Need some help with O2 Sensor placement.
 

Holly Projection System -

Hi I'm new here and need a little help.
I have 1970 24' Caravelle. InBoard / OutBoard with a Mercruiser Ford 302.

Last year I replaced the Carb and Intake Manifold with Holly ProJection replacement throttle body fuel injection system and an Edelbrock IM.

It runs like crap and has no power, I followed the tuning instructions to the letter, but no matter how much I tune it, it doesn't help. I think its running really rich at idle and very lean up top. I want to add an O2 sensor to the system to see if that will help the computer adjust the fuel settings better.

This is where the problem is - the exhaust manifolds are dual wall - one section holds the exhaust from the engine and the other section has water pumping into it. They mix a little ways down and are expelled through the prop.


How or where can I add an O2 where the exhaust is without hitting the water jacket?


Here is a picture of the Exhaust Manifold -

http://www.dolleroffshore.com/parts_...R/57571/E4.gif

And part descriptions.

1 EXHAUST MANIFOLD ASSEMBLY, PORT 1
1 EXHAUST MANIFOLD ASSEMBLY, STARBOARD 1
2 STUC, EXHUAST MANIFOLD TO EXHAUST ELOBW (1 3/4") 8
3 PLUG, EXHAUST MANIFOLD 6
4 PLUG, PIPE - EXHAUST MANIFOLD 2
5 SCREW, EXHAUST MANIFOLD TO CYLINDER HEAD (1 1/4") 16
6 LOCKWASHER, EXHAUST MANIFOLD SCREW 16
7 GASKET, EXHAUST MANIFOLD TO CYLINDER HEAD 2
8 EYE, LIFTING - EXHAUST MANIFOLD 2
9 SCREW, LIFTING EYE ATTACHING (5/8") 4
10 END CAP/CONNECTOR, EXHAUST MANIFOLD (FRONT) 2
11 GASKET, END CAP/CONNECTOR TO EXHAUST MANIFOLD 2
12 SCREW, END CAP/CONNECTOR TO EXHAUST MANIFOLD (1") 6
12 SCREW, END CAP/CONNECTOR TO EXHAUST MANIFOLD (1 1/4") 2
13 END CAP, EXHAUST MANIFOLD (REAR) 2
14 GASKET END CAP TO EXHAUST MANIFOLD 2
15 SCREW, END CAP TO EXHAUST MANIFOLD (7/8") 8
15 SCREW, END CAP TO EXHAUST MANIFOLD (1 1/4") 2
16 BRACKET, SHIFT CABLE 1
17 GROMMET, SHIFT CABLE 1
18 EXHAUST ELBOW ASSEMBLY (90 - STERN DRIVE) 2
18 EXHAUST ELBOW ASSEMBLY (STRAIGHT - INBOARD) 2
19 PLUG, EXHAUST ELBOW (1" - 14) OPT
19 PLUG, EXHAUST ELBOW (3/4" - 14) OPT
20 TUBE ASSEMBLY, WATER SEPARATION - EXHAUST ELBOW 2
21 PLUG, PIPE - EXHAUST ELBOW 2
22 FITTING, HOSE - EXHAUST ELBOW 2
23 PLATE, EXHAUST ELBOW TO EXHAUST MANIFOLD 2
24 GASKET, EXHAUST ELBOW TO EXHAUST MANIFOLD 4
24 GASKET, EXHAUST ELBOW TO EXHUAST MANIFOLD (STERN DRIVE) 2
25 LOCKWASHER, EXHAUST ELBOW TO EXHAUST MANIFOLD STUD 8
26 NUT, EXHUAST ELBOW TO EXHAUST MANIFOLD STUD 8
27 ELBOW, EXHAUST (STARBOARD SIDE)
27 ELBOW, EXHUAST (PORT SIDE) 1
27 ELBOW, EXHAUST 2
28 "O" RING, EXHUAST ELBOW TO TRANSOM PLATE 2
29 SCREW, EXHAUST ELBOW TO TRANSOM PLATE (1 1/4") 6
29 SCREW, EXHAUST ELBOW TO TRANSOM PLATE (1 1/4") ELECTRIC SHIF 2
29 SCREW, EXHAUST ELBOW TO TRANSOM PLATE (4") 4
30 LOCKWASHER, EXHAUST ELBOW SCREW 6
31 BELLOWS, EXHAUST ELBOW 2
32 CLAMP, BELLOWS TO EXHAUST ELBOW 8
33 THERMOSTAT HOUSING ASSEMBLY 1
34 SLEEVE, THERMOSTAT HOUSING 1
35 SCREW, THERMOSTAT HOUSING TO INTAKE MANIFOLD (1") 1
36 WASHER, THERMOSTAT HOUSING SCREW 2
37 GASKET, THERMOSTAT HOUSING 1
38 THERMOSTAT 1
39 COVER, THERMOSTAT 1
40 GASKET, THERMOSTAT COVER 1
38 THERMOSTAT 1
39 COVER, THERMOSTAT 1
40 GASKET, THERMOSTAT COVER 1
41 SCREW, THERMOSTAT COVER TO THERMOSTAT HOUSING (1 5/8") 1
41 SCREW, THERMOSTAT COVER TO THERMOSTAT HOUSING (1") 3
42 LOCKWASHER, THERMOSTAT COVER SCREW 3
43 HOSE, THERMOSTAT HOUSING TO EXHAUST MANIFOLD 2
44 CLAMP, HOSE TO THERMOSTAT HOUSING ANS EXHAUST MANIFOLD 4
45 HOSE, THERMOSTAT HOUSING TO OIL COOLER 1
46 CLAMP, HOSE TO THERMOSTAT HOUSING AND WATER PUMP 2
47 HOSE, THERMOSTAT HOUSING TO WATER PUMP 1
48 CLAMP, HOSE TO THERMOSTAT HOUSING AND WATER PUMP 2

