More TPI questions from me

[John Faubion]

> What is the difference between the 85 vs. 89 system. I know the 85 uses
> a cold-start injector system while the 89 and up units do not. Why is

Another difference is the 85 system used a MAFS module to control the burn
off cycle for the MAF. In 86 it was moved into the ECM. 

> one better then the other? Why does everone want to eleminate the cold

The main reason for this is it adds an additional problem for those
converting to a speed density system. The later model engines don't provide
a way to connect the cold start injector and you would then have to explain
to the smog refs why this injector was not used. (Actually if the wires
were run far enough back into the harness the refs would mostly never know
the difference.)

> start injector? What is the difference between the speed density system
> and the mass Air Flow? Would one be more desirable for my application?

MAF is better for a modified engine since it can adapt to a wider range
than a SD system. SD is better since it doesn't require an expensive MAF
and extra wiring and plumbing. To each his own.

> Is one system better? Also, it seems as if everone on the list perferes
> the 89 EPROM, why?

Actually not everyone prefers the 89 model. I happen to prefer the 90-92
speed density systems. This is mainly due to my preference for big block
engines. The MAF is easily maxed out with a deep breathing 427!  :)

John Faubion
jfaubion at beaches.net