Fuel economy with Pettit unlimited ECU
08-13-12, 01:57 PM
#1
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Fuel economy with Pettit unlimited ECU
Hey guys and gals,
I installed a Pettit unlimited ECU in my RX7 and the I think there is something not adding up. Since installing the ECU my fuel economy is around 9mpg, now if you ask me that is a bit high. I am wondering if this is caused by the pettit ECU or could there be something else causing the high fuel consumption?
Mods:
Full Non seq. conversion
Full 3"exhaust (dp, mp, cb)
Front mount IC
Intake
Fuel pump
And the usual reliability mods
(I know, I need a PFC)
And BTW the o2 sensor has been replaced about 2000 miles ago and injectors have been cleaned when doing the non seq conversion.
Aad
I installed a Pettit unlimited ECU in my RX7 and the I think there is something not adding up. Since installing the ECU my fuel economy is around 9mpg, now if you ask me that is a bit high. I am wondering if this is caused by the pettit ECU or could there be something else causing the high fuel consumption?
Mods:
Full Non seq. conversion
Full 3"exhaust (dp, mp, cb)
Front mount IC
Intake
Fuel pump
And the usual reliability mods
(I know, I need a PFC)
And BTW the o2 sensor has been replaced about 2000 miles ago and injectors have been cleaned when doing the non seq conversion.
Aad
08-13-12, 07:02 PM
#3
I had a M2 stage 3 ecu, which is very similar to the pettit. Almost all of my driving is around town, and I got about 9 mpg too. You dont get good gas mileage sitting at a stoplight. The Pettit, like the M2 runs very rich, especially when boosting. After getting my pfc tuned, I get about 12 mpg, which is a 33% increase over the M2. These cars are going to get shitty gas mileage unless you are cruising on the fwy. Get used to it 
08-13-12, 07:48 PM
#4
RX-7 Bad Ass
iTrader: (55)
You should be able to get better fuel economy than that. With my PowerFC when I was daily driving the car I could easily get 19mpg around town with exhaust, intake, more boost, etc.
Now, if you're droppin' the hammer at every stop light, your fuel economy will suck. The more you're in the throttle the more fuel you're using.
That bad, though, I'm wondering if you've got some problem like a bad water temp sensor, O2 sensor wire is broken somewhere, etc. That's just awful.
Gas ain't cheap either.
Is it eye-watering-ly rich? Does it start right up cold or hot or does it bog down? Idle smooth and at a respectable RPM?
Dale
Now, if you're droppin' the hammer at every stop light, your fuel economy will suck. The more you're in the throttle the more fuel you're using.
That bad, though, I'm wondering if you've got some problem like a bad water temp sensor, O2 sensor wire is broken somewhere, etc. That's just awful.
Gas ain't cheap either.
Is it eye-watering-ly rich? Does it start right up cold or hot or does it bog down? Idle smooth and at a respectable RPM?
Dale
08-14-12, 05:01 AM
#5
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Thanks Guys,
Yeah I know gas mileage on these care is not great. But still 9mpg seems too high. I am not dropping the hammer at every turn and stoplight, even with normal cruising I get around 9mpg.
Dale it starts up fine hot and cold, idle is a bit rough when cold but smooths out when warmed up. I had to bump the idle up to about 900-1000 rpm, but I figured this was due to emissions delete. Since my car is JDM, could not having a egr connector have anything to do with it? I used the proper resistors on all other emission plugs. I forgot to add in the original post that I am pretty sure my fans don't turn on, they do turn on when I turn on the ac, could this have anything to do with it? Possible faulty temp sensor?
Yeah I know gas mileage on these care is not great. But still 9mpg seems too high. I am not dropping the hammer at every turn and stoplight, even with normal cruising I get around 9mpg.
Dale it starts up fine hot and cold, idle is a bit rough when cold but smooths out when warmed up. I had to bump the idle up to about 900-1000 rpm, but I figured this was due to emissions delete. Since my car is JDM, could not having a egr connector have anything to do with it? I used the proper resistors on all other emission plugs. I forgot to add in the original post that I am pretty sure my fans don't turn on, they do turn on when I turn on the ac, could this have anything to do with it? Possible faulty temp sensor?
