ISBe -Hard Start

[mathura]

Engine In DAF LF 45 Truck but will not start unless you use starting fluid.
Monitor Fuel pressure with Insite and pressure does not rise more than 830psi while cranking.
After engine starts by using starting fluid command pressure and actual pressure reads about the same at any acceleration rate, and engine works normal without probelms.

Your suggestions is appreciated friends

[jctech]

Engine In DAF LF 45 Truck but will not start unless you use starting fluid.
Monitor Fuel pressure with Insite and pressure does not rise more than 830psi while cranking.
After engine starts by using starting fluid command pressure and actual pressure reads about the same at any acceleration rate, and engine works normal without probelms.

Your suggestions is appreciated friends

Check fuel leakage from rear of cyl head, internal injector leakage excessive is a very common failure mode.

[mathura]

Check fuel leakage from rear of cyl head, internal injector leakage excessive is a very common failure mode.


I am not sure how to carry out this check JC can you give some instructions please

Thanks

[RUCKUS]

check if you have excessive nozzles return

[DiegoAC]

Engine In DAF LF 45 Truck but will not start unless you use starting fluid.
Monitor Fuel pressure with Insite and pressure does not rise more than 830psi while cranking.
After engine starts by using starting fluid command pressure and actual pressure reads about the same at any acceleration rate, and engine works normal without probelms.

Your suggestions is appreciated friends


First thing I would do is check the high pressure solenoid valve (that`s the one at the bottom of the high pressure pump-below the fuel filter), one way to check if this one is messing around is just unpluging it, it`s a three cable connector, if it`s jammed, the engine will start fine but you`ll hear it rattle after a few seconds, then plug the solenoid again and it should continue running fine.

Second, the rail pressure return valve (don`t know the exact term in english) that`s the one at the end of the rail (on the other end there`s the fuel pressure sensor).

Third, what has been said here, check for a leacking injector. (that last since it involves higher stripping).

Oh! I forgot, check for clogged fuel filters!

Shouldn`t take more than 20 minutes to do that ;-)

good luck.

Regards,
Diego.

[jctech]

I am not sure how to carry out this check JC can you give some instructions please

Thanks

here you are

[mathura]

Thanks gentlemen for your contribution

[mathura]

Changed fuel filters, unpluggeed actuator solenoid and still cranking a excessively before starting.
Noticed when engine is running a constant flow of fuel from engine head and no fuel from high pressure manifold.
When try to do leak test with insite, got this message- calibration does not support this test.

Is this a sign of injector seals

Thanks

[jctech]

Changed fuel filters, unpluggeed actuator solenoid and still cranking a excessively before starting.
Noticed when engine is running a constant flow of fuel from engine head and no fuel from high pressure manifold.
When try to do leak test with insite, got this message- calibration does not support this test.

Is this a sign of injector seals

Thanks

You can do the leak test without insite connected, plug in the fuel pump pressure regulator (MPROP) the engine will stall if you try to connect it while running, engine runs with very advanced timing when MPROP unplugged.
A lot of return fuel, more than 1/2 litre minute cranking is excessive injector leakage

[Poptest]

Common problem is excessive fuel back leakage from the injector/s. One leaking injector can cause rail pressure to drop. Isolate one injector at a time. Remove 1 high pressure pipe between rail and injector, plug the rail, and start the engine. Do this to all injectors. Plug part number is on JC's post.

[DiegoAC]

Changed fuel filters, unpluggeed actuator solenoid and still cranking a excessively before starting.
Noticed when engine is running a constant flow of fuel from engine head and no fuel from high pressure manifold.
When try to do leak test with insite, got this message- calibration does not support this test.

Is this a sign of injector seals

Thanks

How did this end up anyway? One thing missing here, are there any related trouble codes showing on insite?
Could be that some injector is returning too much fuel when it shouldn`t BUT, if with MPROP (thanks for clarifying the right term) connected the engine doesn`t start at all and with it disconnected it does (even if it`s after a few cranks) I would suspect of a failed MPROP (we had sooo many of these with Ford Cargo trucks around here do to bad quality diesel) It`s easy to see if you take it out (3 torks) and see any oxidation residue on the nozzle hole.
BTW: Any difference between cold and hot start? Does it start right after having it running for some time?

Cheers.

