Thanks Connaught I have another near new Fuel filter sitting there as they had to change it over when the did the injector for the warranty... so I may change it over and see what happens. The vacuum lines look in pretty good nick I would say they were replaced before I got it but may go down the path of changing them all over if it is only $15 it is still an inexpensive potential solution.
Loss of Revs and Power on Acceleration...
- Thread starter slcrugby
- Start date
Help Support Nissan Navara Forum:
Thanks to everyone for their input so far.
I have been doing some thinking and some reading and I am starting to think that perhaps my surge followed by loss of power was perhaps a little misleading. I am starting to lean towards the surge being a slip of the clutch and then the loss of power actually being the clutch grabbing again....
It is worse under heavy acceleration and then it is also worse going up hill. I have also combined this increase in revs (surge) with no real increase acceleration during the surge from what I can see and feel. The friction point in the clutch is also very high compared to the diesel i30 we also own but I just assumed this friction point was normal given that the car has felt like that for the 20k we have had it.
Given this potential change in diagnosis has anyone got any other tests or tips to try?
Also any thoughts on clutch kits after reading through the forum it appears that a Single Mass Flywheel will be the way to go but I am also looking at the heavy duty exedy, 4terrain or the NPC Clutch kits?
I have been doing some thinking and some reading and I am starting to think that perhaps my surge followed by loss of power was perhaps a little misleading. I am starting to lean towards the surge being a slip of the clutch and then the loss of power actually being the clutch grabbing again....
It is worse under heavy acceleration and then it is also worse going up hill. I have also combined this increase in revs (surge) with no real increase acceleration during the surge from what I can see and feel. The friction point in the clutch is also very high compared to the diesel i30 we also own but I just assumed this friction point was normal given that the car has felt like that for the 20k we have had it.
Given this potential change in diagnosis has anyone got any other tests or tips to try?
Also any thoughts on clutch kits after reading through the forum it appears that a Single Mass Flywheel will be the way to go but I am also looking at the heavy duty exedy, 4terrain or the NPC Clutch kits?
camo.b
Member
If it was your clutch your revs should pickup.ive toasted my clutch a few times while towing and its always revs more that it moves
If your engine is generally down on power but not exhibiting any outward signs (eg no excessive smoke) there could be a number of reasons for it.
1) CAS misalignment. This will change the timing of the injection pulses which will affect the performance. Retard the timing a little and the fuel is squirted in a little later, so the piston is already on its way back down when it gets the blast from the igniting fuel, rather than all the way at the top. Your engine will run, but it will lack power. Without sufficient time to burn ALL the fuel in the chamber (particularly at higher RPM) you might notice a mild increase in smoke output but it won't be huge unless the CAS is well and truly out of alignment.
2) Fuel flow issues. Could be a number of things here and the usual first step is to fit a clear section of hose before or after the fuel filter (doesn't matter which it's all suction-side), just have to make sure it's securely clamped to prevent air getting in.
3) Clamped fuel line. Had it happen to my own car when I had my long range tank fitted. If you've had work done underneath, it might pay to check this.
4) Injectors not registered correctly in ECU. You can't just whack an injector in. It has to be registered and recognised by the ECU. If you had an injector changed and they didn't do this, it might fire that injector differently to other injectors causing your car to run poorly - like it was on 3 cyliners.
5) Fuel tank pickup holding debris. It's happened, and if memory serves the person took their tank out to fix it! The pickup can very quickly grab stuff floating around the tank, the entire 80L contents can be cycled through in about 10=15 mins.
6) Poor quality fuel. Go try a tank of BP Ultimate Diesel. Very important that you get specifically the fuel known exectly as this, because Ultimate Diesel has antifoaming agents and detergents in it, plus it's a higher cetane rating so it burns sooner and quicker.
I think that'll do for now!
1) CAS misalignment. This will change the timing of the injection pulses which will affect the performance. Retard the timing a little and the fuel is squirted in a little later, so the piston is already on its way back down when it gets the blast from the igniting fuel, rather than all the way at the top. Your engine will run, but it will lack power. Without sufficient time to burn ALL the fuel in the chamber (particularly at higher RPM) you might notice a mild increase in smoke output but it won't be huge unless the CAS is well and truly out of alignment.
2) Fuel flow issues. Could be a number of things here and the usual first step is to fit a clear section of hose before or after the fuel filter (doesn't matter which it's all suction-side), just have to make sure it's securely clamped to prevent air getting in.
3) Clamped fuel line. Had it happen to my own car when I had my long range tank fitted. If you've had work done underneath, it might pay to check this.
4) Injectors not registered correctly in ECU. You can't just whack an injector in. It has to be registered and recognised by the ECU. If you had an injector changed and they didn't do this, it might fire that injector differently to other injectors causing your car to run poorly - like it was on 3 cyliners.
5) Fuel tank pickup holding debris. It's happened, and if memory serves the person took their tank out to fix it! The pickup can very quickly grab stuff floating around the tank, the entire 80L contents can be cycled through in about 10=15 mins.
