94 e320 rough idle and "misfiring" issue
10-30-2008, 06:09 PM
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1994 E320 (current)
94 e320 rough idle and "misfiring" issue
My m104 e320 has a the following symptoms
1. Rough idle. This appeared first and is most notable at stop constant. it is the same wheather hot or cold.
2. Engine surging. This is worst when in reverse. Has a hard surging and RPM fluxuation from 400 to 1100 when it does it. This is constant and the same whether hot or cold.
3. "misfiring". this started a couple months back and happens intensely on a cold engine. When I start to accelerate it is fine with about 10% throttle. When I push it even a little bit the car seems to drop a couple of cylinders or fires late. As the engine revs out it will eventually clear until I let off the throttl and get back on it again. As the engine warms up the problem starts to clear up. After about 1 or 2 hours of driving it is almost undetectible. A few times I have had a back fire but rarely.
The Codes. The engine codes that come up are telling me that the throttle accuator is bad. Also give me that Lambda control O2 sensor code. ( I will post the exact codes when I get home)
Is it possible that there is two issues one is the rough idle since it had been there for a while before the misfiring issue. My thinking is the throttle acctuator is bad but not causing the misfire. I was thinking maybe a coil or posibly even a Cam position sensor.
I have replaced the O2, the OVP and the MAF. I am pretty sure that the wiring harness is newer and not one of the BIO wires.
ANy thoughts on where to start?
1. Rough idle. This appeared first and is most notable at stop constant. it is the same wheather hot or cold.
2. Engine surging. This is worst when in reverse. Has a hard surging and RPM fluxuation from 400 to 1100 when it does it. This is constant and the same whether hot or cold.
3. "misfiring". this started a couple months back and happens intensely on a cold engine. When I start to accelerate it is fine with about 10% throttle. When I push it even a little bit the car seems to drop a couple of cylinders or fires late. As the engine revs out it will eventually clear until I let off the throttl and get back on it again. As the engine warms up the problem starts to clear up. After about 1 or 2 hours of driving it is almost undetectible. A few times I have had a back fire but rarely.
The Codes. The engine codes that come up are telling me that the throttle accuator is bad. Also give me that Lambda control O2 sensor code. ( I will post the exact codes when I get home)
Is it possible that there is two issues one is the rough idle since it had been there for a while before the misfiring issue. My thinking is the throttle acctuator is bad but not causing the misfire. I was thinking maybe a coil or posibly even a Cam position sensor.
I have replaced the O2, the OVP and the MAF. I am pretty sure that the wiring harness is newer and not one of the BIO wires.
ANy thoughts on where to start?
01-05-2009, 10:05 PM
#2
94 e320 help from joe..
My m104 e320 has a the following symptoms
1. Rough idle. This appeared first and is most notable at stop constant. it is the same wheather hot or cold.
2. Engine surging. This is worst when in reverse. Has a hard surging and RPM fluxuation from 400 to 1100 when it does it. This is constant and the same whether hot or cold.
3. "misfiring". this started a couple months back and happens intensely on a cold engine. When I start to accelerate it is fine with about 10% throttle. When I push it even a little bit the car seems to drop a couple of cylinders or fires late. As the engine revs out it will eventually clear until I let off the throttl and get back on it again. As the engine warms up the problem starts to clear up. After about 1 or 2 hours of driving it is almost undetectible. A few times I have had a back fire but rarely.
The Codes. The engine codes that come up are telling me that the throttle accuator is bad. Also give me that Lambda control O2 sensor code. ( I will post the exact codes when I get home)
Is it possible that there is two issues one is the rough idle since it had been there for a while before the misfiring issue. My thinking is the throttle acctuator is bad but not causing the misfire. I was thinking maybe a coil or posibly even a Cam position sensor.
I have replaced the O2, the OVP and the MAF. I am pretty sure that the wiring harness is newer and not one of the BIO wires.
ANy thoughts on where to start?
1. Rough idle. This appeared first and is most notable at stop constant. it is the same wheather hot or cold.
2. Engine surging. This is worst when in reverse. Has a hard surging and RPM fluxuation from 400 to 1100 when it does it. This is constant and the same whether hot or cold.
3. "misfiring". this started a couple months back and happens intensely on a cold engine. When I start to accelerate it is fine with about 10% throttle. When I push it even a little bit the car seems to drop a couple of cylinders or fires late. As the engine revs out it will eventually clear until I let off the throttl and get back on it again. As the engine warms up the problem starts to clear up. After about 1 or 2 hours of driving it is almost undetectible. A few times I have had a back fire but rarely.
The Codes. The engine codes that come up are telling me that the throttle accuator is bad. Also give me that Lambda control O2 sensor code. ( I will post the exact codes when I get home)
Is it possible that there is two issues one is the rough idle since it had been there for a while before the misfiring issue. My thinking is the throttle acctuator is bad but not causing the misfire. I was thinking maybe a coil or posibly even a Cam position sensor.
I have replaced the O2, the OVP and the MAF. I am pretty sure that the wiring harness is newer and not one of the BIO wires.
ANy thoughts on where to start?
01-05-2009, 10:07 PM
#3
LET ME KNOW IF YOU EVER FIGURED OUT YOUR PROBLEM I HAVE A 1994 E320 THAT HAS POOR ACCELERATION WITH BACKFIRE AND HAVE TRIED EVERYTHING ALSO njoeandjen@comcast.net THANKS FOR ANY HELP.
01-18-2009, 03:03 AM
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monowiper
sometimes when an Oxygen sensor is about to go bad, but it's not 100% bad to throw you an exact code, you'll have same symptoms. i remember i had same issue, took a lot of effort to track down, specially getting no codes, after replacing coil packs, plugs, etc.
gl
gl
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