1HD-T glow plugs - info needed

[asutherland]

Ok guys, please school me on the super glow's in the 1HD-T in my HDJ81.

What I think I understand...

- Superglows mean no or little wait before cranking over. Hardly ever see the "glow plug" light on the dash.

- Turn the key onto Ign. position, truck measures the temperature of the coolant and decides whether or not to put voltage to the glow plugs while starting.

- If it decides the coolant is cold enough, it puts 12V to the glow plugs and the truck starts.

-Then reduces it to 50% current (little unsure here???) until the coolant temp reaches a certain value.

- I can test the glow plugs by removing them and checking impedance across them with a multimetre. Low to zero resistance means they are good, infinity means they are bad?

- Do the glow plugs work all the time while the truck is running??? Or only if the coolant temp is below X value?

thanks!

 

[bj40green]

All the info you're looking for is in this thread: -►
which plugs should i be running-b-2b-3b-h-2h-diesels

All plugs should be around or under 1Ω (ohm). More than 2 Ω = bad plug(s).
The glowing process stops after a certain amount of time. The "computer" (read timer) is taking care of that process.

Rudi

 

[Wheelingnoob]

Ok guys, please school me on the super glow's in the 1HD-T in my HDJ81.

What I think I understand...

- Superglows mean no or little wait before cranking over. Hardly ever see the "glow plug" light on the dash.

- Turn the key onto Ign. position, truck measures the temperature of the coolant and decides whether or not to put voltage to the glow plugs while starting.

- If it decides the coolant is cold enough, it puts 12V to the glow plugs and the truck starts.

-Then reduces it to 50% current (little unsure here???) until the coolant temp reaches a certain value.

- I can test the glow plugs by removing them and checking impedance across them with a multimetre. Low to zero resistance means they are good, infinity means they are bad?

- Do the glow plugs work all the time while the truck is running??? Or only if the coolant temp is below X value?

thanks!

Not sure on the 1HD glow system but I have worked a bunch on my brothers 2H.

Glow usually is only on for a set amount of time depending on the temp (coolant). Super glow usually pushes a higher voltage than the plug is rated for to get them glowing fast and hot. It then drops to (usually) the rated value of the plug for the remainder of time to keep from blowing the plugs.

Infinity means bad on a residence check.

Glow plugs are only used for a short period of time to warm the cylinder once the engine is running they are not needed anymore.

On my 4BD I did a bench test of the plugs hooked up to 12v to see how long it took for them to get red/white hot. So on my setup when its cold enough to require a glow i know how long to manually glow for to get them good and hot. No coolant temp sensors or anything.

Cheers

 

[BCR4619]

I had read somewhere on here that the Glow's don't glow until its below 5* C (1HD-T). Out of all my years driving the truck the glow light only stayed on longer than a second a hand full of times, obviously on a cold winter night

 

[Malahki]

I don't see 1HDT's listed in the link above. So what are the best glow plugs to run in my 1992 HDJ81??

 

[bj40green]

I don't see 1HDT's listed in the link above. So what are the best glow plugs to run in my 1992 HDJ81??

The FSM says: 19850-64031 11V glow plugs.

Rudi

 

[asutherland]

Time to revive this thread. Yesterday it was - 2 *c when I started the cruiser in the morning. No issues starting, just fired right up and idle normally.

Today, though, it was - 16 *c. I left it on acc until the glow plug light on the dash disappeared, and then a few more seconds, which was about 10 secs in total, then fired it up. It cranked like crazy (2 new group 27 batteries) but would not catch. I tried again, this time holding my foot against the throttle and coaxing it, cranked for a full 8 seconds and finally chugged to life, sputtering and pissing out white smoke.

I let my foot off the throttle and the revs dropped and it nearly died, so I put the hand throttle on 1,100 rpm for about 2mins. Took the hand throttle off and it stalled. Repeated the above again, this time for longer, and was fine.

Note: my ACSD is removed.

I left the cruiser outside work in the same temps for 5h hours this morning and at lunch tried to start. It fired up perfectly right away.

Bad glow plugs? Air in fuel line? Ideas?

 

[Douglas S]

Sounds like an air leak letting the fuel drain back to the tank when it sits. Mine did it when it was cold until I replaced all the rubber lines in the fuel system.

 

[Wheelingnoob]

Move to a warmer place......I hear Victoria is nice.....

 

[asutherland]

Douglas, where exactly do you think the leak would be? It only did it when really cold? Do you mean air is getting into the system?

