1978 BJ40 Air leaking into the diesel system

[UnkieReamus]

So, I've done my due diligence, spent my time with google, and then again searching various forums, and for the life of me, I can't find anything on this problem, so I ask the founts of wisdom here...

I recently acquired a 1978 12v BJ40, before I got this beauty, it had been sitting for at least a year and a half (possibly longer). As you might imagine, it had a few issues.

After about a month of working on it, I finally got all set, primed the diesel system and cranked, and she started (a little gracelessly, I'll admit, but I've since come to discover that she just REALLY doesn't like starting cold.). She ran beautifully for about 3 minutes, then died. I checked the fuel system, and sure enough, there was a bunch of air in it. So I shrugged and replaced all the fuel lines and hose clamps.

Now, she will idle beautifully, and will in fact run quite happily driving around...right up until I find myself stuck going at a low speed up or idling on a significant hill, when she will fill chock full of air and die.

The only thing I can think of is that it might be the fuel pump/distributor (Please, please tell me it isn't this, since I suspect there's no way I can afford to replace/rebuild it.)

Now, there are of course, innumerable other problems with my 'cruiser, but this is the only one that significantly affects drivability and I can't figure out.

Anyone have any brilliant (or not so brilliant but workable) suggestions?

 

[roscoFJ73]

Ive seen 5-6 owners pulling their hair out over air in the fuel system and the hand primer pump was the cause.
If they are worn out they can still let air in even with the plunger in its lock down position.
The best ones to replace them with are the Bosch primers used on Mercs,VW etc.

Unless you have fuel leaking out the injector pump,I think you can rule that out.
Checking and tightening all the rubber fuel lines back to the tank is the next pace to go.
Also,check the fuel pick up for rust where it joins the tank.

Your starting problem may be due to the glow system not working correctly.
The B engine swill burst into life like any other diesel if it has fuel,heat and cranking power.
Of course low compression can hinder quick starts.

 

[lostmarbles]

I agree with Rosco and also point my finger at your primer pump as a likely source for air to enter (if it leaks ANY diesel when you operate it). And the good news is that the Bosch replacement is quite cheap and better than OEM in my opinion:



Another common source for air to enter is in the little section of rubber tubing in your "bleed line" close to the firewall on the LH side of the engine. The rubber perishes and the tiny hose clamps often loosen up. (Hard to get hose clamps to tighten properly on such a small tubing-size too.) The line is on the suction side of the fuel pump so it will readily suck in air while NEVER leaking out any diesel (thus avoiding easy detection):



And in that same line - This is where mine cracked (partly due to the vibration of the diesel). I had to pressurise my fuel tank in order to detect this leak and even then it was hard to find. (When the tank was under pressure - leaking diesel would wet some facial tissues that I had bunched around there. But without the pressure in the tank no diesel would ever escape.):



Sorry for the small size of this photo. Can't do any better I'm afraid.

 

[lostmarbles]

OK. It's stopped raining and not so cold outside so I took some fresh photos of two of the main air-entry leak areas on my BJ40 (besides the primer pump):



If you can read the small red print in the above photo - that's where my line fractured.



But note that air can enter at any point on the section of the fuel line that I have coloured red in my previous post. And leaks in that region tend to "suck in air" rather than "leak out diesel".

 

[UnkieReamus]

I went ahead and pulled the primer pump today, and based on the method of covering the inlet/outlet and working the pump, I'm going to go ahead and say that it is in fact leaking.

Of course, since I'm in Honduras, I can't actually get another one locally, but I'm going to order one in from the states, meanwhile I will take a look at that line, and I'm going to go ahead and take your word for it and go with the Bosch part.

As I said, I've already replaced all the rubber in the system (Including that little short piece of 1/4" you mentioned lostmarbles, which, sure enough, was one of my worst leaks.), I've also repaired the metal lines that run between the injectors (not one but TWO different leaks on that), so it's so entirely not out of the question that that line your talking about is leaking as well, I'll inspect it in the morning.

