Big Truck I work on Hino trucks. I'll answer any questions I know the answers to.

[greasytshirt]

I have a 04 hino 338 with engine model j08e-tb. The issue I'm having is the u2 act fuse keeps blowing. I have replaced the turbo, went threw all the grounds and cleaned them up. Made sure they are good and cean. It will drive great for about 20ish min and then the fuse blows. Any help would be appreciated
Thanks!
Aplekan

Both EGR valves are on this same circuit. The white wire at both valves are both power supply from U2 act fuse.

Thanks, I'll check it out tomorrow and see what I can find. I'm pretty much looking for a short somewhere that keeps blowing the fuse? Also the cruise control stopped working. Any way they are related? It stopped right when the fuse started blowing. It won't let me idle up for the pto when I run the vacuum.

Yes, you're looking for a short. Either a component or the harness has a short. The EGR valve is pretty expensive.

For the rest of this stuff, i don't know. I don't want to offer a ton of speculation. Yes, they could be related. When troubleshooting this stuff, I have a computer attached to it so I can see what's being input and what's being commanded. I will confirm that when the VNT or EGR valves go down, expect limp mode in an instant.

Edit: A forum member in Florida recently had an event similar to what you're describing, but the U2 act fuse wasn't blowing (from what I understand). It would run fine, then go into limp mode with no check engine light. After a mind-numbing, hours-long, incredibly slow drive to the dealer, the EGR valves were replaced and all problems solved.

Unless you're willing to spend $1200 on a guesstimate, I'd take it in for an actual diagnosis.

 

[wmuhr84]

Hi, I work on light duty diesel, but have a guy who transports for me and is having me look at his truck
he says the coolant is being pressurized, had the head gasket done 70k ago. the truck has 880 on it.

2006 Hino 7.7

Truck runs fine, no smoke, i pulled the pipe off the EGR cooler to see if maybe it was cracked and had coolant in it and it was clean

I know the gasket could have went bad, or possibly a cracked head, Im just not sure on common problems with these trucks.

The heat does not seem to work, do thermostats regularly go bad?
do i need to test the coolant with a strip or something to see if it detect combustion gas?

Thanks,Willy
712.304.2812

 

[wmuhr84]

also, the heater doesnt really work unless driving, which maybe they are all like that

 

[greasytshirt]

The thermostats do not go bad very often at all. If you have no heat, it is probably from air pockets in the cooling system.

The egr coolers don't generally go bad either. Occasionally one will fail after the engine is run extremely low on coolant.

You'll want to do a combustion gas test. You want the dick pump tester, since there's no vacuum source for the traditional style to connect to.
https://www.amazon.com/UVIEW-560000-Combustion-Leak-Tester/dp/B000NPDL76

So, let's say the test fails miserably. If it does, I'd be blaming an injector cup since the head gasket was done 70k ago. This job will take about six hours, and it requires special tools. The EGR cooler isn't a suspect. That would explain a loss of coolant, not a pressurized cooling system. Something like a broken head bolt is also possible. These heads don't just crack unless it had a thermonuclear event. By the way, don't shave the head. There's no provision for adjusting idler gear endplay.


It's possible to get atmospheric air in through the water pump shaft seal, since the thermostat is on the pump intake. When it's shut, there's a region of low pressure around the pump's carbon seal. If it's not sealing perfectly, air can enter.

 

[wmuhr84]

I am down to the point of having the injectors out, and checking the cups. would that mix oil and/or water at all?
before i even dug into it i checked to make sure all injectors were down tight and they were. maybe ill see something obvious on the cups. is there a way to getting them out without a special tool? or post a pic of it so i can make it, there isnt a whole lot of info on these other than the sites you are on haha

 

[wmuhr84]

none of the cups came out with the injectors.. as far as that rear idler gear, is it just going to come straight up with the head? i do not know how to time it, so i just marked the cam gear so i know i can mess it up putting it back down.

 

[wmuhr84]

where can i acquire torque specs and valvetrain specs?

 

[greasytshirt]

I am down to the point of having the injectors out, and checking the cups. would that mix oil and/or water at all?
before i even dug into it i checked to make sure all injectors were down tight and they were. maybe ill see something obvious on the cups. is there a way to getting them out without a special tool? or post a pic of it so i can make it, there isnt a whole lot of info on these other than the sites you are on haha

You won't see evidence of leakage. It's going to leak on the other side of the cup. Head gasket, injector cups, or a crack in the head are the only avenues for combustion gas to get forced into the cooling system. And the head probably isn't cracked.

You can get them out with a giant easy-out. You cannot install them without a special tool with the head still on. You could with the head off. The tip of the cup is swaged into place. A special sealant is required.

Timing it is easy. Put the balancer on the 1/6 mark. Look at cam gear. Two dots will line up with the top of the cam case. An offset dot will either be above or below the cam case cover. If you put the dot above, it's on tdc#1. If it's below, tdc#6. Doesn't matter where the idler gear is. Also doesn't matter if you time the injection pump and compressor. Marks exist, but not required.

Just so you know, the fuel return pipe, the one odd banjo bolt, all seal washers, and the injector bolts are all considered one time use. Resist the temptation to reuse the return line. Messing that up is the #1 human-error cause of blowing one of these up. When it leaks, the crankcase fills with fuel, fills the crankcase ventilation system, then it runs away. If the line is kinked and then bent back, it won't leak initially. It'll just break at random and you'll never see it coming. You need an accurate in/lb torque wrench.

I know the torque specs, but I want some reassurance that you'll replace that pipe and bolt.

 

[FlyingVan]

The thermostats do not go bad very often at all. If you have no heat, it is probably from air pockets in the cooling system.

