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CL65 AMG , white S550 Sport w/ white Giovanna 22s, wild custom chopper
Low fuel rail pressure
Hi, I'm struggling with a random misfire issue at 4800-5000 RPM. Noticed my fuel rail pressure reads around 54-55 PSI. Too light, right? Could this be the cause of my issue? Newly rebuilt coil packs are installed, new plugs and intercooler circuit is bled right with IATs normal range.
Shoild in replace fuel filter first and then fuel pump if I don't get into above 62psi? Was told I need to see at least 62psi.
I see see a few different part numbers for 2008 CL65 for the fuel filter, what is the best number to purchase?
thanks in advance
Last edited by CL55_Serge; Aug 19, 2017 at 09:09 PM.
Reason: Remove pic
It's unlikely to be the fuel filter, but go ahead and replace it if it makes you feel better.
What does the data stream say? Are you getting a lean condition?
CL65 AMG , white S550 Sport w/ white Giovanna 22s, wild custom chopper
I get a P0300 random misfire and some cylinder specific codes. As of few weeks ago, it's wasn't tied to either of the banks or specific cylinders. Today drove the car after a few weeks of sitting and hit it 3 times, two times was cyl 7 and 9, last time was 7,9 and 11. Will post freeze frame data right now.
Originally Posted by Geraldius
It's unlikely to be the fuel filter, but go ahead and replace it if it makes you feel better.
What does the data stream say? Are you getting a lean condition?
: Intake Air Temperature : 100 °F
: Mass Air Flow Rate : 42.81 lb/min
: Absolute Throttle Position : 88.2 %
: Commanded Secondary Air Status : 0
: Run Time Since Engine Start : 90 seconds : Fuel Rail Pressure : 61 PSI
: Commanded Evaporative Purge : 100.0 % : Fuel Level Input : 20.0 %
: Barometric Pressure : 29 inHg
: Control Module Voltage : 13.912 V
: Absolute Load Value : 175.7 %
: Commanded Equivalence Ratio : 0.820 λ : Relative Throttle Position : 76.1 %
: Ambient Air Temperature : 79 °F
: Absolute Throttle Position B : 87.8 %
: Accelerator Pedal Position D : 94.1 %
4A : Accelerator Pedal Position E : 94.1 % 4C : Commanded Throttle Actuator : 99.6 %
Originally Posted by Geraldius
It's unlikely to be the fuel filter, but go ahead and replace it if it makes you feel better.
What does the data stream say? Are you getting a lean condition?
Fuel pressure in the freeze frame looks ok.
What are the individual cylinder codes? All in one bank or on both banks. edit - I see that you already answered that.
Looks like the engine is not yet up to operating temperature and system still open loop?
What spark plugs did you install and what were they gapped to?
What was the reason for changing the coil packs and did that fix the original problem?
Last edited by Geraldius; Aug 19, 2017 at 10:12 PM.
CL65 AMG , white S550 Sport w/ white Giovanna 22s, wild custom chopper
Yes, ithe car was only on for a few minutes. Should I clear the CEL and capture he freeze frame data after warmed up?
Originally Posted by Geraldius
Fuel pressure in the freeze frame looks ok.
What are the individual cylinder codes? All in one bank or on both banks.
Looks like the engine is not yet up to operating temperature and system still open loop?
Not necessary. Usually this is an ignition related code. Looks like that was near full throttle acceleration. Does the problem only happen on high engine load?
OH, Speedriven ECU... haven't been hearing good things about them with the W216 CL65...
Last edited by Geraldius; Aug 19, 2017 at 10:35 PM.
CL65 AMG , white S550 Sport w/ white Giovanna 22s, wild custom chopper
The gap was rechecked and set a little tighter than the recommended 0.028" - should be around 0.024" pst month. Original NGK Iridium plugs were purchased 4 month months back. When re-gapping the plugs. They didn't look fouled up or other damage according to the shop.
The reason I had the coil packs rebuilt was that passenger side failed, no spark on all right bank cylinders. Car wouldn't start. After doing passenger cool pack rebuild, car started and ran. I did the driver side just in case, because I tougher it wills fail. Car has a little under 60k miles.
Originally Posted by Geraldius
Fuel pressure in the freeze frame looks ok.
What are the individual cylinder codes? All in one bank or on both banks. edit - I see that you already answered that.
Looks like the engine is not yet up to operating temperature and system still open loop?
What spark plugs did you install and what were they gapped to?
What was the reason for changing the coil packs and did that fix the original problem?
CL65 AMG , white S550 Sport w/ white Giovanna 22s, wild custom chopper
Yes, under load - WOT or even high throttle but not fully to the floor.
Originally Posted by Geraldius
Not necessary. Usually this is an ignition related code. Looks like that was near full throttle acceleration. Does the problem only happen on high engine load?
I had an intermittant ignition voltage transformer on mine. Changing coil packs would seem to fix it for a while but then the problem would come back. Often when a whole bank quits it's the transformer.
CL65 AMG , white S550 Sport w/ white Giovanna 22s, wild custom chopper
is that the unit in the center of the engine on top?
Originally Posted by Geraldius
I had an intermittant ignition voltage transformer on mine. Changing coil packs would seem to fix it for a while but then the problem would come back. Often when a whole bank quits it's the transformer.
is that the unit in the center of the engine on top?
That's it.
It's the power supply for both coil packs.
Now I'm wondering if the high boost you saw is blowing out your spark. Higher cylinder pressures are more difficult to get a spark (which I'm guessing is why you reduced your plug gap.)
CL65 AMG , white S550 Sport w/ white Giovanna 22s, wild custom chopper
Thanks for all your help so far. I'll start another thread with more data.
Originally Posted by Geraldius
I had an intermittant ignition voltage transformer on mine. Changing coil packs would seem to fix it for a while but then the problem would come back. Often when a whole bank quits it's the transformer.
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