Did you by chance half the cylinder volume?

 

No, am I supposed to half my cylinder volume, also?

Eric

 

Dont halve the cylinder volume!! DO NOT!

I think by doing that your cancelling out the injector size halving? or something like that.

 

I basically just downloaded the tune that engineer had into my computer, but changed what pertained to my vehicle. I dont remember if engineer's car is an A4 or an M6, but my car is an M6. Would this cause the issues Im having? Also, I didnt change the VIN. Another, possible reason? Like I said, Im really "green" at this tuning stuff so I hope Im not coming off as an idiot. Maybe should start another thread, that way Im not putting information that is not pertinent (SP?) to this thread. If so, lemme know.

Thanks

Eric

 

Mine is a M6

When dealing with 1/2 resolutions things have to be closer, and your the first to use this tune with such small injectors.

If you can tell if it's rich or lean (sounds to me reading words is lean) then you need to richen it up.

 

It took a lot of modifications to engineer mikes tune to get mine to even idle. With the lean spot(27kpa), it would show it was lean on my wideband just after startup so I would add fuel. Then it wouldn't run because it was rich. I also had to change my startup VE to get it to start smoothly.

 

engineermike or 1982z28with18s, did you guys ever figure out your lean spot at 27 kpa?

Thanks,

Eric

 

Yep, it was the minimum PW. I changed that to 1.0 and everything below 30 kpa went really lean. I had been reducing the VE in the <25 range trying to get it to stoichiometric, not realizing the injectors weren't allowed below 1.4 ms PW. Once I changed it to 1.0 and started adding VE down there, the problem went away. Apparently, I've been rich at low load ever since I put in the 83# injectors.

Mike

 

Changing the minimum PW helped mine a lot, I just spent one night on driveability and it drove great after that. It would still hit that lean spot though, but wouldn't lean out as bad(15.7-15.8) so I wouldn't even notice it when driving really.

 

Just giving an update... I've been running Closed loop forever with a somewhat larger cam and finally decided to turn off the 02's and realized 75% of the cam surge was due to the 02's. Now, I think one reason why it always seemed to run very good was I was loading new files almost every time I drove it (sometime every day) and the 02' s didnt have time to mess the Lterms up but just the other day I loaded a new file and I noticed the difference immediately.

After turning them off I was suprised how well it actually ran with no other modification... it actually ran rich (~12.0-14.0) according to the WB02 (anything above 900mv on the NB02 = lower than 14.0AFR) the thing is I am now able to cruise at 10mph in first gear without clutching it (Alum Flywheel, Mcleod twin - no springs). Impressive to say the least.

Back to the 2 Bar Tune... the reduced resolution is again not causing any problem for me even with the 02's not feeding input.. I made only a couple changes to some light load cruise AFR and idle AFR.. both changes (+ or -1 to each value in the SD tables gave me ~0.25-0.5 AFR).

I do notice a wall - Major increase in AFR at anythign less than 0.99 Msec for the injector pulsewidth (think the unit is Msec anyway) but that's because of the 83lb injectors and that low flow rate is only used when I'm actually decelling from 2000rpm and the "decel fuel cutoff" hasnt kicked in (Datamaster cells turn Yellow or Red I dont remember) and I think that's the PCM limit.. not 1 or 2 bar limit.

 

The weather was cool here this afternoon and I did a lot of tunning for my 2 bar map. Ive got drivability pretty good. Still a lean and rich spot here and there but for the most part I could drive the car everyday and not worry about it. Its a SD, open loop tune.

I guess you can add me to the list of people running a 2 bar map tune with a stock pcm! Couldnt have done it without this thread!!!

 

That's sweet Jchevy... this site really does RULE!! All the progress on this tune in such short time pretty amazing. The tune really runs good for me.. I can jam the throttle at any RPM or LOAD and it's smooth and ready to go.. after playing around in open loop Im an idiot for trying to make closed loop work and think I could change anything since it all reverts back to the same readings anyway... Open loop is far easier to change than I ever imagined... only 2 or 3 changes and Im good... I made probably 20 changes in closed loop only to find the flat spots keep coming back... annoying!


Hey Engineer, I tried to PM you but your full like I was.,, the 2bar setup still working good for you? What max boost are you running and how's it handling it? Im still at 7psi.

I just went Open Loop and it's better than Closed loop with my cam, everything else is perfect.

Im thinking it runs smoother in the cam surge area if AFR's are closer to 13.5 - 14.0 rather than 14.5... thinking this could be because the WB02 is reading incorrectly?

Wondering what will happen with weather changes or winter time, do you know if that throws off the AFR?

Next time you see a Prius pass them with tires smoking.. they apprieciate it.

 

Are you guys using TunerCat? In mine, you can select a number lower than 1.0ms for the min. PW. It looks like the scroll bar stops at the left at 1.0ms, but if you use the up/down arrows or manually enter a lower number, you can get it lower than 1.0ms. Maybe that will help you guys?

This is definitely a great option for people running big boost on LT1s!

 

What's your minimum pw set at?

 

I've never even attempted to tune it in closed loop. I've been open loop the whole time. The computer correction either masks or creates problems. In open loop, you get what you get, if that makes any sense.

Mine is working great. I do have a strange re-start problem I have to work out, though. It starts fine the first time, but if you kill it soon after it doesn't want to start. Also, if it doesn't start immediately when you hit the key it will be stubborn after that.

I'm running 17 psi boost with it right now. However, I do have Meth injection taking care of some of the high boost enrichment. I love this setup because the A/F ratio is 14-15 at cruise and, as you put your foot down, it richens up to 11-12 instantly. With the old MAF and closed loop tune, it had a lean tip-in pop, then pig rich, then it would lean out to around 11/1.

The Speed Density calculations take into account the IAT reading when calculating the fuel. It should work fine.

I became much more comfortable with tuning a car this way when I started checking out my jet ski's ECU. It's supercharged (converted to a turbo now) from the factory and runs 2.5 bar speed density with no MAF and no O2 sensors at all. Those things run great. I'm making ~280 hp from a 1.5 liter engine at 14 psi boost and all is well.

Mike