Unconstant Acceleration
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Unconstant Acceleration
Hi Fans of the fast US Cars
sorry for the bad english.
Im really happy with my Corvette but have now a weird issue.
When i accelerate in moderate Mode (Pedal 50% to 80%) i have a acceleration like the engine dont fires accurate. I changed the Plugwires allready. Like the engine shuts off for a milisecond and then fires again.
Sometimes when i have the failure the MAF Error Code 101 does appear but not allways (new one is ordered). I have also sometimes both O2 Sensores before the Cat reporting an Error (P0131 and P0151). But not often.
any idea what the Problem can be? In Fulltrottle the machine accelerates really straight but i cannot at every Trafficlight in the city hit the pedal to the metal.
i have hptuners and can make every diagnostic if that helps. but have no idea what to log.
mfG René
sorry for the bad english.
Im really happy with my Corvette but have now a weird issue.
When i accelerate in moderate Mode (Pedal 50% to 80%) i have a acceleration like the engine dont fires accurate. I changed the Plugwires allready. Like the engine shuts off for a milisecond and then fires again.
Sometimes when i have the failure the MAF Error Code 101 does appear but not allways (new one is ordered). I have also sometimes both O2 Sensores before the Cat reporting an Error (P0131 and P0151). But not often.
any idea what the Problem can be? In Fulltrottle the machine accelerates really straight but i cannot at every Trafficlight in the city hit the pedal to the metal.
i have hptuners and can make every diagnostic if that helps. but have no idea what to log.
mfG René
Melting Slicks
Joined: Apr 2009
Posts: 2,479
Likes: 36
You don't state whether your car is stock or not.
However, you have pretty well answered your own question. A bad MAF would cause the problems that you describe. I would also go ahead and change out the O2 sensors.
However, you have pretty well answered your own question. A bad MAF would cause the problems that you describe. I would also go ahead and change out the O2 sensors.
Melting Slicks
Joined: Nov 2008
Posts: 2,938
Likes: 65
From: Rochester Hills MI
+1 for the MAF. spray it with some contact cleaner.
if that doesn't do the trick, i'd check for vacuum leaks. then try some fuel system cleaner. then go on to plugs and wires. how many miles does your car have?
if that doesn't do the trick, i'd check for vacuum leaks. then try some fuel system cleaner. then go on to plugs and wires. how many miles does your car have?
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Melting Slicks
Joined: Apr 2009
Posts: 2,479
Likes: 36
You need to definitely check for leaks in the Vararam system. They are notorious for air leaks. It is especially important to not have any air leaks after the MAF because this would introduce unmetered air into the intake and cause the types of problems you describe. Even a brand new MAF would not fix the problem if air leaks are present.
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Thread Starter
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You need to definitely check for leaks in the Vararam system. They are notorious for air leaks. It is especially important to not have any air leaks after the MAF because this would introduce unmetered air into the intake and cause the types of problems you describe. Even a brand new MAF would not fix the problem if air leaks are present.
But how can a leak before the maf bring this failure up? I mean its the same air as the air that came from the front and its also be measured by the maf.
mfg René
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Well Maf P0101 apeared again with a short acceleration break. ^^.
Nope no Traction loss. Have a 2.73 Diff right now have to hit the Pedal trough the Floor to loose Traction
So i think i have to wait for a new MAF.
Thank you for youre hints.
mfG René
Nope no Traction loss. Have a 2.73 Diff right now have to hit the Pedal trough the Floor to loose Traction
So i think i have to wait for a new MAF.
Thank you for youre hints.
mfG René
Tech Contributor
Joined: Dec 2006
Posts: 10,962
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From: Van Buren Arkansas
Wounded Warrior Escort '11
Try an experiment while you are waiting on the replacement MAF to arrive, with the engine idling, tap on the MAF itself and listen for any engine changes. If it does or suddenly stumbles, yep, bad MAF. The MAf works by heating an element hanging there inside of it. The air passing, past the element cools it off slightly therefore the PCM has to increase the heating to the element to compensate. By doing this, its measuring the amount of air passing through there and via its algorythms, it sets the fuel mixture via timing pulses to the injectors, coil timing and so on. This is why any air getting into the engine without going through the MAF is so important as the mixture is leaned out, the O2 sensors pick it up then the PCM wakes up and says, hey what's going on here and tries to compensate.
Melting Slicks
Joined: Nov 2008
Posts: 2,938
Likes: 65
From: Rochester Hills MI
Try an experiment while you are waiting on the replacement MAF to arrive, with the engine idling, tap on the MAF itself and listen for any engine changes. If it does or suddenly stumbles, yep, bad MAF. The MAf works by heating an element hanging there inside of it. The air passing, past the element cools it off slightly therefore the PCM has to increase the heating to the element to compensate. By doing this, its measuring the amount of air passing through there and via its algorythms, it sets the fuel mixture via timing pulses to the injectors, coil timing and so on. This is why any air getting into the engine without going through the MAF is so important as the mixture is leaned out, the O2 sensors pick it up then the PCM wakes up and says, hey what's going on here and tries to compensate.
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Instructor
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mfG René
Thread Starter
Instructor
Joined: Aug 2011
Posts: 114
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whoa this morning i hat a really weird issue.
Hitting the Pedal to the bottom and notthing was going. car really slowly accelerates to about 20mph. i bring pedal to 50% and again to 100% nothing happend. I letting pedal go (car slows down) and hit it again to the ground and car really speeds up.
DTC brought up some Codes P101 H (MAF as knowing) but now also P0131 C plus P0151 C.
Now im dissapointet if i should also buy new Oxigen Sensors.
And where are the groundings locatet for those sensors? I didnt found the Grounds G105-G107. Do i need a Lift for them?
mfG René
Hitting the Pedal to the bottom and notthing was going. car really slowly accelerates to about 20mph. i bring pedal to 50% and again to 100% nothing happend. I letting pedal go (car slows down) and hit it again to the ground and car really speeds up.
DTC brought up some Codes P101 H (MAF as knowing) but now also P0131 C plus P0151 C.
Now im dissapointet if i should also buy new Oxigen Sensors.
And where are the groundings locatet for those sensors? I didnt found the Grounds G105-G107. Do i need a Lift for them?
mfG René
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Instructor
Joined: Aug 2011
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addendum. Now i unplugged the MAF wile Engine was running. it short choked but didnt die.
After a few rounds on normal Speed and Higway about 180mp/h i have to say it runns very smooth and powerfull.
The only code it drops is P0102 C for now.
Are there any danger if i let the maf disconnect until the new one commes?
mfg René
After a few rounds on normal Speed and Higway about 180mp/h i have to say it runns very smooth and powerfull.
The only code it drops is P0102 C for now.
Are there any danger if i let the maf disconnect until the new one commes?
mfg René