[mathura]

How did this end up anyway? One thing missing here, are there any related trouble codes showing on insite?
Could be that some injector is returning too much fuel when it shouldn`t BUT, if with MPROP (thanks for clarifying the right term) connected the engine doesn`t start at all and with it disconnected it does (even if it`s after a few cranks) I would suspect of a failed MPROP (we had sooo many of these with Ford Cargo trucks around here do to bad quality diesel) It`s easy to see if you take it out (3 torks) and see any oxidation residue on the nozzle hole.
BTW: Any difference between cold and hot start? Does it start right after having it running for some time?

Cheers.

I am awaiting injector seals on this job because even with MPROP disconnected the engine has to be cranked execessive before it starts.

Oh I should let you know the owner told me that the engine starts when cold but does not start when hot.

[Poptest]

Did you check injector backleakage as per JC's post. From experience, injectors with excessive backleakage cannot be detected by Insite as the fault is mechanical, not electronic. Pump discharge volume is low during cranking. Rail pressure will be insufficient to start the engine if injector leakage is high.

[DiegoAC]

I am awaiting injector seals on this job because even with MPROP disconnected the engine has to be cranked execessive before it starts.

Oh I should let you know the owner told me that the engine starts when cold but does not start when hot.

Aha, then most likely injector is leaking (or pump not able to build start up pressure, we had those cases too-found out after replacing injectors-).

Cheers.

[DiegoAC]

Did you check injector backleakage as per JC's post. From experience, injectors with excessive backleakage cannot be detected by Insite as the fault is mechanical, not electronic. Pump discharge volume is low during cranking. Rail pressure will be insufficient to start the engine if injector leakage is high.

Let me mention-Slightly out of topic- that we had cases where cold start problems where due to a failing pump (not able to detect it via insite either just as an injector leaking).

Cheers.

[jctech]

How did this end up anyway? One thing missing here, are there any related trouble codes showing on insite?
Could be that some injector is returning too much fuel when it shouldn`t BUT, if with MPROP (thanks for clarifying the right term) connected the engine doesn`t start at all and with it disconnected it does (even if it`s after a few cranks) I would suspect of a failed MPROP (we had sooo many of these with Ford Cargo trucks around here do to bad quality diesel) It`s easy to see if you take it out (3 torks) and see any oxidation residue on the nozzle hole.
BTW: Any difference between cold and hot start? Does it start right after having it running for some time?

Cheers.

DiegoAC,
The problem with disconnecting the MPROP, is that it instantly goes to full open allowing maximum uncontrolled fuel pressure, fuel pressure will be regulated by the pressure relief valve on the fuel rail - no problem in ISBe engines with the single stage relief valve the pressure will regulate at about 1400 bar.
The problem comes with second generation ISBe engines with two stage relief valves, the relief valve triggers when rail pressure goes over 1400 bar (or 1600 bar for those systems) and then drops the rail pressure to about 800 bar and will not reset until rail pressure goes lower (cannot remember the reset pressure)
Result - you unplug the MPROP and only get 800 bar rail pressure, most likely you would change the fuel pump - wrong, the problem is still there with a new pump....

[DiegoAC]

DiegoAC,
The problem with disconnecting the MPROP, is that it instantly goes to full open allowing maximum uncontrolled fuel pressure, fuel pressure will be regulated by the pressure relief valve on the fuel rail - no problem in ISBe engines with the single stage relief valve the pressure will regulate at about 1400 bar.
The problem comes with second generation ISBe engines with two stage relief valves, the relief valve triggers when rail pressure goes over 1400 bar (or 1600 bar for those systems) and then drops the rail pressure to about 800 bar and will not reset until rail pressure goes lower (cannot remember the reset pressure)
Result - you unplug the MPROP and only get 800 bar rail pressure, most likely you would change the fuel pump - wrong, the problem is still there with a new pump....

Thanks for clarifying that mate, I believe I haven`t seen those 2 stage relief valves yet but will have it in mind.
So far we have sent to bosch diesel services both injectors and pumps to control when in doubt. Haven`t changed a pump for the sake of it yet ;)
Cheers!

[degame88]

change pump.........dat ur promble..

[mathura]

change pump.........dat ur promble..

Why should I replace pump when it is making the pressures my friend, please share your ideas