Help with a 78 bj40 ideling way too high (1 Viewer)

[macgyver101]

Hey Everyone, I am new to this site but not to land cruisers. I have owned a few FJ40's in the past and have sold them to get into a 78 BJ40. I purchased it in Florida, drove it to NJ. The problem I am having is that is idles at over 2500 rpms after it warms up and does not drop down and blows ungodly amounts of blue smoke while doing this. I shut it off everytime I had to come to a stop to avoid the racing as well as filling the intersections with smoke. I have a feeling it may be something in the injection pump causing this however I am uncertain. Any and all help would be so greatly appreciated. Have a great day!
STEVEN

 

[Chang-kuao-lo]

I hate to say it, but you may have crankcase oil going past the rings and the engine is burning it like fuel. If it is indeed blue smoke and not black. Compression test may be in order.

 

[Tapage]

search about IP diaphragm and vaccum leaks ..

 

[macgyver101]

I thought that might be the case but in the 1800 mile drive home I used less than 1/2 qt oil cruising @ 60-65mph. I thought if I should have used A LOT more the way tis thing was smoking. I will do the compression check though. Thanks for the tip! Steven

 

[MrMoMo]

Not to state the obvious, but you didn't accidentally move the hand throttle out did you?

 

[lostmarbles]

search about IP diaphragm and vaccum leaks ..

x 2

This thread relates to a 3B but yours should be the same:

https://forum.ih8mud.com/diesel-tech-24-volts-systems/182948-3b-diaphragm-replacement.html

 

[macgyver101]

That was the first thing I checked but thanks for the reply. See what everyone chooses not to see which is usually the obvious! Steven

 

[simonliew]

X3 on the injection pump diaphram.
TLC import connection
Diesel landcruiser specialist
Winnipeg
92 HDJ81,locked,lifted,factory winch and locked,ARB bumper
92 HDJ81 wife
92 HZJ77
81 BJ42 rockrawler
82 BJ42 rusty

 

[Chang-kuao-lo]

IP diaphragm = boost/high altitude compensator?

 

[lostmarbles]

IP diaphragm = boost/high altitude compensator?

No.

When you put your foot down on the accelerator, all it does is open a butterfly valve in the air intake of this type of cruiser. (No change in fuel quantity from that!)

So the fuel is controlled by the "IP diaphragm" (injection pump diaphragm).

A high vacuum in the venturi connection (created by the engine "sucking" with the butterfly-valve closed) causes the "IP diaphragm" to pull the rack (inside the injector pump) to the "idling fuel quantity" end of the range.

And a very low vacuum (created by the buttefly-valve being wide open) allows spring pressure to push the rack to the "maximum fuel quantity" end of the range.

So moving the accelerator pedal:

• controls the motor's air supply directly via the butterfly valve, and
• controls the fuel supply indirectly via that diaphragm.

And an "intermediate pedal position" (between "foot-off" and "foot-hard-down") will provide an intermediate rate of air AND fuel delivery to the engine.

So that little bit of leather is pretty important

 

[Chang-kuao-lo]

Ok, I see, it has a throttle body. Makes sense how this would mess with the idle speed.

 

[RufusTheDufus]

It's not the throttle body messing with the idle speed. It's what's connected to those two clear hoses. You can adjust the throttle stop to the point that the plate is closed. It won't matter if the pump diaphram is torn.

 

[Chang-kuao-lo]

yesyes i understand...

 

[golfinw71]

I had the same problem, replaced the injector pump diaphragm and that did it, runs like a charm now. I ordered the part from 4wheel auto in Canada.

Warning, do this when you are really bored and have a ton of patience because it's a son of a b.....

If you don't mind me asking where did you find the cruiser in FL?

 

[lowenbrau]

Injector diaphragm. (just trying to dilute the bad diagnosis)


Tips
Don't pay more than $40 for one.
Buy a small mirror and some hemostats.
Don't drink coffee or go to confession before the swap. You'll need both later.