1hdt fuel solenoid

[Squash]

Doesn't sound like air suck to me. If it fails to start due to suck it is not gonna start again after I/2 hour. The air doesn't magically disappear by sitting a little while - it would have to be bled out again.

A diesel needs to turn over via the starter, some oxygen from the atmosphere and of course fuel. The fuel component is easy, you either have a clear stream or not. The primer is constantly stiff or not. I've seen some strange diesel behavior and always look to eliminate the fuel question first.

 

[OPUS1]

A diesel needs to turn over via the starter, some oxygen from the atmosphere and of course fuel. The fuel component is easy, you either have a clear stream or not. The primer is constantly stiff or not. I've seen some strange diesel behavior and always look to eliminate the fuel question first.

I agree with what you say about fuel Squash and have pretty much said the same thing above - find the run position and check for air at the bleed screw when the problem occurs. We went over the pump being hard as well - I asked if he has installed the new prime pump and he hasn't said yet ( doing so should eliminate that variable ). Your idea about running a hose between the bleed screw and pump seems like a good one.

I also agree that a diesel can have some really strange issues. I just can't imagine air disappearing on its own.

He hasn't posted any photos of the fuel control at the pump so it's a guessing game but like I said above he also has to be sure that things are in run position when the problem occurs ( otherwise it won't start air or not). If it's a mechanical diesel then that should be fairly easy. If he wants to truly diagnose the problem he needs to figure it out right when it occurs by employing these suggestions and not just wait for 1/2 an hour and start again.

 

[franklin40]

so i checked the solenoid when it wasn’t running to see if i can hear a click as you’ve mentioned to do. it was clicking. it’s all internal though so there’s no way to see from outside if it’s open or closed.

unless i’m missing something here there is nothing that moves on the outside of the pump.

as i’ve said before i’ve never had “firm” primer but when i crack the bleed screw (at the time when it’s not running) i have fuel when pumping the primer (didn’t change it out for a new one because i was given the wrong one). again while it’s not wanting to run i cracked some injector lines while cranking it and i have fuel dripping out so it seems like the solenoid is ok because fuel is getting to the injectors. the only thing i haven’t done yet because i haven’t had time is get a clear line from the primer to the pump to see if there is air. otherwise i don’t know what else to do.

again. i’m new to there injection pumps. if someone can explain how to check the “run position” on the solenoid please give me direction.

i’m only giving the 1/2 hour wait as info that may or may not be helpful in making the diagnosis. i’m not interested in sitting every time it happens but i have tried employing the suggestions when the symptoms are happening and have not yet been able to fix my problem

oh and for sake of complete info there doesn’t seem to be any vacuum at the fuel cap when it’s running as that was a question asked earlier too

 

[OPUS1]

so i checked the solenoid when it wasn’t running to see if i can hear a click as you’ve mentioned to do. it was clicking. it’s all internal though so there’s no way to see from outside if it’s open or closed.

View attachment 3025805
unless i’m missing something here there is nothing that moves on the outside of the pump.

as i’ve said before i’ve never had “firm” primer but when i crack the bleed screw (at the time when it’s not running) i have fuel when pumping the primer (didn’t change it out for a new one because i was given the wrong one). again while it’s not wanting to run i cracked some injector lines while cranking it and i have fuel dripping out so it seems like the solenoid is ok because fuel is getting to the injectors. the only thing i haven’t done yet because i haven’t had time is get a clear line from the primer to the pump to see if there is air. otherwise i don’t know what else to do.

again. i’m new to there injection pumps. if someone can explain how to check the “run position” on the solenoid please give me direction.

i’m only giving the 1/2 hour wait as info that may or may not be helpful in making the diagnosis. i’m not interested in sitting every time it happens but i have tried employing the suggestions when the symptoms are happening and have not yet been able to fix my problem

oh and for sake of complete info there doesn’t seem to be any vacuum at the fuel cap when it’s running as that was a question asked earlier too

for these reasons and the fact that it starts after 1/2 hour I suspect intermittent solenoid problems but like squash says you can run the clear line to confirm fuel flow and no air to eliminate that possible issue.

 

[franklin40]

from the photo above can you tell me if there is something i can actually test to see if it’s in the run position? maybe other solenoids in other engines are different but i don’t see any movement though i do hear it click. also why would i have fuel to the injectors with the lines cracked if the solenoid wasn’t opening?

thanks for wrestling through this with me?

 

[OPUS1]

from the photo above can you tell me if there is something i can actually test to see if it’s in the run position? maybe other solenoids in other engines are different but i don’t see any movement though i do hear it click. also why would i have fuel to the injectors with the lines cracked if the solenoid wasn’t opening?

thanks for wrestling through this with me?

