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-   -   Carb to Fuel injection conversion? (http://www.mastercraft.com/teamtalk/showthread.php?t=10934)

hz900 08-06-2006 02:33 PM

Carb to Fuel injection conversion?
 
'92 Prostar 205 w/ holley dual feed carb


I've heard there are kits to convert the carbed engines over to fuel injection, is this true. If so where do they sell them. The ones I've heard of are throttle body injection kits, is it possible to install a multi-port injection system?

Also is it worth it? I like fuel injection more than carbs, I know more about how to work on them, and they are typically more reliable and throttle response is better IMO.

Is there anyone on this board that has done it, I'd like to get some first hand experiences on pros/cons.

flipper 08-06-2006 03:39 PM

I put an injected engine in my '91 prostar 190, and love it. I have seen the kits for cars. It is nice not having to pump the throttle, and crank the engine for a while.

jake 08-06-2006 09:40 PM

I was seriously considering the Holley pro-jection marine conversion kit. It's throttle body, seems simple, and isn't too much more expensive than a new carb.

I didn't pull the trigger, because of mixed reviews I read on-line and feedback I got here from JimN and others more knowledgeable in these areas than I, but if you're considering the conversion, you might want to check it out as an option.

erkoehler 08-06-2006 10:32 PM

You can probably sell your 92 and upgrade to an EFI 94 for maybe $2-4,000

hz900 08-07-2006 01:03 AM

Quote:

Originally Posted by erkoehler
You can probably sell your 92 and upgrade to an EFI 94 for maybe $2-4,000

I do all my own work. For $4k I could easily drop a fuel injected crate motor in the boat. I'm thinking more along the lines of $500.

east tx skier 08-07-2006 11:21 AM

I think the Edelbrock MPI kit is over $1K. When I mentioned this to my local ski boat mechanic, the answer I got, and the answer I hear most often, is that it just isn't worth it and if you want a fuel injected boat, sell yours and buy a fuel injected boat. Like Dan, I'm not mechanical. But this has been the consensus from the people I trust most on the subject.

If you're looking to spend $500, spend it on a Holley 4160 single feed marine carb. Greatly improved reliability over the 4010 you have on there now IMO.

hz900 08-07-2006 11:42 PM

Quote:

Originally Posted by east tx skier
I think the Edelbrock MPI kit is over $1K. When I mentioned this to my local ski boat mechanic, the answer I got, and the answer I hear most often, is that it just isn't worth it and if you want a fuel injected boat, sell yours and buy a fuel injected boat. Like Dan, I'm not mechanical. But this has been the consensus from the people I trust most on the subject.

If you're looking to spend $500, spend it on a Holley 4160 single feed marine carb. Greatly improved reliability over the 4010 you have on there now IMO.


I'm a Corvette junkie as a hobby and have read several articles on how they used a throttle body injection unit and wiring/computer off of a '88-'94 chevy truck on the older carbed Corvettes and spent less than $500 total cost, including wiring, just curious if this was possible on a boat, since you also have to take into account for water, which presents a problem for a computer out of a vehicle.

I've been told about the 4160 carb, and I am keeping it in mind. The 4010 I've got on it now has not presented much of a problem so far, other than being cold natured, I just personally like fuel injection is why I'm exploring this topic.


Can anyone tell me if the multiport injection systems from either the 5.7 ford trucks or the 5.0 mustangs will fit these indmar engines (ie will it bolt to the heads and the ports line up)?


Don't get me wrong, I'm not trying to argue the points made about not being worth it, I agree, if you don't know how to do it yourself, then it probably isn't worth it.

H20skeefreek 08-07-2006 11:54 PM

If you REALLY wanted to do it, you could get the injection unit for the 5.8L EFI PCM motors. I forget what they called them, but it was basically a rudementary EFI unit from a Mustang. Those motors aren't available anymore, but if you searched you might be able to find one. You could always call PCM, but I don't know if I'd mention that you have an Indmar.

Matt L. 08-10-2006 02:58 PM

4160?
 
