Cat warmup delete-How to fix cold start idle?

Really?

I'm suffering some dreaded phantom KR all over the place still. Some pulls I'll see 0.00 and then another will see 3.0. Midrange will be clear across the board but as soon as I'm done with a pull and just driving around, I get KR like crazy. Sometimes as much as 4.2 in the midrange.

I'm checking into the position of the knock sensors themselves and also to see if there is any metal on metal anywhere (dp, intake, etc.).

Just rainy weather and not a lot of time is keeping me from getting under the car.

I'm actually in the middle of completely re-doing my DAL table to increase in air load rather than starting high and slowly dropping off. Almost seems backasswards with how they set it up. I understand 400-1000 deal with idle but the rest is just strange.

Also, one thing that BYT, Tom and I had touched on in the past was making similar changes in all ign timing tables rather than just utilizing the int max/exh max table for all. Works well.

I will say that I've tried a multitude of different int/exh cam table configurations and found that I like the stock tables best. However, my car is 100% stock. So for me, by increasing overlap with my terribly restricted exhaust, I believe I'm doing more harm than good at this point, until I open it up with a catless DP and resonator delete.

FWIW after going back to stock MAF cal and setting my MAF correction to all 1's and dialing in my Inj constant, my STFTs look stellar and LTFTs sit at zero. Even with the crazy swings in temps here in the desert, fueling stays consistent. I've also manually calculated better fuel mileage as well. Before, while using the MAF tables to correct, I was getting a best of 23.5-24mpg(Even with the warm temps). I'm now sitting between 26-27. Crazy thing is, my DIC mileage has stayed pretty accurate too but the instant fuel mileage is definitely skewed. I run 1:1 by the way.

Thanks to everyone for being so open and sharing your thoughts and theories. When I'm finished with my DAL, MALT, WG, etc. I'll post it up.

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Originally Posted by T-Man

I'm actually in the middle of completely re-doing my DAL table to increase in air load rather than starting high and slowly dropping off. Almost seems backasswards with how they set it up. I understand 400-1000 deal with idle but the rest is just strange.

Also, one thing that BYT, Tom and I had touched on in the past was making similar changes in all ign timing tables rather than just utilizing the int max/exh max table for all. Works well.

I will say that I've tried a multitude of different int/exh cam table configurations and found that I like the stock tables best. However, my car is 100% stock. So for me, by increasing overlap with my terribly restricted exhaust, I believe I'm doing more harm than good at this point, until I open it up with a catless DP and resonator delete.

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Hey T-Man
You're right, the DAL's are backwards down low, you definitely can make them ramp up like they should.

On the timing maps, I kept the tables different and added the same values to all 4 tables like you mentioned, but awhile back I ditched that idea. I found that having all 4 tables the same keeps the timing WAY smoother. There are cells in the 4 tables that are very different and when the cam is moving back and forth the timing can jump around too much. The secret is like I said above, start with one table, copy and past the second table to it. Save the file, compare to what you started with and zero out any cells that show that you've retarded timing. Save that file, go to the next table, copy and paste it into the first one again and repeat the process. Obviously what you're trying to do is taking all of the HIGHEST numbers from all 4 tables and putting them in one. Once you've got one table with all the highest values, copy paste that table into all the other 3. Make sense?

One word of caution here, if you're on pump gas make sure you're not getting KR.

On the cam timing thing, try the tables I've posted above, with the injection timing tables also. There ABSOLUTELY are gains to be had with cam timing, even on a bone stock motor.

Here's some cam timing and logging info from my old notes guys, it might be helpful here...


Subtract 10 from entire intake table and add 6 to entire exhaust table.
COPY EXHAUST TABLE TO INTAKE TABLE BY "SPECIAL-ADD". THIS WILL SHOW OVERLAP.
NEGATIVE NUMBERS MEAN OVERLAP IS GETTING CLOSER, POSITIVE NUMBERS MEAN OVERLAP IS GETTING WIDER.
Zero would mean overlap is the same as base setting. (?)
Make a custom pid for intake and exhaust, subtract 10 from intake and 6 from exhaust and that will make numbers in logs match numbers
in editor. Exhaust lower than intake means less overlap, Intake over exhaust means more overlap.

-1 in cam timing table equals 10.8 in logs.
10 is actually zero in logs.(intake cam only)

Exhaust cam runs at 0 when at idle.-6 in table equals 0 in logs.

cam tables switch from normal to idle when rpms drop to 800, even when coasting.

Lots to digest, like most of us I do see a bit of random KR in the light to moderate load & rpm ranges at times, mostly seems to show up after stopped at a light for a minute or two when taking off. Happens with no apparent rhyme or reason so I was leery to jack the midrange timing up more. If I get time this weekend I'll try the GMTech approach to get more advance in there. I know some of the midload areas are 6* or more under stock on a few tables. Always room to experiment some more.

Some great information. I feel I am getting an even better understanding of everything, thanks to all the contributions of tips, tricks and facts.

