2 quarters

[sgoeser]

[h=2][/h]

I'm a old dud and bending and twisting over the fender and around the heater just doesn't work for this old body. I want to try your quarter trick. Will the FDC still work like it was intended too? This will turn up the fuel to, in turn, turn up the heat that will create more boost, that will burn the extra fuel to create more horse power. Wordy I know. I can watch the boost and EGT's. If my fuel burn goes to **** or the EGT's goes to high I'll take my foot out of it. Right? I bought the multifuel for that reason and don't want to tamper with it. At this time I really don't want to bypass the FDC. Next question: When I take the cover off (the three Screw Cover) will stuff fly out? Will I be safe in doing this?
Thanks for your help, Steve​

​

 

[scboolitcaster]

I'm a old dud and bending and twisting over the fender and around the heater just doesn't work for this old body. I want to try your quarter trick. Will the FDC still work like it was intended too? This will turn up the fuel to, in turn, turn up the heat that will create more boost, that will burn the extra fuel to create more horse power. Wordy I know. I can watch the boost and EGT's. If my fuel burn goes to **** or the EGT's goes to high I'll take my foot out of it. Right? I bought the multifuel for that reason and don't want to tamper with it. At this time I really don't want to bypass the FDC. Next question: When I take the cover off (the three Screw Cover) will stuff fly out? Will I be safe in doing this?
Thanks for your help, Steve​

​

I'm guessing you meant this to be a PM. But now you've piqued my interest.
What's the two quarter trick?

BTW, bypassing the FDC doesn't mean you can't run different fuels. Pretty much no downside to it from all I've read.

 

[searls84]

Nothing will come "flying out." There is a stiff spring underneath the cover and a plunger beneath the spring. Stick the 2 quarters in between the cover and the spring then tighten back up. If your FDC is bypassed this "trick" won't work...

 

[sgoeser]

I had envision of a jack-in-the-box when I take out the three screws. I understand, I want to do the easy fix first before I try to do the by-pass on the FDC. If I have read right the FDC will still work as intended. All I am doing is turning up the fuel, right. I'll keep a good watch on the EGT's and back off if they get too high. I still want the FDC to work as intended that's why I bought the mutifuel instead of the CAT.
I like your sign. Are they trying to tell you that most hitchhikers along this road don't speak English? I haven't figured out how to post my picture like you have.
Thanks for your help!

 

[red]

The FDC does not determine if your engine can run on other fuels. All the FDC is designed to do is make your power output similar with different fuels. Gasoline has the lowest BTU's, and the FDC allows for maximum fuel flow. Diesel fuel and oils have more BTU's, so the FDC restricts flow.

If you bypass the FDC the pump defaults to full flow.

 

[gimpyrobb]

If you don't like leaning over the fenders to work on stuff, bypass the fdc.

It is known for leaking fuel into the crank case oil and causing issues. In by-passing it you will have more power, seems like a win win to me.

 

[sgoeser]

If I do that I then have to turn down the fuel. Right

 

[gimpyrobb]

As long as you have a pyrometer, i wouldn't change anything till you see how it behaves after the bypass. If its too powerful, turn it down. As you said, you can just let off a bit if it gets too marm.

 

[sgoeser]

The FDC is really clever on how it works to keep all fuels equal. I understand about the fuel getting back into the oil system. I'll be looking for that to happen, if and when. It's kind of like driving at night here. You will hit a deer. it's not if it's when. My daughter in-law took out three at one shot one night. What a mess on the road. She is OK but the truck didn't fair too well.

 

[gimpyrobb]

The fdc only serves to limit the amount of power you have. Diesel has the most btu as a fuel, so its extremely limited in fdc output whereas gas has less btu so the fdc will flow more to keep the power out put the same. One member here(Cranetruck) ran cleaned used veggy oil and reported the fdc read the viscosity wrong and screwed up his fuel delivery a lot(should have been more but delivered less). I'll see if I can find his thread about it.

 

[cranetruck]

The fdc only serves to limit the amount of power you have. Diesel has the most btu as a fuel, so its extremely limited in fdc output whereas gas has less btu so the fdc will flow more to keep the power out put the same. One member here(Cranetruck) ran cleaned used veggy oil and reported the fdc read the viscosity wrong and screwed up his fuel delivery a lot(should have been more but delivered less). I'll see if I can find his thread about it.

The FDC reacts to the viscosity of the fluid and works as long as the viscosity is proportional to the BTU value of the fuel. Biofuels are more dense than diesel, but have lower BTU value, so the FDC compensates "in the wrong direction".

 

[Floridianson]

Hear what is being typed! If you can get to the top of the FDC to put two quarters in there you can bypass the FDC. The heater has four small bolts just move it out of the way. It is a no brainer should I keep it and have diesel fuel in my engine oil or bypass.

 

[sgoeser]

I hope the person that invented the FDC got a bonus in his paycheck. What an interesting useful devise when working right to keep power equal with different fuels.
I am bobbing and rebuilding frame up an 1971 M35A2, just about ready for paint. The engine is a new D1 and I except it to run fine when put to use. I don't except fuel dilution to be a problem at first but having the knowledge to know I can bypass the FDC if it becomes a problem. At this time I want the FDC to be able to work as intended other then turning up the fuel if I feel I need a boost in power. I was looking for the easiest way to do this. Installing or removing 2 quarters seem straight forward to me. Your right the heater is only held on by a few bolts.
I'm looking forward in being able to run the engine on any fuel I can find if the SHTF. That's the reason in choosing the multifuel engine and it would defeat the intention of the engine if i by pass the FDC now.
I have found much information that been helpful through reading these threads and the advice offered me. Thanks to you all.

 

[gimpyrobb]

Actually, the FDC has nothing to do with the ability to run alternative fuels. That is a property of the high compression ratio, the piston design, and the swirl effect of the charge air. All it(FDC) does is keep the power output the same(in theory) from one fuel to the next.

 

[Floridianson]

First the FDC can only measure the viscosity of the fuels listed on your dash. As many have tried to tell you the FDC has nothing to do with what the motor could burn. The bad idea of the FDC was if you ran the fuels listed then the fuel peddle would always be a the same spot for the different fuels. Now the only way to make you truck run at its best on good clean diesel is to leave the quarter dumb azz trick in the closet. You need a good working pyro and start buy bypassing the FDC. The from there you might have to decrease the main fuel or it could be close to perfect. Could even be to high so we reduce the main. After you find the perfect main fuel setting then you can adjust the droop so as not to waist fuel when the RPM are down low. Telling you as others are telling you do it right the first time so read up on the bypass and fuel controls and your truck will run with the best of them. The Quarter trick was so the driver did not bust the tamper wire on the main fuel shield and get in trouble from the CO. Bypassing is not hard and there are many here to help if you have a question.

 

[RAYZER]

Having put 10's of thousands of miles on a couple of multifuel engines burning just about everything pattroliam for fuel, I can think of no good reason to keep the fdc functional and many good reasons to bypass it!

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