SCV Problem?

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MrCBR

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South Australia
Afternoon guys and girls, I have a bit of an issue with my D40 at the moment. It feels like it has a bit surge when light on the throttle. It is mostly noticeable when the auto changes gears in the first few and you can see the tacho needle pulse. I have had a bit of a search and it had led me to think the SCV is the problem. Would you agree or maybe something else? I have checked all the usual stuff and the car is well serviced and had a new fuel filter, air filter and maf clean on the last service.
 
It could be surging as a result of a worn/dirty SCV or it could just want a clean. My own car has done the "hunting" thing on a few occasions and a bottle of Liqui Moly Fuel System Treatment does the trick every time. It's even on special at the moment - I put some in my Goldwing and it helped, might put some more and go score myself another couple of bottles while they're going a little cheaper!

As for the OBD reader + Torque, they are simply awesome to have. It's a pity my bike is pre-OBD or I'd have it on that as well!
 
That first one comes up as a phone cover and the second one is error 404.

First one delete the ciid3a4 or search ob2 Bluetooth

Second one search torque on the Google/Apple store:rock:
 
So I replaced my SCV and the surging and hunting has stopped but now I have an issue where the car has no acceleration after start up until I turn it off and start it a second time.
A little background, Not long after I bought the car it used to do the same no acceleration thing from time to time. I used my scan tool and only found a code straight after it happened (P0089 fuel pressure regulator performance). I asked my Nissan dealer and the told me it would be the SCV. I did some research here and got put onto Fuel Doctor and it went away so I have been using ever since. Fast forward a couple years and I have this surging and hunting issue and it died twice while driving both time when I used quicker acceleration. I tried the treatment Old Tony suggested but no go so replaced the SCV. Now it seems like I'm back a square one.
My thoughts are the new SCV is faulty or is it the fuel pressure regulator. I scanned the car straight after the event and got the same code (P0089) but no engine light. The car runs fine otherwise.
 
I think maybe "fuel pressure regulator" refers to a component other than the SCV.
When my SCV played up i got limp mode a couple times, i scanned the ECU immediately after the second dose of limp mode, and the statement "Suction control valve jammed" was displayed
I scanned with a sony phone with torque app for Android

I replaced the SCV with new genuine, no issues since
 
I'm curious about the time between SCV replacement and second failure, plus where the SCV was sourced from and what brand(s) of fuel are used as well as their sources (large truck stops, small corner servo etc).
 
Yes definitely with common rails the fuel quality is very important

I stick to caltex, a large scale farmer told me a while back that because they use hundreds of litres of diesel a week in various tractors, trucks, utes, excavator etc they really notice the difference in fuels. They use caltex only. He mentioned it has a higher cetane rating than other brands too

Another hot tip from a different bloke was this:
Wherever possible get your fuel from a servo on top of a hill rather than on the flat or at the base of a hill
Much less likely to have groundwater sitting around the underground fuel storage tanks

Avoiding old servos and sticking to recently constructed ones is a good idea too
 
The time between replacement and the first time it had no acceleration was straight away. I finished the job went to test drive and it went nowhere. Restarted and it was fine. I thought maybe the system had to reset itself or something so I let that one go. Now it's doing it at least every second day if not every day on the first start. Fuel used is BP from newish servos that have decent turnover. I also don't run the tank empty, usually fill up by 1/4. The SCV was bought from my local auto parts store but is not a Denso one. I know I could get a Denso from eBay but was able to get it from this shop faster.
 
Doesn't explain the problem then - assume good fuel, and did it on a new part.

Any smoke while there's no power? Might have to be behind it to notice it.

If there's black smoke it's specifically a case of "not enough air for the amount of fuel going in". That could mean several things:

1) Too much fuel going in. You could reset the fuel map (easiest way is grab the radio PIN, pull the battery negative off, press the brake pedal and put the negative lead back on. It does NOT work with assistance, you MUST do it yourself (because you need that time between disconnection and brake pressing and reconnection).

2) Too much fuel going in (take 2). Could be an injector issue but since a restart fixes it I doubt it. More likely going to be either a logic or a self-test failure. Might be a dirty MAFS, which will give the ECU the wrong information about how much air is going past (usually measures on the low side resulting in less fuel being injected but it's electronics, so who knows). Give the MAFS a clean? It can't hurt. Just don't drop it, and don't poke anything in the hole in the side of it.

3) Not enough air. Can be a number of things. First thing is to watch boost figures and see what you're getting. Take a look at the little arm under the actuator on the turbocharger while the engine is idling (while you are having the problem, do NOT turn the car off, check this first). It should be moving in and out a little. If not, get someone to give the engine a rev while you watch it. It HAS to move. If it doesn't, get a clean piece of 3mm rubber hose, pop the hose off the actuator, and suck on the other end. The arm underneath should pull all the way up. If it doesn't, the actuator is stuffed. My bet is it'll work, and that points to the BCS (Boost Control Solenoid). My own BCS has failed, same symptoms - seems down on power - I'm waiting for delivery of my new Tillix valve. Watch this space.

4) EGR commanded erratically. There have been a couple of reports of EGR valves failing and sticking in the open position. This will introduce exhaust gas directly into the combustion chamber dampening the combustion and reducing power. It will feel gutless. It will also blow black smoke like an old diesel loco. Or a coal roller. Now that's something for Prius drivers.