I jinxed myself, though... I decided to log my KR a bit more this morning and everything looked "normal" until I was half-way through my morning commute.... I was getting SEVERE KR EVERYWHERE! Midrange, WOT... everywhere. *sigh*

Reducing all the timing back to stock and starting over. I'll try GMTech's way... I'll try anything at this point.

Ugh, I can't wait until my meth kit arrives so I can mess around with that.

Funny, I just ordered a meth kit for mine this morning. Gotta clean them valves. lol.

Nice! Mine should be on the way as well. Bought a new one (never installed) from a member on CSS.net.

Oh, and just to update on the original reason for this thread:

The cam timing and injector tables worked FLAWLESSLY!
Thanks again! No more cat warm-up noise crap. Just a nice, smooth, slightly elevated idle on cold startup. Perfect.

I've found that I will get some kr after DFCO with either bliping the throttle to up shift or when taking off from a light before the commanded lambda has returned to 1. Wish we had control of that as I can only assume its more for cat protection than anything?

Rich knock or is this another tip in limiter as part of cat protection?

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Originally Posted by T-Man

I've found that I will get some kr after DFCO with either bliping the throttle to up shift or when taking off from a light before the commanded lambda has returned to 1. Wish we had control of that as I can only assume its more for cat protection than anything?

Rich knock or is this another tip in limiter as part of cat protection?

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From what I remmber if you disable DFCO with all zero's in the table the Lambda never leaves 1.0 after a stop. It'd be a tradeoff but worth a test on the KR issue. You'll have to disable a code or two after long decels though. I used to pop one once in a while for the rear 02 I think.

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Originally Posted by Gremlin85

That would be phenomenal, thank you. I found a set of cam tables that you posted but I'm not 100% positive they are the right ones (I think they're warm tables) and I'm doing this on my phone so I can't get the link to the post just yet.

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On your intake cam cold idle set to +10.0 in all cells. I do the same with the intake cam warm idle as well. Exhaust cam idle leave at -6 in all the cold and warm idle cells. You also can smooth out the lumps in the cold and warm cam tables. I posted some that work well in the other thread.

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Originally Posted by gmtech16450yz

Here's some cam timing and logging info from my old notes guys, it might be helpful here...


Subtract 10 from entire intake table and add 6 to entire exhaust table.
COPY EXHAUST TABLE TO INTAKE TABLE BY "SPECIAL-ADD". THIS WILL SHOW OVERLAP.
NEGATIVE NUMBERS MEAN OVERLAP IS GETTING CLOSER, POSITIVE NUMBERS MEAN OVERLAP IS GETTING WIDER.
Zero would mean overlap is the same as base setting. (?)
Make a custom pid for intake and exhaust, subtract 10 from intake and 6 from exhaust and that will make numbers in logs match numbers
in editor. Exhaust lower than intake means less overlap, Intake over exhaust means more overlap.

-1 in cam timing table equals 10.8 in logs.
10 is actually zero in logs.(intake cam only)

Exhaust cam runs at 0 when at idle.-6 in table equals 0 in logs.

cam tables switch from normal to idle when rpms drop to 800, even when coasting.

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This helped me a LOT thank you! I've been gone to long and now that I'm back Im doing as much reading as I can to try and catch up. lol

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Originally Posted by Pandion

This helped me a LOT thank you! I've been gone to long and now that I'm back Im doing as much reading as I can to try and catch up. lol

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So it made sense to you I take it?!

Yeah anyone that hasn't set up a custom pid for cam timing in the logs isn't showing timing properly. Or at least what they're seeing in the logs would be hard to relate directly to what you're commanding in the editor. Setting up a custom pid will make seeing cam timing changes and overlap very easy when logging. And for anyone thinking "there's nothing to be gained going from stock cam timing" (that was a comment I got quite awhile ago)- that's total BS. Cam timing is HUGE. I first learned about ignition timing on a '67 Mercury Cougar, and I first learned about cam timing on a Datsun 240Z. Those two things, of course along with fuel mixture, are where power is made or lost. Period.

Yeah that made sense to me. Now I just gotta figure out the PID thing lol. I'll get it though. I'm a super noob to this stuff but I think I pick it up pretty quick. If it weren't for this forum I prob would never have bought HPT in the first place though.

I first learned about engines on my 72 Nova. Built the engine myself following a build book. I was pretty proud at the time considering I was only 15.

Played with the timing tables today, picked all the highest cells in the GMPP file under 120% load from all four tables, kept pasting in the highest ones & smoothed it out. Ended up with 6-8* or so more in the cruise rpm & load areas. I'll load them before I leave work at 9p. If it doesn't knock all to hell it should help up the cruise mpg some.

My cruise is between 2k & 3k from 40 - 60% load. Here's the table and the difference from what I posted earlier.

http://www.hptuners.com/forum/attach...1&d=1303432438

Hey Tom, try this... 3k rpm @ 120% load- there's an 18 in that cell. Starting from that cell, select all the way to full load and down to lowest rpm, you should have a 5x9 box of cells. Add 3 degrees to all of those. You're still way low in those cells.