My 4160 blew chunks at the lake this weekend. Secondary bowl fuel valve was hanging and pumped so much gas into the secondaries it was flowing down the back of the engine due to the ramp angle. Rebuilt w/ in 50 hours ago. Just a little pucker factor!!!

Larry at:

http://www.larrysengine.com/

is a nationally recognized marine high perfoemance engine builder. Bussy had his engine built there. Larry told him to expect an annual Holly rebuild due to the poor fuel quality in the Southwest and the newer additives being very carb unfriendly. FI systems are not damaged like carbs by these newer additives.

Found a kit and had the boat running perfectly in 20 min.

I will FI my HO 454 powered 1990 240sc someday!

http://www.larrysengine.com/techarticles.asp With lots of good carb info.

My $0.02,

Matt

Quote:

Originally Posted by east tx skier
I think the Edelbrock MPI kit is over $1K. When I mentioned this to my local ski boat mechanic, the answer I got, and the answer I hear most often, is that it just isn't worth it and if you want a fuel injected boat, sell yours and buy a fuel injected boat. Like Dan, I'm not mechanical. But this has been the consensus from the people I trust most on the subject.

If you're looking to spend $500, spend it on a Holley 4160 single feed marine carb. Greatly improved reliability over the 4010 you have on there now IMO.


rcnjson 08-10-2006 04:40 PM

HZ900,
It is 5.8 liter (that attitional cubic inch puts it over the edge) actually it was probably a marketing thing. Like why would you buy a Chevy with a "wimpy" 5.7 liter when you can get a "mucho macho" 5.8 liter in a Ford? When did the big three go to the metric system? Anyways, the MPI EFI off of an old truck or van would work fine on a boat with the only issue being the intake manifold height, you know would it fit under the motor housing. A 351w in a boat has the same bolt pattern for heads, intake, and exhaust as 351w in a car truck or van. The heads from a 302w also fit a 351w and there is only one head casting, you just flip it around for the other side of the motor. The lower (in an EFI situation) intake manifold is different between the 351w and the 302w as the 351w is actually wider where the intake meets the heads as a function of the taller deck height. The upper intake manifold is the same and used with a specific lower like a stock upper and a stock lower or a gt40 upper and a gt40 lower. There are plenty of aftermarket EFI intakes available for windsor motors both the 351 and the 302. The MPI EFI system itself exists in a couple of different forms from the factory. The older system is called speed density and uses air temp and throttle position to determine its fuel tables. This is a very reliable system, just not performance oriented. The other factory system is mass air which uses the amount of air coming into the system as well as temp and throttle position to determine fuel tables. The mass air system is deffinatly the way I would go with a boat. Here is a short list of what you will need.
EFI manifold upper and lower
Mass air meter (has to match the injectors #/hour)
Throttle body
Injectors (probably 24#'s for a 351)
Fuel system which includes lines, rails and a pump
The brains for the mass air (ECU from car or truck)
Engine wiring harness (for injectors and mass air meter)
Misc. wiring and gaskets
From a junk yard I would say you could pull this all off an F-150 for $500. IF you go the buy it new route, aftermarket manifold, Ford EFI conversion kit, new fuel system... you are looking at an easy $2500 and that can go up from there depending what you want. FYI the fuel system in my mustang was $2500 (tank, pump, lines, rails). The moral of the story is sky is the limit, how fast do you want to go?

jimmer2880 08-10-2006 08:02 PM

Quote:

Originally Posted by rcnjson
.....From a junk yard I would say you could pull this all off an F-150 for $500. IF you go the buy it new route, aftermarket manifold, Ford EFI conversion kit, new fuel system... you are looking at an easy $2500 and that can go up from there depending what you want. FYI the fuel system in my mustang was $2500 (tank, pump, lines, rails). The moral of the story is sky is the limit, how fast do you want to go?

funny - I thought it was... how fast can you afford to go?:D

jake 08-16-2006 10:55 AM

OK...here is a new twist on the debate. While doing some research on do it yourself carb to efi conversions I came across "Mega Squirt".

http://www.megasquirt.info/

It's an open source, build it yourself, PC programmable ECM that I'm considering using to convert a simple GM TBI system to my boat. So far everything seems to be relatively simple and understandable.

