kick butt fuel economy for under $20 and 5 minutes!!!

flarearrow · #1 (**permalink**) 02-06-2005, 03:39 AM

For the longest time (and like many others) I have been suffering from declining MPGs for the last year or so. And like everyone else, I've tried all the usual things.... o2 sensors, spark plugs and wires, distributor cap and rotor, fuel filter, air filter, fuel system cleaner, wheel alignment, tire pressure, etc etc etc.....

Then I remembered reading (and theres like only 2-3 threads about it) about the coolant temp sensor. This sensor can go bad, and not throw a check engine light. How can this sensor cause bad MPGs? When this sensor goes bad, it'll tell the ECU that the engine is running hot when it really isn't. This'll cause the ECU to richen up the A/F to cool the engine down.

So I finally got off my arse (I don't know why I didn't order this thing sooner. It's so easy to order online from nissanparts.org) and bought the damn thing. The coolant temp sensor cost around $18. It's easy enough to remove and replace in under 5 minutes.

Now after driving around for a week, there has been a noticable. Driving around the Queens and Long Island area, I would be averaging in the high teen's to low 20's, and barely getting mid 20's on the interstate.....

NOW I'm averaging in the mid 20's, and I can imagine approaching 30 mpg in the interstate.

w00t to me!!!

Everyone who is having MPG problems should change this sensor, even for the hell of it, since it's so cheap and so easy.

SexyGXE · #2 (**permalink**) 02-06-2005, 04:03 AM

I changed mine when I did my coolant change. It does make a big difference. I think that it gets used to getting the temp. from the old coolant and when you put in new coolant, it may knock things off and cause things not to function properly.

Brushedpewter · #3 (**permalink**) 02-06-2005, 09:12 AM

Why spend money to increase fuel economy when you can do it for free?

Back last year i got hired at a place that made me drive on the freeway to work all the time. The best I got was 24.5, after I removed the rear seats i got an average of 28.5mpg, and i drive an automatic. You can raise the B.S. flag but i'll be happy to scan my fill up receits.

Pulski · #4 (**permalink**) 02-06-2005, 01:52 PM

The rear seats weigh almost nothing... I added 4 times that weight when I got my system and I didn't have any noticable hit in milage... so yeah... BS

Brushedpewter · #5 (**permalink**) 02-06-2005, 01:57 PM

Quote:

Originally Posted by Pulski

The rear seats weigh almost nothing... I added 4 times that weight when I got my system and I didn't have any noticable hit in milage... so yeah... BS

would you like to see the slips? you could also say B.S. on the numbers, since it can be from any car. So what's the point of posting it?

**lowriderman3** · #6 (**permalink**) 02-06-2005, 01:57 PM

Quote:

Originally Posted by Brushedpewter

Why spend money to increase fuel economy when you can do it for free?

Back last year i got hired at a place that made me drive on the freeway to work all the time. The best I got was 24.5, after I removed the rear seats i got an average of 28.5mpg, and i drive an automatic. You can raise the B.S. flag but i'll be happy to scan my fill up receits.

You ask for it to be raised.

Brushedpewter · #7 (**permalink**) 02-06-2005, 02:15 PM

here you go. I swear that is real info. My alti is a 99' auto.

http://www.nissanclub.com/forums/vbg...=view&id=36716

Ry · #8 (**permalink**) 02-06-2005, 07:19 PM

Quote:

Originally Posted by flarearrow

For the longest time (and like many others) I have been suffering from declining MPGs for the last year or so. And like everyone else, I've tried all the usual things.... o2 sensors, spark plugs and wires, distributor cap and rotor, fuel filter, air filter, fuel system cleaner, wheel alignment, tire pressure, etc etc etc.....

Then I remembered reading (and theres like only 2-3 threads about it) about the coolant temp sensor. This sensor can go bad, and not throw a check engine light. How can this sensor cause bad MPGs? When this sensor goes bad, it'll tell the ECU that the engine is running hot when it really isn't. This'll cause the ECU to richen up the A/F to cool the engine down.

So I finally got off my arse (I don't know why I didn't order this thing sooner. It's so easy to order online from nissanparts.org) and bought the damn thing. The coolant temp sensor cost around $18. It's easy enough to remove and replace in under 5 minutes.

Now after driving around for a week, there has been a noticable. Driving around the Queens and Long Island area, I would be averaging in the high teen's to low 20's, and barely getting mid 20's on the interstate.....

NOW I'm averaging in the mid 20's, and I can imagine approaching 30 mpg in the interstate.

w00t to me!!!

Everyone who is having MPG problems should change this sensor, even for the hell of it, since it's so cheap and so easy.

I think it's time for me to swap mine out. I haven't seen 26 mpg in awhile.

**Asleep** · #9 (**permalink**) 02-06-2005, 07:34 PM

i agree flare, the cts is often overlooked and can cause idle problems, efficiency, and driveability problems. changing this out along with a good bleeding of the system afterwards can have a big impact on an otherwise good running engine.

Uncle Mole · #10 (**permalink**) 02-06-2005, 09:06 PM

badass

**jserrano** · #11 (**permalink**) 02-06-2005, 09:58 PM

Good info flawearrow. People should remember that the correct sensor has two wires and is called the Engine Coolant Temperature (ECT) sensor which feeds the ECU. The other sensor has one wire and is the coolant temperature sender for the temperature gauge ONLY.

Rejectbaby · #12 (**permalink**) 02-06-2005, 10:23 PM

ordering mine now. thanks for the info. i hope it works.

Decoy · #13 (**permalink**) 02-06-2005, 10:33 PM

Shit... My temperature gauge (about 2 weeks ago) started to act real strange. It would fluctuate down to cold even when the engine was warm. I checked out the coolant temperature sensor which is located on the hose from the radiator to the head on the passenger side. The little metal tab which inserts into the harness was damaged. The metal pin that holds the metal tab into place was lose, thus not making a proper connection/reading. I went to my local dealership and got the part. Total came to 14 dollars 4 cents. Went home and replaced the part in 20 seconds. About 3 drops of coolant came out. After that I opened the bleeder screw for the coolant on the driver side of the block for about 5 seconds. No air came out. I then filled in coolant to the top of the radiator and check my reservoir also. Started the car and so far the gauge hasn't been 'strange' yet. Now I just need the higher pressure radiator cap and my car will warm up much faster.

**Asleep** · #14 (**permalink**) 02-06-2005, 11:04 PM

Quote:

Originally Posted by Decoy

Now I just need the higher pressure radiator cap and my car will warm up much faster.

actually decoy, using a higher pressure cap will raise the boiling point of your coolant. it will probably take longer to heat up. a higher boiling point will make the thermostat open up later than a lower one will. http://auto.howstuffworks.com/cooling-system11.htm

Brian Passarelli · #15 (**permalink**) 02-07-2005, 03:20 AM

Decoy, your problem is not the CTS, it's most likely just a thermostat (5 dollar or so part at a nissan dlrshp). oh, and i suggest getting the nissan dlrshp part. this is just one of those parts that should definetely be OEM. besisdes, the crappy aftermarket part is only 1 dollar less or so. : )