12h-t not starting (1 Viewer)

[Quat]

Hello,

I've been wrestling with my 12h-t not starting for about a week. I believe I have air in the lines after sending the injectors to be serviced. I just replaced the primer pump with a bosch because the original was leaking quite a bit and bled the filter, and I've so far bled 5 of 6 injector lines at the injector.

I have puffs of smoke from the tail pipe when I crank it over.

Before I pull the crossover lines and heater pipes all apart again, I thought I would at least type things out partly as a sanity check, and hope someone might have some insight.

I had also pulled the alternator, nothing needs to be done to re-establish vacuum that I can find in the service manual?
I also adjusted the valves, without the alternator, a/c (non existent) or steering belts on. Timing should remain correct as it is all on the gears inside?

I noticed the actuator for the intake isn't moving at all when I try to start it, I assume it doesnt actually need to move until shut down as open seemed to be the default position when i had it all apart.

Is there a way to bleed or attempt to bleed the injection pump itself?

Thanks!

 

[Dave 2000]

If you did not move the injection pump altering the timing, then perhaps you have diesel lines wrong somehow?

If you have diesel at the injectors and you have smoke then diesel is getting into the chambers and it should start, I would check the glow plug circuit is good as well, just in case.

regards

Dave

 

[Quat]

Thanks, I'll see about double checking the timing on the pump. I didn't take the lines off the pump and they are pretty hard wired to the cylinder they go to.

The other thing that came to me early this morning is that when I got the injectors back, I received new injection seats. I did not find the old ones at the bottom of the holes for the injectors, and assumed they must have been stuck to the injectors when I sent them off. But it is possible there were none in the first place.

 

[Dave 2000]

If the pump was not disturbed then the timing will be the same as it was before you removed the injectors. There should be seats and more often than not they get stuck at the bottom of the bore, having said that, assuming you are not loosing compression from any that are missing or not seated properly the engine should still start even if on only four or five cylinders.

If the weather is a little chilly where you are and the glow plugs or wiring are not up to snuff, this could also be an issue, did you remove any of the bus bar connectors or cables?

regards

Dave

 

[Quat]

If I didn't see the seats down in the bore and they were actually there, the injectors could potentially be sitting on two seats. They are at a uniform height above the deck, for whatever it is worth.

It has been 50F/10C overnight, I haven't tried to start it until after it has been 80F/27C for a few hours and air temp closer to 90F/32C.

I took the batteries out to remove the trays to swap the radiator. The only other wires I touched, at least that I can remember, were the ground strap off the low side battery connection, the wire that plugs in near the thermostat and the ground which attaches to the rear heater tube mount.

 

[Dave 2000]

To put it to bed, at least check you have a decent voltage at the bus bar on the glow plugs, or if you have the time remove the bus bar and check each glow plug. You can do it by checking the resistance but this can be unreliable, pull each of the plugs and connect across a set of batteries and check they glow red hot.

The next thing you can do is to put a drop of petrol in the air intake, now that is a drop! No more than a tea spoon full will cause the engine to start and rev for a few seconds if compression etc is good, this would be more than enough to push air out of the injectors and will also negate the need for the glow plugs to work.

You may find the engine stays running and all is well.

As an aside, were you OK with adjusting the valves? Not meaning to sound disrespectful but valves have to be done correctly, a little too tight and you loose compression preventing combustion, very tight you risk valve piston contact/damage.

regards

Dave

 

[Quat]

The 12ht has glow screens in the air intake rather than plugs, I'll give it a check.

Valves is a valid question. I only adjusted three of them and checked them twice post-setting them all to be sure. But it would likely be worth checking again when I get the cross pipes off.

Pumping on the hand pump a whole lot, it never seems to get difficult to pump like many threads seem to describe. It also feels like it softens up if I leave it for a while. At least at the most forward cylinder injector, I haven't been able to get fuel to come out of the line with just the hand pump.

 

[FJBen]

The 12ht has glow screens in the air intake rather than plugs, I'll give it a check.

Valves is a valid question. I only adjusted three of them and checked them twice post-setting them all to be sure. But it would likely be worth checking again when I get the cross pipes off.

Pumping on the hand pump a whole lot, it never seems to get difficult to pump like many threads seem to describe. It also feels like it softens up if I leave it for a while. At least at the most forward cylinder injector, I haven't been able to get fuel to come out of the line with just the hand pump.

you should be able to push fuel out the lines with the hand pump. That pump is notorious for leaks. You can replace with denso or bosch equivalent.

 

[Quat]

That is good news. To be sure, the hand pump will push fuel into and out of the injector lines?
I put a bosch pump on it a few days ago, as the stock pump was leaking badly. I'd hoped that was the only problem but it seems to not be.

 

[AussieHJCruza]

A 12HT doesn't have glow plugs - single glow screen in the intake and it won't fire that untill close to zero Celsius. I guarantee it's not the issue in this situation.

