CODE P0193 all that was left?

OK that code is for the fuel rail pressure sensor. With the engine at idle toss a scan tool on it and see what the PCM is asking for in fuel pressure VS what the sensor is showing as fuel pressure. Are the values different? Yes - test the voltage at the sensor between pins 1 and 3, you want to see 4.8-5.3 volts. If the values are wrong and the voltage is OK, replace the sensor.

do you mean while running properly the back of the wires while the connector is still in?

Unplug the sensor and test the voltage supplied at those two pins with the key on, should have bias voltage to those pins. If the voltage is good then it's likely a bad sensor or wiring to the PCM.

Was finishing up the rear air struts on it, and when I started it up the check engine light was back, but it ran fine. I decided to scan all systems and deleted all codes. Started it and its rough idle and dies every time with no throttle response, similar to what you would feel if a throttle boot was off the car. I have one code p0191 now instead.

That is a fuel pressure sensor implausible code. IE it's reading higher or lower pressure than the PCM thinks it should. Might want to look at the connector on the sensor and see if the sockets are loose on the pins or if there is damage to the connector. Could even just be a bad sensor itself.

Checked the connector. It has 4 pins but three wires. Removed it looks ok. Tested the voltage by placing meter's pin on pin 1 abd the other on pin 3, got 4.21 then 4 then 4.06 just fluctuates. Started the car and it ran not sure if the pump is weak abd causing that. I want to read the codes again once it stop running

Just retested it, 4.92

Will stay running a bit rough theb dies, also have code p0355

P0355 is a cylinder 5 coil implausibility code. It might share a circuit with the pressure regulator but the diagrams I have doesn't really show one. It does show a connection to the crank sensor and the oil temp sensor. No real way to test the pressure sensor other than replacement as MB keeps that info in the dealer network.

Sorry p0335 not 355

OK that is an odd code, Basically says that the spacing of the teeth on the crankshaft for the crank sender is wrong, or more likely there is a wiring fault to the sensor. You mention you only have 3 wires but there should be 4 and one is shared with the crank sensor.
In the earlier image, B4/15 is the oil pressure sensor, B70 is the crank sensor and B1 is the oil temp. Since you are showing a code for the pressure and the crank, I'd look at the shared parts which is pretty much the 5 volt feed and the PCM, but as your 5 volt feed was bouncy I'd check it right at the PCM pin 44 If it's steady there then I'd unplug the crank and fuel sensors and see if it still bounces with them unplugged. Could simply be a bad sensor pulling the bias voltage down.

Added some fuel cleaner and that didnt help. So i started it and it would start and idle fine, revs fine, leave it for 10 minutes then it dies on itself. Try to start it will start with rough idle then dies. Am sure will start ok once cold again. Here are the codes

Also, ypu can barely rev it up after it starts to do that. How do i test the passenger side fuel pump?

The code you have is fuel pressure sensor implausible. The pressure it is sending is higher or lower than the pressure it is requesting it falls into this tree of codes -
The value of sensor B4/15 (Fuel pressure sensor) is implausible. (P0191)
Fuel pressure is too high. (P0191)
Fuel pressure is too low. (P0191)
Fuel pressure control : The lower limit value is reached. (P0191)
Fuel pressure control : The upper limit value is reached. (P0191)

All of them start with testing the two fuel pump control modules for faults. Then they want you to use the scan tool to select a pressure for each module in turn and use the sensor reading to see if the modules operate correctly. So basically you turn on one pump to say 50 psi, then look at the sensor, it shows 50, now select the other control module at 50 and check the sensor, it reads 25, that pump module is the issue. Probably could do that using a pressure gauge on the rail in place of the sensor, then watch the gauge as you cycle the pumps on and off. If both pumps read the same then it's likely the sensor itself.
Both pumps are in the same pump module, there is a level sending unit and strainer sock on one side and the pumps are both on the same side with one pump connected to the other side with a hose in the tank.

So bot pumps are on the passwnger side. But how will i know which pump is sending which pressure when i connect the gauge to the fuel rail valve? So i can eliminate which one. And if both readings showing sane then module could be bad?

You should be able to power them individually using a scan tool as they can be controlled individually. So if you turn on pump 1 and get a correct reading, then pump 2 and get the same reading the pumps and control modules should be OK. The issue so far Is that nothing I've seen shows the actual fuel pressure, just the range the sensor reads and tells that you compare the requested pressure to the sensor read pressure.

The fuel pressure sensor is located at the front on the left side of the fuel manifold.

The fuel pressure sensor detects the fuel pressure in the fuel manifold.
The fuel pressure is evaluated by the ME-SFI [ME] control unit (N3/10) for actuation of the left and right fuel pump control units (N118/3 and N118/4) (except model 216, 221) according to requirements or the left fuel pump control unit (N118/3) (for model 216, 221).

Function
The fuel pressure deforms a membrane, which affects a potentiometer. This alters the resistance value of the potentiometer and influences the signal voltage (about 0.3 to 4.8 V) in such a way that it serves the ME-SFI [ME] control unit as information about the fuel pressure.

The pressure sensor measuring range lies between 0.5 and 10 bar.

