ECMlink running lean after dyno day!

[Desert DSM]

thanks in advance! please bare with me. ok...ive been fighting this situation for about a month now. i live in the mojave desert area about 3 hours from road race engineering in santa fe springs. I cruised up and had my car dinoed. sam did a dual map tune, first a 91 map tune and e85 map tune. the day went pritty smooth and as i was about mid way home i noticed i had alot of turbo surge if i would get into it atall. i got home late so the next day i activate the fuel pump on link and drained the little bit of e85 that was left. i filled up with 91pump. when loading 91map the car idles and runs extremely lean and sometimes dies. I blamed it on a bad map sensor ### RRE was very sure that was the problem. If you notice on the log the map sensor responds tho throttle position acordingly. it looks perfectly fine to me. globals and deadtimes are correct. very strange but i have to load e85 map running 91 pump to moove the car around the yard when im reorganizing the cars. it idles and runs pritty good. For your information;
no CEL
CR:8.5:1
CT:180psi across the board. healthy new motor.
base fuel pressure: 43
bpr8es gaped at .18 plugs are clean. white insulators. lean indication.
BLT: fixed small leak at iat sensor. sensor was loose.(only leak found)
base and mechanical timming is dead on per sam. eeven double checked myself.
plug and play cable from MAF plug to iat and map.
checlout my profile for morre info. Thanks again for the help.

 

[c2ypt1c]

Obviously the car wants more fuel and when you run the e85 map, the global accommodates for it. Here's a quick fix you can try:
at idle and at operating temp, lock the ecu in openloop and adjust your global fuel until wbfactor is close to zero.

See how that works out for you...

 

[Desert DSM]

Thanks.
I'll give that a try. I suspect maybe a bad or clogged return line. After messing with AFPR With vac line off or on, psi stays the same. fuel setup is only about 2k miles old and its only gone through one tank of e85! I'll check that out and post back what I find.

 

[Desert DSM]

^Stating just another problem I found with the pressure not changing. Also My AFPR reads 44 psi meaning I have good pressure at idle. Why should it even idle way lean on a professional set tune with enough fuel pressure. Maybe clogged injectors??

 

[1SLOW93TURBO]

Also remember when tuning if you don't use a dyno that puts a load on the car then the car will actually make more boost on the street which will lean it out. That's why I tune .3-.4 richer on the dyno so it will lean out on the street and still be safe.

 

[Calan]

Also remember when tuning if you don't use a dyno that puts a load on the car then the car will actually make more boost on the street which will lean it out.

More boost does not necessarily mean a leaner AFR on a modded car. It could just as easily go rich with more boost if airflow and fuel are not calibrated properly. But, it is better safe than sorry.

*****

OP - In my experience, you can't just flip a switch to go between 91 and E85 and get the same results. Although you can switch maps to target different AFR and timing values, injectors can behave very differently with different fuels (not to mention that the fuel itself varies). Because of this, you'll usually need to do some minor tweaking to injector and/or airflow values to bring everything back in line.

Also, you said you drained the tank by using the fuel pump. If that's the case, you probably had a significant amount of the previous fuel left in the tank, which will change the global value needed. It usually takes 2-3 fill-ups when driving the tank to empty before the fuel type becomes "pure" enough that global ends up where expected.

 

[Desert DSM]

Thanks for posting calan. I've been crusing the car on 91 with e85 map just for that reason...to drain whatever possible e85 can be in there. Still been having the same problems. Going to start at the fuel pump and work my way up the fuel system and find out what I come across.

 

[Desert DSM]

So... went thru whole fuel system and FP was fine replaced stock line with 6AN from tank to fuel rail with brand new fuel lab filter. Injectors are operating and ohm good. I've been thinking...my car has been reading -2 map signal with ign on engine off...my car wasn't tuned on a -2 offset it was tuned at 0. So its currently Seeing less air so dumping less fuel. No wiring involved at the map sensor. Its a plug and play cable. Also checked baro wire at ecu. Any ideas??