[Gmecm] 181 merc 730 mixture trim adjusting tool

[Jay Vessels]

Hi there!

> 1. My most intriguing one is-------- about a tuning
> mixture trim device (with one or two lenier potentiometer knobs) to
> instantly lean or enrich the fueling when mapping, Does moates sell a
> tool like this-to use with gm computers?

Is this just for dialing-in the tune (which will then be burned into the 
chip) or is this supposed to be a more permanent installation?  I'm not 
sure why you'd want this on a regular basis, since that's the reason you 
have a computer doing that work for you in the first place.

For that capability, your better bet for tuning would be the ROM 
emulation stuff that Moates has that lets you do on-the-fly chip 
parameter changes.

2. Hartman says that the 91,2 TPI's were just batch fire

Yup, they are.

, is
> it simple/ possible to run it sequential as long as I have a tdc
> sensor and a cam sensor?

Nope, the ECM doesn't have any provisions for sequential fire.  For one, 
it's missing enough injector drivers to do that.

Sequential doesn't get you much beyond emissions.  The OEMs (in the '90s 
anyway, not sure about newer) go to batch fire once the revs come up.

If you want sequential, you probably want to go to a newer PCM.

  3. Some enthusiests have rigged what amounts
> to a "spark trigger" causing the ecu to trigger injections before
> cranking--providing a primer dose of fuel--like pumping the throttle
> on a carbed car before starting. is this do-able with the gm 730

Why?  You should be able to tune this in the chip to get more fuel at 
cold start.

Older TPI hardware have a "cold start injector" which is a 9th injector 
connected to the starter solenoid, though a thermal switch.  On a cold 
engine, this injector sprayed fuel into the intake while cranking.  The 
'85 TPI system we used had this, and it did start almost instantly.  You 
could adapt something like that if you wanted.

  5. There were add on knock sensors avalable in 93 when this book was 
written- would one of those
> cancell out that part of the prom on a 730?

Not sure about interfacing an aftermarket knock sensor, or how they 
would work so much better than the stock one that it would be worth it. 
  There may be a way to hack around the knock filter in the MEMCAL, and 
use the aftermarket knock sensor's signal instead.  I'd be surprised if 
that does anything useful.

Jay Vessels
1982 Chevrolet S-10 Sport, 2.8V6 TBI
2006 Pontiac Solstice
2007 Subaru Outback L.L. Bean, 3.0R