Outer Limits 4x4 Board

Ill try and make a long story short, my 1hd-t injection pump shit itself and I dont want to spend the money to fix it at the moment.
I was given a 1HZ pump(history unknown) which I thought I would fit to see if it would get my truck running again.

I have fitted up the 1hz pump and fired it up. When I first started it, it ran very rough, would barely idle and was chugging out heaps of grey/white fuely smoke.

After having a think about it I figured 1HZ timing would be more advanced due to indirect injection, so I adjusted the timing screw on the pump to see if it would make any difference. I have adjusted it as far as possible and it has definitely helped, it is far less smokey and is running a lot crisper, smoke is now grey/black, but still to smokey to run it as it is.

My question is, what is the injection timing of 1hd-t and 1hz? I believe the timing for a 1hd-t is 4deg before TDC. What is it on a 1hz?

how many degrees of advance/retard adjustment can I expect using the screw on the pump? Will I get more or a larger increment of adjustment by rotating the pump body?

You will need to set static timing first, then put your advance screw back where it was. Plunger lifts between the two are quite a bit different as they use different cam plates.

Timing spec for 1hz is 1.03-1.09mm @ tdc, 1hdt is 1.29-1.35mm @ tdc


Andy

thanks Andy. I think I set the timing at 1.29-1.35 (it was a while ago) is this still going to be relevant with the 1hz pump in use on a 1hd-t ?

sounds like maybe I should set it at 1.03-1.09?