The fuel temperature is also detected by the fuel pressure sensor but not evaluated by the ME-SFI [ME] control unit.

So i need to manually initiate each via scanner basically to see what pressure it sends and then measure the pressure using a gauge at the front bia the sheeder valve?

Yep, compare the reading from each pump to the requested pressure in live data. So say it shows the left pump at 5 bar requested but the live reading is 2 bar. Then you check the right pump and it requests 5 bar and you see 5 bar, there is an issue with the left pump. Also compare the live data reading from the pressure sensor to an actual pressure gauge. If the mechanical gauge reads 5 bar but the live data reads 3 well you know the sensor is an issue.

I see. Will do. The rail pressure is new and a brand name but will see. All this I assume is with ignition on only. Should I compare it when cold then start it and let it idle till it dies and see if I can se a difference with ignition only on?

Just went to see what options the scanner has. I can activate each pump but it does not give me spexifics to any data. I heard both. But when i try to start the car i dont hear that loud noise at all even though the seat is off. Here are few things i recorded. No codes anywhere. Then at the end the sane code about a missing tooth or something came back. I will see about reading the pressure up front next using a gauge

OK look at the PIDS 602 and 603. One is the pressure the system is calling for, looks like 6467? the other is the pressure the sensor sees, 4748?. I would test it against a mechanical gauge, if the gauge matches the sensor then it's a bad pump if the gauge show the requested pressure then the sensor has an issue, probably something in the 5 volt feed as it shares it with the crank sensor which is what is throwing the tooth code. If you have a scope or a way to watch the 5 volts line connect at the crank sensor and see if it drops out if the wiring is moved or as it heats up. Because the pressure sensor uses that same 5 volts it could be what is actually causing the fuel issue if the voltage isn't steady.

I don't think I have a way of watching or any access to the cps harness, tight space. I have access to the harness of the fuel pressure sensor at the rail. But ya something isn't right why the pressure sensor and then this code about the teeth keeps coming back. The weird thing is that I drove it with all the previous codes for 60 miles no issues and it never died. Maybe if its on the move no drop but if let idle it will drop and die and I just didn't notice it. Both the new cps and fuel rail and the low pressure sensor on the left driver side under the seat are all new.

Tight access could mean the harness has a spot that rubbed. You should be able to monitor the 5 volt from the fuel pressure sensor. Just back-probe it and see if it stays constant. Say it is 4.99 key on engine off, but when it's running it bounces around or drops to 4 volts, that is the problem.

no I checked the harness when I replaced the CPS. Tight as in you can barely put your hand in. difficult as in to place any type of meter or to place anything into a wire connector. It is covered in a heat type protector and I removed it to replace the connector and the wire was in great shape. I can do it from the fuel sensor. Is it not supposed to bounce while running?

So this code is for the fuel rail pressure sensor up by the engine on the fuel rail. Have you swapped it out yet?

Code P0193 - Fuel Rail Pressure Sensor Circuit High Input

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, Ken

From my previous posts "Both the new cps and fuel rail and the low pressure sensor on the left driver side under the seat are all new."

It must be the high pressure pump then. You replaced the high pressure pump and the sensor so the high pressure pump is the only thing left.

high pressure pump here means the one in the tank correct? they don't have ones like Audis or the newer bmws do right?

Yes, the fuel pump in the tank, not the transfer pump

I checked the pressure. First reading is when ignition on, second one when started, Stayed around 40, 5 minutes later was around 35-38, when reved up goes to 40 again. After few minutes went to 32-34 and sometimes goes up to 38 or so. Now its hovering around 30. Will update again once it dies

Hovering" around 28-35. Now it wont stall lol. I shut it off and started it back up gauge was at 52, then idles down to 34.

I left it xonnected and cane back an hour after and found it at 50 psi with everything off, so the injectors are not leaking. But am not sure what is the range for the fuel pressure while running. I doubt the 30s is the right range and may indicate a weak pump

Cane back an hour after to see where the pressure is and was holding at 59 when off

Cane back an hour after to see where the pressure is and was holding at 50 when off. Now running and holding at 50

Still idling and pressure at 50. Started it 3 times and its fine. Not sure. Now check engine light went off on its own ugh

I would expect 50 to be about normal, but I would also look at the 5 volt signal to the pressure sensor. If it were lower than 5 volts the sensor would read wrong and tell the ECU the wrong info and give you the wrong pressures. Might be worth it to find the pump power feeds and test them without the control module adjusting them.

I rechecked the harness to the fuel pressure sensor and it reads 4.87v

That should be OK, the question is does it stay at that voltage or does it drop out while the engine is running and cause the issues you are seeing with the crank code and fuel pressure sensor because they share that 5 volt feed.

I guess ill need to find a way to probe it while running right? And not disconnect ot and measure it while running. Isn't it supposed to vary based on fuel needs and ecm pulses? Or it should be constant?

The 5 volts stays constant. The system controls the pumps via a PWM signal. the sensors however get a solid 5 volts on the pink and black and a ground. They only share the 5 volts. If it is dropping out or even just dropping lower it will change the signal back to the ECU.