[Diy_efi] Ford EEC?

Daniel R. Nicoson A6intruder at adelphia.net
Sun Sep 5 03:55:41 GMT 2004


Garrett,

What are the DTCs?  Error codes?

What year and model EEC?  What car is it in?

I looked in both software packages I use to run my EEC Tuner, they do not
have any settings to do with AC that I can see.  I am familiar with the 1994
Mustang GT EEC, T4MO.  The only thing I can think of is that when the EEC
determines it is at WOT it shuts down the AC system.  So possibly the
combination of what the EEC is calculating is that you have hit WOT and it
is shutting down the AC.  I'm not sure what other conditions would cause it
to shut down the AC.  These software packages won't do you any good without
an EEC Tuner or TwEECer hardware to manage the EEC.  That's pretty expensive
to get your AC running.

I assume your Motec is using a MAP sensor?  You say the MAF is still hooked
up to the EEC.  Is it still in the intake tract so that the intake air is
going through?  If you just have it sitting off to the side, not flowing
air, that might trip a code.  The EEC would be seeing all the other
indications of proper engine operation (RPM, temps etc.) but no airflow.  It
might think the MAF is bad and go into a limp mode which shuts off the AC.
Once or twice when re-assembling I have forgotten to connect the MAF.  The
car started right up and drove around the block, seemingly just fine but I
think I got a Check Engine Light.

IF you are leaving the MAF plugged in to keep the EEC happy but not flowing
air through it is sending a very low voltage signal to the EEC.  I would
suggest you loose the MAF altogether and try to supply the EEC it with a
"normal" signal that would suggest the MAF IS flowing air.  I just looked at
a data log, highway cruise typically sends a signal between 1 & 2 volts on
my car.  This would tell the EEC it has air flowing and not trip into a limp
mode that might turn off your EEC.

BEFORE you try the above, I just looked at the EEC connector diagram for my
car.  There are several connections concerning the AC.  Figure out what
these do and take that function away from the EEC by disconnecting them from
the computer.

Air conditioning cycling Switch input - function?

A/C WOT cutout relay - turns off AC at WOT

A/C head pressure Switch input - function?

It is never fun to trick an ECU because we don't know all the "twists and
turns" the OEM engineers wrote into the code and strategy.  I would say if
you can separate control of the AC from the EEC you might be more
successful.

Two possibilities.

Dan

-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
Behalf Of Garrett P. Beauregard
Sent: Saturday, September 04, 2004 5:25 PM
To: A list for Do-It-Yourself EFI
Subject: RE: [Diy_efi] Ford EEC?


Dan,


Thanks for the response. Here's my problem: the new engine is controlled
entirely by a Motec box but the original EEC still has most of its original
inputs (MAF, crank and cam sensors, cylinder head temp, oil pressure, etc.).
The engine runs fine and the dashboard gauges and controls are doing their
thing. BUT, the A/C compressor won't come on with the selector on A/C or Max
A/C. I've jumpered the clutch relay and it works and the air blows cold, so
the system is working. We cleared out all the DTCs and the A/C came on but
only for a minute or so before one of the DTCs popped up and the system shut
off.

I'm trying to find out if one of the EEC tuners (TwEECer) can be used to
force the system to allow the A/C on even with the DTCs active.

Thanks for any ideas you have.


Garrett

-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
Behalf Of Daniel R. Nicoson
Sent: Thursday, September 02, 2004 7:34 PM
To: A list for Do-It-Yourself EFI
Subject: RE: [Diy_efi] Ford EEC?


Why would that be off topic?

Yes, I've been tuning my Mustang for two years.  EEC Tuner using the related
software.

Dan

-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
Behalf Of Garrett P. Beauregard
Sent: Thursday, September 02, 2004 8:52 PM
To: diy_efi at diy-efi.org
Subject: [Diy_efi] Ford EEC?


Here's a marginally off-topic question to fill the current lull.

Does anyone have any experience with the freeware/shareware programs out
there (like TwEECer) used for tuning and modifying some of the Ford EEC ECU
systems?

Please e-mail me off list if you can.


THANKS

Garrett
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