Can I get some eyes

[srobertsfsj]

ok good news! Ran your bin on the way home only changing Initial SA and Bias warm. Why change bias warm to 0? Well, to be honest, IIRC is was FSJ Guy that advised me to set it to 0 and I believe he had a good reason which escapes me at the moment. Maybe he will chime in. Other then BLM being in the 140's and 150's the entire time it did run better, well different at least. I think i just need to do some VE tuning and it will be good to go there. I will do a long run in the morning.

Then, based on what you said earlier I just decided to set the Bias Warm to 10 and what do you know!!!! My idle issue in pk/n went away! Idles at about 950 now instead of 1250....The only thing i noticed is that it has to crank a bit to start. Not sure why yet but at least its something!

So its my understanding that the Bias Warm setting subtracts from the main SA table. Is this doing this in O/L and C/L or just C/L? Also, how does this parameter relate to the initial SA? If I set this to 10 and I change my initial SA to 0 does that mean that on startup it will retard 10 deg from 0? I dont think these engines like be that retarded on startup. I guess I need a quick tutorial on the purpose of these Bias settings.

[EagleMark]

It does it all the time. It effects so many paremeters... there are so many things that should not be changed. I thought of making a new catagory in the $42 XDF for "Only Change These!"

Leave the warm bias alone! That is the way the bin works. If the bin started with 0 warm bias work with it, if it started with 9.84 Warm Spark Bias then work with it. If you change a Bias from 9.84 to 0 then everything in bin is off by 9.84 degrees! Do you know every other paremeter that adds or subtracts from main spark table and how the Bias effects it? I don't and would not even try to, no need to. When I saw your first bin I assumed it started as a 7.4L bin as they have 0 degree spark bias. Both have 20 degree Cold Spark Bias.

Spark bias is to allow negitive numbers, everything is off by "Warm Spark Bias" or "Cold Start Bias" so negitive numbers can happen without being entered, it won't work if you enter -3, "-" is not usable or convertable to hex.

Initial Timing or Base Timing is where the distributor is set. It is supposed to be 0 and the timing table works. If set to 10 then everything is off by 10 so Initial Timing paremeter is set to 10 to take it off and not allow TO MUCH TIMING! Max timing is 41.84 degrees because there is just not enough room between spark plug terminals on cap, 360 degrees and math. Now you added 10 and POOF or better yet BOOM, your firing the wrong cylinder.

Now consider all the other Bias, adder, subtractors, AE spark, PE Spark, Decel Sparl, DFCO, Spark, EGR Spark... ahhhhhh!

This bin is set to be used at 0 base timing, if you need more for solid idle then add it to timing table. Adding to base timing should not be messed with unless your trying to make a huge cam with overlap, like EGR at idle and need more idle timing which I have used 45 degrees (Bias makes this not actual), this is more then available so we need to start adding to base timing. Then all the other complications start!

You can change to much in a bin and it no longer works properly. Change as little as possible and know what else it effects if you change something. One change to fix something can cause 10 other issues.

Now that your idle is closer and things are Biased properly you may be able to set base timning to 0 and see more idle improvements!

[srobertsfsj]

I think that would be awesome if you make a bin that says only changes these!!!! That way people like myself can start out with much less confusion and probably learn quicker.

Anyway, tried to make a long run this morning. I thought I would give your bin a try and see what happens. The only thing I changed was the initial SA (only because I haven't set base timing to 0 yet). I also had to bump up the VE, table wide about 2.5 to get it not to run so lean. I had to cut the run short because only a mile or two down the highway my engine temp quickly got up almost 210deg, and I didnt have any low,mid or high range power at all. I pulled over to the side of road and switched to a previous bin. Also, I noticed that the TCC show locked about 90% of the time. I thought it was turned off in this bin but I guess not. Attached is the short log from this morning.

I think I will try to set the base timing to 0 this evening and give it another try.

Also, I found out the cam in this engine is a Comp Cams 260H.

[EagleMark]

So it ran OK yesterday and you changed 10 degress today and ran bad?

That cam is not mild or RV, it is almost limits of EFI into hard tuning! Did you degree it when installed?

[srobertsfsj]

I ran OK yesterday with the 0 bias warm and the Initial SA at 10. I changed the bias warm to 10 this morning and had the issues.

I spoke to the PO of the engine and he said he was pretty sure that the cam was degreed.

[EagleMark]

OK if you want to figure out what's going on you need to stop changing things. That bin was set to work as is with bias settings and 0 degree base timing and I'll know what's happening. Right now your adding and subtracting 10 degrees from all over the place. Your logs show some ignition timing issues and we haven't even checked timing a timing marks yet. We have to get some baseline data to work with. I know what that bin will do, but not with all the changes, I was trying to rule out this ignition timing issue as bin related. See the method to my madness?

