercat.

but this wont happen for a few weeks. So could someone else confirm? Anyone wanna talk to tunercat to see if he can enable the table? I will shoot him an email anyway.

If this solves the problem of not getting exactly what is commanded in the timing tables can i get a cookie?

Could the iat vs timing tables be throwing you guys off? for some reason i remember that these tables were only avaliable in lt1edit and not tunercat. This could be that "hidden table" you guys were speaking of.

P.s. i started my turbo build this weekend. Im running 60 lb mototrons could anyone suggest a good constant to start with? i was thinking 20-25lb for my 2 bar sd. has anyone wired in their wideband analog output to both inputs for 02 sensors? vemaster needs o2 feedback to work am i correct? my thinking was why not use the wideband for both o2's and assume the motor should be fueled the same for each bank.

I have both Tunercat and LT1_Edit.. unaware of the IAT vs Timing table... I'll look for it though.

20-25 should be good

I wanted to try the wideband 02 wired to both 02 inputs havent tried it yet, yes VE master uses feedback from the 02's (lterms or sterms) Good luck!

:yes: A friend of mine has lt1edit he said the table was there. So im gonna open my tune in lt1edit. Zero the table out, then proceed using tunercat.

but this wont happen for a few weeks. So could someone else confirm? Anyone wanna talk to tunercat to see if he can enable the table? I will shoot him an email anyway.

If this solves the problem of not getting exactly what is commanded in the timing tables can i get a cookie?


I just checked my LT1_Edit and cannot find IAT table. Besides, I think this would only take away timing based on hot air... not increase timing from hot air (hot air = boost). Just my thoughts I could be totally wrong.

I see where you are coming from. Hmmm guess my friend was full on shiiiii. I sent tc a link to this thread yesterday let’s see if he gets back to me. Since the increase is not constant i would assume that its not a table vs rpm that we are lacking but a table vs some sensor. But who knows it could be an algorithm of some sort. Im hoping he gets this one hammered out too. Cause im looking to run 14-18 deg of timing on my stock motor. I don’t need something like this being responsible for popping my motor.

Could i convince anyone else to email tc too?

Hi Brian,

I'm not sure what might be causing the discrepancy in the spark advance values. Assuming the engine is up to running temperatures and the startup spark parameters are no longer active, the spark advance is derived from the 'Main Spark Advance Vs. RPM Vs. MAP' (or the 'Extended Spark Advance Vs. RPM Vs. MAP' above 4000 RPM), the 'Spark Correction Vs. MAP Vs. Coolant Temp.' and the 'EGR Spark Advance Correction Vs Vacuum Vs RPM'. Any knock retard or traction control retard values are applied and the values checked against the min and max spark values.

The spark advance vs. IAT table was not implemented in the LT1 cars until 1996. The OBDI calibrations do not have this table.

Make sure you don't have any error codes set. Sometimes error codes can result in strange behavior where default values are used instead of the normal values. If you are using a 2 bar MAP sensor instead of the standard 1 bar, that might also be causing some problems since this will shift all MAP and baro parameters.


Best regards,
TC

Does that help anyone?

Maybe since were using a 2 bar map the egr is kicking in cause it see's map ranges for part throttle. So it advances the timing.

I got the same email from TC. EGR could be doing something, i did see it throw in 5 degrees in the past but I disabled it. Also, the MAP scale doesnt apply since we are simply halving the injector size, plus this is also happening to 1bar users correct? There's some posts below of people with 1bar having the same problem.

Hi Dan,

I'm not sure what might be causing the discrepancy in the spark advance values. Assuming the engine is up to running temperatures and the startup spark parameters are no longer active, the spark advance is derived from the 'Main Spark Advance Vs. RPM Vs. MAP' (or the 'Extended Spark Advance Vs. RPM Vs. MAP' above 4000 RPM), the 'Spark Correction Vs. MAP Vs. Coolant Temp.' and the 'EGR Spark Advance Correction Vs Vacuum Vs RPM'. Any knock retard or traction control retard values are applied and the values checked against the min and max spark values.

The spark advance vs. IAT table was not implemented in the LT1 cars until 1996. The OBDI calibrations do not have this table.

Make sure you don't have any error codes set. Sometimes error codes can result in strange behavior where default values are used instead of the normal values. The 2 bar MAP sensor might also be causing some problems since this will shift all MAP and baro parameters.

Good news... I did some testing tonight and found RPM is linked to the timing increase, not MAP, or 2 bar MAP... verified using 1 and 2 bar sensor (also 53kpa or 100kpa BARO @ Key On have no affect on Timing).

I've read somewhere else timing is automatically increased as RPM increases.. now we have even more proof of that.

I simulated RPM using an old opti spinning with a grinder, simulated MAP using an air compressor, from 50kpa, 75, and 100kpa.

Held Throttle WOT (and disconnected my injector driver.. ha)

Loaded a file with 10 degrees of timing in all tables beyond 50kpa at all RPM. Set all temp offsets to 0, set all min timing to 1.

