3B diaphragm replacement

[Kon]

thanks guys!

well the old girl is up for sale now.
time to upgrade!

[Big Blue 84BJ60]

my idle just rose about 150 rpm and i now have a wierd shudder as soon as i let off the pedal (from lots of throttle straight to idle idle drops to aboot 450 then back to 650 which just jumped to 800 in a day or two) this all makes me think the diaphram anyone else had this problem?

also my vac lines are not crossed like in the pictures in this thread theyve been this way since ive had the truck would this affect power or anything else?
thanks for any repy

[lostmarbles]

Originally Posted by Kon

thanks guys! well the old girl is up for sale now.
time to upgrade!

Shame on you Kon. (Can't really have been true love in the first place.)

[lostmarbles]

Originally Posted by Big Blue 84BJ60

my idle just rose about 150 rpm and i now have a wierd shudder as soon as i let off the pedal (from lots of throttle straight to idle idle drops to aboot 450 then back to 650 which just jumped to 800 in a day or two) this all makes me think the diaphram anyone else had this problem? ......also my vac lines are not crossed like in the pictures in this thread theyve been this way since ive had the truck would this affect power or anything else?
thanks for any repy

Hi Big Blue

I'm at work otherwise I'd copy and paste the photo here. (The work computer is very user-unfriendly.) But Watrob's thread on his build shows photos of his engine. And his hoses don't appear to cross either. So perhaps "crossing tubes" is just peculiar to B diesels like mine. (His injector pump is on the opposite side of his engine to mine too.)

When was the diaphragm last replaced? And does the exhaust produce more smoke than before? Depending on answers to such questions as these, it sounds like your problem could indeed be a leaking diaphragm.

[Big Blue 84BJ60]

yeah i can get her smoke now just by adding more throttle and if i givver a nice big black cloud comes out so from what i gather the diaphragm is on its way out
but its the shudder that worries me a little its never done this before and im hoping when i replace the diaphragm it will go away (the shudder)

thanks lostmarbles for clearing up the crossing of the tubes (makes me feel better that im not alone lol)

[lostmarbles]

Originally Posted by Big Blue 84BJ60

........ for clearing up the crossing of the tubes (makes me feel better that im not alone lol)

Here's the photo that I couldn't post last night. I'm sure there must be other suitable photos on MUD (showing those tubes) but I went to Watrob's build thread because I remembered he was fitting a diesel and did some good photography.





PS. Of course Watrob's engine is a 6 cylinder 2H.

We know that my "B" 4-cyl diesel has its tubes crossed and that Big Blue's "3B" doesn't. Anybody out there able to say what the "2B" engine's tubes do? And is this "tubes crossed" or "tubes uncrossed" feature specific to the engine models or does it even vary within the same engine model? - Just interested - That's all..............

[Big Blue 84BJ60]

thanks for the pick yep thats the way the vac hoses are hoked up in my truck (except dirty not all shiney and nice)

what would happen if one were to cross the tubes on the 3b or 2h (ide immangine the engine would rev out or am i wrong)?

[lostmarbles]

Originally Posted by Big Blue 84BJ60

thanks for the pick yep thats the way the vac hoses are hoked up in my truck (except dirty not all shiney and nice)

what would happen if one were to cross the tubes on the 3b or 2h (ide immangine the engine would rev out or am i wrong)?

Well the air-intake butterfly would still have some control over the engine rpm - but only through varying the engine's air supply.

The fuel would never move away from the "maximum pedal-to-the-floor" setting.

(Very smokey I would imagine and it certainly wouldn't idle smoothly or at the normal revvs.)

[Big Blue 84BJ60]

makes sense as there still would be preassure in the intake

next step replacing the diaphragm for me thanks again

[wesintl]

What's the cause of them ripping besides age?

[lynchmob]

Originally Posted by wesintl

What's the cause of them ripping besides age?

The diaphragm is leather so any long term exposure to motor oil or diesel will cause it to deteriorate.

[wesintl]

Has anyone tried the denso 090580-0022 ??

Appears to be the same thing with rubber?
Diaphragms for,MERCEDES BENZ,CAV,DIESEL KIKI, NIPPON DENSO,BEDFORD,SIMMS,PULSATOR,MITSUBISHI

[JoeCanadian]

biomechanical parts are cool eh. mabe someone in hick land is cloning them. hahaha

[MOTERRA]

I have alot of black smoke with any load it's most likely this diaphragm thats worn out???yes???

i'll have to get one now...

