cold air intake problem...
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Joined: Apr 2007
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From: Republican Wasteland
HPF E46 M3 Turbo, LET C32 AMG
cold air intake problem...
when i put the cold air intake on my car a few months back i started losing about40 miles per tankful of gas!!!!! ive just been putting it off. it time to have this checked out i think. anyone have any ideas why this is happening? i used to get 325 miles per 15 gallons of gas, now i get 270-280 per tank. it started happening the day i put on the new intake. my guess is that the extra air is making the computer add extra fuel to compensate? if this is the problem, is there anything that can be done to the ECU to make it think this amount of air is OK?
if you think the problem lies elsewhere, please let me know what you think. thanks
if you think the problem lies elsewhere, please let me know what you think. thanks
Thread Starter
Member
Joined: Apr 2007
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From: Republican Wasteland
HPF E46 M3 Turbo, LET C32 AMG
as far as oil, thats not it, it comes from the factory with just the right amount on it.
also, macclk, that is a great looking 320!!!
Last edited by SETSEROCK; May 23, 2007 at 11:50 AM.
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Joined: Apr 2005
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From: SCV SoCal
2002 CLK430
Is it possible you’re driving with a heavier foot? Many times those with a new K&N want to hear the intake, so they’re on the gas a little more. As MACCLK posted, that would cause you to burn more gas.
As for cold air, I don’t know what an early 320 intake looks like, 430’s have dual cold air snorkels. If the early 320 originally came with a cold air snorkel or two, it’s not the cold air that’s making a difference. Your Bosch ME 2.0 has a mass air flow sensor, and an intake air thermosensor so it’s highly doubtful the ECU isn’t making the proper adjustments - – unless your new intake is really ingesting hot air. In that case, the ECU knows exactly how much air is being ingested, and what that air’s temperature is. According to my Bosch FI manual, if the intake air thermosensor determines the incoming air is hotter than normal (although it doesn’t state what “normal” is), the ECU will inject more fuel.
Under what conditions are you seeing 18MPG? With a 320, I would guess you should get something in the 34+ MPG range on the freeway. How old are the plugs? OE wires? What about the O2 sensors?
As for cold air, I don’t know what an early 320 intake looks like, 430’s have dual cold air snorkels. If the early 320 originally came with a cold air snorkel or two, it’s not the cold air that’s making a difference. Your Bosch ME 2.0 has a mass air flow sensor, and an intake air thermosensor so it’s highly doubtful the ECU isn’t making the proper adjustments - – unless your new intake is really ingesting hot air. In that case, the ECU knows exactly how much air is being ingested, and what that air’s temperature is. According to my Bosch FI manual, if the intake air thermosensor determines the incoming air is hotter than normal (although it doesn’t state what “normal” is), the ECU will inject more fuel.
Under what conditions are you seeing 18MPG? With a 320, I would guess you should get something in the 34+ MPG range on the freeway. How old are the plugs? OE wires? What about the O2 sensors?
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Thread Starter
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Joined: Apr 2007
Posts: 247
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From: Republican Wasteland
HPF E46 M3 Turbo, LET C32 AMG
Is it possible you’re driving with a heavier foot? Many times those with a new K&N want to hear the intake, so they’re on the gas a little more. As MACCLK posted, that would cause you to burn more gas.
As for cold air, I don’t know what an early 320 intake looks like, 430’s have dual cold air snorkels. If the early 320 originally came with a cold air snorkel or two, it’s not the cold air that’s making a difference. Your Bosch ME 2.0 has a mass air flow sensor, and an intake air thermosensor so it’s highly doubtful the ECU isn’t making the proper adjustments - – unless your new intake is really ingesting hot air. In that case, the ECU knows exactly how much air is being ingested, and what that air’s temperature is. According to my Bosch FI manual, if the intake air thermosensor determines the incoming air is hotter than normal (although it doesn’t state what “normal” is), the ECU will inject more fuel.
Under what conditions are you seeing 18MPG? With a 320, I would guess you should get something in the 34+ MPG range on the freeway. How old are the plugs? OE wires? What about the O2 sensors?
As for cold air, I don’t know what an early 320 intake looks like, 430’s have dual cold air snorkels. If the early 320 originally came with a cold air snorkel or two, it’s not the cold air that’s making a difference. Your Bosch ME 2.0 has a mass air flow sensor, and an intake air thermosensor so it’s highly doubtful the ECU isn’t making the proper adjustments - – unless your new intake is really ingesting hot air. In that case, the ECU knows exactly how much air is being ingested, and what that air’s temperature is. According to my Bosch FI manual, if the intake air thermosensor determines the incoming air is hotter than normal (although it doesn’t state what “normal” is), the ECU will inject more fuel.
Under what conditions are you seeing 18MPG? With a 320, I would guess you should get something in the 34+ MPG range on the freeway. How old are the plugs? OE wires? What about the O2 sensors?
Last edited by SETSEROCK; May 23, 2007 at 12:11 PM.
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Joined: Sep 2005
Posts: 6,189
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From: Albuquerque
'10 CL550, '12 GL550
You're dreaming if you think your motor's getting "extra air."
The only way it can get "extra air" is to ask for it, and the only way to get it to ask for it is to
increase valve lift
increase valve size
increase valve lift duration
increase displacement
Or you can force it in, which requires a turbo or supercharger.
Your Mercedes came OE with a cold air intake and you've removed it for an underhood intake instead.
