Back Again - Mafless Starting Issue - Choking Then Idles??

[BigDaddyCool]

What in gods name in this tune would cause this issue. Mafless - I attached my stock tune because the VE is already tuned on my copy..... all stock settings that are in file file minus the usual maf disable gear.

1. Startup and it chokes for a second then idles........ sometimes when it's hot, it wont even start.

I did some reading outside these forums due to 'not getting any help' as such...... some people have drilled a little hole in the TB and adjusted some stuff.

My wideband shows it runs 18AFR for the initial second or two, then richens and smooths out..... but it chokes, and timing is in the negative......

Is this some sort of idle overcorrection?........... I want an actual tuner who's done a mafless to respond please, I dont need idea's untested or opinions..... I need someone who's encountered this issue. I have tried all the various idle airflow tables etc.......

I have now tried setting the startup idle flare to a max of -10..... which I will try tomorrow....... I heard increasing the cranking spark can help....... any other idea's? ........ I have also started the car, put it in drive and went to drive off and it conked out...... it seems like some sort of timing issue.

[SultanHassanMasTuning]

the file posted seems like your basic MAF cal. post your mafless cal so we can see whats your issue.

[R8SVton]

Post your current tune so we can have a good look at what the problem is.

[BigDaddyCool]

As attached. Basic Stock Tune, MAF Tuned, VE Tuning In Progress.... (Wideband Setup) ---....

Interesting thing, zero'd TqMgt Spark Min - No Go.... Oddly enough it chocks, idle pulsates sometimes after a drive and restarting and it's undriveable but even with the MAF set to disabled in the tune if I just plug it in........ even tho it's pure VE, it then starts and runs fine...... so now I'm starting to think it's Dynamic Airflow.... because even with the MAF disabled, Dynamics probably would use the reported Airflow as seen by the scanner.......... it's so damn weird.

Now I've attached the tune, a scan from today...... now you can see on the scan it was mafless, unplugged...... on the start it pulls timing chokes then idles ok....... when and picked up a trailer to do lawn work...... got back..... at around 18 mins... tried starting the car again, idle pulsated crazy, started again same thing....... ended up pluggin in the maf.... despite it being disabled, started up fine..... you can see on the scanner where I plugged in the maf because the maf readings start showing.....

It's driving me nuts, it's just like it doesn't want the maf unplugged or something, it's very odd... fuel isn't perfect, but it's damn close. After logging a few more things it seems to be 'Idle Adapt Advance' when it goes crazy.... it pulls timing and adds it....... but what can I really do with that.

[IJ.]

Have you tried it with just the Signal wire pulled from the MAF and the other 2 left connected?

[BigDaddyCool]

Anyone else?

[Kyne]

Do you have a separate iat sensor or is it just in the maf? Either that or you haven't failed the maf properly. Every car I tune I unplug the maf after failing it to make sure I'm only referencing the VE, that is of course unless the iat is in the maf.

[BigDaddyCool]

I have bought a seperate IAT and converter, I also bought another converter to run stock maf and external IAT...... so if my car wont start in VE mode I can just plug the maf back in..... I have thought this through. I went out before messed around with IDLE adapt spark no go, I messed around with startup airflow..... no go. It's like it's associating the MAF and Idle together........ if the maf is not present the idle faults and it just loops trying to adapt the extreme's overrun and underrun regardless of whats actually going on. It just gets stuck in this loop............ so no matter how you change all the main tables to control it, it will just jump to the extreme on the second start.

...... Maybe it's just my software on the car? ...... No idea, from my perspective I've tried everything I can think of short of setting a 8192 for Idle Effective Area Max Fail and messing with the ETC fail settings etc.

I dont think it's tune related, it's faulting something and just being a stupid pos.......

It's only startup idle....... I can flash it, start it...... half chokes and it drives one time perfectly......... then when you go to restart no cigar. It just jumps into some weird idle where the adapt it going from under run to overrun to the extreme like it's trying to compensate but it doesn't no matter how you change the settings.....

It's faulting the ETC or Idle ........... and somehow that associates with the MAF being removed........ It's so weird.

I have a mafless tune that drives good, ready....... I just cant use it due to the starting issue.

[IJ.]

Anyone else?

Just mentioned it as my car rags up if I just unplug it so I have to pull the sig wire...

good luck I hope you get it sorted

[R8SVton]

Hi ,
Tried to open your file but its tuner locked.
Cheers

As attached. Basic Stock Tune, MAF Tuned, VE Tuning In Progress.... (Wideband Setup) ---....

Interesting thing, zero'd TqMgt Spark Min - No Go.... Oddly enough it chocks, idle pulsates sometimes after a drive and restarting and it's undriveable but even with the MAF set to disabled in the tune if I just plug it in........ even tho it's pure VE, it then starts and runs fine...... so now I'm starting to think it's Dynamic Airflow.... because even with the MAF disabled, Dynamics probably would use the reported Airflow as seen by the scanner.......... it's so damn weird.

Now I've attached the tune, a scan from today...... now you can see on the scan it was mafless, unplugged...... on the start it pulls timing chokes then idles ok....... when and picked up a trailer to do lawn work...... got back..... at around 18 mins... tried starting the car again, idle pulsated crazy, started again same thing....... ended up pluggin in the maf.... despite it being disabled, started up fine..... you can see on the scanner where I plugged in the maf because the maf readings start showing.....

It's driving me nuts, it's just like it doesn't want the maf unplugged or something, it's very odd... fuel isn't perfect, but it's damn close. After logging a few more things it seems to be 'Idle Adapt Advance' when it goes crazy.... it pulls timing and adds it....... but what can I really do with that.

[BigDaddyCool]

Yeh sorry, force of habit these days. BUT....... I believe I have finally found my issue at long last!. I had all the MAF DTC's set correctly but one, I dont think that caused it but....... I think the issue was the ECU was faulting idle thus faulting the MAP/MAF/TPS sensor too or something......... in short I set MAX Idle Fail to 8192......... and now it works fine. You start it up once it chokes once after the first reflash while it fails the maf and then it starts perfect everytime after that.......

I'll confirm this is the case in a weeks time after I've drove it around enough to make sure it keeps starting.........

PS. After tuning for MAFLESS...... apart from this start issue, I would never go back to a mixed or maf system again.......... the difference is astounding in terms of the drive..... I have wideband tuned both...... but for whatever reason MAFLESS drives smoother, more consistent, more torque, better economy, better shifts on the auto..... i guess because it doesn't fluctuate like the MAF.

I also had the best results with PE via controlling it via MAP......... so it seems from my point of view, controlling fueling via the MAP Sensor is key to anything v8 with mods.

Anyway.... I'm just over the moon I finally have this start issue possibly sorted now. I can throw that damn maf sensor in the boot somewhere and be done with the damn thing.