SD25 Hard start in cold, but starts fine warm

[Graeme]

Just purchased my first diesel, 1984 Nissan with the SD25, and am having significant starting problems in the cold. I bought a brand new battery (800 CCA) and it still is very difficult to start. I have managed to get it going with starting fluid and lots of cranking and once it does fire up, there is a large cloud of whitish smoke from the tailpipe.

Once it is warm is starts and runs fine. Even after a few hours sitting after running, it will start usually first go.

I replaced one glow plug as it was showing infinite resistance. The other three were all ~2-2.5 ohms. The new one is ~1.5 ohm installed.

I am suspect of the #1 relay, and am tempted to replace it, clean up all the connection points, then try again. Does this sound reasonable to somebody with more knowledge about this system than I? Any other ideas? It seems to me that the 'running' circuit is working fine, and it's just the quick glow function that is not working.

Thanks for your input.

[Nissan_Ranger]

Sounds reasonable to me.

I hope you've got the same plug as the rest of them. And don't be using ether on that engine. It WILL destroy the pistons and rings.

[elminero67]

If you need to use starting fluid to start it you should just sell me the motor because you will damage it ($$$) quickly!

Seriously though, diesel motors dont really want to start when it is cold, they need everything working well or they wont start.

Start with the easier, cheaper stuff first, like checking the relay to make sure the glowplugs are getting electricity, and that they are working.

Also, Im not sure where in BC you are, but if it gets cold you may need to use a block heater.

I generally dont even try to start mine if it is below 25 degrees.

Just remember, if it is too frustrating, just sell me the motor!

[waynosworld]

I agree with the above post, once it goes below freezing, diesels just don't like to start, my neighbors Dodge diesel won't even start below 26 or so. Installing a block heater is the best solution to your issue, I had mine on a timer, so an hour before I leave, the timer turns on the block heater, and when I go out and start it, it's like it's 70 degrees out, hardly misses at all.
You need a block heater, not a radiator hose heater, they are not the same animal, mine are put in the soft plug just in front of the oil feed for the vacuum pump.
NAPA sells them, part#605-3028
there is also another one, not sure which is the good one made out of brass.
NAPA part#605-3133
As mentioned above, ether/starting fluid is bad, I read somewhere that it can break your pistons.
I started mine when it was 26 degrees out this evening, it's hard on the starter having to keep turning it over till it will run on it's own.

[larrynsr]

If you still have the stock quick glow plugs (6volt style) take them out and replace them with the sd22 slow glow 11 volt model. The quick glow plugs heat quickly and then shut off. It does not provide enough time for the heat to soak in to the precombustion chamber. With the slow glow model, you will need to wire up a manual switch and cycle it for 10 seconds or so. I have these in my sd25 and it starts super easy even at 22 degrees f

[elminero67]

Or if you are as cheap as I am, a 100 watt light bulb under the hood works pretty darn well.

[Long-D]

Coldest morning I've fired up my SD22 since I've had it....I have one of those magnetic oil pan heaters (200W, the smallest size) which was on all night, and then for about an hour I propped up a 1000W cube heater under the front bumper pointed upwards. 3 tries on the starter with glow plug cycles in between before she would come up on 3 cylinders, then another 3 minutes or so before running smoothly on all 4. Mornings like today I kinda miss my Z22 gasser!

Graeme is that you with the very fine fleet of 620s off Sherman Rd?
I have the black 720 flatdeck.

[Graeme]

Great thanks for the info; I have thrown out my bottle of starter fluid

I replaced the relay (~$42) and she starts better, but still difficult in the cold.

I wish I was the guy with the fine fleet of 620s...

Another question: My temp gauge starts at the bottom, below the cold line, warms up as normal with heat blowing out of the vents, but only heats up to slightly above the cold line (~15-20% of the total range of the gauge). How bad is it for the engine to (presumably) run that far below its normal operating temperature?

I have never seen the temp go above this point. Is there a chance my gauge system is out of range somehow? Or is it more likely that my thermostat valve is missing or stuck open?

[Long-D]

I think that's normal....my gauge only goes just slightly above that marker line too even when it's at full temp and running at highway speeds. Pretty sure my gas 720 was the same, only about 1/4 of the scale when warm. The gauge going to halfway was a very rare occasion, idling on a hot day in traffic.

[elminero67]

Your temp gauge is probably accurate. I have an aftermarket temp gauge, and it rarely gets above 130 degrees (when its cold, I have an electric fan for summer), and I don't run my radiator fan.

If you don't trust your temp gauge, you can test it with your hand. If it is in the cold range, you should be easily be able to keep your hand on the valve cover or radiator.

If it is going to stay cold, you can block off a portion of the radiator with a piece of cardboard.

