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Discussion Starter · #1 · (Edited)
Hello.
I have a 2002 330CI convertible. M54 engine series. Manual.
This car does not have a cable for the throttle. Drive by wire.
Symptoms:
Start car, no SEL lights or diagnostics.
With car in neutral or in gear, clutch pressed or not, I can rev the engine, good response. idle is also good.
The moment I press the brake pedal, the accelerator no longer revs the engine.

Short background. Car ran well before this. I replaced the air filter. Changed the oil. I did disconnect the MAF while replacing the air filter. But was very sure to reconnect it. However I did not disconnect the battery.
When this happened the first time I did get the DSC light to come on. Was backing up on a slight incline.
To make this go away I restart the car, the gas pedal revs the engine well.
the moment I hit the brake pedal it disable the gas pedal.
I need some help. Thank You Lucas330CI

Also wanted to add that once the brake pedal is pressed the engines stays in perfect idle. around 750 rpm ( approx)
I have tried disconnected the battery for several minutes and reconnected.
 

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Are you using your left foot on the brake? You can't (and shouldn't) press the brake and the gas at the same time; brakes on / no gas... makes sense doesn't it?
Left foot = clutch, right foot = gas and brakes.
 

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Are you using your left foot on the brake? You can't (and shouldn't) press the brake and the gas at the same time; brakes on / no gas... makes sense doesn't it?
Left foot = clutch, right foot = gas and brakes.
Left foot braking and mainly used for racing.
 

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There are plenty of situations where left foot braking applies even on the street, it's just not something you should do if you don't need to.

As for the gas pedal being "disabled". There is absolutely no response from pressing the gas pedal or it just doesn't rev up?
 

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Are you using your left foot on the brake? You can't (and shouldn't) press the brake and the gas at the same time; brakes on / no gas... makes sense doesn't it?
Left foot = clutch, right foot = gas and brakes.
There are many instances where you can press the brakes and accelerator at the same time especially if you have a manual transmission car. Rev-matching and heel and toe techniques can be fun and very useful for smoother/quicker shifts.

OP: I can't think of why this issue would occur,but here is a link I found describing something similar, and it turns out that case was due to the owner forgetting to plug in the MAF sensor. I'm curious to see why this happened so keep us posted when you find the solution. http://www.zhpmafia.com/forums/archive/index.php/t-6545.html
 

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Discussion Starter · #7 ·
Are you using your left foot on the brake? You can't (and shouldn't) press the brake and the gas at the same time; brakes on / no gas... makes sense doesn't it?
Left foot = clutch, right foot = gas and brakes.
Hello Kaptchaos, Thank you for your time in responding.
No... I am not trying any fancy racing moves, too old for that! All of this happens while car is parked at home.
Let me describe the actions this way.
left foot on clutch, gear neutral, start car, car starts, engines reaches idle.
right foot on the gas pedal, engines revs responds to the gas pedal being pressed.
right foot moves to brake pedal, tap it once.
right foot goes back to gas pedal, engine no longer revs when gas pedal is pressed.
 

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Discussion Starter · #8 ·
There are plenty of situations where left foot braking applies even on the street, it's just not something you should do if you don't need to.

As for the gas pedal being "disabled". There is absolutely no response from pressing the gas pedal or it just doesn't rev up?
Hello Jeffwrench, Thank you for your time in responding.
No... I am not trying any fancy racing moves, too old for that! All of this happens while car is parked at home.
Let me describe the actions this way.
left foot on clutch, gear neutral, start car, car starts, engines reaches idle.
right foot on the gas pedal, engines revs responds to the gas pedal being pressed.
right foot moves to brake pedal, tap it once.
right foot goes back to gas pedal, engine no longer revs when gas pedal is pressed.
 

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Discussion Starter · #9 ·
There are many instances where you can press the brakes and accelerator at the same time especially if you have a manual transmission car. Rev-matching and heel and toe techniques can be fun and very useful for smoother/quicker shifts.

