Anyone have one they could post up? Looks pretty simple but I’d like to confirm it gets set up correctly. And it seems to be missing from my FSM.
Thanks!
Thanks!
1HDT Vacuum Routing Diagram?
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Early (1990) HDJ80 1HDT European market, manual transmission. No EGR (thought that was HDFT only?).
Should be pretty basic and I’d like to pare it down to the bare minimum. But not sure what it might currently be missing in stock form.
Should be pretty basic and I’d like to pare it down to the bare minimum. But not sure what it might currently be missing in stock form.
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Thanks Onur. Cheers.
hi all looking for a bit of help here.
i have a 1989 fj62 with a 1hdt swap and an h55 with the original split case
i just had my engine and transmission rebuilt. the transfer case/4wd worked fine before but now it won’t engage. i can shift high to low so that’s not my issue. the 4wd button won’t engage the 4wd and won’t light up. i’ve traced the vacuum lines and i think they are correct but im not 100%. i can hear an electronic “click” when i push the button so assume it’s triggering properly but somewhere between there and the vacuum actuator is where the issue is.
i have good brakes so know im making vacuum
i had one vacuum line that was disconnected in the engine bay. when i plugged it back in nothing happened
it’s the one my finger is pointing to
now my one main question is this… with a turbo charged engine is manifold not pressurized as opposed to vacuum? so why would this vacuum line be connected to the manifold port? or am i missing something here? you can see in the photo this is where that line from the vacuum pump connects
i have a 1989 fj62 with a 1hdt swap and an h55 with the original split case
i just had my engine and transmission rebuilt. the transfer case/4wd worked fine before but now it won’t engage. i can shift high to low so that’s not my issue. the 4wd button won’t engage the 4wd and won’t light up. i’ve traced the vacuum lines and i think they are correct but im not 100%. i can hear an electronic “click” when i push the button so assume it’s triggering properly but somewhere between there and the vacuum actuator is where the issue is.
i have good brakes so know im making vacuum
i had one vacuum line that was disconnected in the engine bay. when i plugged it back in nothing happened
it’s the one my finger is pointing to
now my one main question is this… with a turbo charged engine is manifold not pressurized as opposed to vacuum? so why would this vacuum line be connected to the manifold port? or am i missing something here? you can see in the photo this is where that line from the vacuum pump connects
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The hose that goes to your 4x4 vac valves (the hose on your firewall) needs to be connected to your small fitting on the vacuum pump not the manifold. also keep in mind those vacuum switching valves also fail at times so you'll need to check them too.
so the hose connecting the one along the firewall and the one off the manifold to the fuel pump should be separated? the diagram above by beno suggests that the hose to the vsv is connected to the manifold but maybe i’m reading that wrong?
yes. beno's diagram is for a hdj80 and those are not vsvs in the picture, they are pressure switches to tell the red and green "turbo" lights to come on the instrument cluster.
k i’ll try separating them and see what happens!!
i don’t think it’s the vsv as my understanding is it’s “most often” the brown one that fails leaving the truck stuck in 4wd. i can’t get my 4wd to activate. not that it couldn’t be the green one but i’d bet it has something to do with the way things got hooked up after the rebuild. i looked back at previous photos and the vacuum hoses seem to be in the same configuration and it worked then so im a bit stymied.
i don’t think it’s the vsv as my understanding is it’s “most often” the brown one that fails leaving the truck stuck in 4wd. i can’t get my 4wd to activate. not that it couldn’t be the green one but i’d bet it has something to do with the way things got hooked up after the rebuild. i looked back at previous photos and the vacuum hoses seem to be in the same configuration and it worked then so im a bit stymied.
A diesel will never see "vacuum", as diesels get all the air they want all the time, most don't have throttle plates (if they do it's only for smoothing shutdown). The manifold/boost compensator/boost sensor circuit will see atmospheric pressure and boost only. Vacuum is only present on the brake master cylinder/vacuum pump circuit on these trucks.
this is what i thought so it was strange to me to see that vacuum line connected to the manifold. that’s going to have an affect on my boost compensator function too i’d imagine
disconnecting it temporarily didn’t fix my 4x4 function so i probably have a vacuum leak somewhere or a bad vsv. i’ve ordered a vacuum tool to test
disconnecting it temporarily didn’t fix my 4x4 function so i probably have a vacuum leak somewhere or a bad vsv. i’ve ordered a vacuum tool to test
well i have a report and a question. now that my boost line and vacuum line are disconnected the engine runs much more efficiently. i dont make as much black smoke when i take off and ive gained about 10% in mileage. pretty terrific
now i still am having troubles with the vacuum side. again my brakes are good and i get a good “woosh” of air if i take off my vacuum line at the brake booster. the small line seemed plugged so i just swapped it out. i’m getting almost no vacuum at all through it. there are no kinks in the line and air moves freely when i blow through it when its disconnected. i dont know how the internals of these pumps work but is it possible that its just a blocked port or is there a reason inside that im getting vacuum out of the large port and not the small one?
on the small line with the engine running i can pressurize the line and it very slowly leaks back to 0. this seems wrong as i dont think in should be able to pressurize a vacuum line
now i still am having troubles with the vacuum side. again my brakes are good and i get a good “woosh” of air if i take off my vacuum line at the brake booster. the small line seemed plugged so i just swapped it out. i’m getting almost no vacuum at all through it. there are no kinks in the line and air moves freely when i blow through it when its disconnected. i dont know how the internals of these pumps work but is it possible that its just a blocked port or is there a reason inside that im getting vacuum out of the large port and not the small one?
on the small line with the engine running i can pressurize the line and it very slowly leaks back to 0. this seems wrong as i dont think in should be able to pressurize a vacuum line
take a picture of the "small vaccum line" it should be right next to the vaccum pump where the brake booster hose connects. If it's clogged, un clog it. it's only like 1" long before it connections to the large brake booster fitting.
i was looking at it a little closer and i think the junction of the large and small hoses is a banjo fitting. i’ll try taking that off and cleaning it out. hopefully that’s all it is.
got it!! that little tube looked like it was dropped in mud that then hardened!! took a while to clean it out with some carb cleaner and a piece of welding wire!! but it works now.
