Shift assist module for retrofit fuel injection

[Davidgoodin]

Greetings'
I just installed a new engine replacing my 5.7 literr driving a cobra outdrive. The boat is 1988 vintage.I decided to replace the carburetor with fuel injection. That, part works great. Boat starts like it never did before. Am still trying to perfect the shift assist. The original model pulses a ground connection to the negative side of the coil to prevent firing. This causes the ECM ( engine control module) to throw error codes.

Anyone know of a shift assist module designed to work with a fuel injection setup? My distributer is NOT the delco electronic ignition model that many people retrofit their boats with. The ECM, tbi and distributer Are out of an old gm truck.

Any ideas will be welcome.

 

[Bondo]

Greetings'
I just installed a new engine replacing my 5.7 literr driving a cobra outdrive. The boat is 1988 vintage.I decided to replace the carburetor with fuel injection. That, part works great. Boat starts like it never did before. Am still trying to perfect the shift assist. The original model pulses a ground connection to the negative side of the coil to prevent firing. This causes the ECM ( engine control module) to throw error codes.

Anyone know of a shift assist module designed to work with a fuel injection setup? My distributer is NOT the delco electronic ignition model that many people retrofit their boats with. The ECM, tbi and distributer Are out of an old gm truck.

Any ideas will be welcome.

Ayuh,.... Welcome Aboard,..... Yer buildin' a Huge Fire Bomb,....

Automotive distributors are NOT ignition protected, which is Why ya gotta use a Marine Distributor,.....

 

[bruceb58]

Not only is your ignition system a fire bomb but your TBI is a fire bomb as well.

 

[HT32BSX115]

Greetings'
I just installed a new engine replacing my 5.7 literr driving a cobra outdrive. The boat is 1988 vintage.I decided to replace the carburetor with fuel injection. That, part works great. Boat starts like it never did before. Am still trying to perfect the shift assist. The original model pulses a ground connection to the negative side of the coil to prevent firing. This causes the ECM ( engine control module) to throw error codes.

Anyone know of a shift assist module designed to work with a fuel injection setup? My distributer is NOT the delco electronic ignition model that many people retrofit their boats with.

Howdy,

The OMC ECM shift-assist "pulsing" was an internal function in the OMC ECM I believe, and of course, was an external module in carbureted models.

The ECM, tbi and distributer Are out of an old gm truck.

That's going to be fairly unsafe since none of those components are rated for SAE J1171. They will of course "work" until you experience a spark that ignites fuel vapor in the enclosed engine compartment.

Then there'll be a "boom" that could result in injury or loss of life. (like if you took the neighbor fishing or his kid skiing etc)

When you call your insurance company for covereage and they get wind of a big non-USCG approved installation, they'll have a way out to either not pay or if the surviving family can prove negligence, (I.E. you intentionally installed NON-SAE J-1171 // NON-USCG approved "stuff" ) it could get VERY ugly in the ensuing civil action.

Most of us here will likely limit our suggestions on how you should convert your engine back to USCG compliance etc.

On another note, you may also cause damage to the lower shift-cable and/or drive unless you use some sort of ignition pulsing device to facilitate getting it out of gear.

I would go back to a carburetor and use the existing Shift assist module as OMC intended. (Actually, I would remove the OMC "stuff" and replace it with Mercruiser "stuff" like I did with my previously installed OMC 460 King Cobra.....but that's another thread.........)

Good luck!


Rick

 

[Davidgoodin]

Thank you for the comments and concern. The system I installed is from " affordable fuel injection" who states that his systems are for "marine" applications. I was a it off on the description. The distributer was new, however, I obviously need to verify it is truly marine rated. I elected to go with fuel injection when replacing the engine because I had no end of trouble with the carburetor. Hard starting, stalling etc.

Obviously I do not want a fireball popping out of the engine compartment so more research is warranted. Newer boats have fuel injection so I know it can be done. I just need to ensure it is up to spec.

Regards

 

[bruceb58]

The ECM, tbi and distributer Are out of an old gm truck.

Why did you say this then?

Show us a picture of your fuel injection, ECM and distributor.

 

[HT32BSX115]

If the system you installed is USCG compliant, you're essentially "good to go"!

Getting the shift assist system to work might still be a problem though.

You could try going to an ignition interrupt like the Dog-Clutch Alpha has but ignition interrupt has been tried with the Cobras and the results have not always been optimum. OMC had to develop that module that "pulses" the ignition to get their drives to reliably come out of gear.

Maybe the company that produces your EFI system can give you some ideas on how to interface the Shift Assist system with it or possibly they have a work-around.....

 

[bruceb58]

Should be easy for "affordable fuel injection" to disable the misfire counter. I looked at the kit and don't see a crankshaft position sensor in the kit. Yours does have one right?

 

[Davidgoodin]

Ok, to clarify, the ECM is an older unit and is indeed out of an old truck. It is a 16146299. The throttle body injector is new, but from the same vintage. The fuel pump is uscg rated. After the comments here, I looked more closely at uscg fuel system requirements and am verifying that the those requirements are met.


Bruce, as soon as it stop raining, I will take photos of the system and post them.

