Cat warmup delete-How to fix cold start idle?

[Gremlin85]

.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.

I swear on my life that while tuning on the dyno, the difference in power numbers between a .88 (which I originally had) and .82 were practically nothing on my car. I think it reduced torque by a couple ftlbs. I was being as safe as I could seeing as that I get on this thing quite a bit and take it to the drag strip in the summer (it's also my DD). It was also recommended by my tuner friend.

I'll bump it up to .88 to see what happens.

This ECM is crazy. KR without really reducing timing? Are you kidding me? Honestly, I've read this somewhere before and payed no attention to it .

And I'm PRAYING for an E85 station to pop up closer to me. The closest ones are an hour away from me. My Methanol kit comes in in a week or so. I know that will help up top a lot.

It's gonna be a long month of tuning for me

[Iam Broke]

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.

Ran well, less KR than normal in the midload areas. Still a few hits in the histo, but MPG is up some after a reset (25) even with two long pulls in the run.

I have the boost pretty well nailed down now and 60 - 100 pull times match the TF layer tune I was running. .898 commanded PE Lambda. I'm still trying to get my old brain around the cam tables. I'll study more on what GMT wrote this weekend.

[JoshMass]

Is all this KR still showing up after clocking your knock sensors at 90*?

http://www.hptuners.com/forum/showth...ock+sensor+lnf

[Gremlin85]

Is all this KR still showing up after clocking your knock sensors at 90*?

http://www.hptuners.com/forum/showth...ock+sensor+lnf

I'm planning on doing that this weekend. I'm gonna have to really dig to see the sensors and I'll be damned if they're positioned correctly.

[shabby]

Is all this KR still showing up after clocking your knock sensors at 90*?

http://www.hptuners.com/forum/showth...ock+sensor+lnf

In the end i noticed no difference after clocking them correctly.

[Iam Broke]

No difference here to speak of either.

[gmtech16450yz]

No difference here to speak of either.

Yeah that's still kinda hit and miss. I've done it on 3 LNF's, 2 it absolutely made a difference and one it did nothing no matter where I turned them. I still think there is something to clocking them because I did find it mentioned in a GM TSB or service procedure somewhere. I think another big one is making sure the leads aren't up against the block or being able to hit against anything. I route the leads towards each other then tie strap them together before they go to the mounting brackets.

I wouldn't pull the manifold or do anything too involved to try it at this point. The front one is easy but the back one is hard to get to. If you ask me, these LNF's have the most retarded (ha) KR system I've seen on any car or truck. Practically useless compared to how good it can and does work on other ECM's and motors.

[silverbullet08]

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.

I actually have been running a timing table for quite some time like this one. It helped a little bit but not much. The cam tables posted helped me the most as far as gasmilage. It was funny i started to compare the tables you posted for timing and mine were within .5 in the areas that really matter. I do see 1-2* kr occasionally set up like that though. but very random

[stratosteve]

Can the cam tables gmtech posted on the first page be used by those still using cat warmup?

[Iam Broke]

I believe he ran those long before HPT gave us the cat warmup disable. Why not disable it altogether?

[stratosteve]

I believe he ran those long before HPT gave us the cat warmup disable. Why not disable it altogether?

I am still running the stock catted downpipe. Cat warmup is an emissions thing or does it help with cat longevity as well?

[Iam Broke]

Emissions as far as I know.

[roadconetuning]

cat warm up also seems to get the wideband hot and reading faster...

[gmtech16450yz]

Here's the truth about cat warmup...

It's to lower cold start emissions, nothing else. It does it by massively retarding ign timing and running a super rich mixture, which makes the cat heat up quickly. Basically loading up the motor and superheating the cat right off the bat on a cold motor. Airload levels on a cat warmup cold start are sometimes into the 80%'s, usually 60-70% average. With the cat warmup delete on, loads are usually around 30-40% on a cold start. The downside is it's very hard on the motor itself, is actually harder on the cat and it uses more fuel. (Anyone that lets their car warmup for a minute or two on a cold start notice that when you turn off the cat warmup your mileage goes up?)

It will not make your cat last longer leaving it on. It may help the Lambda sensor heat up quicker, but it has a heater anyway so not much of an issue there. They start working pretty damn fast anyway.

[Pandion]

Trying to log my Cam timing this week and I keep getting an "unsupported parameter" in the table.

I set up custom PIDs using [PID.2172]-10 and [PID.2178]-6. I also tried [PID.2172.-10] and [PID.2172-10]. But I'm thinking I am doing something wrong there.

[gmtech16450yz]

This is what I've been using...

Intake- ([PID.2172]-10)

Exhaust- ([PID.2178]-6)

Try this for showing cam overlap in the logs...

[PID.2172] - [PID.2178]

Make sure you have "Exhaust Cam Angle" and "Intake Cam Angle" PID's in your chart.

[Pandion]

Ill give it a try.

I'm driving up to Kansas City today. Gonna log the whole trip if the laptop doesn't die this time.

[96sunfire]

Where are you at in Kansas? I'm just south of Wichita.

[Pandion]

I'm stationed at fort riley.

[Pandion]

Ok, so the intake and exhaust PIDs work perfect now. But I can't get the overlap PID to work.

I tried [PID.2172] - [PID.2178], [PID.2172]-[PID.2178], ([PID.2172] - [PID.2178]) and ([PID.2172]-[PID.2178]). None of those combinations seemed to work for me.