That cam specs are 1000 or 1200 RPM and up, not idle and up. So at 600 RPM idle and an auto? Your going to have some lack of power from idle to 1000 to 12000 with a stock tourque converter. This also explians the low vacuum at idle compounded by elevation. Idle spark may need to be increased as well as idle RPM as much as you can handle. When running better idle will not be revved high like the issue you were having if done correctly getting into closed loop, we can try and get open loop idle down as well.

Knowing the cam now you could change base timing to 5 at distributor and bin. Are all the AMC guys adding 10 degrees to base timing and setting warm bias to 10? That just makes idle timing the same. But skews all other timing like we discussed.

The changes you made to VE don't make sense either, you said you needed to add everywhere? Should have been less at idle and lower RPM with that cam compared to milder cam it was tuned for.

Need a starting point!

[srobertsfsj]

I definitely see the method to your maddness. My plan for the weekend is to start over basically, I am going to verify my timing first and see if how far off it is, if any. Then I should probably adjust my base timing to 0 or 5 like you said.

Looking at the bin you made. You turned off the TPS% hack but turned on the BPW and SA hacks, is this correct? In an earlier post you mention the TCC not locking up anymore, on this last run the TCC showed locked most of time when I was on the highway, is this an issue?

[shimniok]

I'm the PO of the engine. :) A few points of information that may or may not help.

I had the engine rebuilt. The shop degrees cams as part of the basic rebuild. They told me they did. So, supposedly they did but lack of power on the mountain passes made me wonder and I let Scott know that it might be something to check when he got the motor.

Without fully understanding the nuances of GM EFI timing, from a carburetor, duraspark, AMC 360 standpoint, I haven't had much luck with an AMC motor idling at 0 degrees actual timing (no vacuum advance). We usually set them around 16 actual (no vacuum advance, but with mechanical advance) to get a decent idle.

Eagerly watching this and other threads because I'll be neck deep in this soon. Learning as fast as I can.

Michael

[EagleMark]

I definitely see the method to your maddness. My plan for the weekend is to start over basically, I am going to verify my timing first and see if how far off it is, if any. Then I should probably adjust my base timing to 0 or 5 like you said.

Looking at the bin you made. You turned off the TPS% hack but turned on the BPW and SA hacks, is this correct? In an earlier post you mention the TCC not locking up anymore, on this last run the TCC showed locked most of time when I was on the highway, is this an issue?

Yes we want those 2 on and will not effect knock counts or other useful data.

I may have goofed on TCC? I'll look at it...

[EagleMark]

I'm the PO of the engine. :) A few points of information that may or may not help.

I had the engine rebuilt. The shop degrees cams as part of the basic rebuild. They told me they did. So, supposedly they did but lack of power on the mountain passes made me wonder and I let Scott know that it might be something to check when he got the motor.

Without fully understanding the nuances of GM EFI timing, from a carburetor, duraspark, AMC 360 standpoint, I haven't had much luck with an AMC motor idling at 0 degrees actual timing (no vacuum advance). We usually set them around 16 actual (no vacuum advance, but with mechanical advance) to get a decent idle.

Eagerly watching this and other threads because I'll be neck deep in this soon. Learning as fast as I can.

Michael

Thanks for sharing info so we can work this out.

When we speak of timing set to 0 it is base timing, where distributor is set. When set and bypass wire reconnected timing is controlled by ECM, just looked at his timing table and if LEFT ALONE it comes out to 15.5ish although the timing table says 25.5ish... back to leaving Warm Bias alone which takes out 10. So good baseline to start with your AMC engine experiance. I'm guessing stock as a cam like this usually likes more. Also do you know what vacuum advance adds on these? Right now we are at 15 without vacuum added...

[srobertsfsj]

This weekend I also plan to pull a couple of plugs and see how much damage I have done running to too advanced and lean for awhile :)

[shimniok]

So good baseline to start with your AMC engine experiance. I'm guessing stock as a cam like this usually likes more. Also do you know what vacuum advance adds on these? Right now we are at 15 without vacuum added...

I recall it being in the ballpark of another 10-15 at idle.

[EagleMark]

That would have been about 10 to 15 less then what he had and 10 short of where he is. Thanks!

[shimniok]

Well... I might be low on my estimate for vacuum advance. :( I am looking in my TSM (84 but should be applicable)

Mechanical ranges to between 14° and 19° total at 4400rpm. Vacuum advance is 21°-27° at between 11-13 in-Hg (allowable ranges). Base timing is 16° at this altitude. So is this vacuum curve the total advance or is it added to the mechanical advance?

2012-07-26 17.52.05.jpg

[EagleMark]

I'm not sure what to make of that graph? There's got to be some more info?