Re: TBI, was Re: Hornet status

[Glen Hoag <hoag@xxxxxx>]

> On Thu, 9 Jun 2005 farna@xxxxxxx wrote:
>
> > EFI is the only way to go! Remember, you can go real cheap and
> > use a GM 2.5L four setup. Has a 400 cfm or so throttle body. If
> > you use the GM computer you need a system from a 84-85 car or up
> > to 87 (I think) truck. Has to be one with a regular distributor.
> > Then you really need a HEI distributor so you can gut the original
> > four distro and put it in the HEI for spark changes as well.
>
> If I can assemble a TBI system from junkyard parts (and strategic
> new) I will do it this year, and write up the process.
>
> I want only a carburetor replacement; I'm not looking for maximum
> performance, I want reliability, simplicity, good fuel economy.
> Plus I'm very lazy.
>
> I don't want to use knock sensors, crank-position sensors,
> multi-coil or HEI ignition. I know all those things make for a
> better system, but I don't have the time, money nor inclination.
> I just wanna get rid of the !@$$%! carburetor. I want to bolt it
> to my existing, installed, bracketed and hand-fitted, intake
> manifold. I assume I'll have to make an adapter.
>
> I know this is technically possible.
>
>
> Here's what I've determined so far:
>
> *** All-GM OEM parts are the way to go. Cheap reliable and
> plentiful!
>
> *** Throttle bodies are the easiest component to select. I'll go
> to U-Pull-It.
>
> *** A booster pump (9 - 12psi) following the existing mechanical
> pump should be just fine. No tank recirculation or tank-mounted
> pumps.  All that just seems silly to me. Mechanical pumps suck
> fine, you can filter between the two pumps cheaply and safely.
>
> *** The hard part to me right now is picking the ECM to use. I
> know I want one that works with distributors -- but can I pick one
> that is capable of changing ignition timing, and simply not use
> those outputs? Can I ignore or terminate unused inputs like knock
> sensor?
>
> I'm looking...

Tom,
While it's not an OEM GM part, at $140 for the kit, it's cheap 
enough.  The MegaSquirt ECU works with a distributor, needs only 
coolant temp, intake air and throttle position sensors.  It has a MAP 
sensor built in, so needs a hose to the intake manifold. It'll work 
with either a throttle body or MPI setup.  The base code for it 
handles only fuel, but there are a number of fuel+spark options 
available through alternate firmware loads.  It's tunable to just 
about anything, from a lawnmower to a 500+ cu. in. monster.  Well, 
maybe not something as small as a lawnmower, but pretty close.  The 
tuning software is designed to be run on a low-end PC laptop.  A 
number of people have installed them on AMC engines, mostly in Jeeps. 
There is also an active community of users involved in all aspects of 
its operation.

Info at <http://www.megasquirt.info>.  User community is at 
<http://www.msefi.com>.

DISCLAIMER: One way to build a MegaSquirt ECU is through a kit that I sell.



--
Glen Hoag
hoag@xxxxxx                             '75 Pacer 258 (x3)
Limestone County, Alabama               '76 Pacer 258 (for parts)
                                        '81 Concord DL 258

AMO #7895    AMCPC #471                 '82 Spirit 151