Need help with Spark Table

[midgetracr]

I have been tuning a modified L-32. AFR is pretty close to commanded, KR is 0.2* at max. and I've begun playing with ignition timing. The timing at high loads does not seem to be following what my spark tables command. The low octane spark table is 4* lower than the attached hi octane spark table. The ECT and IAT spark tables (which are also attached) do not seem to be causing this. Please refer to the section around frames 2700 to 2710 in the attached HPL file for an example. IAT was 73* F at frame 2707.

Specifically, spark is at 14.5* in frame 2707 and I think it should be 10*. I know 10* is not enough but am reluctant to advance spark until I can get it to do exactly what I want.

What am I missing?

Mods are available but don't seem relevant to this question.

Thanks

[midgetracr]

Doesn't anyone have an idea about this? Someone must have run into this situation. I am road racing next weekend and today/tomorrow are the only times I'll have to finish my tuneup. Thanks in advance for any suggestions .

[MMGT1]

Are your trans settings affecting spark? Torque reduction?

[midgetracr]

Don't think so because it is a manual trans car. How can I tell? Thanks for your reply.

[joe02]

I think he means to check the torque management settings. To make sure you are not exceeding what you have set.

It is a safety setting, but many in the aftermarket world (especially v6) will set this on the max. 640 or whatever it happens to be.

Usually I only see spark that is not as high as commanded. I do know that if i go too low(timing), my car won't idle.

hopefully someone will chime in.

[midgetracr]

That is the strange thing Joe. The commanded timing is HIGHER than the Hi Octane table calls for.

My Max Engine Torque vs RPM vs Gear table is set at 380 ft lbs thruout, the max torque vs RPM is set at all 258's and the Max torque vs gear is 300, 384, 500 and 500 in first thru 4th gear. Because my engine is connected to a 5 speed Tremec trans, I don't think the VCM could know what gear it is in, unless somehow it computes it via RPM vs Speed. The VSS is connected and properly calibrated.

Should I change all the settings to 640?

Thanks for your suggestions Joe.

[Bill@HPTuners]

Have you tried tuning in closed loop at all or just open loop? There are very few open loop parameters available for this particular V6 engine.

[midgetracr]

Thanks Bill for your response. I was unaware of a separate "closed loop command". I think it is in open loop when my issue occurs because the PE enable is set at 15/20%. Does the open/closed loop thing impact ignition advance? If so, how do I A) find out and B) change it?

[Bill@HPTuners]

I think its because your bank 1 sensor 1 o2 is not funtioning which might be causing it to fall into open loop automatically.

[midgetracr]

I see from the logs that the O2b1s1 signal is not changing. Because I have a wide band I've neglected to notice this. I'll change the sensor to another sensor that I've got and see if it makes a difference. Thanks Bill.

[midgetracr]

Changing the O2 sensor brings back the O2b1s1 signal. However ignition advance is still well above where it is set in my cal. Prior to running the attached log I did verify that the VCM controls Fuel & Spark closed loop button was "ON". Since the postings of last night I've also set all the torque control settings to 640 ft lbs.

It seems like the system is ignoring my Hi and low octane spark tables.

What else should I try? Thanks.

[Bill@HPTuners]

can you post your hpt file or send it to me & I'll have Chris take a look to see if theres other tables he needs to add in the calibration.

[midgetracr]

Just sent via PM Bill.

Thanks

[Bill@HPTuners]

forwarded the info to Chris to have a look at.

[Russ K]

I would say the there is PE spark being added. This table is not yet in the editor, Chris @Hp Tuners zeroed that table on for me.

Russ Kemp

[midgetracr]

Thanks Russ. That would explain what is happening.

Do you know how to zero that table? Or how can I display what is in that table? If I know what is there, I can proceed and account for what the "PE Spark" table will add. Presently I am afraid to do much for fear of timing suddenly jumping way higher than it should and hurting my nice new (and expensive) engine.

[johnh]

AFR Spark...

On stock 2004+ calibrations for the L32 this table adds timing based on AFR.

12.7 adds 2*, 11.7 adds 4*, 10.7 adds 7*, 9.7 adds 9*

So even though say High Octane says 14, you hit PE at 11.5 and you're gonna see 18* timing....

[midgetracr]

The mystery may be solved. Thanks John.

If I understand correctly, under PE with a commanded AFR from 12.70 to 11.71 spark will be +4* over the appropriate Hi or Lo Octane table and from 11.70 to 10.71 it will add 7*, etc.

Is this correct?

[johnh]

I believe so, I think there might be some scaling involved because I have seen small variances (.5 to 1*) of timing....

[midgetracr]

You were correct John H.

With Bill Henn's (of HPT support) help I now have a beta test version of VCM Editor that allows me to display and modify a table that changes timing based on AFR. It took a couple of days, but this table allows me to dial in and maintain exactly the timing that I want.

On the stock 2001 Grand Prix L-32 V-6 table the timing added was 8* at a commanded AFR of 9.7, 6* at AFR of 10.7 and 3* for AFR of 11.7. It is my understanding that this table will be added to a regular release at some time in the future.