Your situation reminds me of a story I heard from a friend a number of years ago who was working in a big shop filled with excellent journeyed mechanics with lots of combined experience. One of the mechanics trucks had an intermittent electrical gremlin that the whole group of mechanics took turns trying to solve and none of them could figure the problem out. So one of the young mechanics had the idea to basically hard wire the test equipment in and mount the meters on the dash. Then he told the owner mechanic to check the meters as soon as the problem occurred. Nothing happened for several weeks of driving but when the problem did re-occur the owner checked the meters immediately and was able to determine what the issue was.

How would this apply in you situation? First of all lets go over how the solenoid activates. 12 volts is applied to open the solenoid when you turn the key on. And you might have 2 -12 volt lines coming in - one for start which puts it in overfuel mode (when the starter is cranking) - then one for normal run position when the key is on. Then you shut the key off and the 12 volts stops and the solenoid closes and the engine shuts down. Next determine which wire is start , which is run and which is ground and label them - or make a wire color schematic for future reference. You should be able to do this with your 12 volt meter. Find which wire is hot when the truck is running ( and should be 0 volts when the truck is not running). Then keep your 12 volt meter in the truck. The next time the problem occurs then leave the key on and test the correct wire for 12 volts immediately. I'm not sure if there is a actual ground wire from the photo - if there is make sure you are getting a really good ground ( no one has suggested this yet but poor grounds are notorious for causing issues like this). However, maybe the ground occurs when the solenoid screws in. What will this test tell - if there is intermittent power coming into the solenoid. If you found that there was no power from the correct wire then you could disconnect that wire and do what someone suggested above - have a wire ready to connect a temporary hot in from the battery and see if that does the trick.

If there is 12 volts feeding to the solenoid then again check for air at the bleed screw ( or have the clear tube on like squash suggested). If you've got steady fuel at the bleed screw ( a better indication than seeing fuel when you crack the injectors) then its gotta be the solenoid.

How does the solenoid itself work? The 12 volts activates an electromagnet that opens and closes which then moves a plug ( for want of a better term) that stops the fuel from flowing. one way to test the solenoid would be to bench test. Take it out and apply ground and 12 volts to the electrical connection that you have determined as the correct one. Then you should be able to see the plug actually moving - from the picture I would say it's on the left side. But we know it works some of the time so this test doesn't address the intermittent issue. Maybe the solenoid is sticky and doesn't want to move sometimes or a weak electromagnet etc. So it really takes you back to having be ready with the field test.

Good on you for persisting with this hair pulling exercise. When you're finished and have won you'll know a lot more about the system and will be much better prepared if it ever happens again in a remote location . You probably have one of the best diesels that Toyota ever built. But just like the big dogs - the mighty cummins and caterpillar diesels rocking 500+ HP a little air or other fuel disruption and their dead in the water - but nothing much else will stop them!

 

[franklin40]

i only have two wires to the solenoid 12v and ground so i don’t think there even an over fuel option. it’s on or off as far as i can tell so it shouldn’t be too hard to test.

my plan at this point is start easy then move to hard. i’m going to try the clear fuel line first to see if there’s air and flowing fuel. then i’ll work at getting the solenoid out and testing that.

another thought about it being electrical is that it never shuts off while it’s running. it just won’t restart again. that to me seems like it’s more likely (i won’t rule anything out) a weak magnet or sticky plunger. if it was wiring you’d think i’d loose power randomly at times while driving which would then shut the solenoid. just a thought

 

[OPUS1]

i only have two wires to the solenoid 12v and ground so i don’t think there even an over fuel option. it’s on or off as far as i can tell so it shouldn’t be too hard to test.

my plan at this point is start easy then move to hard. i’m going to try the clear fuel line first to see if there’s air and flowing fuel. then i’ll work at getting the solenoid out and testing that.

another thought about it being electrical is that it never shuts off while it’s running. it just won’t restart again. that to me seems like it’s more likely (i won’t rule anything out) a weak magnet or sticky plunger. if it was siri g you’d think i’d loose power randomly at times while driving which would then shut the solenoid. just a thought

good point about the not surging. The plan sounds good. If you can confirm the fuel in the clear line and have 12 volts to the solenoid at the same time then it should be the solenoid.

 

[franklin40]

i think i may have figured it out. i think it is the solenoid after all. while stuck yet again in a parking lot i had a light bike moment/ duh moment. i figured that if the solenoid was truly sticking maybe tapping on it might help it open. sure enough next try it fired right up. coincidence maybe but pretty likely. now i have to figure out if i can actually replace it without taking the pump off. it’s right between the pump and the block.