Tomorrow morning maybe I'll test that theory by manually priming the system before attempting to start. But would it run for a couple minutes really rough like that?

 

[Wheelingnoob]

Douglas, where exactly do you think the leak would be? It only did it when really cold? Do you mean air is getting into the system?

Tomorrow morning maybe I'll test that theory by manually priming the system before attempting to start. But would it run for a couple minutes really rough like that?

Yeah I cant see a 10c difference in air temp making it all of a sudden leak back or let air in?

Can you test the glowplugs per the FSM?

 

[Douglas S]

Yeah I cant see a 10c difference in air temp making it all of a sudden leak back or let air in?

Can you test the glowplugs per the FSM?

Mine would be fine at -5, not so fine at -15.

I changed all the supply lines. The lines from tank to hard line and then from hard line to filter and filter to IP. The filter housing itself is also known to leak air.

 

[asutherland]

Mine would be fine at -5, not so fine at -15.

I changed all the supply lines. The lines from tank to hard line and then from hard line to filter and filter to IP. The filter housing itself is also known to leak air.

This is good info, it's exactly what I am experiencing. Fine at - 3 and terrible at - 15.

The fact my recirculating coolant heater (block heater) does Nothing to help this situation would also support this theory.

What ID size hose did you use and how long piece? Maybe I'll pick some up on my way home.

I'll also test the glow plugs, a good idea.

 

[Douglas S]

IIRC it was 3/8", but had to be stretched on as it is slightly smaller than the factory 10mm fuel line.

A good way to check if this is your issue is to temporarily install some clear line in place of the rubber in the engine bay so you can look for air bubbles or an absence of fuel.

 

[Wheelingnoob]

What kind of block heater? If its the kind that goes from the block coolant drain to the heater line those are suppose to work great. I have seen one warm up a 6BT to almost operating temp in 3 hours think it had a 2000W heater.

I see where the difference in temp would play in at -3c the fuel is flowing nice and easy but at -15c its maybe causing an increase in suction and sucking air in through an otherwise good connection. Does your truck have the heated filter head? I have hear those can fail and allow air in when its cold.

The clear line is a great idea and I have used it a few times to narrow down issues.

 

[asutherland]

Yes and yes to both questions...

 

[Squash]

A 24v starter 1hdt should fire up even without glow plugs at that temp. Use the clear hose between your fuel filter and IP. to ensure you are not sucking air. Mine has been in place for at least three years now(carry a spare)
Some engines like a little throttle some are fine without so experiment

Fast way to check glow plugs is to leave them in place but remove/manipulate bar connecting them to one another. The first three are easy after that just change them all because you are half way there.
Using your 12v test light clip on to positive battery post an touch top of glow plug with pointy end.
A light means working, nothing means dead. Change all at the same time if in doubt

 

[asutherland]

Update... So last night I left the truck plugged in for the block heater. This morning, I opened my drivers door, turned the key to ACC to start the glow plugs, opened the hood and manually primed the pump about a half dozen strokes.

Got inside and she fired right up no problem. Took about 1.5 seconds of cranking to turn over, and didn't shutter at all. The rpms were a tad low though (probably from no acsd device) so I used the hand throttle to up them to just over 1,000 rpm.

While I waited for the truck to warm a bit I noticed the rpms were slowly dropping. In about 3 minutes, they had reached 500 rpms. I upped them again using the hand throttle, and within a minute they were back down. I let off the throttle completely and the truck stalled.

Then when I went to start it again, it was like yesterday, instead of 5 mins before... Shuttering and stuttering to life, only kept alive by my foot on the throttle, sounding and feeling like it was running on 5 cylinders.

After a few more minutes of that I noticed the temp gauge had starting to move up a bit so I tried removing my foot from the throttle, the truck was then completely fine on its own, idling where it normally does at about 800.

 

[bj40green]

I don't know much about diesels other than driving them and that you have to switch to winter diesel in time.
Teach me: What is an "acsd device" ?

Is it possible that there is a water pocket/bubble somewhere in the fuel system that blocks the flow partially and when the engine and tubing warms up the problem disappears?

Just thinking.....

Rudi

 

[Squash]

ACSD is to diesels what a choke is to gas engines, except it advances the timing via thermo wax.

Sounds like a fuel issue. Get some clear fuel line first, line should be free or air bubbles. Your primer should stay stiff. if soft you have air, so work from IP, clear hose, fuel filter, line from tank.
Deisel engine IP's love to suck air. Air= No fuel...No fuel= no run!

How long ago did you remove the ACSD? there is a filter under the fuel solenoid, but start with clear hose first.