1) Ran 50kpa MAP (0 boost) from 400-6375rpm, showed the following:
400-700rpm = 10 degrees timing
800-2100rpm = 11 degrees timing
2200-3700rpm = 12 degrees timing
3700-5300rpm = 13 degrees timing
5300-6300rpm = 14 degrees timing

2) Ran 75kpa MAP (7.5psi) at same RPM's as above with same timing results:
400-700rpm = 10 degrees timing
800-2100rpm = 11 degrees timing
2200-3700rpm = 12 degrees timing
3700-5300rpm = 13 degrees timing
5300-6300rpm = 14 degrees timing

3) Ran 100kpa MAP (14psi) at same rpms as above with same timing results:
400-700rpm = 10 degrees timing
800-2100rpm = 11 degrees timing
2200-3700rpm = 12 degrees timing
3700-5300rpm = 13 degrees timing
5300-6300rpm = 14 degrees timing

4) I then ran "stock" 100kpa BARO Key On with 100kpa load... same results (so I wont post them).

-----------------------------------------------------------------------------------------------------------------------------
Edit - Added the following timing tests... All were tested with varying amounts of MAP pressure from 50-100kpa with no affect on timing...

---------------Setpoint-5 degrees--10 degrees----15 Degrees----20 Degrees
400-700rpm---=--------5----------10------------15------------20
800-2100rpm--=--------6----------11------------16------------21
2200-3700rpm-=--------7----------12------------17------------22
3700-5300rpm-=--------8----------13------------18------------23
5300-6300rpm-=--------9----------14------------19------------24
6300+rpm-----=--------10---------15------------20------------24-25

Thats awsome!! lol well atleast we know that we just have to enter 5 degrees less or so in our timing tables. Why cant the op get his timing to below 26 :irk:

Why cant the op get his timing to below 26 :irk:

I dont know, I asked to see his datalogs and LT1 file and never got a response. There's probably other stuff affecting the timing but the MAP/BARO had absolutely no affect on it.

quick reference for me to get a base tune done. what kpa translates to atmosperic? what kpa translates to say 5 psi? 9 psi?

thank you

I dont know, I asked to see his datalogs and LT1 file and never got a response. There's probably other stuff affecting the timing but the MAP/BARO had absolutely no affect on it.
Are you asking for mine? I started with your tune actually that I got from Engineermike that he slightly modified then it was doing the 26 degree timing thing.

My laptop is too old to connect to the internet so I have to go through a work computer via a floppy disk to get the tune back to where I can email it. Do you want a copy of my tune/datalog? :confused:

Yea if you can email the file and the datalog somehow that would be good.

I was thinking it had something to do with the BARO being half of what is normal but when I start at normal KPA (100) the timing does the exact same thing.

Only other sensors/things that werent as they usually are on a running motor are coolant temp and closed loop, but I wouldnt think closed loop would affect timing and coolant temp shouldnt matter if the values in all the coolant temp boxes are the same (0).

codytherott
@
hotmail
.com

Update to an older post i made about the timing

Reason: My latest non-running timing simulation shows up to 4-5 degrees of additional timing based off of RPM and I didnt know why that didnt match the one running/driving datamaster log comparing 15 and 20 degrees requested timing since those logs started with lower timing but but ended up at redline with about the same results...

I just looked back at the file I used and saw I had the stock "minimum spark advance" tables which look like this:
15@4800, 17@5200, 18@5600, 19@6000+... so this explains the reason why 15 and 20 timing settings end up close in that post...

First run I set timing to 20 in ALL wot tables, and results (using 15-19 degrees in "Minimum Spark Advance" from 4000+rpm")
4400rpm at 23 degrees,
5200rpm at 24 degrees
6100rpm at 24 degrees where I have rev limit set.

Second run I set timing to 15 in ALL wot tables, and results (using 15-19 degrees in "Minimum Spark Advance" from 4000+rpm"):
4400-5000rpm at 18 degrees,
5000-5800rpm at 20-22 degrees
5700-5900 22-23 degrees where I have rev limit set.

Sent TC an email about the max of 5 degrees of additional timing linked to RPM and they didnt know why that happens but wanted a look at my file so I sent it today:

Hi Dan,

Hmm, strange. I can't think of anything that would add advance based on RPM like that but if you get a chance, send me the calibration (.bin) file you are working with so I can take a look at it.

Best regards,

TC

I posted a few links about that in reference to how the timing increases with RPM, there is one on the first page someone asking as well, thanks for the exact numbers though, on my old setup I had the timing at 28* at 7000rpm or so so that I would get about 33* in the end, even saved a word pad, thats cool how to simulated it with an opti spinning :)

I posted a few links about that in reference to how the timing increases with RPM, there is one on the first page someone asking as well, thanks for the exact numbers though, on my old setup I had the timing at 28* at 7000rpm or so so that I would get about 33* in the end, even saved a word pad, thats cool how to simulated it with an opti spinning :)

yea I didnt remember who posted it but I could remember it being talked about here and other places as well.

Strange thing in my datamaster logs is the rpm maxes out at 6375 but it appears the PCM continues to calculate RPM since the injector duty cycle increases to climb. Is that normal?

The 15,000rpm angle grinder really gets the opti spinning! Even managed to blow the rotor apart in the beginning!