Thanks to both of you, when I get the new primer pump (in 5-14 days), I'll let you know how it went.

 

[lostmarbles]

I went ahead and pulled the primer pump today, and based on the method of covering the inlet/outlet and working the pump, I'm going to go ahead and say that it is in fact leaking.

Of course, since I'm in Honduras, I can't actually get another one locally, but I'm going to order one in from the states, meanwhile I will take a look at that line, and I'm going to go ahead and take your word for it and go with the Bosch part.

As I said, I've already replaced all the rubber in the system (Including that little short piece of 1/4" you mentioned lostmarbles, which, sure enough, was one of my worst leaks.), I've also repaired the metal lines that run between the injectors (not one but TWO different leaks on that), so it's so entirely not out of the question that that line your talking about is leaking as well, I'll inspect it in the morning.

Thanks to both of you, when I get the new primer pump (in 5-14 days), I'll let you know how it went.

Sounds like you are onto it.

In case you're not already aware - the Bosch part numbering system is CRAZY. That Bosch pump is most likely to be found under part numbers 2 447 010 033 or 2 447 010 038. But it may also be found under part numbers 2 447 222 125 or 2 447 222 126.

The OEM toyota part number is 22501-77020 which has apparently been substituted with 22501-77021.

And according to other MUD members (in previous posts) Denso 092130-0050 and 09219-50 fit (but maybe they should have given the last part number as 092190-0050 to conform with the first ...... who knows?)

 

[toms42]

Thanks to a bit of searching was able to fault find the air leak in my system thanks to this thread narrowing it down for me, so heres and thought I would add that the replacement primer pump was off the shelf at repco PN: 138-006680 $46 looks like an after market jobbie that will fit 2H as well

 

[tmarx]

.. (if it leaks ANY diesel when you operate it)...

Think you just solved another of my problems Tom !

Got a Bosch part no perhaps ?

 

[toms42]

there is a heap of part numbers in lost marbles last reply

 

[tmarx]

:whoops:

Dunno how I missed that

 

[cruiser user]

IT Worked , Thanks!!

I read your post last week and then changed the small piece of tubing in the diagram and added clamps to the tubes between the injector pump diaphragm and throttle body and.... the engine smoothed right out and my EGT's dropped about 200 degrees!!! It used to easily go over 1200 with any kind of a load on the engine, now it stays at around 900 -1100 even up hills. Can someone explain the temp drop to me??? Tim

 

[lostmarbles]

I read your post last week and then changed the small piece of tubing in the diagram and added clamps to the tubes between the injector pump diaphragm and throttle body and.... the engine smoothed right out and my EGT's dropped about 200 degrees!!! It used to easily go over 1200 with any kind of a load on the engine, now it stays at around 900 -1100 even up hills. Can someone explain the temp drop to me??? Tim

Fuel delivery is controlled by the governor diaphragm.

And excess fuel causes high EGTs.

So my guess is that you were previously over-fueling and whatever you've done now has fixed that.

 

[D0g]

OK. It's stopped raining and not so cold outside so I took some fresh photos of two of the main air-entry leak areas on my BJ40 (besides the primer pump):

View attachment 357867

If you can read the small red print in the above photo - that's where my line fractured.

View attachment 357868

But note that air can enter at any point on the section of the fuel line that I have coloured red in my previous post. And leaks in that region tend to "suck in air" rather than "leak out diesel".


View attachment 357867View attachment 357868

@lostmarbles how did you take off that return hard line? Mines leaking from there

 

[BreckenridgeCruiser]

@D0g ... LostMarbles lost his BJ in an accident a few years back.... He's fine and drives a new LC, but hasn't been on the forum for a few years now...

This thread was last touched in 2009 so some people may not respond in a timely manner!

 

[D0g]

Sad.... he had some really good knowledge about these rigs.

 

[BreckenridgeCruiser]

Yeah... Luckily a ton is archived here on the forum ..