[Diy_efi] Holley projection questions

Lee M. Lemoine llemoine
Fri Mar 10 16:05:42 UTC 2006

Welcome to the list...

I had issues similar to this with my Haltech -- there were two sets of
'grounds'..  some were 'sensor grounds' (floating 'grounds') and the other
type was a chassis ground.  I got those confused at first and got some funky
readings, as the grounding strap between the engine and the chassis had some
corrosion...    This caused intermittent leaning out / stalling conditions,
the ECM would reset as soon as it the ground.  I had to repin all the
connectors on the factory ECU)  so....  sure enough, i figured out it was
the ground after really looking closer at all the black wires in the
harness... and the diagram a little more :P

As far as this wiring harness goes... Can you e-mail me a copy of the PDF?
I'll take a look at that wiring and see what i think.  If i don't see
anything glaringly obvious, i'll post it on my website and post a reply with
the link so that i can share this with the others..

I've never seen the Pro-jection

On 3/10/06, Simon Juncal <sjuncal at erols.com> wrote:
> Hello new to the list here. I found some of this lists posts googling my
> pro-jection problems and thought maybe I could find some help and
> opinions.
> I got the digital 1d system used for next to nothing, open loop for now,
> So I've got a bunch of ideas and questions... like has anyone hacked the
> ECU so that the fuel maps can be programmed via laptop?
> I notice the closed loop "system" they sell for 200 dollars is just an
> o2 sensor, 3 wire harness and a proprietary connector... has anyone
> patched in their own o2 sensor? Does anyone know which post in the input
> connector accepts signal from the sensor?
> I've asked holley tech sup a few basic questions and gotten canned
> replys and multiple copies of the instructions sent to me in PDF :)
> The PO of the system had it on a Sazuki Samurai, on which it ran super
> rich... it's now on my Jeep 4.2, (with 4.0 head conversion, original
> intake and 4.0 header) which is the target aplication of the 1d system.
> The PO along with the help of someone at Holley had the TPS wiring
> turned around and spliced in the harness ground, the voltage range is
> 3.7 to 4.7 nowhere near the 0.63 holley's instructions recomend. I can't
> explain why, because as near as I can determine this range ENRICHES the
> overall fuel mix (making it harder to lean out via the ECU knobs) and
> makes the fuel curve more drastic.
> That said this TPS setting get's me a running, smoothly idling (for a
> jeep) engine but it runs constantly rich, doesn't start easy, gets 10
> MPG (16 to 18 is normal)... SLOWLY leaning it out in the tuning process
> gets me JUST to the Stoich on my autometer gauge, better MPG, hessitant
> acceleration, and inconsistant dropout's where it leans totally out if I
> _barely_ touch the throttle, but riches back up when I get further into
> the pedal. Crusing with foot resting on pedal leads to long off the
> scale lean conditions, and occasionally it leans out at idle, and will
> stall if left alone without pedal.
> Problem is just reversing the wiring back to what the instructions show
> doesn't get me any fuel, the ground as I said is spliced in or Y'd to
> the Grey TPS wire both then going to the black harness wire back to the
> ECU... Seems strange to me but I can't find anywhere else in the harness
> that the ground wire might actually have been attached to.
> There's only one black wire at the ECU input connector, the TPS has a
> black wire, and this ring terminal ground. are they really supposed to
> be Y's together like that?
> Sorry for the long assed post, but I've never been too worried about
> being in over my head. I'm too used to the feeling :)
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Lee M. Lemoine
'06 Subaru Legacy GT Limited - 250/250 AWD 5EAT
'93 Chevy Cavalier Z24 Convertible - 300/330 FWD 5MT (Mclaren Turbo!)

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