Another diesel non start problem... - Page 3

Johnny2R · 29th April 2015, 18:32

The quick test I did earlier didn't show any gross leakage, and certainly there was no diesel around the injectors (I don't know whether that means anything). But I'll try to do a more thorough test. I wish I could just get the car to the local Bosch diesel specialist now, as I think I've confirmed that whatever the problem is, it's not something I can sort myself - whether it's injector leakback or a problem with the HP pump itself. That involves getting it started first, though...

FrenchMike · 29th April 2015, 18:48

Quote:

Originally Posted by Johnny2R

The quick test I did earlier didn't show any gross leakage, and certainly there was no diesel around the injectors (I don't know whether that means anything). But I'll try to do a more thorough test. I wish I could just get the car to the local Bosch diesel specialist now, as I think I've confirmed that whatever the problem is, it's not something I can sort myself - whether it's injector leakback or a problem with the HP pump itself. That involves getting it started first, though...

Of course it could be the pump but it's rather rare.

See also the modulator little o ring on the pump side :

HP.jpg

Valve reg.jpg

Johnny2R · 29th April 2015, 19:19

Quote:

Originally Posted by FrenchMike

Of course it could be the pump but it's rather rare.

See also the modulator little o ring on the pump side :

Attachment 48157

Attachment 48156

If this would be enough to explain the low pressure, then it may well be just a development of what I was suspecting as the cause of my cold starting problems. I have already bought the O ring, just haven't fitted it yet (not a job I could comfortably do myself).

Johnny2R · 12th May 2015, 11:17

As a follow-up on this, it's still proving seriously problematic. I had to get the car to the local garage which had replaced the alternator back in January, so that they could redo the work and replace it again, but this time with one which didn't make a whining noise. I also wanted them to sort out my brakes. I knew they weren't up to the task of diagnosing the starting problems but was happy to handy over the job of replacing the O-ring on the HP pump modulator to them.

I did manage to get it started with a blast of Easy Start again, and got it down there. When I got there, though, the car wouldn't start again without another blast of Easy Start, which is a different pattern from a while back (where once it had been started that day, it ran OK for the rest of the day).

Anyway, the car has been at the garage for a while, they've done the brakes and alternator, and have replaced the O-ring (plus a couple of other gaskets which I didn't ask them to do). They've also replaced the glowplugs, which I also didn't ask them to do (and which I wouldn't want them to have done, as it's pointless, particularly outside winter). They've done an injector leakback test which didn't show a problem. But the starting problem is still there. Engine cranks but won't kick into life, without a squirt of Easy Start - except occasionally, when it starts OK.

So, I'm looking for suggestions as to what to do next. Go to a diesel injection specialist? Or might this be unconnected with the fuel/air question? To me, it's looking like a problem with the HP pump, but I don't want to have that replaced at great cost if it isn't that.

Johnny2R · 13th May 2015, 09:04

Just a thought about this...If there was some pressure loss problem in the HP pump itself, such as might be caused by a failed seal, would this not be evident as some kind of fuel leak?

FrenchMike · 13th May 2015, 12:16

If you don't take a HP measurement,you can't know what is wrong !

Measuring is knowing

Johnny2R · 13th May 2015, 14:13

What measurement are you talking about, Mike? As I mentioned a few posts back (29 April), I did your HP pump test and said this:

"With the high pressure test, the voltage is only going up to around 0.7V when cranking (it's correctly showing 0.5V at position 2). So I think this is probably telling me something useful from a diagnostic point of view, but what, exactly? HP pump issue?"

Is there some other measurement I could usefully do?

James.uk · 13th May 2015, 16:56

You need to know what pressure the main pump is producing. Not sure how you check it though...
...

FrenchMike · 13th May 2015, 17:25

Quote:

Originally Posted by Johnny2R

What measurement are you talking about, Mike? As I mentioned a few posts back (29 April), I did your HP pump test and said this:

"With the high pressure test, the voltage is only going up to around 0.7V when cranking (it's correctly showing 0.5V at position 2). So I think this is probably telling me something useful from a diagnostic point of view, but what, exactly? HP pump issue?"

Is there some other measurement I could usefully do?