[plenzen]

Just caught up to this post.

#1 The starting fluid will damage the cylinder head and in particular the pre-cup and perhaps even blow it out of the head and into the cylinder.
Lots of drama associated with that event.

Ether ( or starting fluid ) should never be used on an IDI engine.
I think it was made for the old 2 stroke Jimmies and that is the only place it should be used. ( IMO )

#2 SD 22's and SD 25's hate the cold. -10 C and they WILL NOT GO without being plugged in or be fitted with an air heater. -20C is the extent of the usefulness of the aforementioned air heater. ( after a 6+ hour cold soak )


There is a link on the site to the one that I fitted to my truck.
That being said, it's in a D21 and has a slightly different glow system and a different fuel pump that you have on yours.
If you have to, and there is a plug in nearby, remove air cleaner and run hot air gun or hair dryer on high down the hole. It will go pretty quickly after that.

http://nissandiesel.dyndns.org/viewtopic.php?t=1427

#3. I suspect that someone has changed your thermostat with a "Fail Safe" stat or an aftermarket thermostat. ( Can Tire, Pep Boys. Wal Mart etc. ) Mine did the same thing until I put the actual Nissan thermostat in.
Nissan Part # 2120064W010
The temperature gauge now reads around the middle of the gauge depending on the ambient temperature and how hard I'm working it.
It ALWAYS comes to mid gauge now before the stat opens and you can see when that happens by the gauge.
I have just run my truck here in Calgary Alberta for the past week with -30's and never put the heater fan above the #1 position and stay nice and warm. These trucks have an awesome heater in them. You will notice on the Nissan thermostat that there is a small disc on the bottom of the shaft with another smaller bi-metal spring on it. That is to allow the coolant to flow to the heater core quicker rather than waiting for the engine to come up to 190 degrees. ( or is it 180 I cant remember ) This allows for the cabin to get heat more quickly.

Question????

I am assuming that you have a 720 PU with the SD25 in it. The one with the inline fuel pump ? Yes ?

There are a number of different glow plugs available for this engine and depending on the glow system you have ( quick glow/slow glow ) or the earlier version there are numerous options for glow plugs.

Search this forum for the ones that will work the best in your application.

Al has done quite a bit of research on them and they have been discussed to death on here over the years.

5-40 Rotella (or equivalent) will help your cold start as well.

For me, I just plug it in while in the garage on the real cold nights and have it on a timer that comes on 90 minutes before I want to use it.
As you stated it's good after that and will still start after 4 hours on a -30C soak.

HTH

Paul

[asavage]

What Paul said about using the Nissan t-stat. This was hashed out in some thread . . . ah, here it is:
.

Definitely read that post.

If you don't have the correct t-stat, you'll get condensation (water) in your oil, which combined with normal blowby acids forms sludge.

Ether is great stuff . . . until it hits a warm glow plug.

I use ether on diesels that don't have heaters (manifold or glow plug), but never on an engine with a working glow plug (piston damage) or manifold heater (explosion that can hurt you).

Synthetic oil is the only way to go for cold. I love AMSOil, but any PAO-process synthetic is better than any conventional oil.

Put a voltmeter on your GP bus, right at a GP and not upstream, and see what you have at cold start before cranking. Below 10.5v? Then (assuming a modern, digital voltmeter than can stand having reverse polarity applied) put positive meter lead at GP, negative lead at battery positive post and repeat test (engine cold, key ON). More than one volt? You have voltage drop between the battery and the GP that is unacceptable. Keep repeating the test, moving the positive lead up the circuit. Test at every wire harness junction, relay, fusible link. You'll find it fast using this method.

Cold brings out all the weak spots in your diesel vehicle.

HTH

[dn29626]

Old timers believed in ether for diesel engines. I have mixed feelings, but believe it to be unhealthy for diesel engines.
Unfortunately, many people, even today, will spraaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaay it in.
When used, you should spray it in (one quick touch and you are finished).

With low temperatures, my truck requires several cranks before it starts. Each crank is only a few seconds per and i go through the glow plug cycles.

[plenzen]

The diesel engines of "OLD" needed help to get going because very few of them had glow plugs. The old farm tractors were DI engines and even the air box heaters of old were pretty much meant for a summer or late spring early fall day. Using ether with an additional heat source ( air intake heater or glow plugs) is really inviting disaster.

Then there are the 2 strokes of yesteryear and I think that a case of ether was sold with them when they were brand new. ( Detroits/Jimmies/UD series Nissan etc )

Ether is just BAD for IDI engines mostly because of the cylinder head design.

BAD !! ! !

If you must use something use wd 40.

Have a look here

http://www.youtube.com/watch?v=s_LWm4g35Jw