What I'm struggling with is how one would set up the fuel delivery from tank to high pressure pump. From what I can tell, most factory systems use a two pump system, one low pressure to move volume from the tank to the engine, then a high pressure pump to supply the right pressure to the injectors. Would it be reasonable to use the existing mechanical pump as the low pressure pump and just install a high pressure between the low pressure and the injectors?

Another alternative seems to be a fuel control cell like PCM uses. But again with this setup, is it reasonable to use the mechanical pump as the low pressure feed pump or would you have to replace it with an electrical low pressure pump?

east tx skier 08-16-2006 11:32 AM

Quote:

Originally Posted by Matt L.
Larry told him to expect an annual Holly rebuild due to the poor fuel quality in the Southwest and the newer additives being very carb unfriendly. FI systems are not damaged like carbs by these newer additives.

Any idea which additives? My new 4160 has managed to survive two seasons without a rebuild. Fuel is always stabilized and it is run at least monthly.

rcnjson 08-16-2006 11:34 AM

Jake,
I have seen the megasquirt system and it seemed like a pretty good setup for the price of admission. Other options for stand alone EFI get pretty spendy like FAST or SDS.

The simple solution for fuel delivery is an intank pump. As long as you aren't going nuts with the motor, you can get an intake pump for a fuel injected ford application. For instance a 255 LPH in tank pump will eaisly support 400 HP's and can be had for around $100. It might take a little fabrication to mount it in your tank, but shouldn't be too bad. Another option is just use an inline pump and get the pickup down to the bottom of the tank or in a sump.

Using the current carb pump to get fuel to an inline pump won't work. There is no way the carb pump will keep up and the inline pump will either run dry, cavitate, or collapse the line.
k

jake 08-16-2006 11:42 AM

Quote:

Originally Posted by rcnjson
Using the current carb pump to get fuel to an inline pump won't work. There is no way the carb pump will keep up and the inline pump will either run dry, cavitate, or collapse the line.
k

Good info, thanks. I was reading on the mega squirt site that many people have been using an in line pump from a late 80's to early 90's ford pickup or econoline van. Any idea if proximity to the tank matters when deciding where to mount it?

Was thinking it would be easier to plumb a return if it was mounted very close to the tank. Running electrical connections back to the tank area sounds easier then running new fuel return line up to the engine area.

rcnjson 08-16-2006 12:07 PM

Jake,
You do have to run a return from the engine to the tank. The fuel pressure regulator controls pressure by regulating flow returning to the tank. Meaning that the line runs from the tank to the pump, pump to the rails, through the rails, through the regulator (just a restriction to build pressure), and then back to the tank.

As far as where to mount an inline pump, you would have to be below the tank. You can use a pickup style feed line like your carb pump uses, the line goes in the top of the tank and extends to the bottom of the tank. Problem here is if the fuel is low and sloshing arround, you may lose the siphon and that could cause problems. I think the best bet is gravity feed. Again, mount the pump below the tank, then put the pickup for the pump at the bottom of the tank or even better is build a sump for the bottom of the tank and put the pick up there. The best location is at the back of the tank because fuel will slosh back when you accelerate and that would put the fuel right over the pickup. For the gravity feed system, the feed line from the tank to the pump should be bigger than the line from the pump to the rail. This gives the pump an extra supply of fuel to draw from and reduce starvation problems at the pump.

I've got a good fuel system basics article (from a car magizine) that I could scan and email to you if you are interested.

k

jimmer2880 08-16-2006 06:49 PM

On my stock '95 PS190, TBI my fuel pump (electric), is in-line at the rear of my motor, between the stringers. The pump is $250.00 new. My system runs a return line from the pump back to the tank, but only 1 line from the pump to the TBI.

