FJ75 Stalls when running on subtank ony (1 Viewer)

[Liam99]

Hello,

I've been looking for a long time at this forum and have finally become a member. The knowledge on here has been so useful, and I am so grateful for all the help it has given me. However, I've finally come along a problem that I can't figure out.

For context, I have a 1992 Landcruiser Cab Chassis, 3f motor - carbureted. I picked it up about six months ago, and It's only got 80,000km (original everything) and has been running great mechanically after some general maintenance.

The trucks runs great on the main fuel tank, but after selecting the auxiliary fuel tank it stalls out after about two minutes - seems like a fuel starvation issue. It is hard to start back up after stalling, and the main tank has to be used to restart it. You can then run it again on the subtank for about two minutes and the problem repeats. This is repeatable at low rpms, high rpm, while driving, and while parked.

I've done a lot of work to chase this problem - the sub tank hadn't been used for a long time when I first got it.
- dropped and fully cleaned the sub-tank which was quite rusty
- installed new fuel sender
- installed new fuel filter sock on pump intake (mechanical pump driven from engine)
- checked for correct operation of fuel change over solenoids - both click when the sub tank is selected/deselected, and fuel is taken and returned to correct tank
- blown air through all of the lines - these are all clear
- checked all breathers were clear and blown out.
- installed a secondary inline fuel filter to catch any debris that may still be in tank - still clean as a whistle (I don't think this impedes flow)
- installed additional hose clamps on all connections of the feed fuel line in case it was a loose connection

I also had a mechanic look at it, and he couldn't figure it out. I really don't know what the issue is - the system works great in front of the solenoids (like when its running from the main tank), and everything backwards from here seems to be in good condition. The flow seems strong when pumping - when pulling the return line while running it is a good strong flow.

I'd be really grateful for any help you could give me, and I look forward maybe helping someone else one day (I'm not the greatest shade tree mechanic by a long shot).

Cheers!
Liam

 

[roscoFJ73]

Ive heard of it happening before on a HZJ75. The owner reported back that he found orange plastic (the type that used for sealing off dangerous areas in a workplace) and it was blocking the solenoid switching valve.
Even though you have observed a strong flow, the petrol and diesels use a lot on acceleration, something like a litre per minute
If you need a low klm used fuel 3F pump cheap, send me a message.

 

[Liam99]

Ive heard of it happening before on a HZJ75. The owner reported back that he found orange plastic (the type that used for sealing off dangerous areas in a workplace) and it was blocking the solenoid switching valve.
Even though you have observed a strong flow, the petrol and diesels use a lot on acceleration, something like a litre per minute
If you need a low klm used fuel 3F pump cheap, send me a message

 

[Liam99]

Hey,

Cheers for that, and the quick reply! I'll take the valve apart this weekend, and hopefully that can be the cause of the issue!

Thanks again,
Liam

 

[Liam99]

Hello,

Quick update - I finally got around to pulling the solenoid in the weekend (life got in the way) and found it wasn't actually the issue. After going through the system again, I found that the fuel pickup pipe in the subtank was actually the culprit. It seems to have been blocked since I cleaned out the subtank, or I didn't do a very good job... I'm trying my darndest to get it unblocked, but still struggling - I'm going to try soak in some CLR tonight to dissolve some rust that it might have picked up. I think the toyota part number for it is 77017.

Thanks for your help with this, I found this after I was bypassing the solenoid with joiner. \


Thanks!

 

[Whoosh]

Just a thought - have you tried running the engine off the aux tank with the lid off? I heard you loud and clear mentioning the breathers, but just to be sure...
And, on the same note, have you tried to establish whether the fuel line from the aux tank might suck air somewhere? If it would be above tank level you might never notice. A worn fuel lead somewhere?

 

[Liam99]

Just a thought - have you tried running the engine off the aux tank with the lid off? I heard you loud and clear mentioning the breathers, but just to be sure...
And, on the same note, have you tried to establish whether the fuel line from the aux tank might suck air somewhere? If it would be above tank level you might never notice. A worn fuel lead somewhere?

Hello, I gave that a try beforehand, and it didnt' help sadly. I've got it sorted now though, and she's running smoothly! I had to cut the pickup to access and clear the blocked section in the middle and have temporarily held it together with some fuel line and hose clamps. It's working great, but I'm in the process of chasing down a new pick - part number 7724060141. Unfortunately, Toyota no longer makes this anymore, and I can't find at a wreckers for the life of me. I think I'll have to go to a pick-a-part when I'm closer to one.

In the meantime, I've ordered some submersible fuel hose which will be suitable until I can get a replacement sorted. Thanks for your help!

 

[Whoosh]

Hello, I gave that a try beforehand, and it didnt' help sadly. I've got it sorted now though, and she's running smoothly! I had to cut the pickup to access and clear the blocked section in the middle and have temporarily held it together with some fuel line and hose clamps. It's working great, but I'm in the process of chasing down a new pick - part number 7724060141. Unfortunately, Toyota no longer makes this anymore, and I can't find at a wreckers for the life of me. I think I'll have to go to a pick-a-part when I'm closer to one.

In the meantime, I've ordered some submersible fuel hose which will be suitable until I can get a replacement sorted. Thanks for your help!

I've looked for you, but got the same results, sorry. Best of luck, and keep me posted!