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Old 07-13-2012, 05:32 AM
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Default Shifting a fuel injected motor

I have converted to EFI from carbs and also added transmissions and surface drive from Bravos. Every time I put it into gear it stalls is this a tuning issue or is something needed mechanically? I can save the motor by giving it gas but seem to be very hard to do. I have neutral safety’s on the shifters but can also hook some up on the trans if needed. the trans are ZF 85A.
Ken
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Old 07-13-2012, 05:39 AM
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You need more tuning. Look IAC settings, response when shifting and if needed you may need to add fuel in some of the map cells.
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Old 07-13-2012, 06:23 AM
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We have tried adding and subtracting, timing, fuel, Pulse width and so on.
Do I need a EFI interrupt switch?
Thank you
Ken
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Old 07-13-2012, 10:27 AM
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Originally Posted by ken sampson
We have tried adding and subtracting, timing, fuel, Pulse width and so on.
Do I need a EFI interrupt switch?
Thank you
Ken
Sounds like you do need a shift interrupt system.
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Old 07-25-2012, 10:20 PM
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shift interrupt is not required. You just aren't managing the droop correctly. what ECU's are you using
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Old 07-26-2012, 12:51 AM
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Originally Posted by tunertech
shift interrupt is not required. You just aren't managing the droop correctly. what ECU's are you using
Is there another word for droop when looking at the info on the ECU ? I'm using Mefi-burn software and I remember Tyler working on Droop when tuning My boat on the water years ago but I don't remember ever seeing it when I was tuning, Smitty
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Old 07-26-2012, 12:56 AM
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Originally Posted by ken sampson
I have converted to EFI from carbs and also added transmissions and surface drive from Bravos. Every time I put it into gear it stalls is this a tuning issue or is something needed mechanically? I can save the motor by giving it gas but seem to be very hard to do. I have neutral safety’s on the shifters but can also hook some up on the trans if needed. the trans are ZF 85A.
Ken
Where are your IAC counts? I have seen motors with big cams where IAC was maxed out around 150+ and it couldn't open anymore to "save" the motor at idle, when my 540 started making big power and using a big azz cam in order to get the iac counts under 100 where it can actually open/close enough to hold the idle as load changes I had to drill holes right in my throttle blades. I started out 1/16 and just kept making them bigger until the IAC counts were around 75 or so , mine started at 150 plus, Smitty
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Old 07-26-2012, 04:24 PM
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Originally Posted by articfriends
Where are your IAC counts? I have seen motors with big cams where IAC was maxed out around 150+ and it couldn't open anymore to "save" the motor at idle, when my 540 started making big power and using a big azz cam in order to get the iac counts under 100 where it can actually open/close enough to hold the idle as load changes I had to drill holes right in my throttle blades. I started out 1/16 and just kept making them bigger until the IAC counts were around 75 or so , mine started at 150 plus, Smitty
was reading and you just took the words off my fingers,,yes you need to drill a hole in the throttle body,it has to be close to the iac passage tho..this way the iac can compensate with out bottoming out..you have too much prop bite and its killing the engines,have you tryed to bring them up as high as possible to see if you can get some air around the blades to keep them from killing the engines..
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Old 07-26-2012, 05:56 PM
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use the tool bar and the FIND command, type in droop, it varies some what between MEFI type and whether you have the pro version or the standard version XDF

Originally Posted by articfriends
Is there another word for droop when looking at the info on the ECU ? I'm using Mefi-burn software and I remember Tyler working on Droop when tuning My boat on the water years ago but I don't remember ever seeing it when I was tuning, Smitty
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Old 07-26-2012, 06:11 PM
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The other guys have given you great advise... but you might want to try as noted the increase in throttle blade position while maintaining proper TPS voltage. In most case the TPS can be tweeked to maintain desired base voltage. After that you may need to change the 100% TPS multiplier. I have rarely found necessary to drill out the bleed holes. In extreme cases I used a divorced IAC running 2 GM IAC's in parallel.

Happy tuning

Originally Posted by articfriends
Where are your IAC counts? I have seen motors with big cams where IAC was maxed out around 150+ and it couldn't open anymore to "save" the motor at idle, when my 540 started making big power and using a big azz cam in order to get the iac counts under 100 where it can actually open/close enough to hold the idle as load changes I had to drill holes right in my throttle blades. I started out 1/16 and just kept making them bigger until the IAC counts were around 75 or so , mine started at 150 plus, Smitty
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