NO CRANK NO OBD2
- Thread starter finndog
- Start date
Hellshalfacre
2005, 2500
Fuel Rail Pressure Solenoid Test
So I just performed the fuel pressure solenoid test as demonstrated by the service manual and I have a few questions. The manual didn't say to pull the cam position sensor or rail pressure sensor to be able to crank for 10 seconds without starting so I pulled the cam position sensor after my...
Some info on the relief portion of the rail and testing here.
Nautamaran
2004 140” HRC 2500 (Crewed)
The relief solenoid gets a PWM (pulse-width-modulated; used in a lot of control signals…) signal from the ECM that closes it to create a restriction in the rail, which allows pressure to build - unless the valve or injectors are leaking. With no electrical power only the ball spring is restricting flow and you’ll see about 150psi indicated on a scanner, built by the tank pump (this is actually around 80psi, but the fuel rail pressure sensor loses calibration that low…). My rail quickly climbs over 4000psi while cranking. There is a lower threshold (3000psi?) required for injection, and it will max out well above 20,000psi at full load.
There are separate “return leak off” tests for the injector return line ports and for the rail solenoid valve. Excessive return flow will prevent the rail from building pressure at lower cranking speeds, which can prevent starting.
Reading up on the operation of common rail injectors will help interpret results, but less is better. Note that’injector leak-off measures the control-valve wear and has nothing to do with needle-valve seat wear or sticking, which causes injector dribble.
Yes, there is a separate “fuel quantity control valve” on the hpfp that kicks in about 30 seconds after startup. This is also pwm controlled and limits the amount of fuel entering the hp pump, which in turn limits fuel heating and power consumption.
You can bleed lines at the rail fitting, but yes the injector fittings are superior, though access requires that the plastic engine cover be removed. Be sure to counter-hold the injector-side fitting with a 13mm wrench, then a 14mm crowfoot on the collar. As always, stay clear of HP fittings while the engine is running!
Be gentle with the plastic return “T” fittings - they’ll be brittle at their age.
The ECM gets power from the grey relay on the fuse box below the steering wheel (Fuse Box #1) and grounds on the firewall behind the battery.
Lack of power to the ECM manifests as a no-crank with the A/C Aux fan running. The A/C control unit looks for the coolant temp over the canbus (broadcast by the ECM) and lacking this data activates the electric fan behind the grille. Often just the relay is bad, and can can be swapped with one from under the driver’s seat (daytime running lights or Body Mfg D+ make good donors). This “fan on” can also indicate a canbus fault. In any case, good for troubleshooting…
Good luck! Keep us posted on progress, and keep the questions coming - many here like a good puzzle!
-dave
There are separate “return leak off” tests for the injector return line ports and for the rail solenoid valve. Excessive return flow will prevent the rail from building pressure at lower cranking speeds, which can prevent starting.
Reading up on the operation of common rail injectors will help interpret results, but less is better. Note that’injector leak-off measures the control-valve wear and has nothing to do with needle-valve seat wear or sticking, which causes injector dribble.
Yes, there is a separate “fuel quantity control valve” on the hpfp that kicks in about 30 seconds after startup. This is also pwm controlled and limits the amount of fuel entering the hp pump, which in turn limits fuel heating and power consumption.
You can bleed lines at the rail fitting, but yes the injector fittings are superior, though access requires that the plastic engine cover be removed. Be sure to counter-hold the injector-side fitting with a 13mm wrench, then a 14mm crowfoot on the collar. As always, stay clear of HP fittings while the engine is running!
Be gentle with the plastic return “T” fittings - they’ll be brittle at their age.
The ECM gets power from the grey relay on the fuse box below the steering wheel (Fuse Box #1) and grounds on the firewall behind the battery.
Lack of power to the ECM manifests as a no-crank with the A/C Aux fan running. The A/C control unit looks for the coolant temp over the canbus (broadcast by the ECM) and lacking this data activates the electric fan behind the grille. Often just the relay is bad, and can can be swapped with one from under the driver’s seat (daytime running lights or Body Mfg D+ make good donors). This “fan on” can also indicate a canbus fault. In any case, good for troubleshooting…
Good luck! Keep us posted on progress, and keep the questions coming - many here like a good puzzle!
-dave
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Thanks for all the info and encouragement Dave.
I didn't have much time to test today. I did look over the end of the rail where the solenoid is and the banjo bolt. The fuel return line from the banjo bolt back to the metal return line is missing the hose clamp, making me suspect that someone before me has tried to test the solenoid before.
More tomorrow...
I didn't have much time to test today. I did look over the end of the rail where the solenoid is and the banjo bolt. The fuel return line from the banjo bolt back to the metal return line is missing the hose clamp, making me suspect that someone before me has tried to test the solenoid before.