6) Poor quality fuel. Go try a tank of BP Ultimate Diesel. Very important that you get specifically the fuel known exectly as this, because Ultimate Diesel has antifoaming agents and detergents in it, plus it's a higher cetane rating so it burns sooner and quicker.
I think that'll do for now!
Foxtrot16
Member
I had a similar problem and it turned out to be the suction control valve (scv) was faulty - it got so bad it would stall as soon as I put my foot on the pedal - which wasn't good as it is an auto.
It won't show up in the diagnostics either if it is the scv.
Cost me about $300 for the part to replace.
Karl
It won't show up in the diagnostics either if it is the scv.
Cost me about $300 for the part to replace.
Karl
An update Suction Control Valve has been replaced and an ECU reset has been completed with no change to symptoms.
Old.Tony the ECU was reprogrammed when the new injector went in I ensured I asked Diesel Australia about that when I picked it up. By good luck more than good planning I have been running about a tank of BP Ultimate Diesel once a month since the new injector and also been using Diesel Power additive to all tanks of Diesel since the injector also. I will have a look at the fuel tank pick up after exams as that is going to be a bigger job from the sound of things. I have managed to check the lines underneath and it doesn't appeared that any fuel lines are clamped or pinched.
I have uploaded a YouTube clip http://youtu.be/RNiygGJVjHk
The flat spots are in 2nd gear and the drops are in 3rd gear. I was driving down the pacific motorway yesterday and it was much worse in 6th but didn't have the camera attached the wheel as I did in this clip.
Old.Tony the ECU was reprogrammed when the new injector went in I ensured I asked Diesel Australia about that when I picked it up. By good luck more than good planning I have been running about a tank of BP Ultimate Diesel once a month since the new injector and also been using Diesel Power additive to all tanks of Diesel since the injector also. I will have a look at the fuel tank pick up after exams as that is going to be a bigger job from the sound of things. I have managed to check the lines underneath and it doesn't appeared that any fuel lines are clamped or pinched.
I have uploaded a YouTube clip http://youtu.be/RNiygGJVjHk
The flat spots are in 2nd gear and the drops are in 3rd gear. I was driving down the pacific motorway yesterday and it was much worse in 6th but didn't have the camera attached the wheel as I did in this clip.
camo.b
Member
Is that what happens to if you flatten it? If you baby it from say 1st gear takeoff all the way to say 5 or 6th can you get it to perform normally?
And by babying it i mean use half throttle but take the revs 3-4000tho.
And by babying it i mean use half throttle but take the revs 3-4000tho.
camo.b
Member
My next question would be is the engine maintaining boost thru these episodes? If you dont know hook up your phone and setup a boost gauge in torque and have a squizz.
Im thinking it will be because you have no smoke.
Im thinking it will be because you have no smoke.
Yeah that is pretty close to full throttle and if I don't give it anything and keep it under 2200rpm then nothing happens. In 6th gear it goes from about 2400rpm to 3000rpm and drops back to about 2500rpm without much extra acceleration.
Yeah I have been watching the boost on the Torque pro. Appears to be doing that normally there.
Yeah I have been watching the boost on the Torque pro. Appears to be doing that normally there.
camo.b
Member
Can you baby it up to say 4000rpm in 2-3-4 and 5th
happy john
Member
The taco doesn't seem to match the sound of the engine with that jump just after 2000.By that I mean the progression of the taco is faster than that of the engine. I thought you would smell the clutch if slipping.
Ok that's very interesting. I'd love to get about 30 seconds worth of data from Torque.
Start Torque, get to the main menu. Tap your menu button, choose 'Settings'. About the 6th option down is 'Data Logging & Upload", tap this. Tap "Select what to log" and choose these items:
1) Throttle position
2) MAFS
3) Boost (intake manifold pressure)
4) Fuel flow rate/hour
5) Engine RPM
Scroll down a bit and REMOVE the "automatically log GPS" because that will give us (within 10m) your actual position on the planet.
Now go back to the normal display, tap that menu key again. With the engine running, get ready to do the drive to develop the fault and tap "Start logging". Drive, cause the problem, stop. You can send me the file, I'll convert it to an Excel spreadsheet and produce charts of the information so we can analyse it.
Listening to the video it sounded like either the engine was starving for fuel, or the injection timing had been retarded. We can't pull the CAS data from the ECU and it's worthless without being there so that's one for the mechanics.
Start Torque, get to the main menu. Tap your menu button, choose 'Settings'. About the 6th option down is 'Data Logging & Upload", tap this. Tap "Select what to log" and choose these items:
1) Throttle position
2) MAFS
3) Boost (intake manifold pressure)
4) Fuel flow rate/hour
5) Engine RPM
Scroll down a bit and REMOVE the "automatically log GPS" because that will give us (within 10m) your actual position on the planet.
Now go back to the normal display, tap that menu key again. With the engine running, get ready to do the drive to develop the fault and tap "Start logging". Drive, cause the problem, stop. You can send me the file, I'll convert it to an Excel spreadsheet and produce charts of the information so we can analyse it.
Listening to the video it sounded like either the engine was starving for fuel, or the injection timing had been retarded. We can't pull the CAS data from the ECU and it's worthless without being there so that's one for the mechanics.
