Cold Starts Problem

[buddabeast]

Hello people,

I have a new LD28 in my Laurel but it doesn't stay running on cold mornings without using the accelerator. My old LD28 had no issues idling away even on the coldest mornings.
Might there be differences in the fuel pumps?
My old Ld28 IP and new IP can be seen on this link:
http://nissandiesel.dyndns.org/viewtopic.php?t=3223

Thanks!

[plenzen]

Does your new IP have the CSD on it? If it does, then set the cold idle screw in further to slightly open the throttle when cold. Not too much as it will over fuel the engine when cranking. I just fought with this on my VE pump on my SD25. When I had it rebuilt, the shop had set this measurement/setting to what the book said, however, for my truck, it was too much and I had to adjust it. Works fine now.
That adjustment can be seen in your photo of your original IP pump just below the ball stud that's sticking up. It has a lock nut on it. Best adjusted when engine is stone cold. Wind this screw so that it is just touching or 1/2 turn past just touching and try from there. It also depends on how cold it is when you make this setting. I would say for this time of year, when it only gets to 8 - 10 C at night, then just touching will be enough. When the engine is warm it should move further away. I say "should" because those CSD's are notorious for air locking and remaining in the "cold" position for a long time. Once the air is out they move a lot faster. You can tell if there is air in the CSD by checking it when the engine is at operating temperature. The CSD should be hot, coolant temp hot. If its only warm, or if you come back from a drive and its cool to the touch it's air locked. It's a proper SOB to get it to "burp" but eventually it will.

That is what I think is happening

HTH

Paul

[asavage]

Here's the picture of the original engine's IP, according to your other post:



That cylinder at the bottom of the picture with the two 10mm coolant hoses on it is the Cold Start Device ("CSD").



Does your new engine have a similar CSD?

If so, is it operable? They are noted for becoming corroded and no longer moving. Check the CSD's plunger with the engine cold and with it hot, and see if it retracts any distance when the engine is up to operating temperature.

[buddabeast]

Ah yea I thought it might be that device which helps with cold starts. Yea nah my new IP doesn't have that CSD. I think LD28s with the stock oil cooler don't have the CSD but LD28s with the oil filter directly on block do have CSDs on their IPs..
Thanks for advice.

[asavage]

Ah yea I thought it might be that device which helps with cold starts. Yea nah my new IP doesn't have that CSD. I think LD28s with the stock oil cooler don't have the CSD but LD28s with the oil filter directly on block do have CSDs on their IPs..

In the US, that's not true. All the automotive-spec LD28s have oil coolers, and they also all have CSDs here, because most diesels need a small timing advance for reduced smoke and misfire when cold.

That lever that the CSD operates? It doesn't just prop the idle, it goes inside and rotates the plunger cam, giving some timing advance, at low RPMs only.

The one in your picture is what I call the "later style". In the US, the '81-82 had a different style CSD. See pics of my brand-new LD28 injection pumps. This is the "early style":



If you're interested in learning more about the CSD, I wrote a bunch about it back in 2008.

[buddabeast]

Cool thanks asavage, do you have a write up on how to change an IP? I might give it a go, maybe just with the engine manual seems clearish enough.

[asavage]

No, I don't, sorry.