The egr coolers don't generally go bad either. Occasionally one will fail after the engine is run extremely low on coolant.

You'll want to do a combustion gas test. You want the dick pump tester, since there's no vacuum source for the traditional style to connect to.
https://www.amazon.com/UVIEW-560000-Combustion-Leak-Tester/dp/B000NPDL76

So, let's say the test fails miserably. If it does, I'd be blaming an injector cup since the head gasket was done 70k ago. This job will take about six hours, and it requires special tools. The EGR cooler isn't a suspect. That would explain a loss of coolant, not a pressurized cooling system. Something like a broken head bolt is also possible. These heads don't just crack unless it had a thermonuclear event. By the way, don't shave the head. There's no provision for adjusting idler gear endplay.


It's possible to get atmospheric air in through the water pump shaft seal, since the thermostat is on the pump intake. When it's shut, there's a region of low pressure around the pump's carbon seal. If it's not sealing perfectly, air can enter.

Didn't know that hinos have a dick pump.

Sent from my SM-G900P using Tapatalk

 

[FlyingVan]

The thermostats do not go bad very often at all. If you have no heat, it is probably from air pockets in the cooling system.

The egr coolers don't generally go bad either. Occasionally one will fail after the engine is run extremely low on coolant.

You'll want to do a combustion gas test. You want the dick pump tester, since there's no vacuum source for the traditional style to connect to.
https://www.amazon.com/UVIEW-560000-Combustion-Leak-Tester/dp/B000NPDL76

So, let's say the test fails miserably. If it does, I'd be blaming an injector cup since the head gasket was done 70k ago. This job will take about six hours, and it requires special tools. The EGR cooler isn't a suspect. That would explain a loss of coolant, not a pressurized cooling system. Something like a broken head bolt is also possible. These heads don't just crack unless it had a thermonuclear event. By the way, don't shave the head. There's no provision for adjusting idler gear endplay.


It's possible to get atmospheric air in through the water pump shaft seal, since the thermostat is on the pump intake. When it's shut, there's a region of low pressure around the pump's carbon seal. If it's not sealing perfectly, air can enter.

Didn't know that hinos have a dick pump.

Sent from my SM-G900P using Tapatalk

 

[FlyingVan]

The thermostats do not go bad very often at all. If you have no heat, it is probably from air pockets in the cooling system.

The egr coolers don't generally go bad either. Occasionally one will fail after the engine is run extremely low on coolant.

You'll want to do a combustion gas test. You want the dick pump tester, since there's no vacuum source for the traditional style to connect to.
https://www.amazon.com/UVIEW-560000-Combustion-Leak-Tester/dp/B000NPDL76

So, let's say the test fails miserably. If it does, I'd be blaming an injector cup since the head gasket was done 70k ago. This job will take about six hours, and it requires special tools. The EGR cooler isn't a suspect. That would explain a loss of coolant, not a pressurized cooling system. Something like a broken head bolt is also possible. These heads don't just crack unless it had a thermonuclear event. By the way, don't shave the head. There's no provision for adjusting idler gear endplay.


It's possible to get atmospheric air in through the water pump shaft seal, since the thermostat is on the pump intake. When it's shut, there's a region of low pressure around the pump's carbon seal. If it's not sealing perfectly, air can enter.

Didn't know that hinos have a dick pump.

Sent from my SM-G900P using Tapatalk

 

[wmuhr84]

I did not get the new bolt or return line, but i did get the injector bolts as hino recommended them, just not the line. it is kind of similiar to the lb7 duramax with those lines, and before i put them back together i pressure the lines when tight and check for leaks.

 

[greasytshirt]

Didn't know that hinos have a dick pump.

Not with that attitude.

 

[greasytshirt]

I highly recommend replacing that line and bolt. Cheapest insurance available.

 

[wmuhr84]

head gasket was done 70k ago and he said a whole top end kit was done at the time including the bolts,lines, and bango seals. just the kit alone cost him $1500 which is unreal. i understand that it is cheap insurance but nobody around has them on hand and the driver needs the truck tuesday morning, i guess if they leak he is screwed, but if they dont, he will ahve a truck tuesday morning. I will definitely be cautious about it, and i really do appreciate all the help!

 

[greasytshirt]

Injector hold down bolts 18 ft/lbs . Injector lines 33ft/lbs. Return pipe 110-115 in/lbs. Blow oil out of hold down bolt holes so they don't hydrolock. Injector wire pigtails 7in/lbs.

 

[wmuhr84]

what are steps for the head itself, Cam, and Rocker Rail. i have two local hino shops and they apparently have too hard of a time looking it up for me. Thanks Greasyshirt for the help

 

[greasytshirt]

what are steps for the head itself, Cam, and Rocker Rail. i have two local hino shops and they apparently have too hard of a time looking it up for me. Thanks Greasyshirt for the help

Rocker shaft 43, but do it at 38. Newest bolts that are just now available 35, I think.
Cam:. Two different torques per cap. One threads into cast iron, the other aluminum. Into aluminum 16. Into cast Iron 23.

 

[wmuhr84]

The 1 bolt did pull apart and i started at 90" lbs, luckily enough for me, cummins piston cooling jet bolts are pretty well the same other than its a 10mm head. pressure checked it and leak free. She'll be on the road in the morning

 

[greasytshirt]

The 1 bolt did pull apart and i started at 90" lbs, luckily enough for me, cummins piston cooling jet bolts are pretty well the same other than its a 10mm head. pressure checked it and leak free. She'll be on the road in the morning

May his connecting rods stay off of the freeway.

Godspeed!

 

[wmuhr84]

sounds like you are doubting me.