E38 idle tuning

[Tre-Cool]

have you played with your eoit? a cam like that with such a short lsa is probably throwing a fair bit of fuel straight out the pipe.

[LastCall]

have you played with your eoit? a cam like that with such a short lsa is probably throwing a fair bit of fuel straight out the pipe.

I did play with it, I took 25 out of the entire table (shifted it down). After you posted, I looked at what Hymey posted about it, in this thread. He mentioned 400 in the B1205 table (ECT Injection Timing) and Zeroing out the B1206 (RPM Injection Timing). So I am off by a considerable amount in the ECT table and need to zero out the RPM table. Going to try that. Seems like a pretty big adjustment though. About 2X the original values at warm temps (154 F and up). Wondering if I should scale it the high number, right now I have 465 in cold temps, so maybe going down to 65 across the board?

What role does that play in hot starts?

[Tre-Cool]

I've found once you get the eoit set and find good mixtures/timing base. even cold to hot starts won't vary to much. using hymey's method i've gotten a high comp 402 motor idling at 750rpm with a lot more vacuum than another tuner that was using a higher idle with less vac & because it was an auto car it made a big difference to brake assist when in gear.

[LastCall]

Thanks for responding back. So you have a flat 400 thought your ECT injection timing table and zeros on your rpm based injection table?

[Tre-Cool]

correct. same value for the entire map. I don't always use 400 though it varies based on cam etc.

[LastCall]

Cool, I'm going to give that a shot. Based on the math, the MS4 should be 403. So I'll try 400 and go from there.

[bubba68ss]

I have a small cam in my 5.3, 212 218 214lsa. With stock tune it would fire up cold but idle wouldn't flare up like it used to. Once warm it wouldn't start without multiple tries. I started playing around with the min airflow tables and I got it to work but I knew it wasn't right. I was directed to this thread and read it all twice. I then tried following the steps on page 3 from hymey. Here's what I have done:

At first I drilled a 3.5mm hole, set max idle air to 1.10, maxed out min idle airflow, zeroed out corrections and then warmed it up. At first my timing with negative so I pulled the max idle air (both of them) down and down to damn near .65 before I got my desired idle (720) and timing of about 16*. I ASSUME this is right? Or does that number seem too low?

Then I populate the correction tables to 80% of stock values, set min idle airflow table to 14 across the board. I start it up and this is where I get confused. I am supposed to be looking for idle trim after 10-15 seconds? I don't even know what I am supposed to be looking for. I see TP at about 18.8 but it just sets there. Once in a while I will see it blip around in .4 increments but never when I am looking for it.

Perhaps I am also a little confused coming from the ls1 technology... this e38 isn't as intuitive. I'd like to learn though. Dumb question, but in my mind, using these steps, I am trying to find an operating range for the idle control? If so, can someone elaborate on that a tad?

Where I stand now... It's running (cold start seems a bit sluggish) and seems to run great. As I'm slowing a stop I can feel the truck try to accelerate just a bit. If I shift into neutral while stopping the idle flares up to about 1200 RPM's (which may explain the acceleration while in gear) until I stop then it settles back down.

I'd really like to get this close enough to be happy with it.

[Naf]

Tune plz

Also discribe your restarts a little better, like it starts but struggles to get to revs or struggles to start but gets to revs once started.

[bubba68ss]

I went back to square one. bumped the min idle air tables up about 2, bumped idle 100 across the board and bumped startup airflow. It starts great, hot or cold and runs great. The ONLY thing I don't like is when coming to a stop it wants to rev up just before I stop completely. Almost lunges forward a bit. Which parameter do I need to adjust for that? I haven't altered my max idle area cells yet. They are set to around 2.4, both of them. Should I lower them? Just one?

[LastCall]

I went back to square one. bumped the min idle air tables up about 2, bumped idle 100 across the board and bumped startup airflow. It starts great, hot or cold and runs great. The ONLY thing I don't like is when coming to a stop it wants to rev up just before I stop completely. Almost lunges forward a bit. Which parameter do I need to adjust for that? I haven't altered my max idle area cells yet. They are set to around 2.4, both of them. Should I lower them? Just one?

Try taking some idle air out (start with 1 gram) of the min idle airflow table at the RPM the flair is happening out.