hello,
i have a 2005 aveo 1.6l. i am looking from the MAP sensor. i believe i may have a crack in the MAP sensor house. my car shakes violently and the HOLD light comes on and the CEL flashes. when i read the code it says "random misfire". sometimes i can turn the HOLD light off and others i have to turn the car off and back on to get it to go away. does anyone know how to fix this or even what the problem is.
if it says random misfire. its probably a plug, wire or coil pack but could also be a stuck injector.
a MAF would send its own code.
how many miles do you have and have you even had a tune up?
There is not MAF in the car. It is a MAP based system. It should be somewhere on the intake manifold between the throttle body and head.Originally Posted by petrified.rabbit
A cracked MAP could lead to alot of problems since that is what determines injector flow at WOT. It will also make the car run like it has a large vac leak.
its called an IAT sensor
FASTEST AVEO IN ONTARIO
i may have the same problem, my light is on and it says random misfire and ive changed the plugs and wires
IAT stands for Intake Ambient Temp
MAP is Manifold absolute pressure
They are 2 completely different things.
Will changing the map sensor to 3 bar map sensor benefit a NA motor?
No. It will actually mess everything up if it is not calibrated for the car.
This graph will explain it simpler than I ever could
Now I know this particular table is for a neon but the same principle applies. Running a larger MAP without calibration to the ECU will make the computer think it is taking in much less air than it actually is causing the engine to run critically lean during open loop.
This is the one I am talking about.
http://cgi.ebay.com/ebaymotors/GM-3-...Q5fAccessories
The reason I am thinking of buying is because, at the last tuning session. When my tuner is trying to keep the AFR or lamda sensor at 13.5 at above 4k rpm. He mention something like my sensors is not very wide band resulting in sometime the ECU kicks in and interupt the mapping when he go above 4k rpm. So he can maintain a good 13.5 befor 4k rpm. But after 4k rpm, he is unable to get the best tuning result due to the "unstable" sensor he said. One step he change above or below, it goes crazy and the dyno lamda sensor shoot up and down instead of mantain a beautiful straight line at 13.5. It is now like a bit zig zag between 13.2-13.7 for rpm above 4k. I think he mentioned engine loading sensor or something like this. Which I duno what he is talking, I guess is either O2 sensor or MAP sensor since my aveo is without a MAF.
Does a car goes above 14.7psi at manifold? I have seen only 14.5 or 14.6 psi at the Scangauge from my OBD II while driving. If I change to 2 bar or 3 bar sensor, is it possible to detect some boost of maybe 1-2 psi?
usually wide-band refers to O2 sensors. The MAP sensor (sorry for the F earlier, still used to vw, force of habit) measures the vacuum. which a naturally aspirated vehicle should not need to jump to a 3 bar for any reason i am thinking of, unless you have the management to back it up and account for the change in signal like that graph shows. But 3 bar MAP sensors are used be people running boost..
wait Xiaogary, are you running boost? a n/a engine doesn't see positive psi. its vacuum.
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