thunderstruck507

iTrader: (18)

Once again I deeply appreciate the patience.

I went back and I was mistaken, I had a stock 2000 Camaro tune file and copied the table from it into mine and like magic the car runs better than ever. I drove around last night on 3 different trips and on none of them did I get more than a single 100-200rpm flutter doing my best to put it in conditions which used to cause severe surge/stalling.


I will compare the stock table to the one you added to my tune and if it's different I will try it too.


The first cold start of the day is still different. This morning for work I started it and even once coolant temp was up to 194* it wanted to surge a little at stops, it never died though and the surge was much less severe.


So I guess my question is what is different about the first cold start of the engine for the day as opposed to subsequent "cold" starts? Is there something specific to this activity which I can target or will the tuning have to be done to blanket that?

Upon reading your last paragraph again it sounds like you mean to compare what the car is doing to give itself airflow and compare that to what I have for base airflow during those temperatures?




I am just grateful for the progress, the car is becoming pleasant to daily drive again instead of dreading it.

wait4me

iTrader: (10)

Your DESIRED airflow table is wrong.

Also the values from pn to drive should be a bit closer together. I dont think your drivetrain is that tight for it to look like that.

Does the car idle good not in gear??

If the car ran better with THROTTLE cracker table adding airflow, then that means that the MAIN desired airflow table is not high enough.

Throttle cracker was meant to Make the engine Rpm INCREASE higher than commanded while the car is in motion to prevent a stall condition.

I personally delete the cracker table, and fix the BASE TABLES first, then you can always add back in the ADDERS later.

That being said, when you add RPM commanded idle "in your case over 900rpm", this also effects how much Desired airflow you need for your engine. This messes up some people as they wonder why you have to add so much to maintain the desired idle. Airflow requirements for 900rpm+ are a bit more than say 600rpm stock.

What i normally do is this.
Add .4 -.5 to the desired airflow table to make it run. After it idles and runs on its own, then i temporarly work on spark.

Log Timing for a bit at idle, then shut off the car. Look What the AVERAGE spark while idling was. Make that my BASE and low area spark value. Once i put in those values, that gets me my spark starting point.


THEN i shut off spark correction for idle, then i start to add in airflow.

I add to the desired airflow tables until the car just starts to hang, then back it down about 5%. This gives you a window where idle airflow correction will do its job.

then, you can put the spark correction at idle back in.

Note that when spark correction is working, your spark will be jumping all over the place.

This is a HINT as to what your airflow is actually doing. If spark values are lower than commanded, then you have too much desired airflow. IF they are higher, then you have not enough desired airflow.

AFTER all of this is done, THEN you move to THROTTLE cracker tables. YOU only add airflow in where you are having an idle or coast down problem. Log the mph to show you those areas..

Throttle follower should be adjusted to help with your tps transistions. Say you rev the engine in park then it dies, Add to the values. If it hangs or comes down to slowly, then pull some out.

wait4me

iTrader: (10)

Another thing to note is, IF the car runs better at a certain engine temperature, Then look at the tables in that area as that is a clue to what it needs. In this case, your desired airflow table is probably wrong at 176 degrees on.. It is a pretty large drop in that area on your tune. Im guessing that it would like being the same values you have at 154 in the remaining cells..

thunderstruck507

iTrader: (18)

Thanks Jesse, I will print out those posts and go over those tonight and try some of those changes. Everything you're saying makes sense in my head. I also like how you outlined the "plan of attack", that was something I seemed to be struggling with: which to do first and why.

Based on some other examples from my tuning books and printouts, I was under the impression I was already on the high side in my desired airflow by a good margin so I was hesitant to just keep adding. Being a beginner I have been trying not to stray from examples I can find of similar setups to mine.

To answer your question the car idles good both in gear and in park. Going from drive to park sometimes causes a flare, but not all the time and it's usually only to 1200rpm or so when it happens and it decays back out fairly quick.

Thanks again for an informative post


EDIT: Should I be shooting for a lower idle? I don't know how low is reasonable with a cam of my size. When the car was previously dyno tuned with stock heads and 230/224 cam the shop had it set to 900rpm even for that. I know when you did my original mail order tune a couple years ago, you had it idling at ~650 with that same setup but it did have some surge. IIRC I bumped it to 750rpm and drove it that way for over a year and a half before I got a dyno tune.