Won't start after cooler replacement

vette850

Member
So I just finished putting everything back together after replacing the oil cooler due to a leak. Now, it will turn over, but it won't start. The battery seemed drained so I charged it, but it still won't start. I checked all plugs, fuel lines, vacuum lines. I'm not seeing anything wrong. There are a bunch of error codes ( turbo actuator, glow plug module, etc.) but I'm sure that's just from when I had everything disconnected. Any ideas?????
 

Picoscope

New member
Cranks? Does it sound dry? Might be lack of fuel. If the rail pressure regulation valve is unplugged, all pressure is returned to tank. It requires signal to close rail return.


Sent from my iPhone using Tapatalk
 

Picoscope

New member
Did you keep the valley clean. IE clean the engine valley prior to removal of the cooler to prevent all that debris from going straight down into the crank main bearing. Did it ever run after the repair? Main bearings usually fail after running for some time, not when cranking.


Sent from my iPhone using Tapatalk
 

lindenengineering

Well-known member
Obviously make sure the battery is in a good a state of charge.
Remember after an exercise like this it takes awhile to get full through the fuel rails to the injectors etc.

Crack open one or two of the injector lines at the rail which you can get access to.
Then crank it over until fuel flows from the pipes. Tighten up and retry.
If you have all the connections and sockets in place she will fire.
Dennis
Mechanic
 

vette850

Member
I'm getting plenty of fuel out of the filter outlet but VERY little out of the high pressure pump outlet. Is there anyway to blow debris out of them with air? Do they typically go bad?
 

lindenengineering

Well-known member
No they don't!
Since it was running OK before you opened it up , this suggests to me you have something not connected up properly like cam sensor, maybe the quantity valve connector, rail connection(s) .:thinking:
At this stage my first activity is to grab a scanner, clear the codes and crank, looking for codes or data suggesting that something isn't connected right.

Frankly that is your next course of action, the issue is most likely staring you in the face.

I give wannabe Sprinter mechanics tests like this to see how they cope--those that don't make the grade stay in the north shop doing Brake, Lights, Steering and Tyres!

Come on don't let us down!
Man made it man can fix it!:thumbup:
All the best
Dennis
 

Picoscope

New member
I'm getting plenty of fuel out of the filter outlet but VERY little out of the high pressure pump outlet. Is there anyway to blow debris out of them with air? Do they typically go bad?


Alway test the low pressure first. Some specs: 4.5 bar before filter. Cannot lose more than 0.5bar in filter. So >4.0Bar after filter. Flow rate of 500mL in 9sec. Also the pressure will fall within a few seconds. This is normal. If you are certain in the validation of the low pressure circuit then the high pressure circuit remains. To your question:

The high pressure pumps can get clogged. I have seen it happen after repairs. If you have no fuel spraying out of the top then it is clogged. It has very small ports with ball check valves and a tiny set of three Pistons inside. I will not the last one I found was from the workshop that installed the feed and return lines backwards at the connection under the driver side manifold. Filters don't work in reverse


Sent from my iPhone using Tapatalk
 

vette850

Member
The only code that it could be is " Fuel pressure high, relief valve open" I checked all connections again, everything looks fine. What would cause the high pressure? Is the pressure sensor on the front of the high pressure pump?
 

moondawg14

New member
The only code that it could be is " Fuel pressure high, relief valve open" I checked all connections again, everything looks fine. What would cause the high pressure? Is the pressure sensor on the front of the high pressure pump?

Ding ding ding. If this valve is open, your van will not start (the pump can't create any pressure to the injectors)

Not familiar with this particular fuel system... but the high pressure relief valve is usually on the fuel rail.

You should be able to follow the high pressure line from the pump to the rail. There should be some lines coming out of the rail to the injectors. Then, there should be another line exiting the rail through a valve. That is the valve that is either stuck open, or the electrical connector to it is disconnected.

Again, I'm not familiar with this particular fuel system... but this may be a valve that should be replaced after it 'pops' Some HPCR fuel systems control rail pressure with this valve, and it is always in operation. Some HPCR fuel systems only use this valve as a safety: Once it pops, the valve should be replaced. (in reality, they're good for 3 or 4 pops before they are totally wasted...)
 

showkey

Well-known member
Slide 39-40 in the link below shows the high pressure components

http://aie-services-2.net/Sprinter/NV3-Sprinter_Overview_Part_2.pdf


As others have stated .........confirm the pressure regulator and high pressure sensor are plugged in and the lock tap on the connnectors are locked in ( not soft set ). Front of driver's side rail and back of passenger side rail.

The high pressure sensor on the back of the passenger side rail is often left off.
 
Last edited:

vette850

Member
Both plugs are nice and snug. Is there are way to test them with a multi-meter? Is the pressure reducing valve removable? (I know it only comes new with the driver's rail)
 

vette850

Member
How do I apply external voltage to the fuel quantity valve to manually open it? (I'm assuming that its normally closed) I'd like to troubleshoot if it's that, the pressure sensor, or something else before I spend $300, $900(cause it comes with the driver's rail only) or possibly more.
 
Last edited:

Top Bottom