Help/Problem with fuel delivery adjustment

[FormerNewMVGuy]

Well its just from looking at the pictures, I dont see what could be damaged. And i like to know how things work! But i really dont want to take mine apart to find out.
You seem to be a wealth of MV knowledge so i just thought i would ask. Do know which TM covers the IP?

Who ever said Elvis is dead was wrong! your obviosly living in NY state somewhere

 

[m-35tom]

you guys are going to get into a lot of problems messing with something you know nothing about. 1/6 turn will make almost no noticeable difference unless you have changed something else as well. patrick, your note is backwards, clockwise pulls the rod out which increases fuel rate

 

[doghead]

Take a look at TM 9-2910-226-34. It covers the IP. The adjustment rod is attached to a stop wedge, if the stop were to turn inside while making an adjustment it may mess up something inside(I know what but I am not going to go into detail here). I think there is mention in the tm about being cautious of not allowing it to turn.

 

[doghead]

you guys are going to get into a lot of problems messing with something you know nothing about. 1/6 turn will make almost no noticeable difference unless you have changed something else as well. patrick, your note is backwards, clockwise pulls the rod out which increases fuel rate

Tom, I posted right after Patrick's post to correct his info. Read the whole thread.

And i like to know how things work!

I will stop posting about things I "know nothing about". Please take over from here, Tom.

 

[m-35tom]

"Bad internal damage" ?? really? the rod is made onto a shoe that cannot turn and is quite substansial. i cannot imagine you would be able to cause any damage unless you tried to strip the threads. this kind of information does nothing to help or educate members. just like the guy that said that a d/c electric fan motor being turned by the air would produce a/c and damage things. if you don't have a pyro installed or at the very least a boost gauge, you can cause real engine damage.

 

[doghead]

Bad was used in a humours and lazy response at the time of posting because I did not feel like going into detail.( I guess I should have noted it was humour for those that don't have a sense of humor). The follow up posts by NewMVGuy just shows his interest to learn what its all about. I believe that I recall reading in the TM(IP in field Adjustments) stating to be cautious to not allow it to turn( or damage would result). I am not going to waste my time looking for it in the TM, just to show you. I could be wrong(memory). I think any/all damage is bad.

 

[FormerNewMVGuy]

Sorry to cause any trouble here guys. I just have an inquiring mind and wanted to better understand how things were put together, Thanks for the direction to the proper TM doghead!

 

[doghead]

I understand where your coming from Scott, no trouble!

 

[doghead]

you guys are going to get into a lot of problems messing with something you know nothing about. 1/6 turn will make almost no noticeable difference unless you have changed something else as well. patrick, your note is backwards, clockwise pulls the rod out which increases fuel rate

Tom, your information contradicts the TM, why?

 

[m-35tom]

since you ask, 1" hg (mercury) is .49 psi. you simply will not notice it. measure it yes, notice it no. 18" is 8.84 psi and 20" is 9.82 psi. experience has shown 12 psi is usually safe, i run mine at 14 to 15 psi with a 'd' turbo and the egt is about the max. the tm is simply erring on the side of caution, they don't want someone putting 2 turns on it all at once. just my 2¢

 

[OPCOM]

you guys are going to get into a lot of problems messing with something you know nothing about. 1/6 turn will make almost no noticeable difference unless you have changed something else as well. patrick, your note is backwards, clockwise pulls the rod out which increases fuel rate

OK. I removed that picture, so as not to confuse anyone.

 

[OPCOM]

"Bad internal damage" ?? really? the rod is made onto a shoe that cannot turn and is quite substansial. i cannot imagine you would be able to cause any damage unless you tried to strip the threads. this kind of information does nothing to help or educate members. just like the guy that said that a d/c electric fan motor being turned by the air would produce a/c and damage things. if you don't have a pyro installed or at the very least a boost gauge, you can cause real engine damage.

The DC electric fan guy was uninformed. The "pulsations" in the DC coming from a air-driven fan are akin to AC, could set up AC current in the DC-operated devices and trip them up, but that is an extremely minor concern because the aggregate of the DC busses contain enough filtration to absorb the damaging curents. That argument should be defenestrated.

More likely to a point of damage, the fan (and I have seen this in my old race car) which naturally has no regulator can generate an over-voltage on the vehicle's DC bus if spun hard enough, and overcharge batteries, etc, if the load on the electrical system is light.

 

[Floridianson]

From what little I have found. First if your FDC is bypassed changing the servo pressure needle valve will do nothing. If you are still running the FDC you just screwed yourself and as Bjorn said the whole IP is going to have to be taken off and sent out as no TM I found covers adjustment of needle valve. There are only two adjustments for fuel. The double nut and the droop screw.
I have talked about the droop screw before but not much interest I guess. I will try and find where I saw it but if you are one of the people who have disabled there own FDC the the droop my be needed to be backed off to. The droop takes care of the boost up to 2000 rpm.
The TM calls for 20 hg boost at 2400 rpm adjusted by double nut and 10 hg at 1600 rpm by droop screw.
If someone who has a boost gage wonder if you would mind doing the brake hold thing and tell me what your boost pressure is at 1600 rpm. 20 will be 9.82 psi and 10hg 4.91 psi if my calculations are correct.

 

[m-35tom]

yes the manual i had said 1600 rpm for droop and that is in fact close to 5 psi and 2400 rpm 9 psi. my suggestion is to just remove the droop screw as some later pumps did, performance at low rpm will be better. having tampered with the needle valve i would suggest bypassing the fdc and then resetting the main fuel adjustment for 9 psi. my 1600 rpm boost is very close to 5 psi with no droop screw even with the main fuel turned up to the max. (14 to 15 psi with a 'd' turbo) do not do this without egt gauge.

 

[Dueceownerjoe]

Thanks for the info guys

 

[lavarok]

Sounds reasonable. On a side note, in response to earlier posts in this thread regarding "Bad damage". I can attest that improper adjustment allowing the metering rod to turn can lead to the rod breaking. Once broken, fuel delivery is either cut off completely or too low to allow the engine to run. I'll be taking the fdc and metering assembly, from my M109, apart very soon to fix and will post photos for all those interested.