2.5 Diesel turbo boost control ?
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Joined: Dec 2005
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From: Nashville
1991 300d 2.5 turbo diesel
2.5 Diesel turbo boost control ?
Hi, first post here.
I am a decent machanic but a diesel dummy as in my log-in name.
I have a 1991 300d 2.5 turbo that is having intermintant boost issues that seem to be and electronic based problem. I installed a boost gauge so I can track whats going on and half, some, most, or none of the time my car will boost and when it's not, I can get it to attain full boost just my activating the Accl. lever of the cruise control. Once it starts to boost it runs great and may go 1 min./day/week working correctly before the boost drops out again.
Whatever electrical device the Cruise Control circut is controling must be getting or not getting a signel from whatever is supposed to control it. What controls the boost system, is it the CPU or something else? What can I look at ?
thanks in advance!
kevin
I am a decent machanic but a diesel dummy as in my log-in name.
I have a 1991 300d 2.5 turbo that is having intermintant boost issues that seem to be and electronic based problem. I installed a boost gauge so I can track whats going on and half, some, most, or none of the time my car will boost and when it's not, I can get it to attain full boost just my activating the Accl. lever of the cruise control. Once it starts to boost it runs great and may go 1 min./day/week working correctly before the boost drops out again.
Whatever electrical device the Cruise Control circut is controling must be getting or not getting a signel from whatever is supposed to control it. What controls the boost system, is it the CPU or something else? What can I look at ?
thanks in advance!
kevin
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Joined: Dec 2005
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From: Manchester, UK
W210 E300DT Saloon
Well I'm just wondering, as I had a similar problem on my Audi 1.9Tdi, and it turned out to be a faulty MAF. The turbo didn't even kick in, and the car was taking forever to accelerate.
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Originally Posted by DiesalDummy
Hi, first post here.
I am a decent machanic but a diesel dummy as in my log-in name.
I have a 1991 300d 2.5 turbo that is having intermintant boost issues that seem to be and electronic based problem. I installed a boost gauge so I can track whats going on and half, some, most, or none of the time my car will boost and when it's not, I can get it to attain full boost just my activating the Accl. lever of the cruise control. Once it starts to boost it runs great and may go 1 min./day/week working correctly before the boost drops out again.
Whatever electrical device the Cruise Control circut is controling must be getting or not getting a signel from whatever is supposed to control it. What controls the boost system, is it the CPU or something else? What can I look at ?
thanks in advance!
kevin
I am a decent machanic but a diesel dummy as in my log-in name.
I have a 1991 300d 2.5 turbo that is having intermintant boost issues that seem to be and electronic based problem. I installed a boost gauge so I can track whats going on and half, some, most, or none of the time my car will boost and when it's not, I can get it to attain full boost just my activating the Accl. lever of the cruise control. Once it starts to boost it runs great and may go 1 min./day/week working correctly before the boost drops out again.
Whatever electrical device the Cruise Control circut is controling must be getting or not getting a signel from whatever is supposed to control it. What controls the boost system, is it the CPU or something else? What can I look at ?
thanks in advance!
kevin
I just can't make sense of the cruise control causing boost to be restored. All the cruise control stalk does is, upon engagement, sends a signal to be processed via the amplifier to the actuator. The cruise control actuator is a big metal box attached to the linkage underneath the intake manifold of the engine. The actuator is attached to the linkage via a lever, and electronically engages the linkage keeping the vehicle at a steady speed as it senses engine speed and drag conditions (hills, wind resistance, etc) to compensate.
If the EGR malfunctions on these engines, it will trigger a sensor that will cause boost to be dropped by half. Other than that, these cars can be run without any charge at all (dead alt, dead batt, doesn't matter).