More tomorrow...
I did the relief solenoid test today. I pulled the bigger fuel line from the metal return pipe and put it in a container. I turned the engine over for 10 seconds. Nothing there. I didn't follow the procedure exactly but should this not give the same results?
After cranking for 10 seconds, twice, I noticed fuel leaking under high pressure line #3. Seems the flare nut was pretty loose. I tightened it down. I also noticed some fluid leaking down back end of engine on exhaust side. Pressure sure that its diesel, and it may be from the leaking #3 line but seems strange that it would end up back there. I'll check again once is dry.
After cranking for 10 seconds, twice, I noticed fuel leaking under high pressure line #3. Seems the flare nut was pretty loose. I tightened it down. I also noticed some fluid leaking down back end of engine on exhaust side. Pressure sure that its diesel, and it may be from the leaking #3 line but seems strange that it would end up back there. I'll check again once is dry.
Hellshalfacre
2005, 2500
Hi Finndog, for your test did you clamp the injector return line? If you didn't and still got no fuel in the cup I would think this would indicate a lack of HP fuel getting to the rail.
Were you able to monitor fuel pressure while cranking during your test?
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Nautamaran
2004 140” HRC 2500 (Crewed)
@finndog
There is a drain hose at the rear of the injector gallery to direct spilled/leaking fuel down onto the road (motorcyclists beware…) If your #3 hp line was loose that would explain the lack of rail pressure… your lack of flow is still a puzzle.
A stuck-closed Fuel Quantity Control Valve (mounted low on the HP fuel pump) would explain the lack of fuel in the rail? Fuel from the tank pump *should* simply push past the ball-check valves within the HP fuel pump and show up in the pump’s return line and rail solenoid valve return line (which join together under the intake manifold). Lack of return flow would seem to indicate low tank-pump pressure. The intake screen on the tank module can clog and restrict flow… I’d pop the supply line off the fuel filter and confirm pressure and flow rate from the in-tank pump before diving further into the HP system?
-dave
Added: did the fuel pump relay seat properly after you “hot wired” the socket for priming?
(can you hear the pump run its 30 second timeout when you twist the key?)
There is a drain hose at the rear of the injector gallery to direct spilled/leaking fuel down onto the road (motorcyclists beware…) If your #3 hp line was loose that would explain the lack of rail pressure… your lack of flow is still a puzzle.
A stuck-closed Fuel Quantity Control Valve (mounted low on the HP fuel pump) would explain the lack of fuel in the rail? Fuel from the tank pump *should* simply push past the ball-check valves within the HP fuel pump and show up in the pump’s return line and rail solenoid valve return line (which join together under the intake manifold). Lack of return flow would seem to indicate low tank-pump pressure. The intake screen on the tank module can clog and restrict flow… I’d pop the supply line off the fuel filter and confirm pressure and flow rate from the in-tank pump before diving further into the HP system?
-dave
Added: did the fuel pump relay seat properly after you “hot wired” the socket for priming?
(can you hear the pump run its 30 second timeout when you twist the key?)
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Hellshalfacre
2005, 2500
Agreed, but I would think a leaking #3 fuel line during the test would indicate at least LP fuel is making it to the rail?
Edit: will the HP pump relief open at in-tank pump pressure? I assumed the HP pump relief would be higher than in tank pump pressure.
Edit again: Brain flatulence...There has to be HP Pump return at LP. Other wise the intank pump would dead head. This is the purpose of clamping the larger return hose during the test, in addition to the normal return of fuel while the Hp pump is supplying flow during the test. I'm a dumb dumb...
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The fist thing I did to the van was drop the tank. I did see some rust/corrosion on the pump but it seemed to be working fine. I did check the little plastic pickup fitting and made sure it was clean (is that what youre calling the intake screen?). After cleaning the tank and filling with fresh diesel I tested the flow at the first fuel line, then again after the new fuel filter. The flow seemed strong to me, but I dont have a fuel pressure testing kit. When I replaced the fuel filter and fuel lines, I removed a brass T fitting between the filter and the hp pump that had a Schrader valve on it. I assumed it was some sort of diy air bleed system but perhaps someone was trying to measure fuel pressure? I didnt want it in the fuel circuit so off it went. I can definitely hear the fuel pump relay kick on and off. Will there be a low pressure fuel sensor in the scan or just a high pressure?
I spent my spare time today cleaning a rats nest out from under the drivers seat. What a mess. I didnt see any wire damage upon initial cleaning but I'll be doing more detailing in there tomorrow. I pulled the ground straps in there, cleaned, greased, torqued. Also, my ap200 scanner just came in so tomorrow I plan to bleed #5, do injector leak off test and fuel rail relief test again.
