M156 P0191 CEL is ON and White smoke from pipes
08-31-2013, 07:33 PM
#1
Junior Member
Thread Starter
Join Date: Jul 2010
Posts: 57
Likes: 0
Received 0 Likes
on
0 Posts
e55 2004
M156 P0191 CEL is ON and White smoke from pipes
Hello, everyone!
I having problem with my AMG, the check engine light is ON and white smoke from exhaust pipes when I start the car in the morning (no smoke when the engine is warm).
STAR diagnostic fault code is:
*3699, P0191 Fuel pressure control:the upper limit value is reached*
Tried erase fault code: check engine light came on every time after second engine start when I accelerating on highway
Checked the voltage from ECU to Fuel pressure sensor: OK (4.9V);
Replaced Fuel pressure sensor: did not fix the problem;
Checked coolant level: OK;
Checked engine oil: no milky stuff.
The white smoke just started week ago, before it was just Check engine light on. No missing performance from the engine, idling good, a lot of power, maybe some "farts" in the exhaust pipes when braking (not sure if it is normal).
Guessing:
1) Stuck open fuel injector. Any idea how to detect one? No misfire in cylinders...
2) Faulty fuel pressure regulator? (not sure how it looks, maybe somebody know the part #?)
3) your opinion???????????????
Please help me to detect this problem. Thank you for your time!
I having problem with my AMG, the check engine light is ON and white smoke from exhaust pipes when I start the car in the morning (no smoke when the engine is warm).
STAR diagnostic fault code is:
*3699, P0191 Fuel pressure control:the upper limit value is reached*
Tried erase fault code: check engine light came on every time after second engine start when I accelerating on highway
Checked the voltage from ECU to Fuel pressure sensor: OK (4.9V);
Replaced Fuel pressure sensor: did not fix the problem;
Checked coolant level: OK;
Checked engine oil: no milky stuff.
The white smoke just started week ago, before it was just Check engine light on. No missing performance from the engine, idling good, a lot of power, maybe some "farts" in the exhaust pipes when braking (not sure if it is normal).
Guessing:
1) Stuck open fuel injector. Any idea how to detect one? No misfire in cylinders...
2) Faulty fuel pressure regulator? (not sure how it looks, maybe somebody know the part #?)
3) your opinion???????????????
Please help me to detect this problem. Thank you for your time!
09-04-2013, 02:01 PM
#2
Junior Member
Thread Starter
Join Date: Jul 2010
Posts: 57
Likes: 0
Received 0 Likes
on
0 Posts
e55 2004
Thank you. Just checked and I found engine oil on the PCV valve, looks wet to me. It is the symptom of bad PCV valve? How to test PCV valve? Thank you very much for your time!
09-26-2013, 09:49 PM
#3
Junior Member
Thread Starter
Join Date: Jul 2010
Posts: 57
Likes: 0
Received 0 Likes
on
0 Posts
e55 2004
Update: replaced PCV Valve/Breather hose. The check engine light comes back on after second engine start when the speed of 50 MPH is reached (just like it did before). Coolant is clear and level still the same. Can be the ECU software? Left and Right fuel pumps does not have any fault codes. What 374A fault code means? No information about it in WIS and STAR, just I know the internal data could not be stored in control unit....??? Thank you for your time.
Last edited by e55igor1; 09-26-2013 at 09:52 PM.
10-02-2013, 03:31 PM
#7
Junior Member
Thread Starter
Join Date: Jul 2010
Posts: 57
Likes: 0
Received 0 Likes
on
0 Posts
e55 2004
Update
Finally, I found and resolved the problem with "Check Engine Light". In my case it was bad PCV Valve / Breather hose (part of emission system), part# A156 010 03 70 ($90.00). In regular maintenance routine, it needs to be changed every 70,000 miles.
Maybe this information will be helpful who have similar problem with M156 6.2 engine
Symptoms:
If the faults codes P0191 P2187 P0451 present, CEL is ON, can be white smoke from exhaust after cold start, no misfiring, engine oil around the PCV Valve, engine oil dipstick popping out, part# A156 010 03 70 must be replaced.
In some cases, it can be the Purge Valve, fault code P0444. Check if it pulsing by holding it, you will fill the vibration if it working good.
Thank you everyone for help!!!
Maybe this information will be helpful who have similar problem with M156 6.2 engine
Symptoms:
If the faults codes P0191 P2187 P0451 present, CEL is ON, can be white smoke from exhaust after cold start, no misfiring, engine oil around the PCV Valve, engine oil dipstick popping out, part# A156 010 03 70 must be replaced.
In some cases, it can be the Purge Valve, fault code P0444. Check if it pulsing by holding it, you will fill the vibration if it working good.
Thank you everyone for help!!!
