Planning my first carb to EFI project

[Kbert]

This will be my third vehicle installing a Megasquirt in. This should be easier/harder than the previous two. Easier in that I will not be trying to tune the ignition at all. Harder because unlike the other vehicles this one did not come with fuel injection from the factory.

The vehicle in question is a motorhome built on a 1984 Ford E350 chassis. It has a carbureted Ford 460 engine with dual gas tanks. The reason I am looking at fuel injection is that the thing is difficult to start. It doesn’t seem to be that I just “haven’t learned the tricks of starting a carbureted engine” as even the previous owner (my father in law) has admitted that it is trickier that it was/should be, and I have had two carbureted cars that I was able to start just fine in the past. The ignition system has been given a once over and seems to be in good working order with mostly new parts. However, every time we try to start it, it floods and I always fear that the battery will run out of juice before the engine is running.

So my reason for switching to fuel injection is twofold. The first is to get it to start easier and in all temperatures. The second is to be able to keep the proper tune while driving over the mountains, which are less than an hour’s drive from my house and a favourite camping destination. I am not looking for or expecting any performance or fuel economy improvements.

I haven’t had a chance to dig around too much into this vehicle as it was only recently brought to my place and it is -20C outside. From the research I have done online there is a fuel pump in each one of the tanks and an electronic three port valve for switching between the tanks.

I would like to keep this conversion as simple and cost effective as possible using some junkyard parts. In doing so I believe that it can be done for less than the cost of rebuilding the carburetor. I am planning on the following:

-MS II – from one of my previous cars that has since been sent to the scrapyard. The car ran well and idled better than it did on the stock ECU. That car had a GM/Buick wasted spark ignition so I need to change the tach input to run off of a coil negative signal. I also still have the GM AIT and CLT sensors which I will use. Again, because I drove that car over the mountains it has two MAP sensors in it for barometric corrections.

-GM TBI – from either a 350 or a 454. From what I read they are the same housing with different injectors, and I would like to use new injectors if I can find some at the right price, probably the biggest I can to feed this monster. It will also come with idle control valve, TPS and fuel regulator. The idle control valve should be the same as the one I had in the previous car as well. While at the junkyard I will get the air filter housing from atop the throttle body as well. I will use a piece of aluminum to build an adapter plate to mount the throttle body to the intake manifold.

-An Innovate Wideband Controller and Sensor – my previous install used an Autometer WB which I still have, but it was very inconsistent. I am not comfortable reusing this. I also do not feel that I need a gauge to view AF ratios at all times.

-A six port tank switching valve to accommodate the return lines from the throttle body to the tanks. Hopefully this will be another junkyard find.

-An external fuel pump to get the pressure and flow up to where they need to be. I will keep the original in tank pumps as lift pumps and to keep everything as simple as possible (I hope this is possible as I haven’t done this before).

-I will also need a new external fuel filter and fuel line.

The one change I do want to make to the ignition is to remove the ballast resistor and replace it with a relay. I will use the fuel pump relay output to run both the fuel pump relay and the ignition relay. This will keep the power to the ignition off unless the fuel pump is on.

I am still a few months away from doing any of the work (still too cold outside), but I like to plan ahead. So my question is: Can anyone see anything I have missed?

Cheers,
Kbert

[LAV1000]

I would be very tempted to also control ignition.
Even if you use the the oem distr and coil.
Especially if the old setup is vacuum driven, don't know this type of engine.

[grom_e30]

The one change I do want to make to the ignition is to remove the ballast resistor and replace it with a relay. I will use the fuel pump relay output to run both the fuel pump relay and the ignition relay. This will keep the power to the ignition off unless the fuel pump is on.

this may not work. the ecu will only turn the fuel pump relay on once it sees a rpm signal and if the coil has no power there will be no rpm signal to the ecu.

[Six_Shooter]

Add in the ignition control. You're throwing away like 60% of the improvements an EFI system can have by not using it. This should also help with starting, since most hard to start engines I've done across its due to ignition side not fuel side issues.