Oh sorry Johnny, i have forgotten

So ,
-you get a leak somewhere in the HP circuit (including injectors)
-the HP sensor is faulty
-your HP pump is weak .(worst case )

BTW ,have you tried with rail sensor disconnected ?

Mike Noc · 13th May 2015, 19:46

Also could be a problem with the HP fuel pressure regulator, which, as you say Mike, is part of the HP circuit.

.

13th May 2015, 19:46	#30
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,588 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Also could be a problem with the HP fuel pressure regulator, which, as you say Mike, is part of the HP circuit. . Last edited by Mike Noc; 13th May 2015 at 19:49..

29th April 2015, 18:32	#21
Johnny2R Gets stuck in Rover 75 CDT Club Tourer Join Date: Apr 2007 Location: Norwich Posts: 712 Thanks: 98 Thanked 47 Times in 24 Posts	The quick test I did earlier didn't show any gross leakage, and certainly there was no diesel around the injectors (I don't know whether that means anything). But I'll try to do a more thorough test. I wish I could just get the car to the local Bosch diesel specialist now, as I think I've confirmed that whatever the problem is, it's not something I can sort myself - whether it's injector leakback or a problem with the HP pump itself. That involves getting it started first, though...

12th May 2015, 11:17	#24
Johnny2R Gets stuck in Rover 75 CDT Club Tourer Join Date: Apr 2007 Location: Norwich Posts: 712 Thanks: 98 Thanked 47 Times in 24 Posts	As a follow-up on this, it's still proving seriously problematic. I had to get the car to the local garage which had replaced the alternator back in January, so that they could redo the work and replace it again, but this time with one which didn't make a whining noise. I also wanted them to sort out my brakes. I knew they weren't up to the task of diagnosing the starting problems but was happy to handy over the job of replacing the O-ring on the HP pump modulator to them. I did manage to get it started with a blast of Easy Start again, and got it down there. When I got there, though, the car wouldn't start again without another blast of Easy Start, which is a different pattern from a while back (where once it had been started that day, it ran OK for the rest of the day). Anyway, the car has been at the garage for a while, they've done the brakes and alternator, and have replaced the O-ring (plus a couple of other gaskets which I didn't ask them to do). They've also replaced the glowplugs, which I also didn't ask them to do (and which I wouldn't want them to have done, as it's pointless, particularly outside winter). They've done an injector leakback test which didn't show a problem. But the starting problem is still there. Engine cranks but won't kick into life, without a squirt of Easy Start - except occasionally, when it starts OK. So, I'm looking for suggestions as to what to do next. Go to a diesel injection specialist? Or might this be unconnected with the fuel/air question? To me, it's looking like a problem with the HP pump, but I don't want to have that replaced at great cost if it isn't that.

13th May 2015, 09:04	#25
Johnny2R Gets stuck in Rover 75 CDT Club Tourer Join Date: Apr 2007 Location: Norwich Posts: 712 Thanks: 98 Thanked 47 Times in 24 Posts	Just a thought about this...If there was some pressure loss problem in the HP pump itself, such as might be caused by a failed seal, would this not be evident as some kind of fuel leak?

13th May 2015, 12:16	#26
FrenchMike This is my second home Rover 75 Saloon Join Date: Aug 2007 Location: Avignon Posts: 4,466 Thanks: 94 Thanked 661 Times in 554 Posts	If you don't take a HP measurement,you can't know what is wrong ! Measuring is knowing

13th May 2015, 14:13	#27
Johnny2R Gets stuck in Rover 75 CDT Club Tourer Join Date: Apr 2007 Location: Norwich Posts: 712 Thanks: 98 Thanked 47 Times in 24 Posts	What measurement are you talking about, Mike? As I mentioned a few posts back (29 April), I did your HP pump test and said this: "With the high pressure test, the voltage is only going up to around 0.7V when cranking (it's correctly showing 0.5V at position 2). So I think this is probably telling me something useful from a diagnostic point of view, but what, exactly? HP pump issue?" Is there some other measurement I could usefully do?

13th May 2015, 16:56	#28
James.uk Passed Away 2002 Pale Blue. Rover 75 CDTi Connoisseur auto. 170K miles Join Date: Dec 2008 Location: Near the M67. Posts: 14,509 Thanks: 199 Thanked 585 Times in 397 Posts	You need to know what pressure the main pump is producing. Not sure how you check it though... ...