HT, the stock shift assist works...mostly. It is the style that pulses a ground connection to the coil to "stumble" the engine. However, it kills the engine sometimes. Usually at the most Inopportune moment. Usually while docking. This unit also has an admonishment that it is not designed to work with high energy coils ( which the fuel injection system wants). I have also had many discussions with "affordable" about this and even though they claim to have done "100's" of these, this question never came up before.

As to the crank position sensor. There is no separate unit. Essentially, then distributer sensor does that function.



Cdi has another model the is deigned to work with the delco elextronic ignition but is not directly compatible with the ignition used on the tbi. If someone made,a module, I would just use that. I have not found one yet which is why I posted e query originally.

If there is no simple answer, then the next thing is to construct a circuit that will interface the interrupter to the existing ECM "bypass" line that will retard the timing in a pulsating fashion.

Regards,

 

[Bondo]

Ok, to clarify, the ECM is an older unit and is indeed out of an old truck. It is a 16146299. The throttle body injector is new, but from the same vintage. The fuel pump is uscg rated. After the comments here, I looked more closely at uscg fuel system requirements and am verifying that the those requirements are met.


Bruce, as soon as it stop raining, I will take photos of the system and post them.

HT, the stock shift assist works...mostly. It is the style that pulses a ground connection to the coil to "stumble" the engine. However, it kills the engine sometimes. Usually at the most Inopportune moment. Usually while docking. This unit also has an admonishment that it is not designed to work with high energy coils ( which the fuel injection system wants). I have also had many discussions with "affordable" about this and even though they claim to have done "100's" of these, this question never came up before.

As to the crank position sensor. There is no separate unit. Essentially, then distributer sensor does that function.



Cdi has another model the is deigned to work with the delco elextronic ignition but is not directly compatible with the ignition used on the tbi. If someone made,a module, I would just use that. I have not found one yet which is why I posted e query originally.

If there is no simple answer, then the next thing is to construct a circuit that will interface the interrupter to the existing ECM "bypass" line that will retard the timing in a pulsating fashion.

Regards,

Ayuh,...... I'll start with I donno Squat 'bout OMC's,.... But,.....

What yer discribin' above is the Classic symptoms of a Draggin', sticky shift cable,... With a Mercruiser Alpha,....

Maybe that's why they've done 100s of 'em before, without issues,..??..??

I know shift cables can go bad, regardless the name brand,...

 

[bruceb58]

An ECM out of a truck is not going to work well in a boat unless you have gone in and changed all the fuel tables.

So what did you actually buy from "affordable fuel injection"?

 

[Davidgoodin]

Bondo, you are correct about the sticky shift cables. However, I replaced my shift cable when I dropped the new engine in. Tested it for the four pounds of drag.

Bruce, you are correct. A truck ecm would not work without reprogramming the ecm. That is what "affordable" does. As to what I actually got in the deal...
Ecm, throttle body, fuel pump, sensors (temp, o2) distributer and wiring harness. Oh yes, let's not forget the "check engine" light.

It did pretty much drop right in and it started right up at the first turn of the key. Just need to get the shifting sorted out.

 

[bruceb58]

So have you asked them about the shift interrupt? Seems like they might be able to help you with that.

 

[Davidgoodin]

Yes, I have spent a good deal of time discussing the shift interrupt with them. They say they have never had an issue in the past. They also tell me I am "over thinking" the issue. But, being an electrical engineer, I want the gazintaz and gazoutaz to interface properly and when one component maker says their system is not recommended for my configuration, I want to understand why and make it so everything plays nice AND the boat does not stall when I approach the dock. It's just SO hard to look cool smashing in to the dock knocking people in to the water...

 

[bruceb58]

I am also a EE so I understand the frustration. OMC never used fuel injection with the dog clutch Cobra and GM engines. It was only incorporated into the Ford systems and only for a short time.

I would think the only way you can get around your issue is ask them how they interface with a Mercruiser Alpha type interrupt and use your existing shift switches to implement that.

The problem with that is that the OMC engineers found that the ESA method was way better for the OMC Cobra drive. Since OMC lower shift cables seem to bind up easier than Merc ones, it is preferred to stay with the ESA but I don't think you have a choice. I would think you would still have a problem with getting detections for a miss even with the Mercruiser method, They must have come across that issue.

I would have stayed with a carb if I still had my Cobra. I know all about the pains people have just adapting an electronic distributor let alone what you are doing. The boat with the Volvo in my sig starts in a split second and it has a carb.

 

[Davidgoodin]

Thanks Bruce,
I considered staying with carb, but fuel injection just seemed sexy. Plus, it really does start first time every time. I have heard other people swear by carbs as well.but mine was not reliable.

It's looking like the solution will be to use the electronic ignition ESA module from cdi and build an op amp circuit to essentially bypass the ecm timing control signal when the ESA module starts pulsing.
Take care,
David

 

[Davidgoodin]

Also, Bruce, I did some research on the mercruiser alpha shift. They don't use an ESA module, they just ground the coil directly from the switch. If have heard of people doing this to the omc as well. I am pressing on with my other circuit...

 

[bruceb58]

The problem with doing the circuit is that it may be less reliable than doing the mercruiser method.

 

[Davidgoodin]

I will let you know...