Hino Misfire no one can solve..

hinobraga

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Figured i could try my luck here for some input as no shop could help me so far..
( been to hino dealer...and two other shops..no error code we can't tell whats going on is the usual response )

2008 Hino 268 around 440 000 km on it automatic airbrake.

Have spent a ton of money in this thing to date. over 10k+ serviced regularly and such forth...
This issue has come and go over the past few months but now is a daily thing..
While driving the truck would misfire..this is how it would work:

The yellow airbrake light would come on and off and on and off before it misfires ( playing with the airbrake switch on and off does not do anything ) right when the light turns off...the truck misfires and needle jerks between 1 - 2k rpm and shakes violently no power truck wouldn't move when hitting throttle..just bounces between rpm....sometimes on the highway it does this i put it in neutral shut her off then back on. This happens more due to the colder months perhaps ? not sure. now i've been to a hino dealer at first no codes no misfire nodes no nothing they could not do anything without seeing codes. second shop cleaned the transmission lines, did a manual regen twice..nothing. Third shop said they could not tell what it was without any codes.

Now I'm stuck..not a clue whats going on and no one can figure it out. Should i clean the dpf filter ? rebuild airbrake no clue anyhelp is appreciated. I am a new member so i cannot upload any videos..if you go on youtube and simply type in " hino misfire " it will be titled Hino misfire 2007 if you guys would like to view the videos.
 
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Ragman

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Hope this helps..... perhaps our resident Hino experts will see it.




 

greasytshirt

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I can't really tell what's going on in those videos. There are some things that can cause jumping like that, including intake throttle valve sticking and bad connections at the scv and rail pressure sensor.

There are times when the exhaust brake comes on when the driver doesn't command it, like 'white smoke prevention mode', and when the truck becomes stationary during an auto regen.

I have a strong feeling that this problem is a simple one, but the cause is obscure enough to stump everyone.

What's your location? I'm in VA. Hino123 is in FL. I'm sure either of us can figure it put.

Sent from my XT1585 using EO Forums mobile app
 

Treadmill

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I can't really tell what's going on in those videos. There are some things that can cause jumping like that, including intake throttle valve sticking and bad connections at the scv and rail pressure sensor.

There are times when the exhaust brake comes on when the driver doesn't command it, like 'white smoke prevention mode', and when the truck becomes stationary during an auto regen.

I have a strong feeling that this problem is a simple one, but the cause is obscure enough to stump everyone.

What's your location? I'm in VA. Hino123 is in FL. I'm sure either of us can figure it put.

Sent from my XT1585 using EO Forums mobile app
He’s from Toronto.
 

BigStickJr

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Sounds like a trip Southeast may be worth his time.
Just tell him not to bring that funny money.
 

hinobraga

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greasytshirt

Yes i am in Toronto really would make the trip down there ...it is weird the exhaust brake light flashes couple times..misfires and smoke does also come out the back..i have done two manual regenarations also. i will look into the intake throttle valve and the connections to see if something is going on but i have a similar feeling it is a simple problem but no one can identify the cause of this..any idea of anything else it could be ?
 

hinobraga

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Ragman thanks for the upload
greasytshirt going to drive it in the AM tomorrow and take a look at the DPR graph when it misfires and will follow up here i do believe it is under 3 bars but will check.. really appreciate the help and input once again thank you
 

greasytshirt

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While it's idling, put your hand on the common rail pressure sensor and give it a wiggle. As these trucks age, I'm seeing more and more of them develop a bad connection here, and it makes them go berserk.

The common rail is the metal log that has all of the injection lines coming off of it. The pressure sensor is near the center of it, and has three terminals inside. Just grab the connector and wiggle it around.
 

greasytshirt

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So while it's kind of ridiculous to assume I can fix this without looking at it from 800 miles away, I can still do some research.

upload_2018-1-11_20-35-4.png

#4 is the exhaust brake relay, and the wire to the right of it has a box on the end labeled engine stop. Engine stop, I believe, is a remote stop command, like for PTO work or whatever. I am assuming that engine stop will want to see power to command engine off. If there's a short to power between these two wires, I can see a case where the exhaust brake could come on without being commanded on by the switch, and the engine might misfire or stall.

The only way to tell for sure if this harebrained idea is valid is to hook a computer to it and monitor the engine stop signal and exhaust brake signal while the symptoms are occurring.

These connectors are at the engine ecu, which is visible with the fuse panel cover removed. perhaps enough coffee got dumped back here to make a tentative connection when it's wet outside. Might be worth a gander.
 

hinobraga

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So while it's kind of ridiculous to assume I can fix this without looking at it from 800 miles away, I can still do some research.

16769


#4 is the exhaust brake relay, and the wire to the right of it has a box on the end labeled engine stop. Engine stop, I believe, is a remote stop command, like for PTO work or whatever. I am assuming that engine stop will want to see power to command engine off. If there's a short to power between these two wires, I can see a case where the exhaust brake could come on without being commanded on by the switch, and the engine might misfire or stall.

The only way to tell for sure if this harebrained idea is valid is to hook a computer to it and monitor the engine stop signal and exhaust brake signal while the symptoms are occurring.

These connectors are at the engine ecu, which is visible with the fuse panel cover removed. perhaps enough coffee got dumped back here to make a tentative connection when it's wet outside. Might be worth a gander.


Thanks alot for the help ! Really appreciate it more help than you think. i am getting the three Holes drilled into the plate right now as we speak..going to test it for a bit and see how it goes then going to check that common rail pressure sensor and move from there..i have been reading alot of your threads very informative and very helpful ! will keep you posted then follow up with the idea and check the wires out (hopefully not the wires ) thanks once again !
 

hinobraga

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Update :

All three holes drilled into the ITV plate, and the common rail pressure sensor is also okay. My best belief is that it does have something to do with the exhaust brake relay. Going to look into any stored codes as well see if anything pops up, problem with checking connections is I have to find a shop that will ride the day out with a truck with a computer hooked up to it ..
 
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