OP: I can't think of why this issue would occur,but here is a link I found describing something similar, and it turns out that case was due to the owner forgetting to plug in the MAF sensor. I'm curious to see why this happened so keep us posted when you find the solution. http://www.zhpmafia.com/forums/archive/index.php/t-6545.html
Hello OCD+, Thanks for your time and response. I had read that thread about having the MAF unplugged. I went back to the car after reading and made sure it was connected.
 

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Hello Jeffwrench, Thank you for your time in responding.
No... I am not trying any fancy racing moves, too old for that! All of this happens while car is parked at home.
Let me describe the actions this way.
left foot on clutch, gear neutral, start car, car starts, engines reaches idle.
right foot on the gas pedal, engines revs responds to the gas pedal being pressed.
right foot moves to brake pedal, tap it once.
right foot goes back to gas pedal, engine no longer revs when gas pedal is pressed.
One thing I'd recommend, as well as the suggestions from other, honestly more BMW savvy, people, is to verify that your MIL (SES,SEL,CEL,whatever you call it) actually is able to illuminate. When you turn the key to on without starting, does the MIL light up?

A few years back I had a car come in with really odd drivability issues and no MIL. I was racking my brains trying to figure out how it could be missing and bucking like it was and not throw a code. It wasn't till I plugged in my scantool to start checking livestream data that I realized it had dozens of codes and showed the MIL was on. The bulb was burnt out.
 

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Discussion Starter · #11 ·
Hello, here is an update: I believe to be a solution.
After re-reading all of the responses, I went back to make sure there was no SES light on or other clues.
I used an Advance Auto ODBII scanner with the key on, engine off and got no active codes, pass. HOWEVER, I tried reading the codes with engine running and got a single fault code, P0101 MAF fault circuit range /perf. code "pending".
This raises more questions...
Is keeping the engine from being revving up the "limp" mode behavior for my 330?
For anyone who experienced an MAF sensor going bad, does it happen quickly? One day it works and the next it does not?

Before I plug a $400+ part in, is there any checks I can do to the car/harness. Dont want to plug in and burn a new sensor.
Is there anything I could have done to damage the old MAF sensor? unplugging it with battery connected?
I will try and clean the old sensor and test it. I saw lots of posts on MAF testing...
Any further suggestions?
Thanks for everyones help.
 

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Check the Maf's electrical hook up,,have read many places that the wires inside that part where it hooks to the maf were not getting contact
 

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I posted a few months ago about a very similar issue. I was away for just over a year. When I returned, the battery was dead (of course) but interestingly my gas pedal was intermittent after the new battery was installed. I could press it to the floor sometimes and get zero response. This occurred only from a dead stop, never when actually driving. I'd pump it a few times and off we'd go. After about a week of this it just started working fine again. In fact, I believe it's better than ever. I used to notice a slight delay at stop signs, etc. I simply chalked it up to drive by wire. Now it seems more sensitive to slight inputs. No idea why it began or why it stopped. One thing I do know however, is that if I put my left foot on the brake I'll get no response from the gas pedal.

Edit: I was seriously looking into buying a Shark Injector. For your manual I believe the consensus is Sprint Booster.
 

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Are you using your left foot on the brake? You can't (and shouldn't) press the brake and the gas at the same time; brakes on / no gas... makes sense doesn't it?
Left foot = clutch, right foot = gas and brakes.
It may make sense until you learn to drive better, then it makes no sense. I brake and apply gas often with the right foot. It may be a "racing move" that I learned at VIR but it is definitely a good way to drive.
 