It's the same pump that was put on a similiar vintage LT1 for my boat.

rcnjson 08-17-2006 10:44 AM

Quote:

Originally Posted by jimmer2880
On my stock '95 PS190, TBI my fuel pump (electric), is in-line at the rear of my motor, between the stringers. The pump is $250.00 new. My system runs a return line from the pump back to the tank, but only 1 line from the pump to the TBI.

It's the same pump that was put on a similiar vintage LT1 for my boat.

This pump must have an internal regulator then. If that is the case, the pump from the ford truck or van that Jake mentioned will not work for the TBI system. I guess I am not all that familiar with that system. Is that just one big injector at the throttle body? I guess if that is what the general used, that might be what you are stuck with.
k

pilot02 08-17-2006 10:47 AM

Quote:

Originally Posted by jake
Good info, thanks. I was reading on the mega squirt site that many people have been using an in line pump from a late 80's to early 90's ford pickup or econoline van. Any idea if proximity to the tank matters when deciding where to mount it?

Was thinking it would be easier to plumb a return if it was mounted very close to the tank. Running electrical connections back to the tank area sounds easier then running new fuel return line up to the engine area.

Early 90's ford trucks are in-tank pumps. Had to replace both of mine in the last year.

east tx skier 08-17-2006 11:05 AM

Quote:

Originally Posted by rcnjson
This pump must have an internal regulator then. If that is the case, the pump from the ford truck or van that Jake mentioned will not work for the TBI system. I guess I am not all that familiar with that system. Is that just one big injector at the throttle body? I guess if that is what the general used, that might be what you are stuck with.
k

I think there are two injectors on the Indmar TBI setup.

jimmer2880 08-17-2006 07:00 PM

Quote:

Originally Posted by east tx skier
I think there are two injectors on the Indmar TBI setup.

Correct, my TBI has 2 injectors.

If I remember correctly, I thought our stock MC TBI's were the same as an early 90's Camaro.

[email protected] 09-10-2006 11:19 AM

Hey, I have had a lot of experience in this - and there is hope for you! TBI Injection is fine for the reliability that you're after, and a complete kit with in-tank fuel pump, high pressure lines, filter, and the TBI will run you around $1500 and take a fairly skilled back yard mechanic 8-10 hours to install. Electrical work is also required.

Port Injection aftermarket kits for marine apps don't really exist - you'd have to retrofit from a totalled boat, including HEI ignition and the manifold. It would be a major hassle...

The good news is this: I've been through it twice on my last two PS190 boats. The simple fact is that marine carbs aren't built to last 15 years. That doesn't mean, however, that they aren't any good. If you want an easy, fast, painless solution, I'd go down to the local NAPA store in your town, and have them order you a brand new HOLLEY Marine carb for your boat (4000 series, probably). They retail at MC dealerships for $730, but go for $509 at NAPA!

Trust me on this one - I've done it twice, and my boats start on the frist turn of the crank, and run like a fuel injected boat. Most people can't believe how well my boats run...

Good luck!

TIM

[email protected] 09-10-2006 11:20 AM

Oh - One more thing - VERY IMPORTANT!!!!

NO Carb or FI designed for street cars is either SAFE or EFFECTIVE on a boat! Please don't try it.

TIM

jake 09-10-2006 03:01 PM

Quote:

Originally Posted by [email protected]
Hey, I have had a lot of experience in this - and there is hope for you! TBI Injection is fine for the reliability that you're after, and a complete kit with in-tank fuel pump, high pressure lines, filter, and the TBI will run you around $1500 and take a fairly skilled back yard mechanic 8-10 hours to install. Electrical work is also required.

Port Injection aftermarket kits for marine apps don't really exist - you'd have to retrofit from a totalled boat, including HEI ignition and the manifold. It would be a major hassle...

