496 EFI in Jet ?

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Chinewalker

New member
I have a new 496 efi HO that came out of a I/O could u make this run in a Jet I know it has stuff u wont need but would it work ? :huh:
 
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scarabscs

New member
You can do it, you just have to make sure all of the sensors are where they need to be.  That would be a kick ass combo, but you would have to buy software if you needed to tune it (if you stayed EFI.)  It shouldnt be that hard, but you would need a wideband O2 gauge installed infront of your water injection for tuning.
 
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blazeracer

New member
If it came out of a boat it most likely already uses an open loop system, ie doen't required an O2 sensor. It most likely just works off of a TPS and air temp sensor. I'm no expert on EFI at all, but I've heard of systems that can run closed loop with dry exhaust for tuning, save the settings, then take the O2 out and run water in open loop mode.

Without any feedback from the motor it can not engage in machine learning and also cannot correct any errors. For WOT in a jet boat open loop is just fine provided the fuel map is right, or basically not too lean.

You'll also need to add a high pressure fuel pump and a return line for the fuel as those systems constantly circulate the fuel under high pressure.
 
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Chinewalker

New member
It is a boat engine  fuel system is.all on it  I have the software it dose not have a o2 sensor  the kicker is cooling and exhaust  and to get rid of the power steering  the cool thing is 3 wires and it fires up or should I use this block and heads and put. Carb and dist on it  I work on o/b engines.not  big v-8  just know how to do.simple.stuff on them
 
Patchman

Patchman

Administrator
Staff member
Carb and dist would keep it simple. The fuel infection would be cool also. I don't like the price of diagnostic equipment needed to acces the GM diagnostics. think.gif
 
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HellinnFrnt

New member
Patchman said:
Carb and dist would keep it simple. The fuel infection would be cool also. I don't like the price of diagnostic equipment needed to acces the GM diagnostics. think.gif
Click to expand...

GM Diagnostics lesson #1  ..... If it starts it's just fine ...... #2 If it doesn't start some Ford guy jacked with it ......


:smile26:
 
Patchman

Patchman

Administrator
Staff member
It takes a Ford guy to figure out that goofy crap. GM ran crap like Cross Fire injection. Just shoot me now so I don't have to deal with that crap again. :smile26:
 
Patchman

Patchman

Administrator
Staff member
scarabscs said:
Im not sure if the 496 is open or closed loop.  I know my 502MPI is a closed loop computer system.
Click to expand...
I would think a closed loop system if you don't have O2 sensors. think.gif
 
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scarabscs

New member
Im pretty sure it is.  Thats why they are so sensative to mods, if you get out of the "map" your are goin to be running lean until you get it tuned.
 
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blazeracer

New member
Other way around. Closed loop uses the O2 sensor to complete the circuit providing feedback to the ECU making adjustments as necessary. Open loop has no O2 sensor to complete the circuit.

Here you go...

ECM_Diagram.gif


Even the current EFI systems use open loop until the engine is at operating temperature. There's nothing wrong with an EFI from Ford or Chevy if it's mapped right. GM's TPI was one of the sweetest systems ever made. If someone made an intake to put a TPI runners on a 460, I'd have it on my boat! Just sayin.....

But there are systems out there that can go closed loop to tuning, then open loop for operation. That would most likely involve either paying someone to get it right or doing A LOT of reading and buying some high dollar software...

But the motor on the topic, if there's no O2 it's open loop. It should drop right in with the three wire hookup like you stated. the only work will be the fuel pump and return line. I'd like to see that in a jet boat.
 
Patchman

Patchman

Administrator
Staff member
Your rite, I had it backwards. O2's don't work well when cold. So open loop doesn't use them. think.gif I'm awake now! :grin:
 
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Chinewalker

New member
The fuel hook up is no problem either the fuel is return thru the cool fuel system it dose not have a return line to the fuel tank the problem is water cooling I will have to put a raw water intake in the boat for the raw water pump then it gos thru the engine and the cool fuel then out the exhaust I guess like some one said dry exhaust Im looking into it I would really like the efi on it and in it I have to put a smaller oil pan on it first
 
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blazeracer

New member
Chinewalker said:
The fuel hook up is no problem either the fuel is return thru the cool fuel system it dose not have a return line to the fuel tank the problem is water cooling I will have to put a raw water intake in the boat for the raw water pump then it gos thru the engine and the cool fuel then out the exhaust I guess like some one said dry exhaust Im looking into it I would really like the efi on it and in it I have to put a smaller oil pan on it first
Click to expand...

Then it's probably a returnless system which needs the fuel pump (probably out of the doner boat would be best) that has the regulator attached. Those returnless systems are real picky about the fuel pressure being just right. As little as 4psi can throw the whole thing out of whack.

For the water, have the line going from the pump go through the cool fuel system, then follow normal jet boat routing from there. Are you using OT headers or logs and risers? I wouldn't go dry exhaust at all, but that's just me. The exception would be dry to tune it IF you're going to use a wideband O2 sensor, then pull the sensor and go wet to run it. They just get way too hot running dry.
 
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