Rough Idle / Difficult Cold Weather Starting

team_ream · Post by **team_ream** » Mon Feb 27, 2017 3:29 pm

On a recent trip to the snow, my L300 took quite a bit of coaxing to get running. It would turn over and sputter out almost immediately. The only way I wa sable to get it going, was to hold the gas down while continuing to turn the key, for about 5-10 seconds, spewing a bunch of smoke in the process. Once it was running and warm, everything was fine including restarts. After a few hours and especially overnight, I would have the same problem. Also, it has the dual battery, which I believe is supposed to be better for cold weather starts.

It might be worth noting that the the van does idle a bit rough. It's the only delica I've ever been in, so not much to compare to, but I would venture to say that it is rougher than it should be.

Any suggestions where I should start?

Morgonzo · Post by **Morgonzo** » Mon Feb 27, 2017 5:26 pm

Hey Team-Ream, I can tell you that my problems with hard starting were eased with fresh Mitsu GP's and a new Temp Sensor (located on the top of the block by #1 injector. Even with fresh GP's, if your Temp sensor is bad it will run rough because the temp sensor is responsible for telling the GP's how hot or cold the engine is. I would also look at the fuel lines from the filter to the IP to look for wear or possible cracks. Air intrusion can cause very rough running till it's pushed it out of the system. Also If you have not done so yet, replace the fuel filter. I had a air leak from the o-ring that lives in the fuel/water separator that screws on the bottom of the filter. Changed it for a fresh one from a Metric Viton kit from Horrible Freight an it solved my problems. Mine will still run rough on cold mornings requiring a bit of throttle till it evens out but that seems par for the course with these old vans.

Sylquebec · Post by **Sylquebec** » Wed Mar 01, 2017 6:05 am

How cold it was?
Any diesel engine can be hard to start at extreme cold temp.
When beyond -30 in my 2009 volks tdi, i need to hold the key while the engine is trying to start...
So sound normal to me. Really depend on how cold it is outside.

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team_ream · Post by **team_ream** » Wed Mar 01, 2017 10:36 am

Thanks guys. Sylquebec, definitely wasn't THAT cold - about 28f/-2C. Spewed lots of black smoke in the process. Got quite a few dirty looks in the parking lot of a ski resort

.

It is my 1st diesel and I do realize that they are a different beast when starting cold (glad i hvae the 2 battery setup), buit does seem a little extreme, especially bc it will occasionally sputter out on a brisk san francisco morning, which is pretty warm by many peoples standards (45f/7c), though it doesn't require the cranking that it does in the snow.

The thing is, even at a red light after its nice and warm, the thing idles with some very pronounced shake. Morgonzo, was that an issue for you before replacing glow plugs/ temp sensor?

Post by **Growlerbearnz** » Wed Mar 01, 2017 2:19 pm

team_ream wrote:The thing is, even at a red light after its nice and warm, the thing idles with some very pronounced shake. Morgonzo, was that an issue for you before replacing glow plugs/ temp sensor?

The glow plugs/temp sensor won't do anything for idle quality once it's warm. Idle speed should be a minimum of 750rpm in neutral when warmed up. If your engine's a bit tired it might benefit from a slightly higher idle, but try and keep it below 900rpm.

Morgonzo · Post by **Morgonzo** » Wed Mar 01, 2017 7:59 pm

Hey Team-Ream. No, i've not had any bad shaking at idle out on the road. It is a stick, so that might be a variable. I've adjusted the cold idle screw on the IP to raise my idle up to 850/900 when warming up. It won't sit there right off the bat, I hold the throttle down for a couple of secs then it settles in at 850/900 and does not move. I think i'm due for a injector rebuild which can make cold starts worse if they're popping wrong or there is leak-down (injector not closing fully allowing a trickle of fuel into the combustion chamber all the time.. do I have that right GB?

...) When it's cold here she coughs out some decent smoke and you can feel the uneven combustion in the engine, but the F350 does the same thing. Once it warms up, she's fine. Also, I feel like my injectors have quieted down and pop more evenly after I started the 2-stroke treatment. I would recommend it. I did have aftermarket GP's in for a bit and they ROYALLY SUCKED!

my cold start issues got much better after I put in fresh Mitsu green tops, I also run a copper GP rail that is supposed to offer more conductivity than the factory metal one. I can't say whether it really works or not but it sure looks shiny compared to the old one

Morgonzo · Post by **Morgonzo** » Thu Mar 02, 2017 10:10 am

I should clarify that when I say "Hold the Throttle down.." I don't mean put the pedal to the floor. I give it just enough to bring the RPM's to 1000. My hand throttle knob is broken and does not lock in place at a particular RPM, otherwise i'd use that instead.

Killbert · Post by **Killbert** » Sun Mar 05, 2017 7:54 am

team_ream wrote:Thanks guys. Sylquebec, definitely wasn't THAT cold - about 28f/-2C. Spewed lots of black smoke in the process. Got quite a few dirty looks in the parking lot of a ski resort .

It is my 1st diesel and I do realize that they are a different beast when starting cold (glad i hvae the 2 battery setup), buit does seem a little extreme, especially bc it will occasionally sputter out on a brisk san francisco morning, which is pretty warm by many peoples standards (45f/7c), though it doesn't require the cranking that it does in the snow.

The thing is, even at a red light after its nice and warm, the thing idles with some very pronounced shake. Morgonzo, was that an issue for you before replacing glow plugs/ temp sensor?

Mine does the same thing when warm. I'm getting an almost miss. This could be a few tnings. Injection pump, injectors, or a burned valve. I'm going to dig into mine next weekend and find the problem. I have two other Delicas near me and mine idles the worst by far.

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Morgonzo · Post by **Morgonzo** » Sun Mar 05, 2017 9:31 am

Hey Killbert, having the ability to compare one Deli against another is a great resource I imagine

It will be interesting to see what you find when you dig in to locate the rough idle. I really feel like running the 2-stroke has smoothed out the running of my engine. I used to have that miss type of feeling when first starting the engine, and it would take 10 to 15 min to warm up enough to stop doing it. Now, it seems to be closer to 5.

Post by **Growlerbearnz** » Mon Mar 06, 2017 2:33 pm

Morgonzo wrote:I think i'm due for a injector rebuild which can make cold starts worse if they're popping wrong or there is leak-down (injector not closing fully allowing a trickle of fuel into the combustion chamber all the time.. do I have that right GB? ...)

That's right, a failing injector fails in one of three ways and you've got two of them. The third way is probably more relevant to hard starting- dirty nozzle causing uneven spray pattern. Popping at the wrong time will cause rough running all the time (and can even melt a piston), and leaking when closed will cause white smoke at idle all the time, but dirty nozzles will usually be less noticeable when the engine's warmed up.