MG-Rover.org Forums banner

diesel Injector Pump pressure regulator

59K views 263 replies 20 participants last post by  blackadder 
#1 ·
I've seen lots of threads recomending checking the HP pump regulator and inlet filter, but they never say how.
I need to do this task next in my search for an idling problem fix.

Has anyone done it / know how to do it / know what to look for etc and like to share it with me? Pictures would be great.
 
#3 ·
Sure tony, and vice verca of course.

Lots of chaps on here are quick to recommend inspecting the regulator but without saying what to inspect for and how to fix what you find .

Do I just risk replacing it? More ££££££ on trial and error?

Surely there must be someone with that nugget of gold who's actually done it or knows how?

Anyone?
 
#4 ·
Hi pressure pump regulation is controlled by a solenoid in the back of the pump. The ECU senses the fuel rail pressure, by means of the fuel rail pressure sensor, the ECU then sends a pulse width modulated signal to the fuel pressure regualtion solenoid. This then allows the ECU to keep the fuel rail pressure between it's upper & lower limits.

The fuel pressure upper & lower limits are determined by the ECU, dependent on many factors, i.e. pedal demand, engine revs, etc.

It is not very easy to test the fuel pressure regulator in it's own right, but the use of actual values on a decent scan tool will at least give you two important pieces of live data, these being ACTUAL FUEL RAIL PRESSURE & NOMINAL FUEL RAIL PRESSURE.

From these two it can be seen whether the ECU is able to regulate the pressure dependent upon demand.

If it needs further investigation, then a test kit would be required to test the regulated & unregulated output of the HP pump.

You would really need to get the car to a diesel specialist if these tests need doing.

HTH, regards, Rob.

P.S. you need to take a bit of care, don't crack the HP system down for some while after running, the HP side can run in excess of 2000BAR, which is around 29,000PSI in old money, so can do you some damage.
 
#6 ·
Dont worry my friends the danger of high pressure fluids is old hat to an Engineer like me.

I always crack one of the injector pipe nuts to get rid of residual pressure before commencing work. (like changing the injectors in January !!)

Rob, I'll remove the regulator anyway tomorrow and use my experience to look for scoring, wear and seal problems.
Beyond that, as you say, its time to get professional help from diesel specialists.

Colvert, I've been swallowing diesel for years with no problems, others use castor oil to keep regular !!

Let you all know if I find anything obvious.
 
#7 ·
Don't worry my friends the danger of high pressure fluids is old hat to an Engineer like me.

I always crack one of the injector pipe nuts to get rid of residual pressure before commencing work. (like changing the injectors in January !!)

Rob, I'll remove the regulator anyway tomorrow and use my experience to look for scoring, wear and seal problems.
Beyond that, as you say, its time to get professional help from diesel specialists.

Colvert, I've been swallowing diesel for years with no problems, others use castor oil to keep regular !!

Let you all know if I find anything obvious.

Whatever you do, DO NOT crack off a common rail injector. With the pressures up to four times higher than a radial/in-line pump system, you WILL hurt yourself.

As regards drinking it, it's probably better that way than having the diesel blasted through you skin, into your blood stream & dying of septicemia.

Regards, Rob.
 
#8 ·
Rob,
Thanks you are spot on. It is important to make members aware of the risks.

HP fluid leaks are invisible and thats the true danger of the beast.
Most fluid penetration wounds occur when people put their flesh close to the point of HP leak unaware that it is there.
Ie 'feeling for leaks' - absolute NO-NO!

I use great care and the longest open ended spanner I have and leather gauntlets to crack an injector nut.
Any residual pressure, and with it the danger, is gone in an instant under my control.

Never work on pressurized injection systems. Complete NO-NO.

Let you all know what I find after the weekend.
 
#12 ·
Just remove the regulator and replace the seal. Its £5 from http://lynxdiesels.com
It is this that causes most of the regulator related issues.
If this doesn't do any good and you have eliminated injector(S) then a new one is £100.
Certainly replace the regulator before the whole pump or even the ecu.

Ron
Ron, did just that TA.
Lumpy idle remains, nothing on testbook.

If I disconnect the fuel rail pressure sensor the tickover becomes perfect.
Plug it back in and it is lumpy again. No lights on dash.
May not be the regulator.

I guess if anyone knows this part of the engine control system it would be 'Rover Ron'.
What would you do next, please?
 
#10 ·
Thanks Ron,

Job was easy, found some jelly-like crud on the shaft behind the seal and cleaned it off with a rag. Seals looked OK. Probably best to get new ones from Alan at Lynx as you suggest or even fit a new one..

Couldnt see the fabled inlet filter, the inlet port is the other side of the pump.
 
