E40 Closed Loop / Spark Limit

[HackAbuse]

Hey guys,

I'm having trouble getting my E40 to stay in open loop and a separate issue where I cannot get commanded spark below -10*.

I have closed loop ECT and delay maxed out, but the vehicle goes into closed loop almost immediately after starting. I can defeat it with the bi-directional controls if needed

Also, I've implemented the IAT two-step trick, but commanded spark will not go below -10*. I'd like to go a little lower if possible. See attached for my latest tune file

tune_181009.hpt

Thanks!

[jpierro79]

Car mods and original tune posted and maybe i can help but without that your asking a lot without any info to go on? its clearly running boost thats all i have here need info
you have it in maf fail mode with check engine light youll never get open loop properly eliminate maf my setting to no report if you dont want to run it. unless your forgot you disabled it. Having check engine lights in ecu will cause open loop issues and ecu limitations

[HackAbuse]

You're right. After re-enabling the MAF, the car ran like shit, but stayed in open loop like it should. Is there no way to run OLSD on an E40 with a failed MAF then?

[jpierro79]

it means your sd is wrong if your enablind you maf cause it to run like crap. Or youve tuned your maf to too low of an rpm. Its a blended calculation only designed for high rpm/volume flow. I wouldnt suggest setting it lower than 2400 rpm.Try that and rescale your vve on stock maf then retune your Maf. Everyone does it backwards here. If your maf is always going to be blended below a certain rpm why on earth would you tune your VVE without it enabled. Think about it you if you its going to effect your fueling why disable it. Heres what i do an it never fails. Tune your vve to 3200 rpm as best you can on stock MAF then if you have to lower maf rpm to get your Proper AFR then only lower it to where You need to. Not this crazy 600 rpm crap it just doesnt work. It will never tip in right as there is a large delay in maf vs actual manifold and tps readings. Hence the most common problem of lean tip in.

[HackAbuse]

It's disabled because I keep hitting the airflow limit (512 g/s) and I occasionally get erratic readings from it like it's seeing turbulence. I used to run a blended tune, but have had a much better experience since going to full SD

[jpierro79]

I personally havent done it but there are some poeople using ls3 maf or zl1 maf and scaling it. Im guessing that you have a return fuel system cause your flow rates are set all exactly the same unless you dont have injector data?

[HackAbuse]

I personally havent done it but there are some poeople using ls3 maf or zl1 maf and scaling it. Im guessing that you have a return fuel system cause your flow rates are set all exactly the same unless you dont have injector data?

Return style, yes. And I'm running the LS3 card-style maf already, it's blow-through with a large 1" honeycomb flow straightener about 4" upstream

[jpierro79]

well i can say this if your using any inline alterations in your intake before up withing 4 - 6 inches or especially after the maf it will ruin the readings. The zl1 maf works without honey comb same with ls3. Its not going to make them left field but can cause issues. Either way you dont know honeycomb on ls3 maf as the card is that way for a reason provided your at least the oem tubing size from maf to throttle body and at least 4 inches before it reaches the card you should be ok. The Rotofab intake I use is larger but still its equal length end to end so tuning is easily compensated. The card style MAF should not use honey comb. I have an extra zl1 Maf card with 20k on it if you want to go that route. please Keep in mind that the Maf Is truly only best served high flow not low flow throttle changes and steady state only like idle anything part throttle isnt really beneficial. The VVE is there for the part throttle you get a lot less burst spark retard with correct VVE. I hope this info is benificial to you

[HackAbuse]

I gave it a shot last week. Cleaned the sensor really well, then spent about 3 days re-calibrating it. It threw off my transient fueling a little bit, as I had lean tip-in after enabling it again. It was fairly accurate 10-200 g/sec of airflow, but beyond that the car ran super lean (15-20%).

I get nice smooth data from the sensor, but it just doesn't seem to measure consistently. I'll hit the 9000hz cell, on one pull, and it'll be ~10% off, then the next pull in the same cell ends up being 8-10% off from that.

Failed the MAF, went back to SD and the car runs beautiful. Tip-in is super responsive, and fueling is dead-nuts accurate.

Personally, I love the idea of running blended MAF mode, but in application it just does not seem to be working well for me.

Maybe I just have a cheap chinese knockoff sensor or something

[jpierro79]

have you been reseting your long term fuel trims after every flash?? its very possible your maf has simply failed. Its a super sensitive sensor. I have literally seen a tiny piece of a new airfilter stuck on one make a car fall on its face