still burning too much gas...

[mikeinaus]

ive got the same size winter tires as you. all the readings were done post cat, getting a reading before the cat is kind of a pain at this point. i also have a high flow magnaflow $80 cat and i doubt its having a large impact on my emissions...

my o2 sensors are new so i doubt they are out of spec. im also getting similar mileage with the new o2s as i did with the old ones. i dont remember what my other readings were but they were quite a bit higher then the 3 other cars we tested in every aspect. my last tank i used 35l of gas and made it 277km. your getting close to 100km more for the same amount of fuel as me.

as for school im in a pre-apprentice automotive tech program at Vancouver community college.

im also doubtful its playing a big part in my fuel economy, however it is a problem that needs to be fixed. perhaps instead of 1 obvious problem having a large affect i have a bunch of tiny ones that are hard to spot that add up to alot of wasted fuel. anything i can do that steps closer to solving the problem, and making me able to pass emissions testing next time around is definitely worth it. im not expecting record breaking mileage, i just want a clean properly running engine...

ill see if i can use the analyser again tomorrow and ill record the results after/if ive fixed my pcv problem.

[Tavman_1213]

Ok I'm going to throw out a dumb question when was the last time you changed your fuel filter? Cause I read through the thread an couldn't see if you replaced it.

[mikeinaus]

2 or 3 months ago.. .

[crazycanadian]

ive got the same size winter tires as you. all the readings were done post cat, getting a reading before the cat is kind of a pain at this point. i also have a high flow magnaflow $80 cat and i doubt its having a large impact on my emissions...

my o2 sensors are new so i doubt they are out of spec. im also getting similar mileage with the new o2s as i did with the old ones. i dont remember what my other readings were but they were quite a bit higher then the 3 other cars we tested in every aspect. my last tank i used 35l of gas and made it 277km. your getting close to 100km more for the same amount of fuel as me.

as for school im in a pre-apprentice automotive tech program at Vancouver community college.

im also doubtful its playing a big part in my fuel economy, however it is a problem that needs to be fixed. perhaps instead of 1 obvious problem having a large affect i have a bunch of tiny ones that are hard to spot that add up to alot of wasted fuel. anything i can do that steps closer to solving the problem, and making me able to pass emissions testing next time around is definitely worth it. im not expecting record breaking mileage, i just want a clean properly running engine...

ill see if i can use the analyser again tomorrow and ill record the results after/if ive fixed my pcv problem.

Nice to know about the tires... That rules that out for sure as part of your problem...


You do really need to do precat readings, even if it is a pain in the a--... Your cat does have an affect on your readings post cat no matter what... The only way it wouldn't is if there nothing left of it...

After that you scope your O2's not just to see if they are bad, but to see if they are biased rich/lean or happy switching... with having headers I am sure yours are set up like mine are and the O2's are only reading 1 cylinder perbank... If thats the case expect a low switch count compared to what most cars are...

If you are biased rich, High CO, then pull a couple plugs.. If they are black then you are over fueling... If you have no codes, you've tested and know the coolant temp is working then you are left with either and air flow meter/air temp or computer programing problem...Also check tps adjustment for the idle switch... I say this because and idle switch not working can cause the computer to be rich and sit in open loop mode at idle... A bad tps will cause a driveability problem before it causes a fuel economy problem...

[davmac]

FYI your fuel economy isn't that horrible... My stock KLDE swap doesn't do a while lot better... Tires do play a big roll in your perception of fuel consumption... With my little 185/65/14's I'll go about 360 - 380km per tank.. Usually between 34 - 38L per fill... With my summer 205/40/17's I'll average about 320 - 340km per tank... same fill amount... Tire weight and the force it takes to rotate different size tires all play a roll, but thats not all of it... The physical distance measured while driving down the road is different also... Going out of town when you head back east you get odometer checks on the hwy... My summers messure out 900m for every 1km traveled.... My winters measure out 1.1km for every 1km traveled when compared to these odometer checks...