As stated above the idea of replacing the ballast resistor with a relay is not correct. The ballast resistor is needed to give the points a long life in addition to just not working the way the you want. You can get ekectronicalky controlled dizzies for the 460, or even just upgrade kits to convert the points to an electronic system. In fact doing this even with the carb might solve your hard to start issue.

The 350 and 454 throttle bodies are different. The 454 TB has a 2" bore, while the 350 TB it's a 1.75 or 1.875" bore. Either way it's smaller than the 454 TB bore. The 4.3, 5.0 (305), and 5.7 (350) all share the same size bore just different injector sizes.

You'll likely fee fest to use a surge tank here, if you don't wasn't to modify the fuel tanks. The existing pumps and valve can be left alone then and use the surge tank as a sort of buffer that will allow the pressure to be raised to where it needs to be for the TBI, and a page to return the fuel to from the TB. A float can be added to turn the intake pumps on and off so that there's no need for the overflow return back to the main tank that is typical in a surge tank application.

[Kbert]

Thanks for the replies! I really do appreciate the free education.

I didn't think about the ballast resistor and the RPM signal, but that is a very good point. I am most certainly wrong, I will leave that alone.

Ignition control is tempting, but I know very little about how to tune it. One previous vehicle was tuned on a dyno by a tuner. The other I did play with the timing a bit, but it still is mostly a mystery to me. I do know the theory from reading manuals and such, but that's it, just theory. I believe I have a Duraspark 2 ignition system which looks to be very easy to control with the Megasquirt (VR sensor, single coil with external control module). However, this vehicle will never see a dyno and I do not have the confidence to street tune ignition. I would like to get the fuel control done first. Perhaps once I have that sorted I will try and do some data logging of the stock ignition to get a good starting point.

I would like to say that I will try and get the 454 throttle body for the larger bores, but I don't know the size bores are on the stock intake manifold, or (more importantly) what is available at the local wreckers.

I admit I know very little about Ford engines. I am mostly familiar with Toyota and GM.

I have no problem modifying the stock tanks and I am planning on dropping them to run fuel returns to each. I was just thinking I would leave the pumps in and have them work with the external pump. Like I said I don't know if this will work. Worst case scenario I replace the pumps with pickup tubes and just use the external pump. The last surge tank system I helped install had a high volume low pressure lift pump that fed the surge tank from the fuel tank and it was plumbed with a return back to the fuel tank. The surge tank then had a high pressure pump that fed the fuel rail that had a return to the surge tank. I thought that was the typical way they were set up. I guess I was wrong.

Thanks for all the advice and corrections!

Cheers,
Kbert

[lazymonkey]

I would like to control ignition (it helps a lot at cranking) and its only a matter of connecting your dizzy to the ms ecu, on the fuel pump I would use a walbro 255 inline, just keep it as close to te fuel tanks as possile, I have cavitation issues by installing it on the engine compartment.

sounds like a great project and you can gain some very good mpg with that monster of truck by going efi

[billr]

I, too, urge you to leave the stock dual tanks alone and have them feed a third ("surge") tank that the high-pressure pump resides in or draws from. Perhaps the biggest disadvantage would be space for the extra tank, but a I doubt that is any real problem in this RV.

I seriously doubt you can do this for less cost than rebuilding a carb, but your choice there. Obviously, many millions (billions?) of vehicles have been run quite successfully with carbs.

[Kbert]

Even with a surge tank I think I would need to figure out a return/overflow from the surge tank to the fuel tanks. In my mind it wouldn't make sense to simply return to a single tank as it would get confusing drawing from one and returning to the other, so I would still need a six port switching valve to switch the return as well as the feed. A float switch has also previously been suggested instead of a return line, but I can't find any examples of this online. However we used to have a Chevy work truck with two tanks and it was set up somewhat like this. It would only draw fuel from one tank and when that tank reached a certain level it would pump fuel from the other tank to refill it. This whole system ended up being a maintenance nightmare and needed to be replaced once every year and a half or so. It also did some weird averaging of the two fuel tank levels for the gas gauge. That was the first thing that stopped working.