Re: Need some help with O2 Sensor placement.
 

I dont think an 0/2 sensor is gonna do the trick. Does the computer even have
the capability to recognize an 0/2 signal? Even if it does,the 0/2 wouldn't make
any difference at W.O.T. as the injector is probably at maximum pulse width. And
last,but not least,the 0/2 absolutly cannot get wet.

Re: Need some help with O2 Sensor placement.
 

It has the an input for an O2. The O2 will read the amount of unburt fuel in the exhaust and and adjust the fuel as needed.

I know it can't get wet, thats why I'm trying to figure out where a good place to tap the manifold is at. Trying to figure out how the water is introduced into the manifold and where it flows too.

:)

Sean...

Re: Need some help with O2 Sensor placement.
 

This is the system - http://www.holley.com/HiOctn/ProdLin...I/502-20S.html

Re: Need some help with O2 Sensor placement.
 

You don't need an O2 sensor.
You need to understand the tuning procedure and follow it to the letter. If you are not completely sure of some of the procedures, call and get verification.

I assume you have the marine ECU? If so, then it is a learning coimputer and will program properly for the boat.

If you have a car ECU then you will pull your hair out...

Re: Need some help with O2 Sensor placement.
 

Its the car system, either the marine system wasn't out at the time I bought it or I some how missed it.

Re: Need some help with O2 Sensor placement.
 

How are you getting the Holley PJ to run w/o an O2 sensor?

Roby

Re: Need some help with O2 Sensor placement.
 

It has settings to run with or without an O2 sensor. Its not running right so thats why I want to spend 40 bucks to put in an O2 sensor, but no one has answered my question yet. :( lol


Just need to know where a I can punch a hole into the exhasut manifold that doesn't have water flowing in it.

Re: Need some help with O2 Sensor placement.
 

Go to chevytalk.com forums and scroll down to the EFI forum. The moderator is a Holley FI technician and the forum is frequented by Dennis Moore who is very familiar with adapting Holley systems to boats.

Re: Need some help with O2 Sensor placement.
 

To run the car system, you are going to have to really hack out your own map (program) for it. You may need a laptop programming tool compatible with that ECU. Hopefully, somebody will have a baseline map for you to use as a starting point.

Where to put the O2 sensor?
It's gotta go in before the top of the elbow.
You'll have to get a custom bung made that will recess the O2 sensor about 2" deep. Then drill thru both side of the elbow casting (outside and inside walls) and have somebody braze in the custom bung.

Just know in advance that water will kill the sensor.
Also, I would advise going with a 4-wire sensor.The 4-wire sensors have an internal heating element that keeps the sensor at correct temp for sensing oxygen properly (they don't sense unburned fuel as you suggested, but only the oxygen content of the exhaust). Otherwise, you will have to wait for the sensor to warm up to proper temp before it gives you any readings worth a crap - and in a boat the presence of water vapor can keep it from EVER reaching that proper temp..

Also be aware that many closed loop systems (using an O2 sensor) don't even begin monitoring the sensor input until the motor is up to normal coolant temp - up to that point, they run on a program map and completely ignore the O2 sensor. They only use the O2 sensor for tweaking off of a basemap.

Now, if you want to use a laptop and the O2 sensor to MONITOR the O2 sensor reading so you can manually program a more compatible fuel curve for the motor, then I think that is a smart choice. To use it for continuous masking of an otherwise crappy program map is not smart.

Question: why would you remove your carb and intake? Carbs work just dandy on a boat application. FI does coldstarts better, but that's about it. If your carb isn't performing to suit you, then get a rebuild kit and tweak a little bit on it. I hate to be the one to inform you of this, but the injection isn't going to make it faster or more fuel efficient, unless you had a badly mismatched carb/intake combo.

Hope you got this ProJection system as a gift.
I'd hate to think you paid for it, given the hassle you are in for.

If you do run across a proper marine map you can upload into the ECU, though, you'll be well on your way to getting some satisfaction.

mc