Where to get EEC-IV ECU specs/schematics.

[thomas walter x5955]

> From: Hans Steiner <hs283 at bard.edu>
> 
> My mechanic just told me that the code 41(always lean) code that I am 
> getting is caused by a bad computer.  And a "rebuilt" one costs $225.  So 
> I thought I'd first try to fix it myself, since I would be buying a 
> "rebuilt" one anyway.  So I was wondering whether anyone knows where to 
> get the schematics and/or specs for the EEC-IV ECU. 

Question does appear from time to time, but I do not think any SOURCE 
of the schematics has ever been posted. ;-(  Specs should be listed
in the factory manual.

Probably the biggest problem for us O'scope toting fanatics is the 
Ford EEC-IV boxes use of the custom IC's. Ford seems to have almost
all custom parts in it, unlike -say- a Bosch control box (which use 
common controller and memory, with a few custom built devices). 

I would be tempted to take the manual, and start through the factory
trouble shooting guide. Seems a faulty pump, one clogged injector,
low fuel pressure, cracked rubber manifold hoses, etc. could ALL cause
the "always lean" condition. Seems like a bad (shorted - rare) H20 temp 
sensor, or EGO, would trigger their own codes.
 
In the latest issue of "Design News"  (10-9-95annual Automotive issue)
were some interesting  tidbits: for 1996 year models OBD-II Ford modules 
will have something like 150 troubleshooting codes (vs. 50 for the 
earlier ones). Also the value of the electronic systems will make up 
10-12% of a vehicles price! 

Cheers,

Tom Walter 	'67 Datsun 2000	'68 Datsun 2000  -> convertible's
Austin, TX. '71 Datsun 510  '72 Datsun 510   -> small boxy sedans
            '95 Ford Aerostar -> enough room for kids/dog/camping gear!