The good news is this: I've been through it twice on my last two PS190 boats. The simple fact is that marine carbs aren't built to last 15 years. That doesn't mean, however, that they aren't any good. If you want an easy, fast, painless solution, I'd go down to the local NAPA store in your town, and have them order you a brand new HOLLEY Marine carb for your boat (4000 series, probably). They retail at MC dealerships for $730, but go for $509 at NAPA!

Trust me on this one - I've done it twice, and my boats start on the frist turn of the crank, and run like a fuel injected boat. Most people can't believe how well my boats run...

Good luck!

TIM

Tim: I love to hear from people with practical experience. What benefits do you see to a new carb over rebuilding the existing one. I have the 4010, but don't really have issues with the hot stalls, which is the primary reason to abandon the 4010 from what I've heard. I just can't get it to idle reliably, I have to run it quite rich to get easy starts and smooth idle.

JimN 09-10-2006 06:08 PM

The TBI system on the boats is really the same as what was used on cars and trucks. There's a septum in the intake manifold and one injector feeds each. It's not an Indmar system, Indmar takes an existing one and adapts it for marine use.

JDK 09-10-2006 09:41 PM

Quote:

Originally Posted by JimN
Indmar takes an existing one and adapts it for marine use.

....except for the damn fuel pump (the engine mounted one with the internal by-pass). I've looked and looked and looked for a 'generic replacement'.
Any ideas as to what other applications this pump may have been used in???

Credo 08-19-2011 06:34 PM

The only question that I have with using a car multiport injection system ona boat would be the 02 sensor. I know that Ford ECU's take their main readings from the MAF and O2 sensor wouldn't a wet exhaust system corrupt the reading from the 02 sensor? And make the engine think its running rich?

gr82bgreen 08-19-2011 06:58 PM

Quote:

Originally Posted by Credo (Post 782488)
The only question that I have with using a car multiport injection system ona boat would be the 02 sensor. I know that Ford ECU's take their main readings from the MAF and O2 sensor wouldn't a wet exhaust system corrupt the reading from the 02 sensor? And make the engine think its running rich?

You could run it without the sensors. it would be in open loop and would set codes, but it would run fine. The maf was not used on the older speed density system, but that system is calibrated to the car or trucks camshaft. I think the boat cam would run ok though. I don't know how the prograqming would translate form a car or truck, to a boat though. Ive heard its a bad idea to install automotive efi on a boat. probably cheaper and less headaches to upgrade to a new boat with efi. You would need lots of new parts, intakes, new fuel pump and lines, ecu, a wiring kit to make it work. would have to find a dry sealed place for the comupter.

JimN 08-19-2011 08:56 PM

Quote:

Originally Posted by [email protected] (Post 240264)
Oh - One more thing - VERY IMPORTANT!!!!

NO Carb or FI designed for street cars is either SAFE or EFFECTIVE on a boat! Please don't try it.

TIM

The real difference between a stock GM EFI engine and these is the fact that, if the engine stops running with the key ON, these boat engines shut off because they're programmed to. Other than that, it's basically standard stuff. The LTR and some other intake manifolds are different but the rest isn't exactly what would be considered 'exotic'.

JimN 08-19-2011 09:02 PM

Quote:

Originally Posted by gr82bgreen (Post 782491)
You could run it without the sensors. it would be in open loop and would set codes, but it would run fine. The maf was not used on the older speed density system, but that system is calibrated to the car or trucks camshaft. I think the boat cam would run ok though. I don't know how the prograqming would translate form a car or truck, to a boat though. Ive heard its a bad idea to install automotive efi on a boat. probably cheaper and less headaches to upgrade to a new boat with efi. You would need lots of new parts, intakes, new fuel pump and lines, ecu, a wiring kit to make it work. would have to find a dry sealed place for the comupter.

If you disconnect the TPS, it will default to 12% throttle position at all times and that won't run "fine". If the MAP sensor is disconnected, the ECM will have no idea how much fuel to deliver, so that will default to a setting that won't allow good performance. If the ECT is disconnected, the ECM will think the engine is at about -40F, or below, so it will run exceptionally rich. If the knock sensor is gone, it will want info, so it will prevent correct timing advance and throw a code, too. How does this qualify as "fine"?

