Accel enrichment

[Camaro SS]

If I let off the throttle alittle and then press the throttle pedal back down some I get a lean spike briefly running in closed loop. I have looked in EFILive and haven't found anything for this. My buddy has HPT and he found this description and I think this describes it good.

Acceleration enrichment is a simple throttle transient fuel compensation calculation. Using the change in TPS (TPS delta) as the primary factor, the pcm calculates an enrichment fraction. The enrichment fraction is then added to the current commanded fuel.

Is there anything like this in EFILive?

[Camaro SS]

BTW I am running Custom OS 5.

[dc_justin]

I've put in a request to have these added. Ross has said that it will have to be after the next release.

I have a lot showing a lean spike where commanded is 11.7 and actual is 15.6! :Eyecrazy: Boost comes in at 3psi 1/10 of a second later, 6psi at 3/10 later.

[Camaro SS]

So you are saying right now nothing can be done about it? If that is true then screw closed loop, I will go back to open loop.

[joecar]

OL is fine.

I'll move this thread to the COS thread.

[Camaro SS]

OL is fine.

I'll move this thread to the COS thread.I agree OL is fine. It would be nice to be able to run in CLSD and not get the lean spikes when you increase the throttle.

[A^K^T]

My buddy has HPT and he found this description and I think this describes it good.

Acceleration enrichment is a simple throttle transient fuel compensation calculation. Using the change in TPS (TPS delta) as the primary factor, the pcm calculates an enrichment fraction. The enrichment fraction is then added to the current commanded fuel.




The Acceleration enrichment section is blank in the LS1,LS2 & L76 operating systems in HPT , it's in the V6 calibrations .

[SSpdDmon]

I think this is primarily because the exhaust is down stream from the whole comubstion process. If the PCM switches immediately from 14.6 to 12.5, the injectors will respond virtually instantly. But, you still have to burn the mixture and send it down the exhaust tubes. If the lean spike is for more than .3~.5 seconds, then I would worry. Otherwise, expect a delay in what your WB reads vs what the PCM commands during transitions.

[dc_justin]

I think this is primarily because the exhaust is down stream from the whole comubstion process. If the PCM switches immediately from 14.6 to 12.5, the injectors will respond virtually instantly. But, you still have to burn the mixture and send it down the exhaust tubes. If the lean spike is for more than .3~.5 seconds, then I would worry. Otherwise, expect a delay in what your WB reads vs what the PCM commands during transitions.

It's not that, it's a very real lean condition. Upon throttle application in speed density, the WB will read lean, not just show positive BENs. In my case, the WB will go from 14.7 up to 16.5 for a moment before tapering down to commanded. Detonation is right around the corner when you're boosted. :(

[Camaro SS]

I think this is primarily because the exhaust is down stream from the whole comubstion process. If the PCM switches immediately from 14.6 to 12.5, the injectors will respond virtually instantly. But, you still have to burn the mixture and send it down the exhaust tubes. If the lean spike is for more than .3~.5 seconds, then I would worry. Otherwise, expect a delay in what your WB reads vs what the PCM commands during transitions. I agree with you on your statement but if I get a lean spike to say 16.0 you couldn't even tell it if I didn't have a wideband but sometimes it will go to almost 17.0 and the car stumbes for a spilt second. I am sure if I would run a maf I wouldn't have this issue but I am planning on putting a F1A on soon so I will be running SD and I would like to be able to run closed loop.

[Highlander]

not only that... this issue comes apparent if you are only applying say 60-70% throttle... Either you go WAY rich or you pound it????

There should be some TPS PE table or something like the mustangs have.

[dc_justin]

I can see a 6-7 point AFR swing with as little as a quick 30% stab...

[Highlander]

I am having this issue in two boosted vehicles... the main problem is if you are NOT pushing 100% the throttle...

On the lS7 it can ping at times...

Both are MAFd cars.

[dc_justin]

Have you looked into the Dynamics section of the ECM? Both E38 and E67 computers have this available.

Justin

[Highlander]

yes... but what specifically?

[dc_justin]

The dynamics section is the set transient fuel for the E38/E67. I'd take a look at B2005.