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- Engine Management (https://www.homemadeturbo.com/engine-management-10/)

- - SAFC trouble (https://www.homemadeturbo.com/engine-management-10/safc-trouble-6647/)

First, a bit of a background, I have installed an SAFC, 390 injectors (4G93T) and 10 Ohm resistors in my boosted Mitsubishi Lancer (4G15 engine), Mirage stateside, and set the correction to -40% at 1k RPM and -39% at 2k and so on. The thing is when the car is stationary and in neutral, when I slowly rev the engine to 2k and when it reaches 2k and try to keep it steady at that RPM, it then oscillates. RPM goes to 2k-1.5k-2k.. and so on but if you go higher than 2k it becomes normal again (2.5k). It seems that it is having some trouble when the RPM is at the NE points. But when the car is moving and accelerating it seems that the problem does not exsist. Unless your cruising and the RPM is at 2k and your foot is off the accelerator pedal, then when you step on gas a gain it gives a little jerk. Pretty much like the description in the vacuum jerk post. Is this normal with the SAFC and lareger injectors? Any comments to what might be causing this would be helpful. :)

ps. my stock injectors are 182cc/min

thanks!

I didn't think you would need resistors since you already have a DSM that uses low impedence injectors from the factory? ???

Anyways, my Honda does the same thing. I don't really worry too much about it. I always thought it was the TPS voltage because I know that is off in my car.
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only the Mitsu/DSM with OE turbo uses low impedance injectors and therefore has OE resistor packs. My Lancer is stock NA and has high impedance injectors. ;)

So this is normal with the SAFC and larger injectors ei? :-[

I don't know man, are you sure? I don't know ---- about those crazy ass DSM's, but I could have sworn that all of them were low impedence, even the N/A ones. ???

I don't know if it is normal to anybody else, but to me it is. I have a new TPS I'm going to try out, but other than that I am going to live with it. It makes it a bitch when you want to keep it at a steady idle for whatever reason.
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yup, i'm definitely sure my stock ones are high impedance. i measured them with my trusty multimeter. ;)

i see, well i guess i also have live with it and learn how to drive it properly without jerking the car to much at cruising speeds. :-\

thanks again! ;D

Quote:

Originally Posted by reg22

The thing is when the car is stationary and in neutral, when I slowly rev the engine to 2k and when it reaches 2k and try to keep it steady at that RPM, it then oscillates. RPM goes to 2k-1.5k-2k.. and so on but if you go higher than 2k it becomes normal again (2.5k). It seems that it is having some trouble when the RPM is at the NE points.

I have the same problem too. I posted about it in this thread https://www.homemadeturbo.com/forum/index.php?board=6;action=display;threadid=3751 I'm using an SAFC II and DSM 450cc injectors and my RPM jumps from 2.5k-2k-2.5k Looks like some people have the problem, and others don't :-X

thanks guys, but i think i finally solved the problem. the solution was i tried to select a different sensor number other than what is indicated for mitsu (PR-5). i found that (PR-3) did not show the problem and is nearest to 0 VAC on the SAFC when the engine is not running, key is in the "ON" position. (PR-5 = -14mm/Hg | PR-3 = +.09) the car is running great now but my previous settings were way off, ie. -39% to -50% now.