3b running issues. Fuel issue?

[dakes112]

Hey guys
So im the proud owner of a 12v 1982 bj42. For the last 4 months or so ive been having a few issues with it. Ive tried multiple times to fox it and everytime i think i have but then 2 weeks later the gremlin is back.
So whats happening is basically it wont idle smoothly. As if its on 3 cylinders and then stall. It doesnt stall everytime but it seems to get worse the longer i drive it for. Sometimes ill get a week before this happens and other times it wont even let me drive it before it dies.
When it does die i pump the hand pump for a bit then start it again. Usually it will run for 10 seconds then die. So i open the bleed valve, theres a hiss of air. Then i bleed out the air which there is a fair bit of then its a 50/50 shot if it will run.
So far things ive done are:
Taken off all injector lines and cleaned where they seat on the injectors.
Removed fuel tank and cleaned
Emptied sedimentor
Changed the fuel filter
Checked the small gauze filter in the fuel pump (it was perfectly clean)
Visually inspected all rubber fuel lines

I havent been able to find any drips or cracks in any lines but im at the point where im thinking of replacing them all and giving it some new clamps aswell.
Im also considering buying a bosch primer and replacing the brass looking one thats on there atm just to eliminate that.

Right now its parked and its running and it revs fine. But once i lift my foot off and the revs drop back to idle it goes back to 3 cylinders and is rough and then over the next 15 or 20 seconds it will come back to its normal smooth idle.
When i drive it at highway speed occasionally it will lose all power and i start to slow down as the revs drop and as i get slower and slower they keep falling and i change down to try and keep them up. Then suddenly itll kick back to life and ill be good to accelerate back up as per normal.
It seems that the longer i drive it it gets worse. I was on the highway for 2 hours once and the losing power thing happened a couple of times but i was trying to nurse her home. As soon as i turned off and slowed down a bit the power left and it slowed down until it stalled. No matter how much bleeding i did i cohldnt get it started so i had it towed. Next morning the mechanic bled it once and it started fine. He didnt know what was wrong with it and seemed to think it was fine.
The primer pump doesnt reach the end of the injector lines (not sure if this is normal). It pumps well out of the bleed valve near the filter but when i close that and crack an injector it pumps but jo matter how long i pump for fuel never comes out the end.

Sorry this post is all over the place. I kept remembering new things as i typed so hopefully it all makes sense. I have searched the forums and some of the stuff i checked was from there but i dont have a computer at the moment so it was a little hard.

Anything you can think of would be a massive help. Im not a mechanical genius so please forgive me if i missed something silly

 

[duncanrm]

I havent been able to find any drips or cracks in any lines but im at the point where im thinking of replacing them all and giving it some new clamps aswell.
Im also considering buying a bosch primer and replacing the brass looking one thats on there atm just to eliminate that.

I think you're doing all the right things.. everthing you've said indicates its sucking air.

As you've correctly noted, the primer pump wont prime through to injectors. B and H engines rarely require priming past the filter anyhow.


A few other things to consider:

• Consider deleting the sedimenter altogether.. for the time being loop the inlet hose to the outlet hose with a small peice of steel tube and clamps (whatever you can make work) - a decent combined filter/separator can be added.. preferably one with a sight bowl
• If you've disturbed the banjos on the pump and filter housing you should also have replaced the crush washers at the same time... they often dont seal properly again - they are a one use item - two per fitting, one each side of the banjo
• definitely renew clamps and minutely examine all hoses
• The lift pump itself may be faulty
• replacing the primer pump is a good idea - its a common failure point
• Dont forget the injector return line, another source of air
  
• Also, there's a crush gasket under each injector - its not going to be your problem but when you disturbed your injectors that should have been replaced on each one.. you'll probably get away with that though

 

[gerg]

Fuel tank give a whoosh of air when it's close to empty when you unscrew the cap?
Vacume in fuel lines can suck air even at a good connection.

 

[dakes112]

I think you're doing all the right things.. everthing you've said indicates its sucking air.

As you've correctly noted, the primer pump wont prime through to injectors. B and H engines rarely require priming past the filter anyhow.


