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Discussion Starter #1
My R33 GTS-T is causing me a headache. The car is running rich, or at least seems to be. Gone from around 25 mpg to around 15 mpg ( I only drive the car reasonably steady- most of the time ). The car also stalls occasionally. I have recently changed the spark plugs and it has fresh mobil 1 with clean air filters and new oil filter; but still the problem persisits.

Can anyone advise as to the possible causes of the problems?

I have also removed the MAF and removed the silicone seal around the box and established the 4 active prongs inside have retained their solder connection to the curcuit board inside. All looks clean and healthy. Also MAF element looks clean with no carbon build up on it. I'll try borrowing a MAF from another R33 and see how things go, but I don't think it's a MAF problem.

Does anyone have any better ideas as to the cause of my problems in the meantime?

Any suggestions would be greatly appreciated.

Jimmy C
 

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I would always point the finger first of all at anything changed if it run correctly before hand. Can you remember when it started happening, if anything was done to it in the couple of weeks before hand or has it been a gradual change?

Very Rich running can be a sign of air leaking, O2 sensor failure or not sparking correctly for some reason (what do the plugs look like, is one different from the others in it's look?).

There are probably the usual 100 or so bl00dy reasons for it :bawling: making it difficult to point the finger at one area.

Have you lost a lot of power and does the engine note sound the same as before?
 

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cheers

Engine note as before. The only change I can think of was a de-cat fitted in lieu of a cat. No discernable loss in power, but it's hard to tell without a dyno test. I'll refuell tomorrow and report back a mpg figure. looking like another 15 mpg week though.

Thanks for the input...
 

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Hi Jimmy C,

This could be a number of things. The stalling you mentioned, when is this happening?

I don't think that it's lightly to be the de-cat, that if anything would allow the car to breath a little easier.

Have a look at this post, if the car is stalling, it might be this:-

http://www.gtr.co.uk/forum/upload/showthread.php?t=57555

The job doesn't take too long to do and helps smooth out the running at the low end. Once you've do that and reset the idle, try the car again. If it is still the same, check the plugs and as Skyline69 says, it could be an air leak or a faulty O2 sensor.

If you still having problems, give me a bell, I'm working in your neck of the woods and could meet you if you like. I'll PM you my mobile number.

By the way, you need to change the oil. Mobil 1 is no good for your car mate. See here:-

http://www.opieoils.co.uk/

Check out "oilman's" posts, have a look using the search button, you'll damage the engine using that stuff.


Andy.
 

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are you running a aftermarket bov? (atmosphere venting)

as they will cause the car to run very rich and if not setup correct they will stall the car
 

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more than likely maf or engine temp sensor (ecu one) although as pointed out it could be other things but these are the most likely culprits
 
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