Rough first starts in all temperatures...

[alti2d]

Looking for a little help to get pointed in the right direction... hoping that someone will have some things to suggest.

When I start the van in the mornings, the engine catches quick, but I get a fair amount of white smoke (enough that passing cars have slowed down to ensure there's no fire), the engine lugs along at 500 RPM unless the throttle lock is used, and eventually it smooths out and RPMs increase at idle without the cable lock used. This is at outside temps of around 15 C. This was happening all through the winter, though I attributed it then to the colder temps, but I can't blame it on that now.

I replaced the glowplugs last fall, have no problems with the actual engine catching, and I do wait for the glowplugs to click on then off. When the van has been warmed up or has been running around town the start is much better.

I'm thinking that due to all the white smoke, there's unburnt fuel in some cylinders, but with new(ish) glowplugs that shouldn't be an issue.

I haven't done much poking around, I wanted to have a some direction to go in before doing that.

Any ideas would be appreciated. :)

[Firesong]

Did putting new glow plugs in it make a difference at the time?

[robbieg]

Make sure there's power going to your glow plugs. When I was replacing my glow plugs, it turned out they weren't getting any power (the cord had corroded off in my case.

Also the glow plug temp sensor could be the culprit, they could be disengaging too soon?

[psilosin]

If its happening at 15oC it isn't the glow plugs.

Most likely an air leak. Since it tends to happen most pronounced in the morning (longest time sitting) and gets better as the van warms up it is most likely a seal rather than a hole in a line. When sitting the seal shrinks and air gets in, when it runs for a while the seal swells back up and problem more or less goes away. There should be many many threads here on the usual suspect seals on the L300.

[alti2d]

Thanks for the tips.

I'll have a look at the glow plugs, just in case, but the new plugs did seem to make a difference, at the time, though it was already Fall and 0C ish when I did that work, so it well could have been more in my head than actually making a difference.

I'll have a look for topics on L300 seals as well, and start to look into that.

Any other thoughts or input is welcome. Thanks for the replies already.

[yojimbo]

Changing the glow plugs wont necessarily fix a bad bus bar connection somewhere, so thats one possibility, another is, and I havent found this to be the case but the engine behaviour makes me think it is, is that the engine has a cold start sensor which adjusts the pump timing until its warm. Previous diesels I've had, and as old, have had this, and is supported due to an engine note change after around 5 minutes of running. A coolant sensor in the block alters the injection timing until it reaches a certain temp, and then sets it to its normal running timing. Now I've never yet found this written down, but, from the behaviour I do expect there is something else going on, that when the engine gets warm, something changes, and if its not working right, it might cause this.

[Growlerbearnz]

The Delica's injection pump has no way to change the injection timing based on engine temperature. At least, not on my '91.

On my '91 the entire cold-start coping strategy is for the controller to pulse the glow plugs once the engine is running.

[yojimbo]

Any idea what it is doing then? I've always heard it do it, and just figured it was timing changes like other diesels.

[Firesong]

Remember there is some alteration due to the vacuum lines.

[Growlerbearnz]

My '91 just runs a bit clattery and powerless until it warms up, with the rough running getting gradually less as the engine heats over the course of 30 seconds or so. The only thing I can think of that changes after 5 minutes would be the EGR opening: but that's on my engine.

The only vacuum line on my pump is to the aircon idle up vacuum can, but that only changes the idle speed not the timing.

All Bosch/keiki pumps like ours advance the timing with engine speed. Some of them have an additional external timing adjustment- the blanking plate at the end of the timing piston is replaced with a temperature or electrically operated plunger device which pushes on the piston through a spring. I've not seen one of these devices on a Delica before, but that doesn't mean they don't exist. It may be that they are fitted to earlier or later models that don't have the super quick glow plugs.

As for white smoke at startup, it's usually due to a failed or inoperative glow plug, or less commonly low compression or a stuck injector.

[alti2d]

Thanks all for the tips. I've been busy so haven't been able to get much chance to do anything with it. I'll post back when that chance comes

[cloudchaser]

Mine did the same, and tried many things until I did what the previous owner had done - add diesel fuel conditioner (quite a few different brands available) to each fillup. Doesn't start like a good gas engine, but close.