Rolling Coal? Here's a train doing it.

[YT]https://www.youtube.com/watch?v=RHsp0Q6ISBo[/YT]

Oh, cars can do it too.

[YT]https://www.youtube.com/watch?v=SBQFnUgv37c[/YT]
 
Just got home from work Tony, I'm going to clean the maf and do the ecu reset first as well as have a look at the arm on the actuator. In regards to the rolling coal thing with the egr mine is blocked so does that mean that shouldn't be the happening? Also when we talk about limp mode and down on power does the car still drive at lower speed? When I am saying no acceleration I really mean nothing at all. Like the pedal has zero response as if it were unplugged.
 
Sounds worse than limp mode. In limp mode you put your foot on the pedal and the car moves reluctantly. It shouldn't rev over 2,000rpm.

Having a blocked EGR takes that out of the equation altogether. You still might "roll coal" - depends on the fuel/air mix. The car usually only gets it wrong when some part of the air system isn't working as well as it should (and most often it's the BCS), but even with a busted BCS and a busted turbo (I've had both, recently) the car will still drive. Not fast, that's for sure, and it gives a Hilux a chance to catch it without the assistance of a towtruck, but it still goes.

I wonder if your TPS is ok? Dirty connection? Your throttle will have a connector on it, unplug it and take a peek in it. If you see corrosion in there, give it a clean. I had my TPS replaced, but I think that was a misdiagnosed SCV. And even with a knackered SCV my car still accelerated.

Do you have an Android phone and a BT OBD adapter? If you fire up Torque, you can add a display "Throttle Position Manifold". If you see this move while driving, you'll know that the TPS input is being accepted by the ECU. Of course, if it's not, you might need a new one. Had any water in the cabin?
 
No water in the cab. I cleaned the maf did an ecu reset this morning. Also checked the actuator arm and it was working (although it was not having the issue at the time). Everything stated and ran fine when I left for work tonight and that seems to be when it happens. So fingers crossed and I'll keep you posted. Thanks for your help.
 
Not really. I don't really like iPhones, too restrictive for me. There are apps in the iStore, I guess a search for "OBD" might produce results. There are other members here that have iPhones, maybe they can jump in with what they use.
 
Well it turns out it's not fixed. Did it again this morning. I checked the actuator arm while it was doing it and it's still moving. To me it's still coming back to the new SCV is faulty. This problem only started after I replaced the part and it's the same problem Nissan said was a bad SCV back when it used to do it. The new part fixed the surging and hunting issue but it seems like it sticks on first start up. I might put the old one back in and see if the problem goes back to surging and hunting but gets rid of the no acceleration issue.
 
Hate to play advocate for the devil here but you should probably get a new genuine SCV from Nissan dealer matched to your VIN

When i replaced the SCV on my yd25 d40, i bought a new made in japan denso one from ebay for about $150, then realised it was probably slightly different so donated it to my local mechanic and went genuine which was around $350

Turned out the genuine one was not denso after all, it was made in Holland by another manufacturer to suit the japanese denso system in my Spanish built d40

D40s are a truly global vehicle, so part interchangability is not as simple as it seems
 
Doesn't explain the problem then - assume good fuel, and did it on a new part.

Any smoke while there's no power? Might have to be behind it to notice it.

If there's black smoke it's specifically a case of "not enough air for the amount of fuel going in". That could mean several things:

1) Too much fuel going in. You could reset the fuel map (easiest way is grab the radio PIN, pull the battery negative off, press the brake pedal and put the negative lead back on. It does NOT work with assistance, you MUST do it yourself (because you need that time between disconnection and brake pressing and reconnection).

2) Too much fuel going in (take 2). Could be an injector issue but since a restart fixes it I doubt it. More likely going to be either a logic or a self-test failure. Might be a dirty MAFS, which will give the ECU the wrong information about how much air is going past (usually measures on the low side resulting in less fuel being injected but it's electronics, so who knows). Give the MAFS a clean? It can't hurt. Just don't drop it, and don't poke anything in the hole in the side of it.

3) Not enough air. Can be a number of things. First thing is to watch boost figures and see what you're getting. Take a look at the little arm under the actuator on the turbocharger while the engine is idling (while you are having the problem, do NOT turn the car off, check this first). It should be moving in and out a little. If not, get someone to give the engine a rev while you watch it. It HAS to move. If it doesn't, get a clean piece of 3mm rubber hose, pop the hose off the actuator, and suck on the other end. The arm underneath should pull all the way up. If it doesn't, the actuator is stuffed. My bet is it'll work, and that points to the BCS (Boost Control Solenoid). My own BCS has failed, same symptoms - seems down on power - I'm waiting for delivery of my new Tillix valve. Watch this space.

4) EGR commanded erratically. There have been a couple of reports of EGR valves failing and sticking in the open position. This will introduce exhaust gas directly into the combustion chamber dampening the combustion and reducing power. It will feel gutless. It will also blow black smoke like an old diesel loco. Or a coal roller. Now that's something for Prius drivers.

Rolling Coal? Here's a train doing it.

[YT]

Oh, cars can do it too.

[YT]
 

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