 

[OPUS1]

i think i may have figured it out. i think it is the solenoid after all. while stuck yet again in a parking lot i had a light bike moment/ duh moment. i figured that if the solenoid was truly sticking maybe tapping on it might help it open. sure enough next try it fired right up. coincidence maybe but pretty likely. now i have to figure out if i can actually replace it without taking the pump off. it’s right between the pump and the block.

is it possible to get a photo ? you would think Toyota would design it so you don't have to remove the pump to change the solenoid ?

 

[simonliew]

it is possible to change the solenoid without removing the pump,i bent the front part of my wrench,heat the wrench up with a torch and bend to shape,might have to grind some metal away too,

 

[OPUS1]

it is possible to change the solenoid without removing the pump,i bent the front part of my wrench,heat the wrench up with a torch and bend to shape,might have to grind some metal away too,

I had to do the same thing to remove my primer pump. I used a stubby wrench and ground down the open end so that it was much thinner to get it to fit. Then I used a piece of metal to tap the wrench to crack it loose cause I couldn't get the leverage on it due to the tight spot.

 

[franklin40]

we’ll i’m questioning it again. it’s got me stuck once again but this time no go with tapping on the solenoid. i’ve been told that if the valves are too tight they’ll cause a hard start. but that should be constant right. i’ve just done a valve adjustment about a month ago but i put them all in spec. i left them on the tighter side but still in spec. it fires right up when cold which i would think would be when the valves would cause the most trouble. oh well. i’ll keep at it.

 

[jellis]

Solenoids are tricky, just like all electro-mechanical devices. They will click but not properly actuate, or not far enough. I pulled my PPS valve on my steering box and it was clicking but not properly actuating, luckily I had a spare one to compare with that WAS properly actuating (the difference was very minimal). Force-actuating beyond it's normal capabilities and cleaning did wonders. I'd make the stupid special tool and pull the thing and see what it's actually doing and listen for good consistent clicks and watch for proper actuation. You can cycle it 100 startups in a few minutes on a bench, all you need is one time for an improper actuation to know what's going on (wire it up legit with a good switch and clips to isolate the solenoid and not your janky test fixture as the problem).

What else could it be? Do you still need glow plugs up there this time of year that far north?

 

[OPUS1]

 

[franklin40]

no glow plugs haven’t been needed for three months now. it an all or nothing problem it seems. when it fired up it just takes a bump of the started and it runs great. when it doesn’t it just cranks and cranks but no fire. when it’s running it runs like a top. no smoke no hesitation no misfire no fluctuation in rpm. absolutely nothing. just getting it to start. that why i keep coming back to the one item that makes it start. problems with the rest of the fuel system would i think cause problems even while it running. valve adjustment would to the same i would think. it would be a more co start problem. i would assume the worn injectors would cause some of the other symptoms i’ve mentioned above. i have a new solenoid ordered. i’m still going to do the clear tube thing as it’s really the only other thing i haven’t fully ruled out. i jus t haven’t had time to stop at a store for some clear tube! kids activities after work have left me running like a mad man. i have some holiday time coming so hopefully it’ll give me time to work on it again. for now you guys just get to hear me complain about getting stranded.

 

[jellis]

Be careful with clear tubing, it's not rated for fuel use so don't use it long-term. It was installed on mine when I bought my truck, then a year later I came out to my idling truck in a parking lot with fuel spewing EVERYWHERE because it had finally cracked. Fortunately I was in a city at the time and could limp over to a NAPA and get replacement tubing, I had just been WAAAAAY out in the desert with my family where this situation could have been serious.

Nice video there Opus, thanks for posting it.

 

[franklin40]

lol. yeah i have it in mind to use it just long enough to confirm if i have air in the fuel and proper fuel movement. i won’t be leaving it on

 

[Squash]

Be careful with clear tubing, it's not rated for fuel use so don't use it long-term. It was installed on mine when I bought my truck, then a year later I came out to my idling truck in a parking lot with fuel spewing EVERYWHERE because it had finally cracked. Fortunately I was in a city at the time and could limp over to a NAPA and get replacement tubing, I had just been WAAAAAY out in the desert with my family where this situation could have been serious.

Nice video there Opus, thanks for posting it.

Carry the original on board.

 

[Squash]

Get a hot wire made up and energize the solenoid. You could add a rocker switch in the cab. Grab power from a known secure source and bypass the ignition.
If you hot wire the solenoid you can then extrapolate that it is probably an electrical problem from the ignition or a crapped out solenoid. End of the guessing game.