MSefi.com read only forum (Jan.15,2018)

The car start and runs good. The only trouble i get is when i put it in drive the rpm drops to arouund 650 from 800. And the car dies sometimes when hard braking on high rpms. idles good runs good. Could it be that im using 19lb injector for a 305. Do i need to go to 24lb that comes on 350.

Look at your pulse widths. If they're below 85%, then they aren't too small.

19 are good up to 270-280HP on stock fuel pressure on your setup

best regards

So the injectors are good. So what could could it be to make my rpm drop so much. It didnt do that when i had tbi or a car, it only start to do that when i went with multi-port.

How are you controlling your idle? ARE you controlling your idle?

im not control the idle. i have the iac disconnected. Would that make a big different?

Yes.

Your idle is currently set with no load on the engine. As soon as you put it in Drive, there is a load on the engine, but no additional fuel/air flow, so it slows down.

Chopping the throttles from a WFO run drives your MAP quite low, and your VE table may not be set correctly. Given that you are under braking, the engine is being slowed so quickly that it may not have time to recover.


Figure out something to do with your IAC.

My ancient car had factory Lucas EFI before I fitted MS. Cold fast idle was via a thermostatically controlled extra air valve. No closed loop idle speed system. The factory did a mod with a solenoid air valve which opens when you select drive or reverse, after complaints of stalling. Same in principle as it does when you select AC. Since it all worked well and is so simple I kept it when fitting the MS - as standard code doesn't/didn't do closed loop idle speed control. And the later stepper motor valves used on my engine type were notorious for failing.

I don't see a posted datalog and .MSQ. Those would help us "see" something that might be happening.

Thanks
Holl