l300 low idle

[joebillhill]

Looking for a little advice on my l300. It's an 89 4d56 turbo and has a very low operating/neutral idle. Starting it cold it is low, <100rpm and very shaky, I remedy the situation by adjusting the manual throttle to get it up around 1000 to warm up. when warm it still idles around the same rpm though not shaky. When i throw it into drive or reverse it will drop just slightly (can't go much lower) and occasionally starts to become shaky. I've noticed in reverse it seems worse and if I turn the steering wheel there are points that the shaking becomes really exaggerated.
Doing some research it seems like the normal idle speed is right around 750 so I would think that I need to just adjust the throttle cable? Simple as that, or are there any special steps I need to take to do this?
Thanks
-Joe

[alpo51]

my 91 l300 does the same,shuddering like an old bc ferry leaving whoreshoe bay on start up, I just crank up the throttle on dash a bit n its smooth at around 750-800ish rpm. if idle is to high your on the brakes to much tho, adjustment in eng compartment shud be simple I just havnt bothered turning a screw yet, but I will try soon

[FalcoColumbarius]

I have a remote start (that I had installed) so what I do at the end of the day is set my hand throttle at 1100 RPM, as the engine is at full operating temperature. At first start up of the day I warm the engine until the temp needle shifts, typically four minutes. This is when the thermostat opens and the coolant is circulating. I started this protocol when I came down to my wagon one morning and she was rattling around at 250 RPM.


___________^
As you look at the engine, in the bottom left corner you see a screw. This is your idle adjust. Once your motor has warmed up, lift the passenger seat. With the motor running you can rev the engine with the triangular doohicky that the screw is pressing against. Have a friend sit in the driver's seat to monitor the RPM as you work with the throttle (doohicky). Tell your friend to let you know when the needle is pointing at 750 RPM, then set the screw to hold the throttle there. This is idle, but remember that the motor must be at operating temperature when you do this.

My motor is a '92 but I don't think there are many differences between the '92s and the '89s. When you get to know these machines you will appreciate how simple they are. I hope this helps... smiles.

Falco.

[joebillhill]

Really simple. Thanks Falco. It is interesting though that for the life of me I cant get it to hover at 750. Brought it up from ~500 and right around 600 or so it skyrockets up to 1100. As I slowly bring it back down I got it to ~800-850 and then it just plummets to 500 again. Definitely better than it was but any thoughts on why it doesn't like 750?

[yojimbo]

This isnt normal in my opinion. Once mine is running and shaken off the coldness of the start, idle is up around 750 and stays there till the engine note changes and beyond. From memory anyway, its been offroad a while. I suspect that a lot of this is treating symptoms of something else, but I dont know what. I suspect there are sensors that should be managing the idle somehow and some thing has failed. But I do t know what. Im not even sure what causes the engine note to change. I thought it was timing changes at cold as ive seen on other diesels, but I am told its not.

[Lapprentis]

I understand 750 RPM as recomanded idling speed. Now, I did set mine at this RPM in park position (automatic transmission) but mine did drop a bit (about 50 RPM) when engage to Drive or Reverse. Is it normal ? Also lost another 50 (?) when AC and Fan On. Normal too ? Do not come close and never died but shake more....

Much Thanks

Lapprentis