Help 4JB1T running rough when cold

[Rolledeo]

geeves wrote:It really is a case of is it annoying enough to fix. My 2.8 bighorn did it for 19 years before tinworm sent it to the wrecker but we might be talking different things. The 2.8 was just rough when started and when really cold wanted to idle at 500. Often when cold it would start then stall almost straight away . If the wire was taken off the thermostat housing that controlled the cold start the glow plugs would glow 10 seconds and it would start like it was fully warmed up. There might be fuel and timing tweaks that could make it better
My Wizard had symptoms more like Robs description but its a 3.1 Start fine then after a few seconds start to miss until the first time you got it over 1500 revs. New injectors and turbo improved it but not fixed. Pump rebuild for a leak made it run like new. I put up with it for 5 years and if the pump hadnt leaked it would still be faulty. Pump rebuild by the professionals wont leave change from 1200

Mine definitely sounds like what you described there for your 2.8, I may as well wait until my new injector pump shows up and see how it goes when its cold once that is installed, if its still rough then ill take a look at wiring the glow plugs to stay on for a longer time before it starts

[LeKestral]

My 92 Mu does the same thing.
I'm noticing the cold choke ( Butterfly valve on the top of the intake), the vacuum line that controls the valve is bust.
I've seen other engines where the choke quickly closes then opens when started and they don't run rough.

Could this be my problem?
I'm going back and forth with the manual choke on the dash constantly in the morning to get the revs right as the 4jb1's are supposed to idle at +/- 750rpm right?

Then i'll drive off. Engine will warm up and suddenly my dash choke is set too high and affecting my acceleration and braking... So annoying!!!
I have no idea about the condition of my Injector pump, but it smokes a tiny bit of very light bluish smoke when it first starts.

[turnturn]

The thing that you are adjusting is not a choke. It is simply a fast idle control, sometimes called a thumb throttle. It is connected to the accelerator pedal.
I use mine every morning to adjust the throttle up to where the car runs smoothly while warming up and then wind it back down again when I get down the road a bit.

[geeves]

The butterfly in the inlet is for overboost not cold start. If you have seen one for cold start it was on a petrol car and probably a long time ago.
The book says the knob is for cold start but Ive only ever used it to hold higher revs when winching Careful throttle use works just as well and the engine should settle in a few minutes anyway.

[geeves]

I see your in Wellington I might be able to have a quick look Im up in Newlands

[LeKestral]

That would be great! Would be good to look over incase i'm missing something. I'm still learning all the mechanics of cars at the moment.
Geeves, could you message me a mobile number i could contact you on and arrange something?
Thanks