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View Full Version : E67 GMPP dies on decel



pandreas
February 17th, 2010, 07:23 PM
Hi Guys! I've got an issue with a GMPP E67 on a crate engine that dies upon decel. The idle tables seem a little crazy on this thing! I have dabbled a little with the hi/low rpm spark correction, and B1844 and B1845 intrigal and proportional steps. I had a little success for a bit but ended up with a hanging throttle or dying on decel to idle with small changes. Anyway, need help! no sense droning on!

pandreas
February 22nd, 2010, 04:03 AM
Here is the stock tune.

hymey
February 22nd, 2010, 08:49 AM
B1845, maybe reduce to -.8 in the -256 cell its too aggressive, also min idle airflow, value decreases as rpm in rises in some places. I would also set the timing values in the idle and coast down flat across the board, also do this in the min idle airflow, till you get it working 100% right then you can massage those tables. I strongly have a feeling that you got the timing right, but your min idle airflow table is wrong, looks like its been smoothed in some spots, how come in N its 10 and first gear 6? these should be the same or close. So really Im not sure with what min idle airflow you ended up with? Also with coast down spark its at 10 degrees, as rpms drop so does the timing in coast down but it continues to really to reduce timing and ends up in the negatives and not recovering effectively then the problem starts, combine this with incorrect airflow tables and disaster strikes. You have to keep it simple when you are working it out otherwise it will end up bad believe me:)

I will alter it for you to give you an idea and somewhere to work from. Whats your email address?

Joel

I have just tried to alter your tune, I get access denied trying to save it, lately had lots of little errors with efilive:doh2:

But overall run a flat timing table for idle and coast till u get it right same as min idle airflow run the same the taper is way to high, Basically you need to start again.

Try and send me the tune to my email again

Joel

hymey
February 22nd, 2010, 11:14 AM
OK just went right through it,

I have some questions some parameters are altered to much and contribute to the problem.

How come, Max idle area 1 is set so low, 0.076? and Max idle area 2 at 23.xx? Did you log or just guess these settings? They are a long way out. Also b1650 for area of ETC is only 40? This setting has to be factory at 4725? Did you change this is was it like that in a tune you were supplied.

Your max idle area 1 and 2 can be just left the same whilst setting up i would start at 1.100 at both of these.

hymey
February 24th, 2010, 11:30 PM
Pete I sent you an email of a base test idle tune to start again, send me some logs of it and I will go through it with you.

Joel