Cobb AP + Engine Shaking
02-24-2015, 01:37 PM
#11
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No it isn't the AP. The map that is flashed to the DME from the AP is adding more requested power out of the engine. Even though stg1 maps are a mild increase it is a increase over stock that can and will expose any weakness in the engines ability to produce the requested power.
OP- just curious what stg1 map are you flashing; drive, sport or aggr? Also what fuel are you using 91 or 93 oct and what brand of gas.
OP- just curious what stg1 map are you flashing; drive, sport or aggr? Also what fuel are you using 91 or 93 oct and what brand of gas.
If fuel (octane) is the problem, then normally the knock sensors would take care of that, but then perhaps the AP disconnects that feature. Pre-ignition doesn't give a shakey engine above 3000 rpm, though.
These symptoms do resemble rev limiter effect, however, which is possible if the AP is defective and the rev limiter kicks in too early. Isn't lifting the rev limiter to higher revs another feature of the AP.
Salut, Bob P.
02-24-2015, 02:11 PM
#12
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Even if, as you say, the map requests more power, that is done by changing the advance and fuel ratios at different points on the rpm map, which doesn't put the plugs, coils, injectors etc. under any more stress, thus exposing their weaknesses.
If fuel (octane) is the problem, then normally the knock sensors would take care of that, but then perhaps the AP disconnects that feature. Pre-ignition doesn't give a shakey engine above 3000 rpm, though.
These symptoms do resemble rev limiter effect, however, which is possible if the AP is defective and the rev limiter kicks in too early. Isn't lifting the rev limiter to higher revs another feature of the AP.
Salut, Bob P.
If fuel (octane) is the problem, then normally the knock sensors would take care of that, but then perhaps the AP disconnects that feature. Pre-ignition doesn't give a shakey engine above 3000 rpm, though.
These symptoms do resemble rev limiter effect, however, which is possible if the AP is defective and the rev limiter kicks in too early. Isn't lifting the rev limiter to higher revs another feature of the AP.
Salut, Bob P.
More boost (higher cylinder pressure) on a tuned car will have more pronounced affects when you have weak spark due to worn plugs or coils. It is highly unlikely the fault is due to the AccessPORT. It is very likely the higher load the motor is now experiencing is exposing an underlying issue that would eventually pop up down the road on a stock car.
02-25-2015, 01:38 AM
#13
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Even if, as you say, the map requests more power, that is done by changing the advance and fuel ratios at different points on the rpm map, which doesn't put the plugs, coils, injectors etc. under any more stress, thus exposing their weaknesses.
If fuel (octane) is the problem, then normally the knock sensors would take care of that, but then perhaps the AP disconnects that feature. Pre-ignition doesn't give a shakey engine above 3000 rpm, though.
These symptoms do resemble rev limiter effect, however, which is possible if the AP is defective and the rev limiter kicks in too early. Isn't lifting the rev limiter to higher revs another feature of the AP.
Salut, Bob P.
If fuel (octane) is the problem, then normally the knock sensors would take care of that, but then perhaps the AP disconnects that feature. Pre-ignition doesn't give a shakey engine above 3000 rpm, though.
These symptoms do resemble rev limiter effect, however, which is possible if the AP is defective and the rev limiter kicks in too early. Isn't lifting the rev limiter to higher revs another feature of the AP.
Salut, Bob P.
Let me tell u what happens when u tune this car, you will usually get misfire codes if you haven't recently replaced the coils or spark plugs. This has been documented. And recently happened to guy on N54tech after tuning his 535i and needed up to be new spark plugs.
02-25-2015, 08:08 AM
#14
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The Cobb AP just changes the time at which advance is set, when and how much the fuel is added and the boost slightly. The misfire on one cylinder in normal tune was fixed and is essentially a 'red herring' in this discussion.Your example from N54tech probably had more than the Cobb AP as tuning and ran into those misfires.
Pulling the codes with the AP installed should help clear this up.
With respect.
Bob P.
02-25-2015, 09:14 PM
#15
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I understand that, but OP has stated that he just recently replaced coils and plugs and his symptoms are not that of misfiring. The Cobb AP just changes the time at which advance is set, when and how much the fuel is added and the boost slightly. The misfire on one cylinder in normal tune was fixed and is essentially a 'red herring' in this discussion.
Your example from N54tech probably had more than the Cobb AP as tuning and ran into those misfires.
Pulling the codes with the AP installed should help clear this up.
With respect.
Bob P.
The Cobb AP just changes the time at which advance is set, when and how much the fuel is added and the boost slightly. The misfire on one cylinder in normal tune was fixed and is essentially a 'red herring' in this discussion.Your example from N54tech probably had more than the Cobb AP as tuning and ran into those misfires.
Pulling the codes with the AP installed should help clear this up.
With respect.
Bob P.
02-26-2015, 05:38 AM
#16
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Yes, it can, and does somewhat in this application.
The more I think about this, the more I think that the OP might be using the wrong OTS map i.e. the 'valet' map, which cuts out the fuel at about 3200 rpm to keep valets from taking the car for a spin. He does not experience any problems until he tries to go past 3000 rpm, then the engine shakes and gives signs of misfiring, which will happen if the fuel is cut off abruptly.
Sometimes it is the silliest and simplist things that are the cause of problems, which is why I suspect something with the AP, since it is designed at the state of tuning the OP has installed to operate with a normal well running engine, which theOP has shown to be the case.
Salut, Bob P.
The more I think about this, the more I think that the OP might be using the wrong OTS map i.e. the 'valet' map, which cuts out the fuel at about 3200 rpm to keep valets from taking the car for a spin. He does not experience any problems until he tries to go past 3000 rpm, then the engine shakes and gives signs of misfiring, which will happen if the fuel is cut off abruptly.
Sometimes it is the silliest and simplist things that are the cause of problems, which is why I suspect something with the AP, since it is designed at the state of tuning the OP has installed to operate with a normal well running engine, which theOP has shown to be the case.
Salut, Bob P.
02-26-2015, 08:14 AM
#17
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My Ride: Alpine E60, '09 535i-Premium, Sport and Comfort Access PackageMods: Lux H8 V3 Angel Eyes, Weisslicht LED license plate lights, Interior LED lights, RPI Scoop, Matte Black Grills, Smoked LED side markers & side reflectors, 35% tint all around, and a 3
Yes, it can, and does somewhat in this application.
The more I think about this, the more I think that the OP might be using the wrong OTS map i.e. the 'valet' map, which cuts out the fuel at about 3200 rpm to keep valets from taking the car for a spin. He does not experience any problems until he tries to go past 3000 rpm, then the engine shakes and gives signs of misfiring, which will happen if the fuel is cut off abruptly.
Sometimes it is the silliest and simplist things that are the cause of problems, which is why I suspect something with the AP, since it is designed at the state of tuning the OP has installed to operate with a normal well running engine, which theOP has shown to be the case.
Salut, Bob P.
The more I think about this, the more I think that the OP might be using the wrong OTS map i.e. the 'valet' map, which cuts out the fuel at about 3200 rpm to keep valets from taking the car for a spin. He does not experience any problems until he tries to go past 3000 rpm, then the engine shakes and gives signs of misfiring, which will happen if the fuel is cut off abruptly.
Sometimes it is the silliest and simplist things that are the cause of problems, which is why I suspect something with the AP, since it is designed at the state of tuning the OP has installed to operate with a normal well running engine, which theOP has shown to be the case.
Salut, Bob P.
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