Need a crash course in crossfire.

CFI is batch fire anyways just run same ignition feed to both injectors. I've never seen a resistor in CFI harnesses. I think it's just a crimp type things for the injector wires.
 
CFI is batch fire anyways just run same ignition feed to both injectors. I've never seen a resistor in CFI harnesses. I think it's just a crimp type things for the injector wires.

What about the return (pink wire to the dist)? Are the injectors grounded or something?
 
CFI is batch fire anyways just run same ignition feed to both injectors. I've never seen a resistor in CFI harnesses. I think it's just a crimp type things for the injector wires.

What about the return (pink wire to the dist)? Are the injectors grounded or something?

the ecm grounds the injectors to pulse them is all so on wire to each one will always be hot

for a boat you can run the cfi with just MAP/TPS/IAC/KNOCK SENSOR/HEI/EST/CTS If you are running a non closed cooling system the CTS will never get hot enough to go into closed loop anyways so unless in closed loop the o2 sensor is useless since it only fine tunes fuel delivery in closed loop and if closed loop isn't attained it should run at 14:1 anyways which is still superior to a carb.
 
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So then that pink Wire (3) is probably just a switched 12v hot? I usually adjust the water inlet so the motor varies between 160-200 degrees.
 
And how does the MAP sensor hook up to the motor? Can't find it in the intake, I saw a drawing with it on the firewall.

Can I jack one from TBI F Body?
 
waht you circled on page 2are the injector fuses, look again and you will see it's the fuse box drawn there

The map sensor is hooked to the larger offside port of the TB, either one is fine, cap of everything else that is not used. the center ports are only used for balancing purposes, do not run anything of those
 
OIC, thanks again TT. So the other side goes to a fused pink wire, which becomes pink/black, which is 12V switched hot. Got it. :drink:
 
So I have just about 2 wires left that are confusing me, then it should be ready for a fire!!! ...Sorry for all the questions about this :/

The Crank Discrete (1/ top connector) and the Sys Return (12/ bottom connector).

The crank discrete goes to the post on the starter motor labeled (S) which I would guess would be the switched 12V, and it goes off to a theft control relay. Since I won't be using that relay, can I simply hook it to the 12V switched on the starter coming from the ignition key (which is already wired up in the boat)?

The Sys Return, it goes to the Park Neutral Relay, the Diagnostic Check Connector, the Fuel Pump Relay, and another computer terminal (Single Duel Inj Sel). Since I'm not running a neutral safety switch, diag connector, and the fuel pump wiring will be separate... what should I do with it? Can I just ground the both Sys. Returns (12&13) and the Single Duel Inj Select Terminal? Also, since I'm not running a neutral safety switch, can I leave the Park Neutral Switch (5) open? Or should I feed it 12V switched?


153p445.jpg
For reference, ignore red circles.
 
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Sys return is the ECM ground. The reason it goes to the others is so you can test those things through the ALDL connector,

Crank discrete is simply the cranking signal input, it tells the ECM to fire the injectors and turn the fuel pump relay back on (it shuts off after a couple secs KOEO)

There's also the issue of the VSS and the dual injector select. It's grounded in P/N for starting and also by the VSS to get it into dual injector mode instead of asynch fire @ high speeds when needed (WOT) Without it the engine probably won't rev past 3 or 4K rpm. I'd try it without grounding first
 
Thanks TT. So I should just leave the Duel Inj Select terminal disconnected at first? ...I hope it revs without the VSS, or I might be sort of screwed.
 
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The speed density TPI I installed in '95 on this car, had no VSS on it at first, and the engine would search at idle....putting one in solved that immediately...
 
Thanks TT. So I should just leave the Duel Inj Select terminal disconnected at first? ...I hope it revs without the VSS, or I might be sort of screwed.

will rev fine without a vss signal. besides the earl vss signals were in the speedo head not the transmission. the trans mounted ones are 2k or 4kpuls per mile neither i believe will work with the cfi ecm anyways. No vss signal will also not keep the ecm from going closed loop.

as for a o2 sensor I highly doubt it could reach temps sufficient enough for it to work in a boat. Maybe a heated o2 would be a better choice.

when you mount your map sensor if it is a ways from the vacuum port make sure you use very small vacuum line. I suppose you could just mount it to your air cleaner or something but try and some lines about the thickness of the original plastic lines.
 
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c4 uses trans mounted vss

no vss will trigger the check engine light if you have one.

use plastic line for the map, never an issue again
 
I scored a MAP sensor, the connector and the plastic vacuum line from an TBI junkyard F Body this weekend.

As far as the O2 sensor is concerned, I was actually going to ask if you guys thought it would get too hot if I mounted it in the actual manifold. The water only cools the manifold, it isn't injected until the muffler.

So if you guys think the flames shooting right out of the cyl head onto the O2 sensor aren't too much, let me know. That would be the simplest solution for me.
 

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