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I posted a few months ago about a very similar issue. I was away for just over a year. When I returned, the battery was dead (of course) but interestingly my gas pedal was intermittent after the new battery was installed. I could press it to the floor sometimes and get zero response. This occurred only from a dead stop, never when actually driving. I'd pump it a few times and off we'd go. After about a week of this it just started working fine again. In fact, I believe it's better than ever. I used to notice a slight delay at stop signs, etc. I simply chalked it up to drive by wire. Now it seems more sensitive to slight inputs. No idea why it began or why it stopped. One thing I do know however, is that if I put my left foot on the brake I'll get no response from the gas pedal.

Edit: I was seriously looking into buying a Shark Injector. For your manual I believe the consensus is Sprint Booster.
oh thought you had a manual, perhaps that is the design intent for an automatic?
 

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oh thought you had a manual, perhaps that is the design intent for an automatic?
Not really. Manuals came long before autos and the early manuals controls were nothing like we have today. Autos don't have a hard connection between engine and transmission, the torque converter is a fluid coupling, so the two aren't locked together unless the tcc is engaged. Some cars don't even have a tcc.

You generally don't want to 2 foot an auto because you tend to ride the brakes, which is also the reason for the left foot is clutch only mentality with manuals.

Holding both pedals on an auto called a stall, the engine will rev only to the point where the torque converter is able to flow. It's a good diagnostic test, but can be quite hard on the trans.

That should put it in perspective a little better. Left foot breaking has its place in both street and track driving for both transmission types, is just frowned upon because it can be damaging if done wrong.
 

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LEFT FOOT BRAKING
For the average Joe and Jane, the left foot has one job, and one job only. It operates the clutch. If you have no clutch, leave your left foot at home. Plant it on the floor and never move it. Anything that might happen in a specialized environment is apples & oranges when it comes to the average driver on the street. Using the left foot to operate the brake pedal is generally poor form.

P0101, Pending
A pending code means that an event happened once, and the computer is waiting for it to happen again, or not happen again. If the event repeats, then the Check Engine light will be turned on and the code will change from pending to active. If there are colors on your scanner, the color will change from yellow to red. If the event does not repeat within a certain number of drive cycles then the code should drop, although there is no reason not to store it for historical purposes. A pending code could be from yesterday, or last year. If it does not become an active code then it is an anomaly -- that is, whatever conditions prompted it have not repeated. There is no reason to buy a $400 part to cure a pending code.

Fly By Wire
There is no reason for the brake circuit to disable the throttle circuit. Indeed, it is a hazardous condition that the gas can go away after the application of brakes. Makes me wonder if anybody has been crawling around under the dash board looking for wires to splice in aftermarket stuff -- radio or security, for example.
 

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I had that problem once and thought it was a security override then I changed my control arm bushing and e-brake shoe and it started to work on its own along with cruise control
 

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Wow... maybe I'm going crazy. I just went out and tried braking and gassing at the same time and I have no problem with it. I was quite surprised. My other vehicle is an old Jeep CJ with a 5 speed so sometimes, after driving it and I jump into the BMW, I got the ol' left foot on the brake thing. I am positive that sometimes ( I would have thought always until today) the gas will not function when the brake is even lightly pressed. It reminds me to put my left foot on the floor. Any chance this is DSC related?
 

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Wow... maybe I'm going crazy. I just went out and tried braking and gassing at the same time and I have no problem with it. I was quite surprised. My other vehicle is an old Jeep CJ with a 5 speed so sometimes, after driving it and I jump into the BMW, I got the ol' left foot on the brake thing. I am positive that sometimes ( I would have thought always until today) the gas will not function when the brake is even lightly pressed. It reminds me to put my left foot on the floor. Any chance this is DSC related?

DSC _might_ be the link between the brake pedal making the gas pedal go cold. If this is true, then turning the DSC off should solve the problem temporarily. It's a valid test, that's for sure.

The problem with left foot braking in a stick shift, beyond resting the foot on the brake pedal enough that the brakes drag, is that if one is actively braking and the need to change gears arises, then the feet have to dance. If there is a rapidly approaching tree, then the foot dance can be the difference in hitting or missing the tree.
 
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