LT1 EFI Question

[Jennifer and Brock Fraser]

>From: Ron Tyler <dcmckenna at worldnet.att.net>
>Date: Wed, 01 Apr 1998 20:27:11 +0000
>Subject: LT1 EFI Question
>
>Hello All,
>
>     I installed a '95 LT1 in my 240Z. I have removed EGR, air pump,
>canister purge valve, shift indicator lamp, and MIL. Everything else is
>intact. About 30 seconds after starting the car, the cooling fan
>activates. Is this some sort of quasi limp-home mode due to the missing
>components? The PCM *does* go into closed loop, so I am assuming that it
>isnt a full blown "limp". Would I be correct?
>
>TIA
>- -- 
>Ron & Stephanie Tyler
>'72 LT1/T56 240Z
>http://www.whit.org/jcaudle/LT1-3.jpg


Ron,

I've got a twin-turbocharged LT1 in my Jaguar that runs on a '96 PCM.  I
don't have any of the emissions-related equipment you mentioned on my car,
and my fans don't turn on after startup. (The fans are PCM controlled, as
in the factory f-body)  If '96 can deal with these losses (with OBD-II
diags), then your '95 should.  Come to think of it, I've used my '95 PCM in
the car with no fan errors as well...

How did you defeat the VATS to be able to start the engine?  There are
really only two possibilities...

1.  modify the PCM data (re-program)
2.  used the factory "body" wiring, including ign. key cylinder and factory
key

Assuming you didn't GUT OUT a F/B/Y car to get the body wiring, I guess
somebody re-programmed your PCM.  I'd start there.  The first sign of a
seriously un-happy PCM is a fan-on condition. 

There's one other thing puzzling me...  You say that the fans turn on after
30 seconds.  This is very odd.  Usually the "I've lost my mind" PCM
condition turns on the fans upon key-on, i.e- engine not necessarily
running.  In fact, that's the DIY_EFI insti-check for a clean programming
is "key-on, fans-no".

The reason I mentioned the re-programming was that a programming error
(incomplete file, incompatible T&E side, etc) can make the car run "OK" but
have the fan-on condition.  A 96/97 PCM will set a code (don't recall the
P-number) that indicates a calibration error...  I don't recall if this
code is used in '95 or not.

Does your scan tool indicate "FANS: YES" for the fan status?  Of course, I
don't know what you are using for a scan tool.  Make sure that the PCM is
really commanding the fans.  Are both fans on?

Besides the fans, how does the car run?  Is the real-time data from your
scan tool reasonable?

Good luck,
Brock