Perhaps a better option would be to find an already fuel injected vehicle with two tanks and taking not only the six port valve but the in-tank pumps as well (provided it is set up that way)? I can't get tanks at the wreckers as they slash them all when vehicles are brought in.

I priced out a rebuilt carb and compared it to parts lists from local wreckers and and it came out about $100 cheaper. Probably going to get the WBO2 off a friend. I already have an unused MSII, lots of wires and connectors, the majority of the sensors and tools I need. Mind you this isn't including new fuel lines/clips/etc. or any snags that I haven't thought of. Even if it ends up being a little more than a carb rebuild I have it stuck in my mind that it would be worth it for fuel injection, even though I could very well be wrong (but its fun to tinker with these things isn't it?).

Yes, it's probably safe to say that the majority of vehicles ever built run with carbs. However I know more about fuel injection than carburetor tuning, and I do plan to drive through some significant elevation changes. My old station wagon with a carbed 305 didn't to particularly well with that, especially while towing a trailer. And this engine is essentially driving a house.

[Raymond_B]

I would go JY hunting for a EFI 460 truck with dual tanks, or heck any EFI Ford truck with dual tanks for that matter. You could grab a bunch of goodies off it or just look at the layout. My 95 Lightning came stock with a fuel injected 351w and dual tanks. Pretty sure no fancy plumbing just fuel pumps with check valves. You know when they go bad because you get fuel tank crossflow

The BBC TBI is probably a good idea because it sounds like you'd rather not swap out the whole top end from an EFI 460, although that's what I'd look at You could grab all the sensors throttle linkage cruise control etc.

[ChevelleFan]

You mentioned using an Innovate WB, but that you didn't need a readout. Using something like this:

http://www.ebay.com/itm/Portable-DC-0-3 ... 1615944942

and setting the 2nd output on the Innovate for 1v-2v for 10-20 AFR, gives a really cheap, but usable AFR readout. Yeah, it lacks a little in precision, but for $3, its sure better than nothing. I did this in my Chevelle and it was pretty handy.

-Dave

[Kbert]

I took a quick peek under the hood this morning with a flashlight, and it does look like I have a version of a Duraspark ignition (I also need to replace the rocker cover gaskets). I haven't yet found the control box though. Instead of the two wires from a points style distributor I have three wires (Orange, Purple and Black).

Dizzy.jpg

duraspark-wiring.gif

If my understanding is correct then the control box holds the timing at 10* BTDC during cranking. It also means that if I take over the ignition with the MSII (which I am now leaning towards thanks to advice in this thread) I nee to build the VR circuit and connect it to the purple and orange wires and connect the output from the MSII to the green wire (coil negative).

Again I won't know for sure until I pull the dizzy apart and have a peek.

[Kbert]

You mentioned using an Innovate WB, but that you didn't need a readout. Using something like this:

http://www.ebay.com/itm/Portable-DC-0-3 ... 1615944942

and setting the 2nd output on the Innovate for 1v-2v for 10-20 AFR, gives a really cheap, but usable AFR readout. Yeah, it lacks a little in precision, but for $3, its sure better than nothing. I did this in my Chevelle and it was pretty handy.

-Dave

That's a good cost effective way of getting a WBO2 readout. The reason I don't feel I need a gauge is that I am planning on either having a laptop connected for tuning or my now obsolete smartphone connected via bluetooth.

The temperature made it to just above freezing this past weekend, so I made the first (of many) trip to the local wreckers. I spent about forty five minutes wandering around trying to find any Chevy/GMC trucks with a 454 in them. Not one was there. So I then started looking at 350s. About eighty percent of the ones I found already had the throttle bodies removed. I did eventually find a 1990 Suburban with the throttle body on it. The air filter housing was gone, but the throttle body and collar were still there. So I grabbed those.

TB.jpg

I then found the air filter housing in a nearby truck with the throttle body missing. I had to find the wing nut to hold it on from a third vehicle.

Filter.jpg

Going to have to clean that up and paint it.

