D40 not running properly while cold

[Leeschmidtke]

A mates 2010 D40 has had an issue of running like a dog and stalls unless it's being revved when it's cold As soon as the engine is warm it runs perfectly. A mechanic replaced the injector pump but it didn't solve anything ($5000 later). After a bit of searching around the forum I tried cleaning the MAF sensor with contact cleaner, still no luck. Tried priming it before startup with no luck, primer goes stiff after 2 pumps. Tried unscrewing the fuel cap and starting it, still no luck. When I try to start it with the fuel cap off i can feel it suck in, not sure if that's normal?
Now the problems gotten worse and to start the car someone has to turn the engine over while someone works the fuel primer. So obviously there's a fuel problem somewhere. He's going to leave it with me for a couple days and I was wondering where and what should I start on to try and fix the problem?
Also he said someone with the same problem cleaned some sort of non-return "something" on the fuel side which fixed it, anyone got any clues on what that might be?

 

[nathand22]

I woud change the SUCTION CONTROL VALVE, they have been the cause of lots of fuel type failures, from rough idle when cold to complete shut downs.

They are a relatively cheap part, from memory around $170
some people have had a bit of luck from pulling them apart and cleaning them, but with others it hasnt made a difference and they just replaced them.

I had one play up on my 2010 ST and it had the Nissan Tech guys scratching their heads, they even replaced the timing chain?? lol

Anyway i would just swap it out for a new one.

 

[Leeschmidtke]

Yeah I thought the same thing, but apparently unscrewing the fuel cap will let you know if it's working or not? I'm not sure how.
And the way it needs to be primed before startup makes me believe it might be sucking air in somewhere.

 

[kernels]

The SCV is what the engine uses to control the pressure in the common rail. Trying it with the fuel cap off will point you in the right direction sometimes, but it's not really a test for the SCV.

The SCV would be worth at least cleaning and trying since it is such a common culprit.

 

[nathand22]

^^ 100% agree, actually I logged on to say the exact thing.
For eg, When mine was playing up on the 2010 ST the fuel cap trick didn't make one bit of difference, actually I only really know of one instance where it did work, so it's far from a reliable test.

Checking for air leaks is a simple thing to do and most definitely should be done, but before you go spending coin on other stuff I would just throw one in after all you spent 5k and that didn't work so you may as well put a new SCV in with the new pump and frankly it should of been done along with the pump in the first place if not first.

 

[Ben_W]

If the primer is hard after 2 pumps I don't think it's an air leak. I may be off the mark but I'll also throw in the possibility of a glow plug issue.

 

[kernels]

If the primer is hard after 2 pumps I don't think it's an air leak. I may be off the mark but I'll also throw in the possibility of a glow plug issue.

Yep, certainly fits the symptoms.

 

[nathand22]

Your on the money about the primer, but i highly doubt the glow plugs are an issue as they are only responsible for the initial start up, and if he can get around it by priming it then that points in another direction and also rules out any electrical issue the problem.
IF you look at one of the jobs the SCV has its to control the fuel and if isnt allowing any flow it would explain why it only starts when he manually controls the flow by priming it, and once the fuel pump is being operated from the engine actually running the pressure to the SCV is great enough that it sort of operates, and the more the engine runs and the higher the revs the better the SCV works, but leave it sit for hrs and the problem starts again.

MY VOTE IS SCV, like i said for the money it cost just change it and rule it out once and for all.

 

[nathand22]

Oh an during normal ambient temps a diesel will start with no help from the glow plugs at all, it may take a few extra cranks and will puff a bit of fuel out the exhaust but they will start.

 

[DieselTuner]

The issue sounds more like injectors than anything else to me.

If the engine temp is above about 20deg they will start without any glow plug assistance pretty easily.
Once its running, they dont really need to be on at all.

I know the SCV does cause some issues, but the biggest one Ive found is the engine stalling at random times.
I would certainly change this first just to rule it out as it is quite cheap.

If that is a no go, then time to bite the bullet and put a set of injectors in.

Why on earth would a shop change the fuel pump in a D40 unless there was some serious low fuel pressure issues or similar.

 

[Old.Tony]

To possibly save a little more money (this won't hurt and might fix the problem), try this product from Supercheap. I just put this in my tank and after 100km noticed the uneveness in my car's idle (only when cold) had started to settle. By the end of that tank it was almost unnoticeable, so I ran some in the next tank and now the idle is as smooth as normal.

When cold, diesels will start without glowing anyway, and once it's ticking over it'll stay ticking over - so I don't think it's glows. It shouldn't be turbo, at idle it should be able to get enough air past the turbo impeller even if the turbo's stalled, but you can watch the charge air hose sections (there are two) for collapse during startup. If they do collapse, there's a chance that the turbo vanes are closing all the way at shutdown (possible faulty vac solenoid). Check the hose low on the right hand side of the engine that comes up to the intake manifold, and check the hose between the top of the intercooler on the left hand side of the engine bay that goes to the baffles attached to the left side of the motor. I don't suspect this will be the issue.

MAFS is important to fuelling and can be wrecked by over-oiling a K&N filter. These filters aren't bad, it's the re-oiling method that lets people down. The ECU shouldn't screw up the fuel levels that badly at idle because of the MAFS reading the airstream wrongly.

It's more likely fuel as others have observed (note that I'm just going over the possibilities and discounting them, leaving fuel as the likely culprit).

 

[mike1303]

I second what Tony says. Accept I use a different brand, 10mm every third tank and she purrs like a kitten

 

[nathand22]

SCV needs replacing,

not sure which one is in your model but here are two options for $190 cheap thing to replace so it can be ruled out of the equation, im guessing it will fix the prob.

http://www.ebay.com.au/itm/NISSAN-N..._Parts_Accessories&hash=item27df9a7ba2&_uhb=1

http://www.ebay.com.au/itm/Nissan-N...eavyMachineryParts&hash=item1c425be0ae&_uhb=1



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[nathand22]

Any update on this one?

 

[Leeschmidtke]

Just brought the suction control valve today, should here next week. Il let you's know how it goes

 

[user 10312]

Over the past few days having the same problem. Slight hunting when cold once warm runs fine.
SCV looks easy enough to replace but bloody hell getting to it look chalenging to say the least.

Done an ECU and Fuel pump reset and did make some difference but still there. May get a can of liquid Molly gear while I psych myself self up to change it.

 

[Leeschmidtke]

It was easy to take out, just undo the bolt on your dipstick and move it aside. Then there's just 2 Allen key headed bolts on the scv and a plug on the back.

 

[Leeschmidtke]

SCV needs replacing,

not sure which one is in your model but here are two options for $190 cheap thing to replace so it can be ruled out of the equation, im guessing it will fix the prob.

http://www.ebay.com.au/itm/NISSAN-N..._Parts_Accessories&hash=item27df9a7ba2&_uhb=1

http://www.ebay.com.au/itm/Nissan-N...eavyMachineryParts&hash=item1c425be0ae&_uhb=1


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They're the same aren't they? Same part number.

 

[nathand22]

It was easy to take out, just undo the bolt on your dipstick and move it aside. Then there's just 2 Allen key headed bolts on the scv and a plug on the back.

Could we get you to take a few pics and do a "INSTALL SCV" thread, its seems to be coming up more and more and would be really handy as a reference for others in the future.

would be great if you can,
Cheers.
Nath

 

[Leeschmidtke]

I think there already is one on here. I swear I seen it before