MAF frequency / fuel trims / P0300 questions
MAF frequency / fuel trims / P0300 questions
I have a early 2006 IX MR
Here is my list of mods that I run when they are on. I've only got the catback and wideband on while I try to determine if my car is fixed or not.
Tannabe turbo back / mechanical o2 fix
Works Drop-in
AEM Uego wideband
AEM Truboost gauge / controller w/boost control actuator
History:
My car was throwing P0300's and eventually
replaced the fuel injector's after trying to clean them first. I had previoulsy replaced plugs and wires and swapped the #1 and #2 coils to see if it changed the P030x code. The reason that they told me that they believed the injectors to be the problem was because of the fuel trims were getting out of limits and I could watch them at a stop light getting out of whack and then at some point above 122 or so (evoscan 122) the car would start idling very rough and it would throw a P0303 or P0300code. It was throwing the code more frequently at idle but also at rpm (3k or so). Also, driving in the rain seemed to aggravate the P0300 issue as well as the fuel trims which I suspect is because more accessory's are running (wipers, headlights, fan blower, etc). This was on a stock tune or custom tune (Jestr and Al). The light has not returned since the injectors were replaced although a semi rough idle remains (maybe a plug gap issue). I've removed my mods and am going to run the stock map w/just a catback until I'm sure this issue is fixed because I'm tired of installing / un-installing my dp / test pipe and boost controller.
Questions:
Is there a rough average of MAF frequency values at idle? Evoscan logs mine at idle in the 25.16 alternating to 31.45 - do you think my maf may need cleaning?
My fuel trims are still not staying put even with the new injectors (stock map, only a cat back on the car right now). They dont get as high as 120 but they are hovering at 114 right now.
Here is my list of mods that I run when they are on. I've only got the catback and wideband on while I try to determine if my car is fixed or not.
Tannabe turbo back / mechanical o2 fix
Works Drop-in
AEM Uego wideband
AEM Truboost gauge / controller w/boost control actuator
History:
My car was throwing P0300's and eventually
replaced the fuel injector's after trying to clean them first. I had previoulsy replaced plugs and wires and swapped the #1 and #2 coils to see if it changed the P030x code. The reason that they told me that they believed the injectors to be the problem was because of the fuel trims were getting out of limits and I could watch them at a stop light getting out of whack and then at some point above 122 or so (evoscan 122) the car would start idling very rough and it would throw a P0303 or P0300code. It was throwing the code more frequently at idle but also at rpm (3k or so). Also, driving in the rain seemed to aggravate the P0300 issue as well as the fuel trims which I suspect is because more accessory's are running (wipers, headlights, fan blower, etc). This was on a stock tune or custom tune (Jestr and Al). The light has not returned since the injectors were replaced although a semi rough idle remains (maybe a plug gap issue). I've removed my mods and am going to run the stock map w/just a catback until I'm sure this issue is fixed because I'm tired of installing / un-installing my dp / test pipe and boost controller.Questions:
Is there a rough average of MAF frequency values at idle? Evoscan logs mine at idle in the 25.16 alternating to 31.45 - do you think my maf may need cleaning?
My fuel trims are still not staying put even with the new injectors (stock map, only a cat back on the car right now). They dont get as high as 120 but they are hovering at 114 right now.
Most cars idle from 25-32hz My car idles at 36hz or so with an aftermarket MAF setup.
I've found that if long term fuel trims stay within about +/-10% (I think 115 is about what that would be) That would be considered fairly normal. Weather, altitude, fuel quality, and other things contribute to the fuel trims in closed loop.
I would look for obvious things like leaks that can allow unmetered air. Check your DV, and intake pipe to the airbox.
P0300's are elusive, if your getting one specific bank misfiring, and its the same regardless of swapping coils between the two banks, then there could be a bad connection, or bad fuel injector (or wiring to the fuel injector) to a particular cylinder.
Generally when I look at poor idle, its due to low or disrupted airflow in the MAF, your definitely in a range that looks to be normal, but as it goes up and down, this alters the fueling the engine recieves.
What RPM is your car idling at? You may need to have the BISS (Base Idle Set Scre) on the throttle body adjusted to raise the idle slightly (It should be base at 750rpm approx, but some cars like it a bit higher) This way when the ISC resets, idle speed shouldn't drop and the airflow should no longer stall.
Most cars do idle at 750-950rpm, its what is set in the roms.. Many cars are happier idling at 1000rpm I suspect the idle speed is set at that RPM for a reason (Emissions or whatnot)
Now, you have been telling us you get a P0300, you should look at the snapshot information when the codes are thrown, it will have the throttle position, engine RPM, speed, (OBD-II) Calculated load, Fuel trims, etc.. You need to know the conditions when it happens.
On my car, if its going to happen, it will happen at very low RPM, when the car is somewhat cold. This is due to a genuine misfire, the tip-in lean you get momentarily is usually partly the cause. Since you have stock heat range plugs, what are they gapped at? Factory want's a very large gap. I run my Gap around .026 and it seemed to help, but it depends on the heat range of your plugs.
a P0300 code generated during cruise driving (50-70 MPH) is caused by something different, it could be ignition related, but many have also related it to some sort of driveline noise.
You did the basic first steps, the dealer cleaned the injectors, but I don't suppose they could just replace them with new ones for you if this persists.
Your car is under warranty, so I'd keep complaining to them about it.. But at least you have something to work with.
I've found that if long term fuel trims stay within about +/-10% (I think 115 is about what that would be) That would be considered fairly normal. Weather, altitude, fuel quality, and other things contribute to the fuel trims in closed loop.
I would look for obvious things like leaks that can allow unmetered air. Check your DV, and intake pipe to the airbox.
P0300's are elusive, if your getting one specific bank misfiring, and its the same regardless of swapping coils between the two banks, then there could be a bad connection, or bad fuel injector (or wiring to the fuel injector) to a particular cylinder.
Generally when I look at poor idle, its due to low or disrupted airflow in the MAF, your definitely in a range that looks to be normal, but as it goes up and down, this alters the fueling the engine recieves.
What RPM is your car idling at? You may need to have the BISS (Base Idle Set Scre) on the throttle body adjusted to raise the idle slightly (It should be base at 750rpm approx, but some cars like it a bit higher) This way when the ISC resets, idle speed shouldn't drop and the airflow should no longer stall.
Most cars do idle at 750-950rpm, its what is set in the roms.. Many cars are happier idling at 1000rpm I suspect the idle speed is set at that RPM for a reason (Emissions or whatnot)
Now, you have been telling us you get a P0300, you should look at the snapshot information when the codes are thrown, it will have the throttle position, engine RPM, speed, (OBD-II) Calculated load, Fuel trims, etc.. You need to know the conditions when it happens.
On my car, if its going to happen, it will happen at very low RPM, when the car is somewhat cold. This is due to a genuine misfire, the tip-in lean you get momentarily is usually partly the cause. Since you have stock heat range plugs, what are they gapped at? Factory want's a very large gap. I run my Gap around .026 and it seemed to help, but it depends on the heat range of your plugs.
a P0300 code generated during cruise driving (50-70 MPH) is caused by something different, it could be ignition related, but many have also related it to some sort of driveline noise.
You did the basic first steps, the dealer cleaned the injectors, but I don't suppose they could just replace them with new ones for you if this persists.
Your car is under warranty, so I'd keep complaining to them about it.. But at least you have something to work with.