Finally while I was wandering around I found a 1995 Lincoln Town Car. This thing had obviously had its hood open for a while as the engine bay was packed with snow. Digging through the snow I found that it had an EDIS-8. I took what I could grab from the top of the engine bay, but as I was running short on time and didn't want to crawl on the ground in the melting snow I didn't get the VR sensor. Looking online they are fairly cheap so I am not too worried about it.

EDIS.jpg

This makes me feel better about taking control of the ignition because I can leave the stock ignition as is and simply swap the spark plug wires over to the EDIS and if I ever encounter trouble I can put them back to stock. I still need to get a 36-1trigger wheel and VR sensor.

Once things dry up a bit I need to go back and grab a couple of pumps and a tank switching valve. I feel like I am making progress. Not bad for $48 plus a dollar entrance fee.

Cheers,
Kbert

[Six_Shooter]

454 TBIs will be a hard thing to find in a junk yard. They were pretty rare when they were new. There are occasionally some on Ebay, also check Kijiji and CL.

[Kbert]

454 TBIs will be a hard thing to find in a junk yard. They were pretty rare when they were new. There are occasionally some on Ebay, also check Kijiji and CL.

Yeah I took a look there before even going to the wreckers. The price some people want for them scared me off...

[Kbert]

cleaning.jpg

Ordered and received a throttle body rebuild kit and an 18psi FPR spring. Once I knew the rebuild kit had the injector screens I removed the old screens and put the injectors in an ultrasonic cleaner with some solvent. I have the megasquirt connecter to pulse the injectors while in the cleaner in the hopes of cleaning them inside and out.

Kbert

[Kbert]

I put all the parts that would fit through the ultra sonic cleaner. There is some staining on the aluminum from fuel leaking for a while, but all in all it came out nicely. I then used the rebuild kit to reassemble the parts that hold the fuel injectors and FPR. The kit came with lube for the o-rings. I still have to clean the main throttle body by hand.

Top.jpg

Side.jpg

Bottom.jpg

It is finally warmer here, but we recently had a large amount of snowfall, so everything is a wet icy mess (above freezing during the day and below at night). Already planning my next trip to the scrapyard.

Cheers,
Kbert

[Kbert]

Well here we are over a year later. With my wife wanting to use the RV for camping I haven't had much of a chance to work on it, until last month. I would like to thank everyone for the advice I received. I pretty much followed all of it. I did use the time to collect parts and plan things out though.

In an effort to keep costs down I used as many parts from the local wreckers as I could.

The wiring harness came from a 90's Chevy truck similar to the one I got the TBI unit from.

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This gave me all the connectors I needed and enough wire to bring into the cab and connect to the 37 pin connector. I stripped out what I didn't need.

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I then finally started to take the carburetor off the engine. I must admit I'm not a huge fan of the engine placement.

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It didn't take long to have the carburetor and the EGR plate removed.

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[Kbert]

I used a piece of 1/2" aluminum to make my own adapter for the TBI.

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However I ran into a little trouble getting the Ford cable to work with the GM TBI.

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The difference can be seen here.

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[Kbert]

The length of the GM bit is so it clears the linkage where the cruise control would connect. I would like try to use this to work with my kick down linkage so I didn't want to cut it of. Fortunately I figured out a solution.

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[Kbert]

Next I needed to sort out fuel delivery. Even though this engine had a carburetor it did not have a mechanical pump. Each of the two gas tanks has an electrical pump in it instead. Apparently this engine was prone to vapour lock (according to what I read online anyway). To combat this the fuel system already has a return line in place and a six port tank selector switch.

Here are the hard lines that were on the front of the engine. The larger one is the supply and the smaller the return. The T like connection used to connect to the carburetor as well.

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As per the advice I received I got a surge tank I decided to mount it above the driver's side wheel well. For clearance I had to move the solenoid that engages when the engine is running to charge the RV battery.

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It simply bolts in. It has a Bosch knock off pump in it.

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And here is is plumbed in with a universal fuel filter in line.

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