[Benihana]

So, not to completely hijack this thread or anything but I was just wondering if the fact that the injector pump on my 3b is pissing diesel all over my bottom end has anything to do with a torn diaphragm? Ideas?

[cruise diesel]

Lynchmob thanks for this post, most useful. I do have a question though after reading it. When you install new diaphragm do you have to lube it with something? I remeber reading somethng about Neet's foot oil, or something like that, being leather it must need something, or maybe I am way off here.

cheers,
cruise diesel

[lostmarbles]

Originally Posted by cruise diesel

Lynchmob thanks for this post, most useful. I do have a question though after reading it. When you install new diaphragm do you have to lube it with something? I remeber reading somethng about Neet's foot oil, or something like that, being leather it must need something, or maybe I am way off here.

cheers,
cruise diesel

Let me answer that for Lynchmob if I may.

The diaphragm comes "prelubed with neatsfoot oil" and is nice and soft. So there's no need to apply anything during installation. (Just keep engine oil and dirt off it as you install it.)

It is actually sold in a sealed bag with the neatsfoot as this photo shows:



To keep it nice and soft after it has been installed - Just add a couple of drips of neatsfoot through that "application hole" in the top of the diaphragm housing every time you change the engine oil.

[cruise diesel]

I just checked the part number for the diaphragm I ordered and it is a Denso #090580-0041. For whatever that's worth.

[cruise diesel]

Right on, I just went and grabbed the package, exactly as you described. Good stuff, now I just have to find the time to replace mine. There is a lot of parts in the way, but I love working on these trucks.

Thanks for the quick response.

cruise diesel

[lynchmob]

Originally Posted by Benihana

So, not to completely hijack this thread or anything but I was just wondering if the fact that the injector pump on my 3b is pissing diesel all over my bottom end has anything to do with a torn diaphragm? Ideas?

Not likely as the diaphragm is a vacuum diaphram and has no contact with fuel.

[lynchmob]

what he said.

Originally Posted by lostmarbles

Let me answer that for Lynchmob if I may.

The diaphragm comes "prelubed with neatsfoot oil" and is nice and soft. So there's no need to apply anything during installation. (Just keep engine oil and dirt off it as you install it.)

It is actually sold in a sealed bag with the neatsfoot as this photo shows:

Attachment 232076

To keep it nice and soft after it has been installed - Just add a couple of drips of neatsfoot through that "application hole" in the top of the diaphragm housing every time you change the engine oil.

[Moe R]

Originally Posted by lostmarbles

Let me answer that for Lynchmob if I may.

The diaphragm comes "prelubed with neatsfoot oil" and is nice and soft. So there's no need to apply anything during installation. (Just keep engine oil and dirt off it as you install it.)

It is actually sold in a sealed bag with the neatsfoot as this photo shows:

Attachment 232076

To keep it nice and soft after it has been installed - Just add a couple of drips of neatsfoot through that "application hole" in the top of the diaphragm housing every time you change the engine oil.

I noticed the dates on your iud boxes to have a difference of 14 years. Did you replace them for preventative maint. or did the diaphram give up the ghost? I just replaced mine (PITA) which had a hole in it, RPM's over 1000 but no smoke. It appears that mine was original which would make it 24 yrs. old 170000 K. Not bad for a constantly moving peice of leather.

[lostmarbles]

Originally Posted by Moe R

I noticed the dates on your iud boxes to have a difference of 14 years. Did you replace them for preventative maint. or did the diaphram give up the ghost? I just replaced mine (PITA) which had a hole in it, RPM's over 1000 but no smoke. It appears that mine was original which would make it 24 yrs. old 170000 K. Not bad for a constantly moving peice of leather.

Mine were replaced as part of preventative maintenance and I've never actually experienced any diaphragm troubles.

Wow. 24 years and 170,000km...... I might let this latest one last a little longer then.


(What's written on those boxes are the "dates they were fitted" and the "kilometers the previous diaphragms had covered". So what's inside that plastic bag is actually an old used diaphragm rather than a new one. ..... So in fact I "cheated a bit" in using that photo to show how a new diaphragm is supplied.)

