Another option is a complete DIY job. A programmable computer costs about
$800-$1000. New injectors run at least $400. Add a 4 barrel single plane
manifold, $100. Buy a throttle body, $400, or use a mechanical secondary
carb. Fabricate, hack, slash, weld, plug in your laptop computer, and you'll
wish you had bought the Edelbrock. The Edelbrock is the only sequential
system in the price range. However, I'm stubborn, and if I decide to do fuel
injection, I'll probably try to save a buck. It should be possible to plug
the PROM into an emulator, and use a laptop to adjust the fuel & spark
curves while driving. I have no idea which emulator works or how much it
costs. The computer is quite simple, really. It stores fuel curves in a 16
by 16 matrix. One axis is RPM, the other is load. It rounds the inputs to
the nearest spot on the matrix. It then adds or subtracts a percentage of
fuel based on coolant temp, oxygen sensor reading, and some others that I
can't remember.
The computer has the ability to learn new curves, up to a point. It reads
the oxygen sensor and adjusts accordingly. If, however the correction is too
much, it blames the sensor, sets a trouble code, and limps home.
Having a company burn a custom PROM costs about $200-$300, pretty cheap in
the grand scheme of things.
----- Original Message -----
From: J Forbes <jforbes@primenet.com>
To: Old Trucks List <oletrucks@autox.team.net>
Sent: Wednesday, March 08, 2000 6:10 AM
Subject: Re: [oletrucks]fuel injection
> Brian--
>
> There are many ways to install the factory TPI, so the cost can vary
> greatly, depending on how much you can do yourself. If you can make
> your own harness (or adapt a different junkyard harness, or have access
> to the right stock harness) you can install a factory TPI for well under
> $1000. If you buy all the parts new, you could probably spend over
> $2500. Realistically, you will need to buy a used TPI setup, which
> usually goes for about $500 complete, then you'll probably want an
> aftermarket harness, probably a different stock computer, and an
> aftermarket PROM chip (the VATS needs to be bypassed), plus you'll need
> to deal with the fuel system, which means getting the right high
> pressure pump and doing the plumbing, maybe even buying a cutom gas
> tank...then you'll probably need to replace a few parts on the TPI unit,
> such as the TPS, and perhaps some or all of the injectors. There will
> be some other things that will pop up to surprise you, such as accessory
> brackets, throttle cables, coolant fittings, etc. So, I'd have to put
> the real cost between $1000 (absolute minimum) and $2000 (but it could
> go higher). The difficulty is hard to predict...if you do your
> homework, and are clever, it can actually be easy to do, but if you're
> easily frustrated and don't really understand the system, you can get in
> over your head.
>
> I did a swap like this on a friend's 69 Vette, and spent quite a bit of
> time overcoming the problems with minimum cash outlay...and it still
> cost over $1000, but I learned a lot, and he really likes the way the
> car works now with TPI.
>
> Tough decision....good luck!
> Jim
>
>
> Brian m wrote:
> >
> > hey all, im pretty well sure im going to get the multi-port injection
from
> > edelbrock, but the look of factory GM TPI is pretty nice. what i want to
> > know is what kind of cost difference is there, the edelbrock kit, with
> > underbed tank will run me about $2500, what is it for factory TPI? also
how
> > long will it take for TPI to install it and how easy is it? am i going
to
> > have to modify or custom build a lot of parts/wiring for TPI? edelbrock
is
> > pretty much a bolt on, but what i want to know is just how easy it would
be
> > to go GM TPI.
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
>
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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