A really easy way to upgrade to EFI is to buy a GM Performance Parts crate motor, like the 350 RamJet. 350HP/390Ft-lb of torque, it uses the same ECM and any GM dealer can service it when the warranty is still in force. The thing about MC- they calibrate teh engine to the boat, not a generic weight load.

JimN 08-19-2011 09:03 PM

Quote:

Originally Posted by JDK (Post 240384)
....except for the damn fuel pump (the engine mounted one with the internal by-pass). I've looked and looked and looked for a 'generic replacement'.
Any ideas as to what other applications this pump may have been used in???

The first in-tank pumps were Carter, off the shelf.

JimN 08-19-2011 09:05 PM

Quote:

Originally Posted by Credo (Post 782488)
The only question that I have with using a car multiport injection system ona boat would be the 02 sensor. I know that Ford ECU's take their main readings from the MAF and O2 sensor wouldn't a wet exhaust system corrupt the reading from the 02 sensor? And make the engine think its running rich?

The newer boats (since about '05) have catalytic and O2 sensor and the people who used to do a lot of development for MC and Indmar were working on making it work when I was going to tech training, in 1999 and 2000.

east tx skier 08-19-2011 09:47 PM

In think the cat showed up on the MCX around 06.

Spork 08-21-2011 12:43 AM

No o2 required

http://www.edelbrock.com/automotive_...pf_intro.shtml

CantRepeat 08-21-2011 09:13 AM

Quote:

Originally Posted by [email protected] (Post 782647)

Then why does it come with one?

A narrow band O2 sensor is included and is also wide-band 02 compatible (wide band O2 not included).

CruisinGA 08-21-2011 10:27 AM

As far as the fuel pump problem...

A relatively common practice in my "other" motorsport, rock crawling, is to use the mechanical engine mounted fuel pump to pull fuel from the tank and then have it fill a vertically oriented ~.25 gallon tank which the high pressure electric fuel injection pump draws from the bottom of.

This accomplishes several things- avoids having to run an in-tank fuel pump, uses the mechanical diaphragm pump which is better at "pulling" fuel than electric ones to bring the fuel from the tank, eases load on your expensive high pressure electric pump, and gives you a .25 gallon fuel supply that is available at almost any angle. The angle part is important in rock crawling, but not so much in boats.

Spork 08-21-2011 10:44 AM

1 Attachment(s)
^ sorry didnt read the discription just looked at the pretty ford picture:D

Credo 12-27-2011 03:15 AM

Ok so I have been doing alot of research on the "megasquirt II" system. Well I think it could be done with a Ford 2 bbl carb intake a $40 adapter plate from trans-dapt. And any GM TBI with a built in regulator, TPS, and injector set up. To take control of the ignition advance use a TFI Distributor and now they make marine wideband o2 sensors I think a junkyard TBI is like $100 and the TFI is $60 a boost-a-pump is like $100, Megasquirt II is $250 to $450 and you just need to figure out the tank situation. and you can swap that carb out for a GM TBI. I think you could do it all for about $1k Now the question is the cost benefit analysis. The million dollar question is it worth it?

CantRepeat 12-27-2011 08:27 AM

The wideband o2 you linked to is not a marine o2. I'm running that setup in my Suburban. I do not think there is an o2 sensor made that will work when wet. All of the MC motors use a dry exhaust system that doesn't introduce water until after the o2 sensor.

I'm pretty convinced the only way to convert an older 351 to efi is going to be a well tuned open loop system. Either that or making some sort of new exhaust system.

1redTA 12-27-2011 10:24 AM

holy thread resurrection! In my opinion! a TBI is not worth the hassle of retrofitting on to a boat that has a GOOD 4160 carb. the tbi is really nothing more than a 2V carb that keeps a wet manifold on the other hand, a multi port fuel injection even a TPI with its long runners and torque would be a worthwhile attempt.


I cant wait to get a 205 with a LT-1


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