M104 low idle
07-25-2019, 11:34 AM
#1
Newbie
Thread Starter
Join Date: Jul 2019
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
1995 E320 wagon
M104 low idle
Hello all,
I am new to the forum and have resorted to making this post in hopes some of you may have some useful tips and advice. Prepare for a long post! I purchased my 1995 E320 wagon with some issues that I’ve been steadily working through. I have found an issue though that I cannot quite put my finger on. My car idles at the normal 1000rpm upon cold start, down to 900rpm after a bit, then down to 500-550 afterward. This low of an idle causes my car to vibrate, especially in drive and reverse. I have a check engine light and a mixture of codes but have gotten it down to code 2 (heated oxygen sensor inoperative), 3 (lambda control inoperative), 5 (exhaust gas recirculation inoperative), and 6 (idle speed control inoperative). These are all using the factory led diagnostic codes. The car runs perfectly otherwise. The ASR light has come on once or twice causing the throttle to be unresponsive but doesn’t seem to be an issue anymore. The only other weird thing I can attest to that may be normal is a suction or whistle sound at 1900rpm in drive that I cannot duplicate in park. Okay so now to what I’ve done to try and correct these! I changed the fan clutch (irrelevant), spark plugs (also irrelevant), mass air flow (was getting a code for it), replaced the battery (mostly because it died). I’ve done an at home smoke test to check for vacuum leaks and haven’t had any luck... I suspected my problem was coming from the throttle actuator as I know of the biodegradable wire insulation but after removing it appears to be a new part with nice wires, so since I was already in that deep I replaced the intake bellow, lubricated the throttle linkages, and cleaned the resonance valve which also looked good and in tact. As far as I can tell the harness has maybe been replaced or repaired as it is wrapped with a sort of fabric tape on all the under hood harness. I’m pretty frustrated with this and unsure what steps to take next, and having already done so much digging would prefer to fix myself instead of have a shop do it, as there are many experienced Mercedes shops near me. Any advice would be appreciated
I am new to the forum and have resorted to making this post in hopes some of you may have some useful tips and advice. Prepare for a long post! I purchased my 1995 E320 wagon with some issues that I’ve been steadily working through. I have found an issue though that I cannot quite put my finger on. My car idles at the normal 1000rpm upon cold start, down to 900rpm after a bit, then down to 500-550 afterward. This low of an idle causes my car to vibrate, especially in drive and reverse. I have a check engine light and a mixture of codes but have gotten it down to code 2 (heated oxygen sensor inoperative), 3 (lambda control inoperative), 5 (exhaust gas recirculation inoperative), and 6 (idle speed control inoperative). These are all using the factory led diagnostic codes. The car runs perfectly otherwise. The ASR light has come on once or twice causing the throttle to be unresponsive but doesn’t seem to be an issue anymore. The only other weird thing I can attest to that may be normal is a suction or whistle sound at 1900rpm in drive that I cannot duplicate in park. Okay so now to what I’ve done to try and correct these! I changed the fan clutch (irrelevant), spark plugs (also irrelevant), mass air flow (was getting a code for it), replaced the battery (mostly because it died). I’ve done an at home smoke test to check for vacuum leaks and haven’t had any luck... I suspected my problem was coming from the throttle actuator as I know of the biodegradable wire insulation but after removing it appears to be a new part with nice wires, so since I was already in that deep I replaced the intake bellow, lubricated the throttle linkages, and cleaned the resonance valve which also looked good and in tact. As far as I can tell the harness has maybe been replaced or repaired as it is wrapped with a sort of fabric tape on all the under hood harness. I’m pretty frustrated with this and unsure what steps to take next, and having already done so much digging would prefer to fix myself instead of have a shop do it, as there are many experienced Mercedes shops near me. Any advice would be appreciated
