# 93 altima OBD-I scanner



## metronet (Dec 12, 2005)

Hi there,

My nisscan altima is having excessive fuel consumption problem.
Replacing the fuel filter and the spark plugs doesn't help, checked there was no leakage externally.

I am hoping that someone that can help me look for a correct OBD-I scanner with the adapter for my car... I believe it's a OBD-I type of scanner that I Need as it's the 1993 model.

Will something like this work?
http://www.aldlcable.com/

Any ideas?

Thanks!


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## LONDONDERRY (May 19, 2004)

metronet said:


> Hi there,
> 
> My nisscan altima is having excessive fuel consumption problem.
> Replacing the fuel filter and the spark plugs doesn't help, checked there was no leakage externally.
> ...


If your looking to buy the scanner, to addess your current mechanical issue, I recommend either have Autozone, if you live near one, scan it for you free; or purchase the Haynes manual and it explains on how to do with out the tool and save the 80 bucks


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## metronet (Dec 12, 2005)

Thanks so much for your respond.
I do have the Haynes manaul and it stated in the manual that error code 55 means everything is normal?

(I managed to go into the ECU beside the gas padel and did the self diagnos).

What else could be wrong for my horrible gas mileage?


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## LONDONDERRY (May 19, 2004)

metronet said:


> Hi there,
> 
> My nisscan altima is having excessive fuel consumption problem.
> Replacing the fuel filter and the spark plugs doesn't help, checked there was no leakage externally.
> ...


There could be many issues as to why your car is getting terrible gas milage. 
Start simple first, it sound like your on the right track with replacing the spark plugs, use NGK plus only and fuel fillter. I suggest you finish your tune up, by replacing the air filer, wires, rotor and cap, if you have not done so. Next I would try adding some fuel injector clean, BG product is recommend by some nissan guru's on this forum, with a tank of premium gas. Finally give the car an oil change, if its time. These are pretty simple tasks that most people can tackle themselves. See if this helps first and let us know.

Cheers
Frank


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## Darktide (Jul 29, 2004)

I'll put my money down that its your O2 sensor. And no, it doesn't have to throw a code. I had a friend buy a nice 94 altima and she had serious fuel consumption. The garage changed EVERYTHING except the O2 sensor like I suggested "because it didn't throw a code" so I said "pfff" changed it myself. And lo-and behold the problem fixed itself. Its a pain to get the stupid heat shield off the manifold and it could be stuck in there pretty bad (ask my knuckles how hard I had to push, plan on using a breaker bar). But that's my 2C... good luck


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## tm_94altima (Aug 12, 2005)

Autozone only has OBD II, at least in the east MS region.

For the fuel problem, try replacing your coolant temperature sensor. I went from 25 highway mpg to 30 highway mpg and about 18 city mpg to 23 city mpg. It is a common thing to go out and it doesn't set off the CEL.


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## metronet (Dec 12, 2005)

tm_94altima said:


> Autozone only has OBD II, at least in the east MS region.
> 
> For the fuel problem, try replacing your coolant temperature sensor. I went from 25 highway mpg to 30 highway mpg and about 18 city mpg to 23 city mpg. It is a common thing to go out and it doesn't set off the CEL.


I am going to try and replace the oxygen sensor.

As for the coolant sensor, is it the Thermostat for the cooling system that you are reffering to? I'll see if I can replace that as well. Thanks everyone for the replies, I'll keep you guys posted


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## Darktide (Jul 29, 2004)

no he means the coolant temperature sender (sender, sensor, and switch are all the same, depends on who you ask). It is the sensor that tells your computer what temperature your engine is (based on the temp of the coolant). If it thinks your car is constantly cold or if its just messed up it'll tell the computer to dump more gas in because a colder engine needs more gas. It should help, and it also won't trip the Check Engine light. Changing both will definately increase your MPG and it'll do you some good (though I suggest doing a tune-up relatively soon, wires/cap/rotor/air filter. They'll all help increase MPG and keep your car healthier. Let us know how you make out.


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## gfriedman (Oct 12, 2005)

I agree. Those 2 devices are a good bet to be your problem but I would test them beforehand. Don't get confused with the temperature senders. One sends the signal to your dash temperature guage and the other feeds the engine temp to the computer - obviously you want the latter. Also, take a look at your plugs when you take them out - their condition says alot about the health of your engine. If they are loaded with black soot then your air/fuel mixture is way too rich - hence the poor gas mileage.

