Bolt on EFI systems

I'm sure this question must have come up before, but new and relatively advanced bolt-on EFI systems are available today. All the car magazines (Car Craft is one to which I subscribe) are constantly writing articles about the new systems. I wonder if anybody has looked into this for a 351W? I have seen lots of people take EFI off of mid-90's era Nautiques (Kris), but I wonder if technology is to the point we could go the other direction soon?

Just a point for discussion. I'm not volunteering to try.

I did find one thread tonight that sounds like it worked.

EFI thread from 2011

And good grief, why do you think I would shop at AutoZone... ?

Keep in mind that in Automotive use the EFI reads the exhaust using O2 sensors on both exhaust pipes. In boats I am not aware of O2 sensors that could work with water spray in the exhaust. If the EFI can't read the exhaust it can't self tune and you are giving up many of the EFI advantages. Our 95 with the 351W with a factory looking EFI manifold uses a program developed by engineering to work well in our boats but that fuel map took someone a lot of time to create. It works really well but an aftermarket system would not have the same built in tune developed by the Marine engine builder. You would be on your own and tuning could be a nightmare and very expensive if you pay someone to do it. If you could run O2 sensors those systems can help tune themselves.

8122pbrainard wrote: The O2 is before cooling water goes into the exhaust.

Before exhaust and cooling water for the exhaust meet or mix together.

MrMcD wrote:    Would he need EFI Exhaust manifolds to use the O2 sensors or can the old manifold be modified.

No, the O2 sensor goes on existing manifolds. Both the outside and inner walls of the manifold are machined to fit a threaded adapter that seals both cavities and accepts the sensor. I need to find the thread with all the pictures.

This is the O2 setup on my GT40 with Megasquirt. It has survived 20hrs in this location so far without problems. Once I have the VE and ignition advance tables finalised I will remove the O2 sensor.

You only use the O2 for tuning purposes the ECM runs on open loop with set fuel and ignition tables like the original GT40 ECM. PCM did spend quite some time getting these tables correct.They say closed loop is only for lazy tuners

I converted my 1987 ski centurion (351W) to TBI. This is a GM throttle body system off of a 1989 Chevy pickup. There is a lot of support on web for using GM TBI's in Ford applications. I am using this as a closed loop system. Also, because the GM system has spark control, I modified a Ford Duraspark distubutor to take advantage of electronic timing. If your interested in more information on the conversion, I would be happy to give you more details.

Check out the youtube video.

TBI conversion on Elkhart lake

Interesting O2 sensor mounting.

TX Foilhead wrote: There's another mount that I've seen, I believe it's in the thread Pete linked to that's basically a plumbing spud that goes in the elbow.

Don,
It is in the link I posted

lewy2001 wrote: Mark post up some more pics and details. Looks like it could be a cheap option for owners of boats with old Protec EFI systems that are failing.

This conversion took a lot of time and thought. The part that intrigued me was that I could do the whole conversion with about $600 (yes, a junkyard helps). I have about 20 hours on this boat since the conversion. No problems or equipment failures to report.

A time consuming part of this conversion was modifying the fuel system to integrate an electric fuel pump and add a return fuel line. One of the advantages of running a TBI is it only requires 15 PSI of fuel pressure. You can run rubber hose from the fuel cell to the fuel pump. Even after the fuel pump you can run fuel injection hose to the throttle body (I ran steel 3/8" fuel line, overkill). The return line is low pressure, so standard marine fuel line can be used (again, I used steel line, overkill). I ended up putting in a bulk head fitting in the gas tank for the return line.

The ECM got mounted under the console. I'm sure someone could come up with something more creative to get it closer to the engine and keep it dry at the same time. Mounting the ECM far away from the engine required lengthening the wiring harness from the ECM to the engine.

If I had to do this again, I would graph a GM TBI distributor top to a Ford distributor base. Easy, simple and no need to remotely mount the ignition module. Adding spark control is optional, but I chose to take advantage of it.

There was a fair amount of work with dissecting the wiring harness to remove the unnecessary wires. Devices like the speed sensor (VSS), EGR, Transmission related sensors, air conditioning and knock sensor were removed. Also, shortening and lengthening of wires was needed to reach the distributor, O2 sensor and map sensor.

Closed or open loop fueling is optional. Riser modifications for the O2 sensor are needed if you choose to go closed loop. There are kits available from Howell efi for doing this.

The part I liked the best was tuning. I ended up buying an emulator that would allow me to make active adjustments while the engine was running. Tuning was straightforward and easy with the help of Tunerpro software, gearhead efi website and a wideband air fuel ratio gauge.

mamigacz wrote: The ECM got mounted under the console. I'm sure someone could come up with something more creative to get it closer to the engine and keep it dry.

lewy2001 wrote: I did this more to get away from the heat cycles the than the extra waterproofing that would be required.

Mark (mamigacz),
Do you have a leak under the dog house?

Mark so you were able to use the complete wiring loom that came with the ECM and TB from the donor car? (After removing unwanted wires). What did you need to change to make the distributor work with the ECM. The original Protecs had wasted spark ignition. I wonder if a latter model of the GM TBI had this setup if so you could just take the complete ignition setup.

Just some more general pics of boat

Nice work on your boat rebuild. ( Even though it is not a CC )

EDIS would be easier than grafting a Chevy dizzy onto a Ford and of course keeping it somewhat marine.