Ferrari Mailing List: Re: throttle position sensor???

[Jeff Greenfield (coyote]

Jerry - 

Yes and no. There is a throttle switch but it is not really a TPS.

It is located right on the plenum, next to the throttle butterfly.

There three terminals, you should have continuity between two of them at
idle, these should go open right off idle, and then between one of the same
terminals and the other the switch should close at WOT. Any combination of
terminals should be OPEN at anything other than idle or WOT.

Basically, it tells the ECU to lean the mixture at idle a little, and to
ignore the O2 sensor at WOT making it a little richer under this condition.

The wiring between the throttle switch and ecu goes through several relays
and lots of really convoluted wiring. As I recall too, the throttle switch,
as well as the frequency valve and O2 sensor, all go through one relay which
has an internal fuse which is not meant to be replaced. When this fuse
blows, the whole system acts really weird. I think that this relay with the
internal fuse is NLA, if it is available, it is stupid money.

On the 328, Ferrari wired the fuse externally in line with the relay. You
can open the old relay, solder in a jumper, and then install an external
fuse. 

I did this on my car several years ago, and all is still working fine.

The throttle switch should be available from your favorite Bosch supplier by
the Bosch number, as it is the same part used on several other Euro cars
(BMW comes to mind, but I don't remember the specific applications).

What problems are you experiencing? I went through some weird problems with
this system on my QV a couple of years ago, maybe I can help?

Jeff

-----Original Message-----
From: pvb308 [at] comcast.net [mailto:pvb308 [at] comcast.net] 
Sent: Monday, January 29, 2007 11:01 PM
To: Jeff Greenfield
Cc: The FerrariList
Subject: [Ferrari] throttle position sensor???

Does anyone know if an 85 308QV has a "Throttle Position Sensor", and where
on the engine is it located??

   Thank You,
     Jerry
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