1997 E420 will not rev beyond a certain point
07-07-2009, 02:26 PM
#1
Junior Member
Thread Starter
1997 E420 will not rev beyond a certain point
Hi,
My E65 (E420) is exhibiting a problem where the throttle is only allowing the engine to rev to a certain point (3500-3800'ish rpm) and when more is asked of the throttle, it simply will not allow the car to climb in revs any further. The further the pedal is pushed it just maintains the rpm and will not go upward.
I am able to get the motor to rev beyond this point by manually dropping the car from overdrive to 4th and the motor will rev freely upward as it should although, there is a delay and the revs do not come on immediately. As a note, the diagnostic computer revealed that my fuel pressure is correct per the throttle position. I also do not believe this problem is due to some limp mode being activated...we are not able to find any evidence of this, however I guess that is still a possibility.
I have narrowed it down to something in the trans that tells the throttle to continue letting the motor receive the necessary fuel during kick-down or pressing the pedal to the floor...sorry for my layman's terms. My second theory is it could be a knock-sensor but I don't think it is based on the fact that I can get the car to rev by manually shifting it.
Is there a solenoid or some sensor in the trans that speaks with the throttle pedal or throttle body? Is there something here that sounds like a problem discussed before? Does this sound remotely familiar to anyone?? I've been trying to figure this thing out for weeks and I'm lost as this point. Thanks!!!
My E65 (E420) is exhibiting a problem where the throttle is only allowing the engine to rev to a certain point (3500-3800'ish rpm) and when more is asked of the throttle, it simply will not allow the car to climb in revs any further. The further the pedal is pushed it just maintains the rpm and will not go upward.
I am able to get the motor to rev beyond this point by manually dropping the car from overdrive to 4th and the motor will rev freely upward as it should although, there is a delay and the revs do not come on immediately. As a note, the diagnostic computer revealed that my fuel pressure is correct per the throttle position. I also do not believe this problem is due to some limp mode being activated...we are not able to find any evidence of this, however I guess that is still a possibility.
I have narrowed it down to something in the trans that tells the throttle to continue letting the motor receive the necessary fuel during kick-down or pressing the pedal to the floor...sorry for my layman's terms. My second theory is it could be a knock-sensor but I don't think it is based on the fact that I can get the car to rev by manually shifting it.
Is there a solenoid or some sensor in the trans that speaks with the throttle pedal or throttle body? Is there something here that sounds like a problem discussed before? Does this sound remotely familiar to anyone?? I've been trying to figure this thing out for weeks and I'm lost as this point. Thanks!!!
07-08-2009, 10:30 AM
#2
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300E a couple 1994 w124wagon E320 Wagon/,1971MGB Track/Rally, MG Midget Autocross ,2000 E320 wagon.
Any
codes?
Have you cleaned the throttle body?
CRC brand maf cleaner is good for doing both. Might want to clean the mass air sensor while there anyway.
Any Eta codes
check all vacuum lines and lastly check your cat function. A blocked cat will limit revs like a sock stuffed in the intake.
Have you cleaned the throttle body?
CRC brand maf cleaner is good for doing both. Might want to clean the mass air sensor while there anyway.
Any Eta codes
check all vacuum lines and lastly check your cat function. A blocked cat will limit revs like a sock stuffed in the intake.
07-10-2009, 08:39 AM
#3
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2001 E320 Avant turbo diesel
Does the 420 have a turbo/komp? ... do they come with manifold flap actuators ? sounds a bit like the problem I had heh.. and it might not seem so slugish on a big Vblock as mine was ...which made the problem very noticable ... mine would do they same not rev over 2.5K rpm but when shifting tip-tronically you could get it to go harder...
Deleted the motor, problem solved ... i gues cruse ctrl might loose some economy for doing it.. but no one has explaiend any where its true function .. but that is my supersition
and just thinking about it ... it must screw about with the kick down as well.. as when i drove my car properly for the first time after deleteinng it .. i was heavyfooted after weeks of being crippled and the car immediatly kicked down
Deleted the motor, problem solved ... i gues cruse ctrl might loose some economy for doing it.. but no one has explaiend any where its true function .. but that is my supersition
and just thinking about it ... it must screw about with the kick down as well.. as when i drove my car properly for the first time after deleteinng it .. i was heavyfooted after weeks of being crippled and the car immediatly kicked down
Last edited by ncd20; 07-10-2009 at 08:52 AM.
02-12-2016, 07:37 AM
#6
Super Member
Sounds to me like he is hitting a max speed limit in the ecu. 3800rpm in overdrive is a pretty good clip. How fast are you going when it stops accelerating? Is this a US market car? Does the engine pull to redline when accelerating through the lower gears?