What an interesting problem: Correcting for actual distance traveled do you get better fuel economy in winter or summer?
Using your numbers it turns out you're getting better fuel economy in the summer. 378 actual km per tank in summer versus 345 actual km per tank in winter. I used your high end observed km per tank and assumed the tank constant summer and winter.
Though it is hard to believe the difference in observed odometer versus actual km between these tire / wheel combos since 185/65/14 and 205/40/17 are nearly equal circumference and both are 2 percent less than OEM 205/55/15. This means theoretically your odometer calibrated for OEM size will show 2% more distance than actually driven. Meaning your observed fuel economy is better than your actual fuel economy. Pretty mind twisting.

Back on topic: You've got a great looking car that from this thread suggests it runs great, idles great just uses too much fuel. No drivability concerns or trouble codes to know what to suggest. I feel your frustration - wish I could help.

[Ryan]

There is too much reading in this thread for me




Take out your PCV, but plug the hole in the valvecover with your thumb and see if it acts normal.

[SuperK]

so... in response to something you said in another thread... I am under the impression the proper O2 sensors are the KL o2's. You mentioned you're running K8 o2's.

Now i don't know the difference between the two, but I will ask the forum, would this make a difference? I replaced my o2's on my ZE with KL's. w

[mikeinaus]

The difference is the plug. Output of the sensor is the same. Car dies with pcv out and valve cover plugged. Found a substantial vacuum leak that was made yesterday. Doing intake, valve cover gaskets and fixing the leak today.. im also doing the friction gear springs while i have the valve covers off.

side question... i found where the block off plate for the egr is on the intake manifold. is it possible to just throw one on and walk away? i remember reading something about it needing to be drilled out or something?

[crazycanadian]

The difference is the plug. Output of the sensor is the same. Car dies with pcv out and valve cover plugged. Found a substantial vacuum leak that was made yesterday. Doing intake, valve cover gaskets and fixing the leak today.. im also doing the friction gear springs while i have the valve covers off.

side question... i found where the block off plate for the egr is on the intake manifold. is it possible to just throw one on and walk away? i remember reading something about it needing to be drilled out or something?

FYI I pulled the PCV valve out on my car when it was running tonight... It died as well... Since I don't have a fuel economy problem, chances are your pcv problems aren't related to your fuel consumption...

[mikeinaus]

anyone know how involved the knock sensor is in our cars timing adjustments? one of my teachers was saying that some cars never use a knock sensor or that they are only there to detect problems, he said some others use them to advance the timing until knock is detected then back off on a constant cycle of advance/retard. im asking because if our knock sensor is used for constant adjustments to the timing, that mine could possibly be bad reporting false knock causing the timing to be retarded and lead to a bad (rich) burn. something else to note the wires on my knock sensor finally broke off of the plug and its been disconnected for about a week now. in the half a tank ive driven ive managed 160km which is on par if not a bit better then i was getting with it hooked up (bottom half of tank goes fast). ive gone ahead and ordered a new one from rock auto and im just wondering if i should hope this will fix my problem or not?

[Ryan]

No, it won't.

I hate this thread.

[mikeinaus]

you hate the thread but i have to live with the thread my car is f----- and no matter what i do to it, it continues to run like s---. this car is such a headache, i should have spent the money on something alot better... the worst part is the car has no resale value so if im to sell it id have to take a major loss after owning it for less then 10 months and putting nothing but money and care into it.

what could possibly be left?
02's, injectors, disty, vaf, air filter, exhaust, tire pressure, driving habits, multiple chips, coolant sensors, spark plugs, wires, disty cap/rotor, compression is good. everything has been replaced and yet it still refuses to run properly.

[crazycanadian]

you hate the thread but i have to live with the thread my car is f----- and no matter what i do to it, it continues to run like s---. this car is such a headache, i should have spent the money on something alot better... the worst part is the car has no resale value so if im to sell it id have to take a major loss after owning it for less then 10 months and putting nothing but money and care into it.

what could possibly be left?
02's, injectors, disty, vaf, air filter, exhaust, tire pressure, driving habits, multiple chips, coolant sensors, spark plugs, wires, disty cap/rotor, compression is good. everything has been replaced and yet it still refuses to run properly.

