# Decrease in MPG. Code 11



## jstluise (Mar 20, 2009)

1994 Sentra LE GA16DE 180xxx

I've notice a significant decrease in mileage over the past couple weeks. Its in the low 20s...compared to >30 I was getting. So I got down to business and checked/replaced some things.

-Plugs, old one looked okay (nice color), but they were out of spec a little bit.
-Plug wires were replaced not too long ago
-Fuel Filter
-Air Filter
-Cap/Rotor looked okay, but I might replace them too.

-I checked my timing and found the base timing was only at 5 BTDC, instead of 10 BTDC. So I corrected that. 
-I checked my Throttle Pos. Sensor and it is operating correctly.
-Checked my oxygen sensor and it checked out fine (Mode II, light blinked more than 5 times in 10 seconds at a steady rev.)

I then checked my codes (I should have checked before I did any work). The only code the computer had on it was Code 11, camshaft/crank angle position sensor.

I am wondering if me messing with the timing and other stuff, if that is what threw the code. Would a Code 11 be causing my decrease in performance (mpg)? I cleared the code and will check it in a few days to see if it reappears.

The motor has been running well. Nice idle, steady acceleration, no problems I could notice. Well, over the past couple weeks it does seem like it is lacking a little (just a little) power. Hard for me to tell though. I can still accelerate quickly and run at normal speeds, just pulling hills seems a little bit different. Could be...probably go well with my decrease in MPG.

Any info regarding my decrease in mpg or Code 11 would be helpful. 

Also, is there any way to check my codes WITHOUT gaining access to the mode selector switch on the ECU? I tried jumping the CHK & IGN terminals on the CONSULT connector like the FSM says, but couldn't get anything. I finally did what CHILTON says and turned the little knob on the back of the ECU. It was kind of a pain.

Thanks


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## tlhingan (Jun 8, 2009)

Well, I believe the crank angle sensor on this model is inside the distributor, so adjusting the timing might have tripped it just this once. As far as your loss of power and gas mileage, you covered all the basics. Have you checked your tire pressures?


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## jstluise (Mar 20, 2009)

Thanks for the reply.

Yes, the crank angle sensor is in the distributor. That's kind of what I thought...adjusting the timing might have thrown the code. We will see if it appears again.

Tire pressure is good. I usually keep good tabs on them.

Yeah I dunno...the mileage has really dropped (noticeably) in the last few tanks I've run through it. Besides the basic tune up stuff I've already done, my concerns were with the TPS and O2 sensor, but they checked out fine.

The only other possibility I could think of would be a clogged CAT. But, not really sure how to check it. I had that happen with my Toyota truck...the clogged Cat really made it horrible to drive.

Thanks again


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## tlhingan (Jun 8, 2009)

The only way I know how to check for a clogged cat involves major surgery.

Do you always use the same brand of gas?
I've had power and mileage issues with specific brands.


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## zacward (Aug 23, 2009)

Cam angle sensor is in the distributor. The CRANK angle sensor is on the tranny bellhousing


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## jstluise (Mar 20, 2009)

tlhingan said:


> The only way I know how to check for a clogged cat involves major surgery.
> 
> Do you always use the same brand of gas?
> I've had power and mileage issues with specific brands.


Yeah I know what kind of surgery you are talking about  Not too worried about it right now. We'll see how the mileage looks in the next week...I haven't been driving the car lately.

There are a couple different places I get gas...same places I have been for the time I've had the car. Could be I got a bad batch or something. 



zacward said:


> Cam angle sensor is in the distributor. The CRANK angle sensor is on the tranny bellhousing


You are correct, but Nissan uses both these terms when referring to the same thing. Early systems called it the Crank Angle Sensor (though the sensor was located in the distributor), but the Camshaft Position (CMP) Sensor term took over in later models. In either location, they are sensing the same thing. It wasn't until 1995 that Nissan actually put a Crankshaft Position Sensor (CKPS) on the GA16DE on the transaxle housing, but is not used to control either the fuel or ignition timing.


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## 200SXBrent (Apr 28, 2009)

I have a 1995 200SX, and I too have lost a little power and I think the mpg's are down a little. My 1.6 has 184,000 miles.

From the Haynes manual, here's the list of things to check:
Incorrect timing.
Excessive play in distributor shaft.
Worn rotor, distributor cap, spark plug wires or faulty coil.
Faulty or incorrect gap spark plugs.
Problem with the fuel injection system.
Plugged air filter.
Brakes binding.
Auto trans fluid level incorrect.
Fuel filter clogged.
Emission control system not functioning properly.
Low or uneven cylinder compression pressures.
Obstructed exhaust system.

I hope this helps too.


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## Oldnissanguy (Jan 6, 2005)

Probably a long shot, but make sure your gas doesn't contain ethanol. My mileage really drops when I get a tank of that stuff.


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## nooranichadun (May 18, 2010)

*Urvan 2008*

Hi there. Anyone can help me locating the Crankshaft Position Sensor on my Nissan Urvan / caravan 2008 using engine zd30.
Thanks:waving:


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## tlhingan (Jun 8, 2009)

Oldnissanguy said:


> Probably a long shot, but make sure your gas doesn't contain ethanol. My mileage really drops when I get a tank of that stuff.


That's nice to know. I heard this story before, the GA16DE doesn't seem to like ethanol, dunno why. Some states require ethanol in all gasoline being sold, I can only imagine the havoc it's causing to owners of older cars that can't run well on this stuff.
On a side note, I get a decrease of power and gas mileage with specific brands of gasoline (Shell and PC so far), anybody else have similar stories?


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## Oldnissanguy (Jan 6, 2005)

Actually all my cars seem to run better on the new Shell gas. In fact my Sentra gets a little better mileage with it. I use it whenever I can.


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## tlhingan (Jun 8, 2009)

What's this new Shell gas?
Do you mean the V-Power or the nitrogen enriched?


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