1HDT idle to high??? (1 Viewer)

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Joined
Sep 4, 2007
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56
Messages
284
Location
Edmonton, AB
Hey guys....

We are finally coming out of the deep freeze, and my cruiser even when warmed right up still idles at 1000 to 1100 RPM. I think this is way to high, but I'm not sure. If I remember correctly last summer it was around 600. I did drive it all winter, but assumed the higher idle was because of the cold weather. I'm a bit of a newbi when it comes to diesels...... Is there a choke on a Diesel like on a gasser? My fuel mileage seems to be fine, so I don't think that it would be a stuck choke (if there is such a thing).

The truck is a 1990 HDJ81 with a 1HDT and about 230 000 Km. The only mods that might affect this is an after market metering rod in the fuel pump. And yes I do have a pyro, and all is well on that front.

Any thoughts??

Thanks

James
 
Yes, I agree, but I would like to know the why the change? What caused it to increase in the first place?

Any thoughts????
 
Hi,
l have seen a few with the ACSD stopped working,some even have diesel leaking pass the shaft of the ACSD and some the Ò ring where the ACSD meets the pump,if the ACSD is not leaking from the shaft o ring,you can adjust the screws to the left and front of the IP to lower the idle speed,there are two adjusting screws you can use,l am not talking about the idle adjusting screw.
Simon
Winnipeg
 
for starters, what's the ACDS? (sorry, don't know all the terminology yet).... second, how do you tell if it's leaking?

I gather since no one is mentioning it there is no choke?????

Thanks guys...

James
 
for starters, what's the ACDS? (sorry, don't know all the terminology yet).... second, how do you tell if it's leaking?

I gather since no one is mentioning it there is no choke?????

Thanks guys...

James

ACDS = advance cold start device. It advances the timing and increases the idle to make cold starts more emissions friendly.

Its on the injection pump and has 2 small coolant hoses connected to it.
Heated coolant melts a thermowax container that releases a lever allowing the fuel pump to return to its warm position.
Yours maybe stuck on.
A few on the forum have disconnected theirs.

No choke on a 1HD T. Some of the older toyota diesels did have something like a choke that limited the air intake.
 
Not sure "heated coolant" would help when it's starting in -40 C up here!!! takes 20mins to get that coolant heated...... Will have to check that out, thanks.....
 
James,
I would say 90% it is your ACSD acting up. Get it removed and be done with it. My truck had the exact same problem and I had the ACSD extracted and a blanking plate installed and the RPM went down to 800 RPM precisely. Don't you go messing around with the idle adjustment screws and stuff, you will end up making more problems for yourself.
Search ACSD on the Diesel forum and you will find lots of posts, including a few from me when I had the problem..


Hey guys....

We are finally coming out of the deep freeze, and my cruiser even when warmed right up still idles at 1000 to 1100 RPM. I think this is way to high, but I'm not sure. If I remember correctly last summer it was around 600. I did drive it all winter, but assumed the higher idle was because of the cold weather. I'm a bit of a newbi when it comes to diesels...... Is there a choke on a Diesel like on a gasser? My fuel mileage seems to be fine, so I don't think that it would be a stuck choke (if there is such a thing).

The truck is a 1990 HDJ81 with a 1HDT and about 230 000 Km. The only mods that might affect this is an after market metering rod in the fuel pump. And yes I do have a pyro, and all is well on that front.

Any thoughts??

Thanks

James
 
My idle was low too so I adjusted it a little to about 1000 RPM.
In the summer when the AC motor kicks on the vehicle shakes quite a bit...I thought this was because of the idle being too low.
It still shakes but not as bad with the higher idle.
 
Hmmm, so mine idling at 500 ain't normal then. Good to know.

No, not normal.
I would say, disconnect the ACSD leaving the coolant hoses still attached to it (you have to put the blanking plates in place of the ACSD though) You will know right away if it makes a difference.
If it doesn't then put it back on and seek the cause of the problem elsewhere..But I am putting my bet it is the ACSD.
Those JDM trucks never saw cold weather like here in Canada and after a few months in our climate, the wax pellet inside the ACSD tends to lose its properties and messes up with your RPM whether higher or lower..
 
Thanks, I will try that. Is there a particular place to get a blanking plate, or is this something I have to construct?

James
 
Not sure "heated coolant" would help when it's starting in -40 C up here!!! takes 20mins to get that coolant heated...... Will have to check that out, thanks.....

Thats what Im saying,when it heats up, it goes to its warm posiition even if it does take 20 mins.
Yours maybe stuck
 
Sorry I read that wrong! I thought the coolant was heating the fuel or something.... Dyslexia lures!!
That makes far more sense.
 
Thanks, I will try that. Is there a particular place to get a blanking plate, or is this something I have to construct?

James

You could build your own, but it is actually cheap to buy. It is a very common part in most diesel pumps, including Bosch and Zexel, most diesel shop carry it. Search the threads for ACSD . I attached a pic for you (was posted by a fellow member, credit to him), which you can print and take it with you to the diesel shop so they know what you are talking about. I also attached a second pic showing a similar plate installed in what apperas to be a VW Bosch pump just to show they are interchangeable.

You will need an O-Ring, Two Allen (or Torx) bolts and the plate itself. I found a shop here which could source the parts for 23 C$. I had them fit them too because it was too bloody cold to do it in my unheated garage..
1HZ PICS (Fender Side).jpg
Plate from Bosch pump.jpg
 
search for blanking plate
on this forum, lots of info.

pretty easy job to remove the acsd and fit the plate. several people (myself included) have done it with good results.
 

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