terrible gas mileage b6t

[Chobobulous]

Okay so now I'm not so surprised at why its not working out right.

At least use the b6 ecu to start.

I am trying to get one. I was told that the fuel maps were close so I could run the b3 ecu. The ecu from the Mazda was 3 plug.


Edit, perhaps it was implied I used the b3 injectors.

[bhazard]

I've always heard they'll run *okay* on the B3 ecu but its always better to use the correct one. Adding a turbo to the mix only complicates things more. What are you using to add fuel for that?

[Chobobulous]

I've always heard they'll run *okay* on the B3 ecu but its always better to use the correct one. Adding a turbo to the mix only complicates things more. What are you using to add fuel for that?

The b6 injectors I suppose. It never usually runs more lean than about 16, and that's only for a second if I mash on the gas.

[Chobobulous]

I wouldn't think it would be injector related because I idle right where I'm suppose to. 14.7-14.9

[Chobobulous]

So I replaced the o2 sensor last night. Same problem. On a more dim note, my wide band now reads only 22.4. Wonderful.

[Movin]

After your reset timing may not be an issue but still, you have it correct at idle and mix is good at slow speeds. At high speeds you have a problem. The timing with either ECM is calculated for anything above low speed. The ECM for both uses air flow and TPS to calculate what the advance should be as well as tach input. Temp can shift things a little but not enough for this and your idle readings suggest temp is working. I believe that the B6 throttle body has a TPS that works like normal cars. The b3 computer looks for a switch type TPS that the b3 uses. Could this possibly be a factor ?

[Chobobulous]

I took the cover off the b6 throttle body and it has a switch, there is a huge possibility it is out of alignment. When I looked at it with the tb closed the switch was not making contact like it should. From what I read it should touch the bottom one when closed, not touch any when open .6 mm and touch the top at wot.

Speaking of sensors, what is the sensor that screws into the intake right by the injectors. I used the one from the b6 and maybe I need to use the one from the b3.
I ended up recalibrating the o2 sensor and it fixed itself. After leaving battery unplugged for almost 2 hours I drove home. It ran at 13.8 for about 15 miles at about 65 then out of no where it dropped to 10.2. This makes me think sensor issue? The coolant temp sensor that goes in the thermostat is brand new. The smaller one to the left of the thermostat is from the b6. The b3 sensor will not fit. It is too big.


Any other places I could look? Anything.

[Movin]

The computers temp sensor is by the rail on a B3. It should be the same either way. The B3 TPS should have three positions, idle , cruise and wide open. For max timing, high intake vacuum the tps needs to show the cruise setting during cruise conditions.

[Chobobulous]

Ok so im 90% sure I found the problem. I set the timing. Again. It was off by around 8 °. This time I set it again, let it idle while I cleaned up. Came back checked the advance. It was ok. After it revved down it was idling wrong. So I checked the with the light again. Its firing at tdc. I set it again the same thing happens. No matter what I do it keeps setting itself to fire at tdc. What can cause this.

[Movin]

maybe the timing connector is not signaling the ECM when you set the timing?? Can you dial in about 42 degrees and set timing without jumping the connector at about 3000 rpm? This would be a test to see if it runs better and if the readings from your wideband look better. If so you will need to get accurate with timing as ping can be a lot worse than retarded timing.

[Chobobulous]

I can try, im doing it alone so I cannot see the rpms and set the timing. By timing connector you mean when I ground the sti port, the one that sets off the check engine light?

[Movin]

Yes that connector. You can use your home computer to print a degree wheel the same diameter as your pulley then mark the pulley if your timing light does not do degrees.

[Chobobulous]

I can set my timing gun to 42° then line it up with tdc right?

[Movin]

Yes, and 3 thousand by ear is close enough, you will know by watching the timing advance and retard as you rev it . Don't forget that this is a test and that if it runs better or good the timing issue needs to be figured out. The risk would be ping damage if you go to high with advance.

[Chobobulous]

Well I did that it ran super lean, now it's idling at 18