[Moe R]

That's what I'm thinking. You could actually replace one with an old one . Still lotsa miles left on those used iud's lol. For me, diaphram failure was no big deal. I even drove quite a bit with the problem, while waiting for the new one to come in ($39.00). Used a bit of fuel though. Idle is nice at 650 now. Engine runs smooth with good power. If I have to do this again in 24 yrs I think I'll pay someone to do it.

[rchalmers3]

Originally Posted by lostmarbles

Well the air-intake butterfly would still have some control over the engine rpm - but only through varying the engine's air supply.

The fuel would never move away from the "maximum pedal-to-the-floor" setting.

(Very smokey I would imagine and it certainly wouldn't idle smoothly or at the normal revvs.)

Hey, just reviewed this thread and while I don't have a diesel with the diaphram, I think I have something to contribute in the area of the hoses.

If you look closely at the profile of the throttle body, you should see that the tubes connect to the venturi at different heights.

Given the different configurations of our motors, this may explain the "crossed" and "uncrossed" hoses. Some throttle bodies may have different locations for the placement of the taps or just mounted to the manifold in a reversed position. By understanding why the hoses connect at different heights, guesswork is eliminated.

The different heights will give you indication of what tube goes where. Someone with a few minutes and who cares to do so can confirm this:

The tube that intersects the venturi lbelow the butterfly in the venturi will be your diaphram "signal" that increases and decreases vacuum offsetting the spring. This is because as the butterfly opens and closes, the available vacuum in the venturi rises and falls. NOTE: Look closely at the construction of the throttle body. There may be an internal difference of the outside hose connections and the actual position of the opening inside the throttle body.

From what I have read from your posts the spring pushes the diaphram rod towards rich, so the lower venturi "signal" hose should connect to the diaphram housing on the same side of the spring on the diaphram. Vacuum on the diaphram at idle pulls the diaphram and rod back against the spring, lowering the fuel supply.

The higher venturi hose connection is to equalize pressure on the diaphram in accordance with the presures in the intake above the butterfly. The net effect intended is to create a stable relationship across the diaphram that is solely affected by the throttle butterfly. This upper venturi hose is connected opposite to the spring side of the diaphram.

Feel free to confirm or prove otherwise and post your findings.

Rick

[lostmarbles]

Originally Posted by rchalmers3

...If you look closely at the profile of the throttle body, you should see that the tubes connect to the venturi at different heights. .............

Looking at my inlet manifold - Yes my vacuum (venturi) tube connection is located lower on the outside of my throttle body Rick. --- But it is barely discernible. (Maybe 3mm lower at most?)

(My photo in Post 21 makes it clear that it is lower - but it is actually not so obvious by normal eyesight in the engine bay!)

And I note that you are referring to the throttle body (the "cast alloy throat part" of the inlet manifold that houses the butterfly valve) as a "venturi" but there is actually a little "venturi tube" located inside it. And only one of the tubes actually connects into this little venturi tube. - The other tube simply senses the pressure upstream of the butterfly valve.

... This is because as the butterfly opens and closes, the available vacuum in the venturi rises and falls............

To reduce confusion, I find ya have to be careful when saying stuff like this to get it the right way around Rick.

You should be saying ... "as the butterfly opens and closes, the available vacuum in the venturi falls and rises" (because opening the valve lowers the venturi's vacuum and vice versa).

..From what I have read from your posts the spring pushes the diaphram rod towards rich, so the lower venturi "signal" hose should connect to the diaphram housing on the same side of the spring on the diaphram. Vacuum on the diaphram at idle pulls the diaphram and rod back against the spring, lowering the fuel supply.

Quite true.

..The higher venturi hose connection is to equalize pressure on the diaphram in accordance with the presures in the intake above the butterfly.........

All quite true (IMO) what you say here except I don't think you should be calling this connection a "venturi hose connection". As mentioned before, it is only the other hose that connects to the "real venturi tube".

(I accept that there is a tendency to label all "downwards-sucking air intake tubes" as "venturis" but I think it causes too much confusion to do so here.)

Here's a line drawing of the injector pump which may be a useful addition to this thread. It shows the internals - including the "rack" (22) and the spring (5) we were talking about.