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Warm startup issues usually need a reduction in the coolant temp vs maf comp table. Sometimes it’s the post primer enrich table. Just use common sense when adjusting.
as always log to determine the temperature it’s having the most issues at.
Really? Well that could be it because i raised the crap out of maf vs coolant temp tables because cold start was lean. I just highlighted the whole thing and raised it. Maybe i should lower it at 180f. I know it goes lean when decelerating but i was getting hard shifts and when shifting it would stay lean for a couple secs then jump back. Accel enrich seemed to help. What do the post primer enrich and post primer enrich decay tables do?
Nor, the issue with the car going lean when you let off the gas will always be there because of fuel cut on deceleration.
The second issue with the rpm’s dropping low and car sometimes dies is usually biss screw adjustment and/or idle step position lookup related. Very similar to throttle hang issues just things are backwards. What I do is log your idle step position and see what it’s doing. In the base step position table you want it to read about the same as it does when it’s actually idling warmed up with the a/c off. Get it idling with the same steps as you have in the lookup table and I bet your issue goes away. If it’s only when the a/c is running then you need to change that table.
may the force be with you!
x2 i would do exactly the same. Remember you cant cover the VE adjustment with Accel enrich. I use accel enrichment for fine adjustment and it helps. Unless your MAP and RPM VE tables are close you will not have the smoothness that you are looking for.
Ok, seems like i have alot to learn. I was watching a long log from yesterday of the car idling after driving for a while. It was idling for maybe 10 minutes or so after driving. Through most of the log the isc steps are 15 - 19 when idling and rpms jump from 960 to 1030 ish. Then out of nowhere the steps jumped to 64 and rpms started jumping from 1000 to 1100 or so and held there for about 2 minutes then dropped to 15 - 19 and rpms settled back down. Ive never seen it do this while im watching it at idle but then again i havent looked at an idle log in a while. Now, i dont understand the idle steps situation. I was under the impression that you should get isc steps close to 0 as possible? You guys mention the base step position table. Are you referring to the idle stepper look up table? If so can someone explain that damn table to me? At idle kpa is around 60. Does this mean that according to this table i should try to get my isc steps to be around 69? Im a bit confused. I put up a picture of the tables i think you guys may be talking about. Some clarification would help alot.
Some roms use load(kpa) and some use % of demand factor on the Y axis of your lookup table. Yours is load kpa based table. Either way your ecu has to correct with a negative trim to achieve target idle of 950 rpm. You want your steps to be close to your lookup table at your idle kpa or load. Seems like you idle at a very high load, are you sure it’s so high? I thought you idled at around 40 load? What is your timing while idling? Either way if your steps are lower than the lookup table plus any demand adders at idle, then the ecu is using a negative trim to bring the steps back down to achieve that idle speed. If the trim values are really high then crazy **** starts to happen. I have tried setting the biss screw per factory recommendations and it does work sometimes but not so great with big cams. My point here is common sense is telling us the the ecu is having too Bring the counts way down to get a desired idle speed. I would turn your biss screw in some to get the steps to read closer to your lookup table steps and see how it reacts. I have had good luck with idle set at 1000 rpm and logging idle steps in the high 50’s range.
Yeah at idle 1 byte load reads 40 but I’m also logging kpa and that’s what I was referring to since the lookup table says kpa just took a look at the table and realized it says load (load kpa) sorry lol.. The trims while at idle are not so crazy. Maybe I should post the log for you to see. Thing is, it idles pretty damn good. So if this is the case according to the table at 40 load it says 58 steps. I have to make it read around 58 steps at idle?
Nice find, no I have not read that thread. I have not had to monkey around with those tables very much, usually adjusting the biss screw so the counts read in the 50’s at idle has usually worked for me.
I will try to do that but read through that thread and it’s very interesting. According to mrfred the y axis is actually a combination of a bunch of things. The ecu will use what it needs in the y axis. Seems people are changing the “load” to something else. Have to go back and reread it just don’t have much time. Also, mrfred found a bunch of options to tune various thing individually like power steering compensation etc. Pretty cool!
So I tried messing with the biss screw watching the demand trim and I messed everything up. Car used to idle perfect now it’s driving me nuts. Also I noticed that the lean tip in and take off issue is worse. It’s actually intolerable now. So iscv does have something to do with this issue. Trying to figure it out now.
Jul 21, 2018, 09:12 PM