Since both the injector leak off test and rail relief tests need a 10 second crank and the fuel measuring is separate, then I should be able to perform both tests at the same time? I haven't been pulling cam shaft sensor for testing since engine has not started, but would that effect anything?
More photos and results tomorrow. Thanks for all the guidance.
I spent my spare time today cleaning a rats nest out from under the drivers seat. What a mess. I didnt see any wire damage upon initial cleaning but I'll be doing more detailing in there tomorrow. I pulled the ground straps in there, cleaned, greased, torqued. Also, my ap200 scanner just came in so tomorrow I plan to bleed #5, do injector leak off test and fuel rail relief test again.
Since both the injector leak off test and rail relief tests need a 10 second crank and the fuel measuring is separate, then I should be able to perform both tests at the same time? I haven't been pulling cam shaft sensor for testing since engine has not started, but would that effect anything?
More photos and results tomorrow. Thanks for all the guidance.
Nautamaran
2004 140” HRC 2500 (Crewed)
There’s a rail pressure value visible under “live data” once you have the BENZ_Sprinter and Diag-benz apps/modules installed. There might be an OBD2 pid for it.. don’t recall.
The Autel menues are deep but somewhat intuitive - until the last layer where the values are grouped by numeric codes.
Good to hear you’ve got fuel flow. As I’ve said, my rail sensor shows about 150psi from the tank pump alone. This goes to zero if I let the pump time out (30 seconds) or pull the relay, or up to 4000psi within three cranks - though my engine has generally started by then (sorry… couldn’t resist
)
I don’t see why the leakoff tests can’t be run together, though in truth I’ve never had cause to run either of them on my van (touch wood). Pulling the cam sensor prevents the engine from getting injection signals from the ECM, so can effect the test. You don’t want the servo valves moving as this is what produces return flow in normal operation, and this will increase the return volumes in your test tubing (though their relative volumes will provide comparative data)
Rodents. Thankfully I’ve never had the pleasure…
Good luck with your tests!
-dave
The Autel menues are deep but somewhat intuitive - until the last layer where the values are grouped by numeric codes.
Good to hear you’ve got fuel flow. As I’ve said, my rail sensor shows about 150psi from the tank pump alone. This goes to zero if I let the pump time out (30 seconds) or pull the relay, or up to 4000psi within three cranks - though my engine has generally started by then (sorry… couldn’t resist
)I don’t see why the leakoff tests can’t be run together, though in truth I’ve never had cause to run either of them on my van (touch wood). Pulling the cam sensor prevents the engine from getting injection signals from the ECM, so can effect the test. You don’t want the servo valves moving as this is what produces return flow in normal operation, and this will increase the return volumes in your test tubing (though their relative volumes will provide comparative data)
Rodents. Thankfully I’ve never had the pleasure…
Good luck with your tests!
-dave
Ok. Big update.
I just got off the phone with the business that originally owned the van. He said the van was running great until battery died and they jump started it. They triggered an immobilizer issue with the ECU that they could not resolve. They sent it away to S.O.S. for reprogramming. When they got it back, it fired up and ran for a day and then quit again. At that point they replaced the van and had their mechanic play around with it for over a year when time allowed. They ended up giving up on it. They could not get it to recognize the crank (or maybe cam?) position sensor.
Hopefully there is not a HP issue on top of ECU issue. I think I will need to find a ECU,key,imobilizer,tumbler package unless there are some obvious things I should check first. I already contacted S.O.S and they confirmed they repaired ecu for imobilizer issue.
After pulling the drivers seat off I've found 3 wires to a black box mounted on floor with some rodent damage. Could this be the immobilizer?
I just got off the phone with the business that originally owned the van. He said the van was running great until battery died and they jump started it. They triggered an immobilizer issue with the ECU that they could not resolve. They sent it away to S.O.S. for reprogramming. When they got it back, it fired up and ran for a day and then quit again. At that point they replaced the van and had their mechanic play around with it for over a year when time allowed. They ended up giving up on it. They could not get it to recognize the crank (or maybe cam?) position sensor.
Hopefully there is not a HP issue on top of ECU issue. I think I will need to find a ECU,key,imobilizer,tumbler package unless there are some obvious things I should check first. I already contacted S.O.S and they confirmed they repaired ecu for imobilizer issue.
After pulling the drivers seat off I've found 3 wires to a black box mounted on floor with some rodent damage. Could this be the immobilizer?
Pretty messy....
The deep clean begins...