First port of call is to bleed it properly. The Bosch primer is a good start to getting that done. Having a mental blank now but I'm fairly sure that there's a bleed nipple on the fuel filter (if you don't know when the filter was replaced, replace now too) and pump the primer with this cracked until diesel with no air bubbles comes out. I also can't remember if there is a bleed nipple on the injector pump, from memory there isn't on the 12HT. If there is, repeat the first process. If not, crack the injector lines and crank the engine. I've found it beneficial to have someone pump the primer at this point too. Once you can see 'spurts' of fuel at an injector, tighten the connection. If it's an air problem, she'll start to fire on each cylinder as you tighten the connection. If there's fuel at each injector but no start then we need to start looking elsewhere.

 

[duncanrm]

I put a bosch pump on it a few days ago, as the stock pump was leaking badly.

The primer pump will not push fuel out the injector lines.

Given you have puffs of smoke it suggests its fuelling ok.. puzzling. You trust the people who rebuilt the injectors?

As previously discussed in this thread I would also be considering you've installed them injectors on top of two seats.

 

[Dave 2000]

Sorry I did not know it was a glow screen, but it will be easy enough to test. The OP had fuel coming from 5 of six injectors and smoke coming from the exhaust as he was cranking so fuel was getting into the cylinders, might be worth cranking and loosening injectors again until there is a good squirt of fuel? As above this will not push fuel through the pump and into the actual injector lines but will prime the pump itself.

Initially it was a non start after replacing injectors, then there was the valve adjustment and then the uncertainty about injector seats, so not getting the full story off the bat.

I have found with the hand pump that you pump with the ignition on, this seems allow fuel into the pump chambers a little easier, then the pump tends to stiffen up, if you leave it for a moment and then go back to it I also find that some pressure has been lost.

Also make sure your batteries are spinning the engine fast enough as well.

regards

Dave

 

[hj 60]

Did the shop use the correct service manual because 60 and 61 are different pressure, I think fuel is ok if you bleed so many times and maybe air is coming in but it should start roughly even with some air? no fuel/air bubbles leaking anywhere?

, I would pull start it because it seems to be almost there (but here on a farm that is easy to do so we dont think to much when a diesel is having a hickup) , if battery and starter are a bit on the end it might show now, also pour a gallon of boiling water over the intake and then try to start.

With my hj running engine the primer pump is impossible to push, fsm says about 30x push to remove air? 61 has return line so it should go back to the fuel tank.

always annoying when tring to fix it and end up with headache, good luck.

 

[Quat]

I appreciate all the help greatly.

I've run the primer pump more than 100x in a go, with the circuit closed and it didn't seem to make a difference.

This morning I got my hands on some clear tubing and hooked it to the bleed valve going to the fuel filter. After 50 pumps I still have a very small amount of very small air bubbles. I would not swear that they did not enter through the bleeder valve threading itself, the hose was rather stiff and it was 'breathing' the valve. I can't find any noticeable leaks on the return line or the delivery line, or any of the hoses. The tank pressurizes significantly with the changes in air temp.

I am noticing my starter initially kicks over the engine at about 500-600rpm but after a second at best it drops to 250rpm.

I plan to double (quadruple at this point really) check the valves today, which I'll only be able to do cold unfortunately. After that, I'll re-bleed all the lines at the injectors and then try either adding a bit of fuel to the intake or pull starting it.

 

[wedgetail]

AussieHJcruza is on the money I reckon. You really need to crank the engine with the injector pipes loose at the injectors. I’ve known diesels not start until the lines are bled (Perkins for example, but haven’t played with a 12h-t). I’d crack them all and get someone to crank it. Crank until you’re getting good squirts if diesel and no visible air (although this can be hard to spot). After getting two-three tight you may find it starts, then tighten the rest - they’ll bleed quicker this way! Give the starter a bit of a rest if you feel you’re cranking this *hit out of it.

You’ll have to be the judge of if those tiny air bubbles are an issue or not, on your description they may not be

 

[AussieHJCruza]

A 12HT usually starts from a quick hit of the starter, I personally wouldn't be trying to tow start or otherwise until we've worked out 100% that she's got fuel. If she does, then next check is making sure the intake shutter is properly open when cranking. If it is, then next stop is compression. A DI diesel shouldn't be hard to start. Question though, is it cranking fast enough to be able to bleed or are there battery/starter/electrical issues preventing this

 

[Indestructible 47]

I will say, in my experience the bosh primers take alot longer to prime the system than the genuine pump. I would just crack the injectors and crank it in 15 second bursts. Otherwise, the starter will get mighty hot.

 

[Quat]

She lives again! Thank you everyone.

Somehow a plastic bag got carried into or left in the crossover pipe (I'd like to blame it on the final act of the critter I evicted but it is probably my fault). As soon as I got that cleared out it fired up like snapping your fingers.

A big load off my mind to have it back in action.