FDC bypass info (yes, again)

[doghead]

I'd go by the TM, not a magazine article.

 

[ICAT]

subscribed

 

[Jakob]

I have a non-turbo engine, but I'm wondering if the fuel adjustment will be as much of an issue?

 

[tco3129]

I have a non-turbo engine, but I'm wondering if the fuel adjustment will be as much of an issue?

 

[gimpyrobb]

When I turned my non-turbo up, it had more power and smoked a LOT more. Not a whole bunch of power though.

 

[thehaas]

with the dial indicator what do you think base length or starting measurement should be.you moved it .100 but what length was indicator at.thanks for pictures

 

[Bob H]

The TM shows the stock spec . It is also posted in a thread here on turning up the fuel.
What dial indicator?

 

[Bob H]

I'd go by the TM, not a magazine article.

I've seen far too much misinformation about MV's in magazine articles!

 

[Reaper651]

I know this is an ancient thread but I too am wondering how to turn the fuel down when bypassing the FDC on a NON turbo multifuel. The LDS troubleshooting TM's procedure with the boost pressure only works for a turbo charged truck. So without a pyro, I was thinking the standard 2 full turns down on the main fuel and maybe 1/4 to 1/2 turn down on the droop would bring it to safe levels. I know I need a pyro even for the non turbo, but my truck isn't street legal yet so I really don't have a way to put a good load on the motor, or enough money for a pyro at this point in time. I would like to bypass the FDC though, because I'm going to change the engine oil and I don't want to risk contaminating my brand new oil.

Thanks.

 

[Floridianson]

I'd go by the TM, not a magazine article.

Agreed so maybe we should take down the stickey that is from the magazine.

 

[Issa1554]

I need some clarification from an old thread. So when I bypass my FDC do I really need to reduce fuel delivery, or can I leave it the same? And about how much MPG would I get if I bypass the FDC?

 

[Squirt-Truck]

If you do not turn the fuel down it will cook itself. Typically the re-adjustment is 13 flats.
None of this will impact MPG that is a foot thing.

 

[gimpyrobb]

Your best bet is to install a pyrometer so you don't melt anything.

No you don't have to turn anything down, but you will not know when its melting till its too late.

 

[Floridianson]

Your best bet is to install a pyrometer so you don't melt anything.

If you want to get the most out of the motor the lessen to Chris.
Not every motor is adjusted the same so you can not go buy what worked for someone else also altitude can have a small effect. Sea level you could run more fuel than someone at higher Altitude. Get the pyro and adjust main fuel then adjust the droop.

 

[brianp454]

I have a u tube video that walks through bypassing the FDC. Also, I recall JA Tonka had a web page with his experience with this some years ago that had some great info in it. I did a quick look and wasn’t able to find it. The short version is that prior to bypassing the FDC or modifying the IP, you can stand on the pedal all day and never hit excessive EGT’s. When you bypass the FDC you are eliminating a path that bled off a little fuel all the time (and varied greatly), this “turning it up” a small bit. I find that EGT’s only get too high in 4[SUP]th[/SUP] or 5[SUP]th[/SUP] high on the freeway, especially with heavy grades. I have a pyro and boost gage on my steering column and ran it for a while to learn how it behaved before bypassing the FDC. I advise doing the same. Assuming your injection pump hasn’t been modified and you have an LDT-465, bypassing the FDC will allow you to hit excessive EGT’s under heavy load conditions. You can establish your own method or level for managing how hard you run the engine. If you check the TM for the injection pump there are a couple tables that have great info. Bypassing the FDC has little if any effect on MPG.

I need some clarification from an old thread. So when I bypass my FDC do I really need to reduce fuel delivery, or can I leave it the same? And about how much MPG would I get if I bypass the FDC?

 

[Floridianson]

If you bring up the main fuel to a max Temp. but don't reduce the droop you will waist fuel in the lower end of the rpm scale. Forgot who be he tweeked his droop after a bypass and adjusting the main he said there was a small amount of fuel saving there from what he found.

 

[Issa1554]

Thanks for the help
Can I ask one more question? I don't mind reducing on the fuel flow to the engine. so this would make me get a little more mpg, but at the same time loose power. Is there anyway to boost the multifuel engine?

 

[Floridianson]

Thanks for the help
Can I ask one more question? I don't mind reducing on the fuel flow to the engine. so this would make me get a little more mpg, but at the same time loose power. Is there anyway to boost the multifuel engine?

The way to get the best out of your motor is a pyro, tweek main and reduce the droop. No other way around it.

 

[Champ173rd]

So I plan on hot rodding my Duece a bit this winter. is there a link to order the gauges Pyrometer ect?

 

[pjwest03]

So I plan on hot rodding my Duece a bit this winter. is there a link to order the gauges Pyrometer ect?

The source of gauges is mostly a matter of preference. I went with Hewitt Industries http://www.hewittindustries.com/. They will set them up to your preferences and the prices are quite reasonable. They also supply them with 24v illumination upon request. The are a number of gauge threads if you search the forum.