Anything I should do while I'm in here cleaning this up? I already painted the seat base, and am going to deal with rust on the floor. I've also cleaned up the ground stud and greased that area.
What is black blox in lower left of photo? There are three wires to this box that have rodent damage. I'm splicing new wire tonight. Also upper left box?
Above the lower left box, there is a 2 wire connector that was disconnected and wires were frayed. Can anyone identify this? I think there was a 2 wire connector going into the back of the drivers seat that was also disconnected. Related? Is there a pressure sensor in the drivers seat? The amount of sensors is crazy.
This bracket was fastened to the seat base with rivet nuts. Does anyone know what its used for? Upgraded seat belt?
Nautamaran
2004 140” HRC 2500 (Crewed)
Metal bracket on the seat is for a fire extinguisher mount; you likely also have mount points for warning triangle storage box behind the seat?
The white 2-wire plug is the seat belt buzzer switch (simple path to ground when belt unclipped) that connects to the mate hanging under the seat. Mine has mysteriously remained unplugged since I identified it…
I don’t know my way around those black boxes very well… I *think* the larger lower one is the Central Timer Module (door locks) and the smaller one is the SRS Module (air bags, etc.). The module on the cross-bar bracket (not pictured) is the Transmission Control Module (TCM) - known to get wet with fluid if the 13-pin socket leaks.
-dave
The white 2-wire plug is the seat belt buzzer switch (simple path to ground when belt unclipped) that connects to the mate hanging under the seat. Mine has mysteriously remained unplugged since I identified it…
I don’t know my way around those black boxes very well… I *think* the larger lower one is the Central Timer Module (door locks) and the smaller one is the SRS Module (air bags, etc.). The module on the cross-bar bracket (not pictured) is the Transmission Control Module (TCM) - known to get wet with fluid if the 13-pin socket leaks.
-dave
Metal bracket on the seat is for a fire extinguisher mount; you likely also have mount points for warning triangle storage box behind the seat?
The white 2-wire plug is the seat belt buzzer switch (simple path to ground when belt unclipped) that connects to the mate hanging under the seat. Mine has mysteriously remained unplugged since I identified it…
I don’t know my way around those black boxes very well… I *think* the larger lower one is the Central Timer Module (door locks) and the smaller one is the SRS Module (air bags, etc.). The module on the cross-bar bracket (not pictured) is the Transmission Control Module (TCM) - known to get wet with fluid if the 13-pin socket leaks.
-dave
Thanks.
Looks like the TCM has some oil on it.
Darn, I was hoping one of the boxes was the immobilizer unit and I had potentially solved the issue. I'll have everything back together tomorrow and will carry on. Probably getting a new ECU/immobilizer/ignition...
Nautamaran
2004 140” HRC 2500 (Crewed)
The “immobilizer” is called the SKREEM (sentry key something…) and is located on the back of the speedometer (instrument cluster)
If you don’t see “start error” on the LCD display (a few seconds after cranking with RKE keyless entry; before failing to crank if you don’t have keyless entry) then your chipped key is being recognized, but a new ECU will require reprogramming of the SKREEM.
I believe SOS can reuse your existing fobs and save your replacing your lock sets?
-dave
If you don’t see “start error” on the LCD display (a few seconds after cranking with RKE keyless entry; before failing to crank if you don’t have keyless entry) then your chipped key is being recognized, but a new ECU will require reprogramming of the SKREEM.
I believe SOS can reuse your existing fobs and save your replacing your lock sets?
-dave
I've read that it doesnt always work. Since this vans ecu and skreem were already reprogrammed by SOS I'm skeptical that it will be successful.
autostaretx
Erratic Member
If you can read the MB part number on the mystery box, it would probably be findable in the parts cross-refs and catalogs at http://www.diysprinter.co.uk/reference/
... or just post it here and i'll look it up.
As Nautamaran wrote, the immobilizer (SKREEM) is mounted on the back of the instrument cluster.
--dick
... or just post it here and i'll look it up.
As Nautamaran wrote, the immobilizer (SKREEM) is mounted on the back of the instrument cluster.
--dick
lady3jane
Well-known member
FWIW when I removed the dash cover I found a rodents nest. There were no chewed wires but plenty of poop.
The foam wiring wrap was eaten through in the nest area. I vacuumed everything and unplugged/plugged all the connections.
There is a ground stud in the far back. Mine was in great condition but it never hurts to check.
L3
The foam wiring wrap was eaten through in the nest area. I vacuumed everything and unplugged/plugged all the connections.
There is a ground stud in the far back. Mine was in great condition but it never hurts to check.
L3
By dash cover do you mean the entire dash? Or just the cover under the steering wheel? It looks like pulling the entire dash would be a mission in itself.