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Skyline Vq25dd Loss Of Power On Acceleration


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I brought a 2001 250gt about a month ago, didn't have as much power as i thought it would and after running a full tank through it i found it had really rubbish fuel economy, striped the plenum and swirl valves and cleaned them, cacked with buildup, and has been running like gold ever since, the change was drastic. i wounder how many people have rubbished these cars simply because no one ever maintained them properly.

Totally agree, these aren't too bad as far as direct injection engines go, there isn't much valve overlap on the VQ25dd so the carbon doesn't cake the lower runners as quickly as other engines I have had to scrape clean. It should be regular maintenance to give it a good scrub internally.

As for the swirl valves, you saw the size of the runners when you cleaned them right? I would imagine it restricts the top end badly even with the swirl valve open. The idea is to promote swirl in the chamber by blocking one of the two intake valves to help eliminate knock, it would only work at idle and cruise I imagine.

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  • 8 months later...

Hi Guys I have a 2001 V35 that i bought in June 2013 its now 130,000km started having acceleration issues as described the earlier case since Jan 2016 with Error codes P1110, P0202, P0204 and P0206 ; been to several mechanics that could not figure out the problem; and kept on going and some times the car would stall completely and i wait a few minutes and drive on till when it stopped completely ...Lucky enough grounded at my home!!

Unfortunately I did not know about this forum but did my research that gave me several options. I finally found the pictures on this forum that guided me to the intake valve solenoid which i found one faulty (brown one) on testing with an ohms meter.

I have however failed to get the intake valve solenoid at the local dealership does any one know closest point to Uganda where these can be accessed?

You also talk about the swirl valves can one share a pic?

The car cranks but won't start, thank you

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If the car won't start, just replace the cam and crank sensors. Most likely they are the issue, not the solenoid valve. Not sure what you mean by solenoid valve.

For parts, try Amayama UAE.

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  • 2 weeks later...

Thanks Scotty,

The car was able to start about two weeks ago doing well after considering all the advise on the forum however also found out that faulty Oxygen sensors can also be a big problem for these cars, recommend to do preventive maintenance by changing them after 100K miles

regards

Patrick

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  • 4 months later...
  • 3 months later...

Hi Kweshaz, my silence meant that I had found solutions to the car :)

it rides very smoothly after I changed the selonoid valves, and both cam shaft and crank shaft sensors.

I also did a thorough cleaning of the manifold down upto the the swirl valves using carb cleaner spray and a tooth brash

I did discover a blown O2 sensor fuse that we had all missed to detect as it was so disguised that one would think its ok, thus replaced the O2 sensor which ideally wasnt neccesary at the time but advisable to be changed at 150,000km to meet the required emission levels.

I have learnt a lot about the car and I believe one can easily fix it without a mechanic's intervention so long as you are a handy man

The beauty of it all is that you can know the fault by just using simple manouvers and checking related error codes

Follow the link below for OBD reader and codes respectively I.e no diagnostic kit required

http://www.skylineowners.com/forum/236-vq-electrics-ecu-ice/138289-ecu-self-diagnostic-test.html

Regards

Dr. Patrick

 

 

 

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  • 2 weeks later...

I forgot to mention

A P1110 error code could be caused by any of the following; 

faulty Intake valve timing control solenoid valve Intake valve timing control solenoid,valve harness is open or shorted Intake,valve timing control solenoid valve may be faulty,Crankshaft position sensor (POS) may be faulty,Camshaft position sensor

Read more: https://www.autocodes.com/p1110_nissan.html

An oil change including the filter and spraying WD40 into the intake valve did the trick 

 

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  • 1 month later...
On 4/30/2015 at 4:58 AM, KWESHAZ said:

Hallo guys I am back again.Can anyone assist me with the role played by the 2 solenoid valves (attached)(one brown and the other green) found in front of a VQ25DD engine.

I tested the valve terminals with a multimeter and the green one has a resistance of 30 Ohms but the brown one is open.post-138154-0-21822000-1430333786_thumb.jpgpost-138154-0-85655800-1430333826_thumb.jpg

Hello,

Where did you buy these from and what are the part numbers? 

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On 18.3.2017 at 3:17 PM, xsocruz said:

Hello,

Where did you buy these from and what are the part numbers? 

You can buy these on aliexpress or ebay.

Part number you can check that picture of solenoids. Middle is right part number.

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  • 2 years later...
On 8/22/2015 at 9:51 PM, Block_O_Tron said:

I brought a 2001 250gt about a month ago, didn't have as much power as i thought it would and after running a full tank through it i found it had really rubbish fuel economy, striped the plenum and swirl valves and cleaned them, cacked with buildup, and has been running like gold ever since, the change was drastic. i wounder how many people have rubbished these cars simply because no one ever maintained them properly.

Where exactly is the Plenum valves?? I have a 2006 Nissan Skyline, and it drinks way tooooo much fuel.

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  • 3 years later...

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