A few other things to consider:

• Consider deleting the sedimenter altogether.. for the time being loop the inlet hose to the outlet hose with a small peice of steel tube and clamps (whatever you can make work) - a decent combined filter/separator can be added.. preferably one with a sight bowl
• If you've disturbed the banjos on the pump and filter housing you should also have replaced the crush washers at the same time... they often dont seal properly again - they are a one use item - two per fitting, one each side of the banjo
• definitely renew clamps and minutely examine all hoses
• The lift pump itself may be faulty
• replacing the primer pump is a good idea - its a common failure point
• Dont forget the injector return line, another source of air
  
• Also, there's a crush gasket under each injector - its not going to be your problem but when you disturbed your injectors that should have been replaced on each one.. you'll probably get away with that though

Thanks ill definitely start working along that list.

Fuel tank give a whoosh of air when it's close to empty when you unscrew the cap?
Vacume in fuel lines can suck air even at a good connection.

Yeah theres a gush of air. Im not sure if its pressure or a vacuum but theres definitely an audible whoosh. What does this mean? How can i fix it haha?

 

[gerg]

I suspect as the fuel tank empties your vents aren't allowing air in and its creating a partial vacuum. That's what your hearing when you release the fuel cap. Your lift pump keeps sucking hard to get fuel and your fuel line is also a partial vacuum. Air seeps in at connections but fuel won't leak out at rest like you would see if there was a rust hole or brake in a line. As the engine runs, more and more air enters the fuel system. In a pinch I've removed the rubber gasket off the fuel cap but that is a short term solution. It will allow air in to prevent Vacume, but you can also get crap in the tank fairly easy by leaving it that way for extended periods. You need to put eyes on your tank vents. I suspect there be some shenanigans a going on.

 

[dakes112]

Ahhh ok. Ill try and get a look and those.

These 2 fuel lines that im not sure about. One going up to the fuel filter and one coming back down again. They both have banjo fittings but the fuel lines are attached differently. Crimped might be the word. Are these prone to cracking and should i replace these too? Ill replace the crush washers either side of the fittings but im not sure about the actual lines themselves. Can i somehow replace them or do i need to get them made up by a shop?

Sorry again but im learning as i go on this one. I havent worked much on cars before but i fell in love with this one so i had to get it

 

[Antony]

I'd agree with all the comments above. It does sound like your chasing an air problem. Clear lines are the easiest way to find the source of air ingression. I'd fit one anywhere between areas I suspect air is being drawn in. This is of course pre lift pump, anything after the lift pump you would expect to see a leak. Putting the clearline on the return of the pump would check the post lift pump side which checks restrictions, faulty primer etc.

 

[ozcrusier]

It sounds like your chasing a few gremlins in the fuel system.
There has to be a leak in the fuel lines from your fuel tank to the lift pump that letting air into the system. Once you start driving down the hwy the fuel tank gets a vacuum inside of it causing more air to be pulled into the fuel line hence the engine starts to miss fire and it dies.
I would start at the fuel tank and replace every rubber fuel line forward to the lift pump first.
Then go for a drive and see if the problem returns.
If you have the same problem there's a crack in the hard line somewhere so time to run a long rubber hose from the tank to the lift pump and test drive again.

 

[dakes112]

It sounds like your chasing a few gremlins in the fuel system.
There has to be a leak in the fuel lines from your fuel tank to the lift pump that letting air into the system. Once you start driving down the hwy the fuel tank gets a vacuum inside of it causing more air to be pulled into the fuel line hence the engine starts to miss fire and it dies.
I would start at the fuel tank and replace every rubber fuel line forward to the lift pump first.
Then go for a drive and see if the problem returns.
If you have the same problem there's a crack in the hard line somewhere so time to run a long rubber hose from the tank to the lift pump and test drive again.

Alright that sounds good. I definitely have a few things to work on this weekend.
If the hard line is cracked and i run a rubber hose all the way from the tank is this a good permanent solution? Or should i eventually get the hard line repaired?

 

[ozcrusier]

I would replace the soft line from tank to hard line first as it could be the perished culprit. The 8mm hard line is worth keeping but if it's split you could pick up a straight piece and add few slight bends to replace.
If the tanks sucks air when you pull the cap maybe think about dropping the tank and going through the breather system as well as this would cause more air to be sucked into your fuel system.
1st fix the air leak.
2nd pull tank clean and replace the vacuum hoses.

 

[dakes112]

Thanks everyone for your help. I replaced all the lines and more than one had splits that i couldnt see until i took them off. So new hoses and clamps have completely cleared up all the issues. Ill take it out for a long drive sometime this week and see how she goes but im feeling confident.
Thanks again