M103 3.0 Bosch Troubles
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Joined: Apr 2024
Posts: 12
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1986 300e 5 SPD
M103 3.0 Bosch Troubles
So my engine has been running very rough. It idles fine but if you punch the gas it completely bogs and if you slowly increase the throttle it gets to about 2500 and refuses to rev any higher. I've replaced basic things
Bosch Disturber Cap
Plugs
Bosch Rotor
All Vacuum lines (has 16inhg at idle)
Fuel filter.
Injectors and seals
I've checked fuel pressure and it has 80psi at the upper chamber. It has 71 psi in the lower at idle.
I've checked the duty cycle and it varies between 40 and 50 percent. However if you measure straight voltage at the pins it is between 1.5 and 2.3 volts??? No amount of mixture screw adjustment changes it. Im kind of at a loss? When the car first starts it measures 6.7 volts for the duty cycle then quickly drops into the closed loop around 2 volts and varies.
What next steps should I take?
Bosch Disturber Cap
Plugs
Bosch Rotor
All Vacuum lines (has 16inhg at idle)
Fuel filter.
Injectors and seals
I've checked fuel pressure and it has 80psi at the upper chamber. It has 71 psi in the lower at idle.
I've checked the duty cycle and it varies between 40 and 50 percent. However if you measure straight voltage at the pins it is between 1.5 and 2.3 volts??? No amount of mixture screw adjustment changes it. Im kind of at a loss? When the car first starts it measures 6.7 volts for the duty cycle then quickly drops into the closed loop around 2 volts and varies.
What next steps should I take?
Joined: Nov 2016
Posts: 7,847
Likes: 3,497
From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
You are asking questions about a 38 year old car? You'll be lucky to find members that weren't in diapers 38 years ago!
Do you have a scanner (such as an HHT SDS) to read any codes? Your best bet is to contact @BenzNinja and discuss how to diagnose your problems. www.benzninja.com
Do you have a scanner (such as an HHT SDS) to read any codes? Your best bet is to contact @BenzNinja and discuss how to diagnose your problems. www.benzninja.com
Joined: Nov 2016
Posts: 7,847
Likes: 3,497
From: Maryland
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
You might also want to ask your questions here: https://mbworld.org/forums/e-class-w124-28/