In addition, a K&N filter will oil down your MAF sensor, basically ruining it.
Fantasyland strikes again.
The only way it can get "extra air" is to ask for it, and the only way to get it to ask for it is to
increase valve lift
increase valve size
increase valve lift duration
increase displacement
Or you can force it in, which requires a turbo or supercharger.
Your Mercedes came OE with a cold air intake and you've removed it for an underhood intake instead.
In addition, a K&N filter will oil down your MAF sensor, basically ruining it.
Fantasyland strikes again.
Thread Starter
Member
Joined: Apr 2007
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From: Republican Wasteland
HPF E46 M3 Turbo, LET C32 AMG
and as far as this fantasy land stuff goes... fantasy my nuts on your chin!!!
MBWorld Fanatic!
Joined: Apr 2005
Posts: 3,784
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From: SCV SoCal
2002 CLK430
The plugs should be changed every 100K miles or five years. Original plugs in a 99 mean they've have lasted almost twice as long as they were intended. If so, they are really overdue. Since they're nine years old, I'd change the wires too. When I changed my plugs, I bought them at my local MB dealer. With the Mercedes-Benz Club of America discount, they were $7.50 each. The discount was more than my MBCA annual membership fee (Yes, that's two plugs for MBCA! 
) You may also want to buy a plug wire tool.
I didn't notice any difference in power and mileage (my mileage was FANTASTIC to begin with). However, dead plugs will drive the mileage down. O2 sensors only kill mileage (and cats) at idle and cruise. You won't notice the difference around town unless you spend a lot of time waiting at lights. You may also want to check your tire pressures with a good guage. I've found that those 99 cent pencil gauges are usually way off. I've got one in the garage thats 5 pounds off at 35 PSI.
IHTH
) You may also want to buy a plug wire tool. I didn't notice any difference in power and mileage (my mileage was FANTASTIC to begin with). However, dead plugs will drive the mileage down. O2 sensors only kill mileage (and cats) at idle and cruise. You won't notice the difference around town unless you spend a lot of time waiting at lights. You may also want to check your tire pressures with a good guage. I've found that those 99 cent pencil gauges are usually way off. I've got one in the garage thats 5 pounds off at 35 PSI.
IHTH
Thread Starter
Member
Joined: Apr 2007
Posts: 247
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From: Republican Wasteland
HPF E46 M3 Turbo, LET C32 AMG
The plugs should be changed every 100K miles or five years. Original plugs in a 99 mean they've have lasted almost twice as long as they were intended. If so, they are really overdue. Since they're nine years old, I'd change the wires too. When I changed my plugs, I bought them at my local MB dealer. With the Mercedes-Benz Club of America discount, they were $7.50 each. The discount was more than my MBCA annual membership fee (Yes, that's two plugs for MBCA! ) You may also want to buy a plug wire tool.
I didn't notice any difference in power and mileage (my mileage was FANTASTIC to begin with). However, dead plugs will drive the mileage down. O2 sensors only kill mileage (and cats) at idle and cruise. You won't notice the difference around town unless you spend a lot of time waiting at lights. You may also want to check your tire pressures with a good guage. I've found that those 99 cent pencil gauges are usually way off. I've got one in the garage thats 5 pounds off at 35 PSI.
IHTH
) You may also want to buy a plug wire tool. I didn't notice any difference in power and mileage (my mileage was FANTASTIC to begin with). However, dead plugs will drive the mileage down. O2 sensors only kill mileage (and cats) at idle and cruise. You won't notice the difference around town unless you spend a lot of time waiting at lights. You may also want to check your tire pressures with a good guage. I've found that those 99 cent pencil gauges are usually way off. I've got one in the garage thats 5 pounds off at 35 PSI.
IHTH
Thread Starter
Member
Joined: Apr 2007
Posts: 247
Likes: 0
From: Republican Wasteland
HPF E46 M3 Turbo, LET C32 AMG
The plugs should be changed every 100K miles or five years. Original plugs in a 99 mean they've have lasted almost twice as long as they were intended. If so, they are really overdue. Since they're nine years old, I'd change the wires too. When I changed my plugs, I bought them at my local MB dealer. With the Mercedes-Benz Club of America discount, they were $7.50 each. The discount was more than my MBCA annual membership fee (Yes, that's two plugs for MBCA! ) You may also want to buy a plug wire tool.
I didn't notice any difference in power and mileage (my mileage was FANTASTIC to begin with). However, dead plugs will drive the mileage down. O2 sensors only kill mileage (and cats) at idle and cruise. You won't notice the difference around town unless you spend a lot of time waiting at lights. You may also want to check your tire pressures with a good guage. I've found that those 99 cent pencil gauges are usually way off. I've got one in the garage thats 5 pounds off at 35 PSI.
IHTH
) You may also want to buy a plug wire tool. I didn't notice any difference in power and mileage (my mileage was FANTASTIC to begin with). However, dead plugs will drive the mileage down. O2 sensors only kill mileage (and cats) at idle and cruise. You won't notice the difference around town unless you spend a lot of time waiting at lights. You may also want to check your tire pressures with a good guage. I've found that those 99 cent pencil gauges are usually way off. I've got one in the garage thats 5 pounds off at 35 PSI.
IHTH
Super Member
Joined: Jan 2007
Posts: 566
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From: OC, CA
1999 CLK430 (sold) 03 CL55
Wires I dunno whichever the stock ones it came with.
