E350CGI Suspect overheating
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Joined: Jul 2023
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w212 E350CGI
E350CGI Suspect overheating
Hi, I have a 2010 E350CGI and when it gets hot coolant temp indicating 105deg C, if you apply too much throttle the car will run badly and bring in the code 'Fuel Rail High Pressure' I have done a few things to investigate this, and the fuel pressure regulator appears to be working fine under all other circumstances.
I noticed yesterday that the fan came on with the coolant temp indicating 93degC which seemed too low. Is it possible that the coolant temp sensor is faulty causing the engine to run hotter than it should, thus causing the fuel to boil in the rail giving the high pressure fault?
Any ideas/help would be appreciated thanks in adavence
I noticed yesterday that the fan came on with the coolant temp indicating 93degC which seemed too low. Is it possible that the coolant temp sensor is faulty causing the engine to run hotter than it should, thus causing the fuel to boil in the rail giving the high pressure fault?
Any ideas/help would be appreciated thanks in adavence
MBWorld Fanatic!
Joined: Jan 2009
Posts: 9,225
Likes: 1,798
From: V E G A S
1922 Ford Model T / no OBD
Get scanner and monitor those sensors while driving.
On my diesels I have more things to observe, so I "ask Santa" to bring me ScanGauge 3 for Christmas.
Still for occasional use, cheap dongle with Torque app will do.
On my diesels I have more things to observe, so I "ask Santa" to bring me ScanGauge 3 for Christmas.
Still for occasional use, cheap dongle with Torque app will do.
Out Of Control!!
Joined: Apr 2019
Posts: 12,125
Likes: 6,875
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
ECU in crisis
Hi, I have a 2010 E350CGI and when it gets hot coolant temp indicating 105deg C, if you apply too much throttle the car will run badly and bring in the code 'Fuel Rail High Pressure' I have done a few things to investigate this, and the fuel pressure regulator appears to be working fine under all other circumstances.
I noticed yesterday that the fan came on with the coolant temp indicating 93degC which seemed too low. Is it possible that the coolant temp sensor is faulty causing the engine to run hotter than it should, thus causing the fuel to boil in the rail giving the high pressure fault?
Any ideas/help would be appreciated thanks in adavence
I noticed yesterday that the fan came on with the coolant temp indicating 93degC which seemed too low. Is it possible that the coolant temp sensor is faulty causing the engine to run hotter than it should, thus causing the fuel to boil in the rail giving the high pressure fault?
Any ideas/help would be appreciated thanks in adavence
I would recommend you focus on the fuel supply before suspecting uncontrolled cooling temps. Perhaps both issues are related to a poor connections.
-- Spend some time to measure the live fuel pressure sensor voltages (Input Ref., output Voltage, GND!). If the control circuit is proven good, pressure sensor may be getting marginal.
-- What type of fuel pump(s) does your 2010 V6 uses ? Single pump for low-pressure or double pumps setup for high pressure GDI?
-- Analyse circuits to condider the pressure sensor and temp sensor may both share a poor GND connection or simply clean to begin with. Locate your sensors to help locate their GND supply: engine/chassis ?
Don't be tempted to "Play Russian Roulette" with the parts canon. A thousand things can be bad so test twice and replace once.
If you don't have a decent scanner now is time to help yourself.
Thread Starter
Newbie
Joined: Jul 2023
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w212 E350CGI
Engine Limp-modes during acceleration when hot. A fault code points to the fuel pressure regulator.
I would recommend you focus on the fuel supply before suspecting uncontrolled cooling temps. Perhaps both issues are related to a poor connections.
-- Spend some time to measure the live fuel pressure sensor voltages (Input Ref., output Voltage, GND!). If the control circuit is proven good, pressure sensor may be getting marginal.
-- What type of fuel pump(s) does your 2010 V6 uses ? Single pump for low-pressure or double pumps setup for high pressure GDI?
-- Analyse circuits to condider the pressure sensor and temp sensor may both share a poor GND connection or simply clean to begin with. Locate your sensors to help locate their GND supply: engine/chassis ?
Don't be tempted to "Play Russian Roulette" with the parts canon. A thousand things can be bad so test twice and replace once.
If you don't have a decent scanner now is time to help yourself.
I would recommend you focus on the fuel supply before suspecting uncontrolled cooling temps. Perhaps both issues are related to a poor connections.
-- Spend some time to measure the live fuel pressure sensor voltages (Input Ref., output Voltage, GND!). If the control circuit is proven good, pressure sensor may be getting marginal.
-- What type of fuel pump(s) does your 2010 V6 uses ? Single pump for low-pressure or double pumps setup for high pressure GDI?
-- Analyse circuits to condider the pressure sensor and temp sensor may both share a poor GND connection or simply clean to begin with. Locate your sensors to help locate their GND supply: engine/chassis ?
Don't be tempted to "Play Russian Roulette" with the parts canon. A thousand things can be bad so test twice and replace once.
If you don't have a decent scanner now is time to help yourself.
Out Of Control!!
Joined: Apr 2019
Posts: 12,125
Likes: 6,875
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
The fuel pressure sensor is steady at around 200 bar unless it get hot and then it starts to fluctuate (eventually exceeding the high threshold and putting the car into limp mode), this is why I suspect the car is gertting too hot, I picked up a coolant temp sensor for £15 from Mercedes today, I'll fit that and then see if that improves it.
++++++ Pressure control:
-- I would recommend you focus on the fuel supply before suspecting uncontrolled cooling temps.
Perhaps both issues are related to a poor connections.
-- Spend some time to measure the live fuel pressure sensor voltages (Input Ref., output Voltage, GND!). If the control circuit is proven good, pressure sensor may be getting marginal.
--------------
Good luck with the new coolant sensor.
🤞
Last edited by CaliBenzDriver; Jul 28, 2023 at 04:00 PM.
