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RE: FI Changeover

To: "'Steve Laifman'" <SLaifman@socal.rr.com>
Subject: RE: FI Changeover
From: "Theo Smit" <theo.smit@dynastream.com>
Date: Fri, 7 Jan 2005 13:49:50 -0700
Steve, and Listers,
Probably one of the big differences between the EFI you used on the Fiero
engine and the current (i.e. '89 to '93 Ford 5.0) EEC is that the latter
uses a hot-wire mass-airflow sensor to sense the incoming air mass. The MAF
is calibrated to the injector flow volume, and the EEC takes care of the
rest. This is what has fuelled a huge boom in aftermarket performance mods
for the Ford engine, since the computer compensates for whatever increase in
breathing ability you've installed, provided you don't exceed the fuel
delivery capability of the engine or the ultimate flow capability of the
MAF. You also need to install the exhaust oxygen sensors to allow it to run
in closed loop mode, but welding a bung into the header collector is not
hard.

Older systems like the pre-88 speed-density computer, or some aftermarket
systems like the SDS-EFI, need to be remapped after any engine change. To
offset this disadvantage, they don't require the mass airflow sensor in
front of the throttle body, so that you can run an individual-runner type of
manifold (like the four-Weber induction of yore). You do need to have a good
source of average intake manifold vacuum to make these work. Again, this
stuff is not hard.

Computers and complete wiring harnesses are readily available at reasonable
cost through specialty autowreckers, on eBay, or at your local
Pick-your-Part. There are several books on Ford's EFI system wiring,
including listings of error codes, and there are a bunch of aftermarket
shops that specialize in putting this modern technology into older cars. In
that respect the Tiger is no different from a mid-sixties Mustang or Falcon
- except for the clearance issues, and that's why the body interference is a
primary point of discussion whenever Tiger EFI comes up.

Best regards,
Theo





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