Dead MAF? (OBD2 data and WOT analysis inside)
07-27-2017, 12:50 PM
#1
Dead MAF? (OBD2 data and WOT analysis inside)
Hi guys, so I've been struggling lately with the starts of my car. One month is started completely fine, the other month it would start horribly, then good again and there were no issues to be found in performance. The car hit the 0-100 in 7 seconds, smooth, hit the 235km/h on GPS and so on.
New coils, wires, plugs, 700CCA battery, 2kw starter, the whole thing. It sounds like a 3 cylinder Toyota Aygo, a Smart ForTwo and the engine is rough. If it stalls, I have to pushstart it.
I found the following symptoms, namely that the car could have a bad MAF, dead or unplugged plug/coil, loose or stuck SSV either open or closed (or any other valve).
I cleaned the MAF twice with brake cleaner which only contained aerosol, and I assume that this might have killed it. It's an MAF from 2010, probably some cheap piece of crap, I don't see any branding on it, but anyone is welcome to tell me how I find out the brand. I also overfilled the oil by 0,5L recently, so oil got into the intake which might have messed up the SSV aswell. I hear since recently some air pushing and clicking from behind the black plastic intake where the valves should be. Ticking is related to RPM.
Anway, my main question is whether these numbers are normal, or completely retarded, so I know if I should get a new MAF. Idle is around 6g/s, used to be 4g/s. Doesn't get above 175g/s whatever I tried. This was in 3rd and 4th gear, pushing it to 200km/h. The other one I found on the internet looks really smooth and stable as I would expect it to be. Shouldn't the MAF read over 200 g/s?
My readings
Readings from a Subaru Outback, seems much smoother
Values from a healthy RX-8 from another member:
New coils, wires, plugs, 700CCA battery, 2kw starter, the whole thing. It sounds like a 3 cylinder Toyota Aygo, a Smart ForTwo and the engine is rough. If it stalls, I have to pushstart it.
I found the following symptoms, namely that the car could have a bad MAF, dead or unplugged plug/coil, loose or stuck SSV either open or closed (or any other valve).
I cleaned the MAF twice with brake cleaner which only contained aerosol, and I assume that this might have killed it. It's an MAF from 2010, probably some cheap piece of crap, I don't see any branding on it, but anyone is welcome to tell me how I find out the brand. I also overfilled the oil by 0,5L recently, so oil got into the intake which might have messed up the SSV aswell. I hear since recently some air pushing and clicking from behind the black plastic intake where the valves should be. Ticking is related to RPM.
Anway, my main question is whether these numbers are normal, or completely retarded, so I know if I should get a new MAF. Idle is around 6g/s, used to be 4g/s. Doesn't get above 175g/s whatever I tried. This was in 3rd and 4th gear, pushing it to 200km/h. The other one I found on the internet looks really smooth and stable as I would expect it to be. Shouldn't the MAF read over 200 g/s?
My readings
Readings from a Subaru Outback, seems much smoother
Values from a healthy RX-8 from another member:
Last edited by TomX8; 07-27-2017 at 02:56 PM.
07-27-2017, 02:24 PM
#2
///// Upscale Zoom-Zoom
Cleaning with anything but MAF cleaner likely killed the surface of the MAF and that gives you false air flow readings. The ECM/PCM is likely chasing its tail. Input humidity might also be affecting this since the surface has changed.
07-27-2017, 02:57 PM
#3
Yeah I assume so. First it was pretty dirty, so I cleaned it with the carb cleaner, and later once again, after which the problems got even worse. So it sounds like a dead giveaway, but I would like to judge from the MAF readings I posted here besides what I did with it to make sure whether it's really done for.
Last edited by TomX8; 07-27-2017 at 03:39 PM.