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picked all the highest cells in the GMPP file under 120% load from all four tables

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Look at it this way Tom, if GM thinks those numbers are ok for 91octane pump gas, they'll certainly be fine for your E60 mix.
Actually, you should be good for at least an additional 5-10 degrees above stock in those areas running E60. If you're getting KR, it's gotta be false.

I have a few thoughts about this whole KR issue these LNF's have, since it's such a problem this might put things in a little better perspective...
Anyone consider ditching the whole knock retard system on LNF's running any amount of Ethanol? I pretty much have for quite awhile now. If you feel confident enough in your timing tables, and you're running anything over 40% Ethanol, you're not gonna get any real KR. If you do, something is very wrong because it's very hard to get true knock on even that little Ethanol. For those of you running pump gas, if you go too far on timing not only will you get KR in your logs, you'll HEAR it. So guess what? For decades and decades we tuned igntion timing by ear, and if you knew what you were doing it worked pretty darn good. Why keep looking at that KR in logs and trying to fix it when it can't be "fixed", at least not by retarding timing. Trust your tune, keep your timing tables reasonable and either ignore the KR or turn off the system.

Here's what I've done, I've taken "Max Knock Retard vs. RPM and dropped it down drastically. I've kept at least a degree or two just so I can still keep an eye on it somewhat, but in the lower cells I've turned it all the way to zero. How many LNF's will show a TON of KR on a cold start at 600-800 rpm? Lots. Does anyone really think it's knocking in that situation? No way. I zeroed the 400 and 800rpm cells long ago for that reason.

Here's the big warning- DO THINGS LIKE THIS ONLY IF YOU KNOW WHAT YOU'RE DOING AND ACCEPT THE RISKS! I would say pretty confidently though, if you're on stock timing tables and you're running anything over 40% Ethanol, there is no way you're gonna get any real knock. If your logs are showing KR on Ethanol, you have about a 90% chance it's false, or at least not caused by ignition timing. If this were an LS motor, or any other GM ECM, I wouldn't recommend or even consider this. There are so many ways to deal with knock sensors in say, the E38 ECM's. If we had that kind of control over these Bosch ECM's we could fix a lot of these KR problems. Unless these ECM's are just stupid and don't have that kind of knock learn, sensitivity, retard decay, etc, tables in them. DI is so much different as far as KR goes than normal port injection anyway. I'm seeing LNF tuners richen the cr#p out of people's tunes trying to fix KR, instead it just makes things worse. Absolutely the wrong approach on a DI motor.

Food for thought. Just don't PM me with bills for broken pistons, I won't pay them.

lol. Changes accepted, I ran that much advance down low on the stock plugs last winter and vaporized #2, might have been a cracked center insulator out of the box though.
Time to go load it and drive.

Went out tuning tonight. Trying to get a lot of things in check... I was really concentrating on my timing and I think I'm getting A LOT of FALSE KR... Here's what I'm talking about...

You can see where I am, I command 12.5* there and its giving 12.5*.... only it says theres 3* KR...

http://www.hptuners.com/forum/attach...1&d=1303445067

I've reduced my timing so much because I kept seeing KR. :banghead:

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Originally Posted by Gremlin85

Went out tuning tonight. Trying to get a lot of things in check... I was really concentrating on my timing and I think I'm getting A LOT of FALSE KR... Here's what I'm talking about...

You can see where I am, I command 12.5* there and its giving 12.5*.... only it says theres 3* KR...


I've reduced my timing so much because I kept seeing KR. :banghead:

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.82 Lambda? Damn dude you'd be better off if it was .92! Keep that between .88 to .92.

Seeing KR but not getting it actually reducing timing is common on these. It's not normal, believe me. This Bosch ECM is so weird on stuff like this. Look at any other GM ECM and you can clearly see KR numbers exactly taken away from desired timing. For example, if you're showing 5* KR, and you're commanding 20* in your tune, you'll see 15* in the log. The other thing about tuning most any other motor is if you get 2* KR, you reduce that cell in the editor 2* and you'll never see that 2* KR in that area again. It's not that precise obviously, but pretty darn close. On this LNF, you can see 2* KR and reduce timing till you're blue in the face and the car barely runs, and you'll still get that damn 2*! Or maybe it will just go away on it's own without doing anything, only to come back in another spot at 5*!

Sucks seeing these low timing numbers, these motors REALLY need better fuel to run good. Hopefully with the gas prices back up we'll see more E85 stations popping up.

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Originally Posted by Iam Broke

From what I remmber if you disable DFCO with all zero's in the table the Lambda never leaves 1.0 after a stop. It'd be a tradeoff but worth a test on the KR issue. You'll have to disable a code or two after long decels though. I used to pop one once in a while for the rear 02 I think.

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Yeah, definite tradeoff. I remember messing with that table... It's probably false kr. I enjoy my DFCO :D