Bypassed the FDC today

[Smokinyoda]

Since I switched to 90% wmo I noticed the old girl was sluggish. Also noticed an oil leak right before or slightly after the switch. Started checking the oil level religiously and never noticed it going down. I assumed that with the large oil capacity that it would have to leak alot to be noticable on the dipstick so I kept on driving her.

Then I noticed the oil level rising on the dipstick... Long story short I had developed an internal fuel leak.

So today, after much searching (yes I searched instead of just asking for help) I bypassed the FDC, as it seems to be the first step in troubleshooting an internal fuel leak.

The difference is amazing!!! She had always been more responsive than my other, but after switching to wmo she fell on her face, wouldnt climb a hill in 4th gear ect...

But today she was back in all her original glory! I could climb a hill in 5th that I could barely do in 4th before the bypass.

All my bolts still have the wire attached so I assume its unmolested (until now), which brings me to my next problem.

As I mentioned above I have searched this site extensively, and most reccomend bypassing the FDC as I did.

What wories me is that some (but not all) also recommend turning the fuel down to compensate for a bypassed FDC.

I know I need an egt, and boost gauge to know for sure, but I dont have either. I never drive her pedal to floor, try and keep her under 2100 rpm.

Is it safe to drive like this? As long as I dont go pedal to floor?

I guess what I'm asking is how many have bypassed the FDC and did nothing, versus how many have bypassed and felt the need to adjust the fuel accordingly.

 

[eagle4g63]

I'm in the same boat as you are, just did mine yesterday for almost the same reason, didn't have the "making oil" problem but the fell on it's face when I started running a higher oil%. And as you said the difference is amazing, It runs on this stuff just like it would on just plain clean diesel!!

I'm also in the same boat as not having any of the covers opened (still all the safety wire) and am wondering about the whole turning down the fuel.....In my case if I stay running almost just wmo which is what my plan is. NO pump unless I absolutely have to thin it out come winter, but am going to add block heater and fuel heater first.

I'll be watching the responses to this with you, and maybe chiming in with questions/remarks also.

 

[Billy Bobbed]

I would get a pyrometer just in case.When you bypassed the FDC you changed the fuel system of the IP.The power you are getting is its putting more fuel and boost in the engine now.

 

[wreckerman893]

I would not go over 75/25 WMO/diesel......in my opinion you are setting yourself up for failure (yes I know others claim to be running 100% UMO).

I am running 50/50 and I see a big heat increase during a hard pull........I actually got the exhaust pipe on the M275 (NA engine) so hot it changed colors.....still evaluating if I did long term damage.

I know fuel prices are high but swapping engines ain't cheap.

Your milage may vary.

 

[Smokinyoda]

I would not go over 75/25 WMO/diesel......in my opinion you are setting yourself up for failure (yes I know others claim to be running 100% UMO).
I know fuel prices are high but swapping engines ain't cheap.

Good point Richard. Think I will cut back on the wmo just to be safe.