One other tip... Spray the O2 sensor pretty heavily with some liquid wrench crap. Let it set up for 10-15 minutes while tapping the sensor to let it work its way in. Should make taking it out just a tad easier.


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## Darktide (Jul 29, 2004)

my personal choice would be PB Blaster. While I worked at the auto parts store mechanics ordered it by the case everytime and every time I used it the situation came out to "it either broke free or it broke off", minus using an acetalyne torch there really isn't a better way to get things off. You want to soak it the night before you do the job. The next morning whack it with a hammer (gently) to loosen it up. Soak it again 5 minutes before the job and give it a whirl. Its always worked for me (I didn't use it the time I did the O2 sensor because it wasn't my car and it was an hours drive to get there and they were being cheap about it).


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## metronet (Dec 12, 2005)

I just replaced the oxygen senser, i'm gonna see how it goes =)
Thanks guys, I really appreciate all your helps. I will keep you guys posted.


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## splavin90 (Aug 22, 2005)

money down on o2 sensor


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## stingermaster (Feb 6, 2005)

*coolant temperature sensor*

Hi,

Where is the coolant temperature sensor for the computer located on the engine? My mileage is shot to h*** and I also seem to get a raw gas smell in the exhaust gases coming from the tailpipe. :thumbup: 

Thanks in advance,

Herb


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## tm_94altima (Aug 12, 2005)

stingermaster said:


> Hi,
> 
> Where is the coolant temperature sensor for the computer located on the engine? My mileage is shot to h*** and I also seem to get a raw gas smell in the exhaust gases coming from the tailpipe. :thumbup:
> 
> ...


It is under the intake manifold on the engine block on the passenger side. It is pretty easy to spot. The raw gas smell sometimes means bad catalytic converters.

Hope that helps.


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## stingermaster (Feb 6, 2005)

*Thanks tm_94altima*

Hi,

Thanks for the info. I plan to replace the exhaust with a stainless catback so I will replace the cat also (just a few dollars more). I may also add a header also. :thumbup: 

Herb


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## metronet (Dec 12, 2005)

Two weeks after I replaced the o2 sensor, doesn't seem to have any improvements on the millage haha... am still doing 13.5L/100KM.

Would it be time to replace the PVC valve? (or whatever it's called )


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## gfriedman (Oct 12, 2005)

Look at your plugs first to see if you are running rich. If they look black then you have a fuel problem to fix - O2 sensor, leaking injectors, fuel pressure regulator, plugged air filter. If they look OK then there is something wrong with the performance which you should definately be able to feel. Exhaust blockage, plugged cat, dragging brakes, tranny not shifting.


If it's none of these then set up a spy camera on your car at night. You'll catch the thief that's siphoning your gas tank.


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## KA24Tech (Feb 2, 2004)

I agree that the Engine Temperature Sensor could be an issue if the O2 Sensor has been replaced. To test it unplug the sensor and with a ohmmeter place the leads on the two pins. At 68 F (20 C) the resistance should be 2.1k - 2.9k ohms, at 122 F (50 C) the measurement should be 680 - 1k ohms, at 176 F (80 C) it should read 300 - 330 ohms. Becareful not burn yourselves when you test it at the higher temperatures.

Troy


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## metronet (Dec 12, 2005)

metronet said:


> Two weeks after I replaced the o2 sensor, doesn't seem to have any improvements on the millage haha... am still doing 13.5L/100KM.
> 
> Would it be time to replace the PVC valve? (or whatever it's called )


Hello everyone  

After a year of driving on the bad mileage, I've finally got sometime to tackle around the issue and at last it was found that my *ignition timing* was way off...

It was set tome 12.5 BTDC instead off the manufacture specification 18~22, so I set it to ~20 and off the road I got. Immediately I found the engine now runs a lot smoother.

Anyway, I said a while ago I'd report back my result on the O2 sensor (and I also found that there is no rear 3 wire O2 sensor for my 1993 model) so I thought I'd give everyone an update.

I will report back shortly once the new/good (cross my fingers) mileage has been confirmed.

cheers,


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## metronet (Dec 12, 2005)

oh btw, back to my question back in December, 1995

Would I be able to find out my timing's off by using the OBD-I scanner (console tool)? 

thanks again guys, I really appreciate the help I've received from this forum.


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