You need a scope, 2 channel min... Scope your O2 sensors while driving... You need to see if they are bouncing happy between .8 - .2v, if they are biased rich, biased lean. If they are bouncing happy at idle when warmed up or flat lining baised rich or lean. This is going to tell you how good of fuel control your motor has...

For shits and giggles I can test your knock sensor idea. My gf has a stock mx3 GS.. We track fuel milage on it... I can go unplug the sensor and let her drive it for a week... I don't think you'll find much difference..

I am surrey, if you can kind be on call kinda thing PM me your number... I bring home the scope from work from time to time.. You'd be more then welcome to come over we'll hook it up and go for a drive. Just bring some beer for when we are finished.. haha..

I am almost willing to bet most of your problem is the tuned chips...

[mikeinaus]

the knock sensor is my last resort. the programmer of my chip suggested i look into it. he says the ecu uses the knock sensor below 3250rpm to adjust the timing, and if severe knock is detected the computer will go into a limp mode to protect itself. i also read something on mx6 forums that said something similar, that i cant seem to find at this point in time. even if it doesnt fix the problem, the wiring on my old one was fucked and its one more thing i can say that i have thats brand new...

after the ks im going to go with a de ecu/vaf. i know the chip is looking more and more likely. i just dont see how 2 different chips from 2 different programmers can give me relatively the same mileage/ rich burn when so many other people are using more or less the same chips, with more or less the same setup i have and having such better results. i know chips run a bit rich compared to a stock ecu, but most people are easily getting under 10l/100km with them, and im having trouble getting below 13l/100km.

"Using high-octane fuels (98/100 RON) has benefits on the V6 engines as they have a knock-sensor to take advantage of it; UK Standard unleaded is 95RON, Super-Unleaded is 97-98RON. However using higher than 95 RON is largely unnecessary (re cost/power).
The ECU automatically adjusts timing based on the knock sensor from 6-18 degrees, a very considerable range. Base timing is 10 degrees +/- 1 degree."

thats what i found on mx6.com. from my reasoning, if the adjusts timing between 6-18 degrees based on the knock it reads from the knock sensor, doesnt it mean that the car could in theory retard the crap out of it if the knock sensor is malfunctioning? its not like obd1 is smart enough to actually know if any of its readings make sense. its given a range of whats "ok" and no information to know if this reading makes sense at any given point in time.

[Ryan]

Dear lord.

You need to stop.

Stop what you are doing.

Quit replacing s--- at random.

That is NOT diagnostics, that is a giant waste of money. You didn't need to spend your money on a better car, you needed to spend more time doing your homework and less time buying s--- you don't need. Don't rag on the car, there are many of us with the exact same vehicle that rolled off the exact same assembly line under the same quality control in the same month, who have no problems whatsoever.

Example:

MX-3.com online manuals, F2 section, under the heading "relationship chart"

http://www.mx-3.com/manuals/showimg.php ... F2-018.gif

Knock sensor can only effect ignitor (ignition timing). It can't touch fuel.

SAE 920677

http://www.mazdamaniac.com/tech/SAE_20920677.htm

"

With trace knock control, a single sensor between the engine V-banks detects small knocking, and the ignition timing is then set at a point just prior to the generation of the knocking in low speed ranges. In the conventional method, ignition timing was set in consideration of engine compression ratio and fuel octane number. (Fig. 16) The trace knock control optimizes ignition timing. And this optimizes engine potential, which in turn raises torque. (Fig. 17)

The knock sensor is a peizo electric speaker. It is designed to resonate at the frequency the block vibrates at under knock conditions, which sends a small voltage to the ECM. If it was fucked, the ECM would know, because it would read knock even when ignition is not advanced, and knocking is impossible, it would throw a CEL.

If I'm totally wrong, and it tried reducing timing at, say, idle, the car would stall and die.