That is what has lead me to think it is the clutch that is giving me the issues.
Thank Old.Tony I have sent through a PM with a link to the data to requested.
Some interesting figures, especially for your car. I'm assuming it's chipped or has an aftermarket turbo? There are a couple of occasions in the data that it's hit 33psi and the stock turbo struggles to go past 24psi.
Mostly the responses are fairly typical. I'm not surprised by how the chart pans out, but some of the points being reached are a little extraordinary.
Your ECU will react rather poorly to overboosting and will even throw diagnostic codes. If you have a look through the chart you'll find dangerous peaks at:
16:34:14 - 29.2psi
16:34:20 - 29.5psi
16:35:40 - 29.4psi
16:35:52 - 29.5psi
16:35:53 - 29.5psi
16:35:54 - 33.2psi
and so on. I've stopped there because at that point - where the turbo has reached 33psi - your air flow has fallen from almost 120g/s to 90g/s. There's nothing wrong with this: your throttle at 16:35:51 was at 75% and you'd dropped the throttle to 50% as the revs climbed from 1800-odd to 2756.
The issue I have is how much boost you're getting. Is it a Garrett 206V and is there a chip involved? This does change the equation rather dramatically!
I'm surprised your car hasn't given you a P0234 code yet.
Mostly the responses are fairly typical. I'm not surprised by how the chart pans out, but some of the points being reached are a little extraordinary.
Your ECU will react rather poorly to overboosting and will even throw diagnostic codes. If you have a look through the chart you'll find dangerous peaks at:
16:34:14 - 29.2psi
16:34:20 - 29.5psi
16:35:40 - 29.4psi
16:35:52 - 29.5psi
16:35:53 - 29.5psi
16:35:54 - 33.2psi
and so on. I've stopped there because at that point - where the turbo has reached 33psi - your air flow has fallen from almost 120g/s to 90g/s. There's nothing wrong with this: your throttle at 16:35:51 was at 75% and you'd dropped the throttle to 50% as the revs climbed from 1800-odd to 2756.
The issue I have is how much boost you're getting. Is it a Garrett 206V and is there a chip involved? This does change the equation rather dramatically!
I'm surprised your car hasn't given you a P0234 code yet.
camo.b
Member
Turbo vac solenoid broke? But the oposite way i.e giving full boost all the time
^ It's not boosting all the time, but that could also be in response to a lack of exhaust pressure providing drive for the compressor. It's certainly a possibility.
To test: start the car and watch the actuator arm at idle. It should move in and out about 3-5mm almost randomly. If it doesn't, one of the following events have occurred:
* The vac solenoid (up near the left hand headlight) has failed in the 'open' position. It's a common problem.
* The actuator has jammed in the 'open' position. Not common at all.
* The turbo vanes have jammed in the 'open' position. Has been reported a couple of times.
The solenoid is the very first port of call. Some dealers stock these in quantity because of the number of failures. If the vanes of the turbocharger aren't controlled properly, there will be periods where the motor feels like it's producing decent amounts of power, and others where the exhaust can't drive the turbo as quickly as it normally would, resulting in significant lag and apparent loss of power.
To test: start the car and watch the actuator arm at idle. It should move in and out about 3-5mm almost randomly. If it doesn't, one of the following events have occurred:
* The vac solenoid (up near the left hand headlight) has failed in the 'open' position. It's a common problem.
* The actuator has jammed in the 'open' position. Not common at all.
* The turbo vanes have jammed in the 'open' position. Has been reported a couple of times.
The solenoid is the very first port of call. Some dealers stock these in quantity because of the number of failures. If the vanes of the turbocharger aren't controlled properly, there will be periods where the motor feels like it's producing decent amounts of power, and others where the exhaust can't drive the turbo as quickly as it normally would, resulting in significant lag and apparent loss of power.
4 naving
Member
Is the psi reading 0psi at idle. The scan gauge I have needs to be calibrated for your local altitude to read correct boost. Just check to ensure 33psi is correct as that is extremely high...
Barometric pressure changes every with elevation. Sea level is 14.7psi and increases 0.14psi for every 100m of altitude. If its not calibrated as 0 at idle then subtract at least 14-15psi which would make it about normal...
Barometric pressure changes every with elevation. Sea level is 14.7psi and increases 0.14psi for every 100m of altitude. If its not calibrated as 0 at idle then subtract at least 14-15psi which would make it about normal...
camo.b
Member
33 - baro pressure is about the 19psi it should be..could well be right 4 naving
Old.Tony great questions it is running a stock turbo and no chip. It has only had one previous owner the Father in Law and he has told me he hasn't done anything to the engine, turbo or put in a chip. Only engine mods are an EGR blank, Catch can and a snorkel (if you count a snorkel).
No codes at all I have done regular scans with the Torque App and nothing. I haven't been in limp mode either.
As you know the OBDII and the Torque app are where the numbers have come from so I am not sure if we need to adjust them for atmospheric pressure.
Actuator is moving up and down about 3-5mm at idle. I am just confirming that the motion you mention of 'in and out' is in a vertical direction rather than a horizontal direction? If it is in a horizontal direction then I am probably looking at something other than the actuator...