#15 ·
just a quick note on fuel pressure regulating. at idle the normal current for the regulating solenoid is 0.60 amps. get someone to check it T4 or some other live data reader. if the ecu is having to compensate for something it will be over this, mind it might not be MUCH over. i think above 0.7 is getting suspect if memory serves correct.
 
#17 ·
Thanks, on another thread on fuel pressure regulator Wuzerk gave me the following :
"Rover Ron supplied me with the voltages to check at the fuel pressure sensor plug (must be plugged in) as he was helping me during my' Tortoise'
investigations. Since my car is working ok at the mo' I tried unplugging my fuel rail pressure sensor and it made no difference at all to the tickover which is an indicated 620
revs on my car, but it did make the car more difficult to start. the voltages are: White/Yellow wire=5.0V, Blue/black wire =1.3v at tickover, Brown/green wire = 0V. on my car the 1.3V rose to 2.06V at 3000 revs."

I will be checking it this week and will report back.
 
#18 ·
Please see my entry on the thread "Diesel misfire at idle" posted on 2 march 2009.

Voltages seem OK-
- but then the ECU would try to obtain its mapped voltage even it had to make the fuel pressure out of spec to achieve this.

Thats how tuning boxes work, by giving the ECU a lower signal than expected to increase fuelling.
 
#20 ·
Its probably the hp regulator. A new seal set is £5 from lynxdiesels.com though the starter has to come off to remove it from the HP pump.

Or could be a dodgy (dribbling) injector, esp if there's grey smoke or the exhaust smells strongly of diesel.

Too high a maf signal can give same symptoms and mafs can overfuel as well as the more usual underfuelling. The clone mafs are particularly good at this!

Ron
 
#21 ·
Thanks Ron. To try to solve the lumpy idle :

Injectors were overhauled Jan 09 by Lynx,
Alan kindly supplied seals for the regulator so its not that, although the regulator could be dodgy I guess.

MAF replaced by Rover with original Bosch unit,
makes no difference unplugged.

Lumpy running goes away with a little throttle,
idle speed increased to 800 by Rover but the problem followed it up !!

Not a thing on testbook.

At my wits end with this.
- Bosch specialist ?
 
#54 ·
You know, when you think about it, there must be around somewhere the actual person or persons who designed the electronic circuitry . You would think they would be interested in how the application of their work turned out and look up such things as the MG-Rover forums and give advice straight from the horses mouth, so to speak, to help alleviate our problems !!!:timer:So if you are looking in (and you know who you are) please log on helpppppppp.
 
#26 ·
LOL!
Your right Ron,
its an Engineer's fascination to understand his systems,
more so since the process of elimination of the most common causes so far has cost me £950 I'm loth to throw more good money after bad.

I changed the injectors and more, Rover replaced the MAF and are now flummoxed having failed to find anything on two T4 sessions.

I will either replace the regulator and see, or get the local Bosch experts to have a bash at it.

Keep you all informed of the results.
 
#27 ·
Cautionary tale

Were the injectors brand new?

I ask because a couple of years ago I was contacted by an owner who had has his 'tested' and given a clean bill of health.

Since he still had performance problems, he then embarked on a systematic replacement of everything, including ecu and HP pump. After ending up with a bill for over £2500 and still had not had the problem reolved, the garage removed the injectors and sent them to Lynxdiesels.com

Sure enough they were the cause all along - he'd wrongly but understandably assumed that they could not be implicated because they'd been passed as fit right at the start of his repair attempts.

If your injectors are off ebay or have been 'serviced', I'd have them retested by lynxdiesels if changing the regulator doesn't effect a cure.

Froggy off the 'other forum' had a similar experience but fortunately did not change the hp pump or ecu. He fitted a new intank pump, pressure sensor and regulator and then sent the injectors to Lynxdiesels, who found them to be in a bad way. (i think his car had done about 120k miles so an injector service is not unheard of by any means at this mileage)

Ron
 
#28 · (Edited)
Aye, Ron.

Injectors were supplied by Alan at Lynx but the idle remained exactly the same. I would be really unlucky to have a set of overhauled injectors with exactly the same defect. :eek:)

Lynx is reputable, and Rover T4 says the cylinders are perfectly balanced and I did a leak check recently to be sure and they passed with flying colours so I'm fairly sure the injectors are OK.

Emailed Alan today to see if he can supply a new regulator or at least assist further.
 
#35 · (Edited)
Result : Fuel Pressure Regulator 3 : 0 Blackadder

Replacing it didn't work. In fact its slightly worse.
Getting on for a grand spent now, but I'm closing in..

With Synergy off or removed, disconnect the rail pressure sensor and the engine stops.
With Synergy active, disconnect rail sensor and it not only continues, but I get my old smooth idle back.

I need to measure the signal from Synergy under these conditions tonight to understand more what is happening and go from there.
The pressure sensor is def. responding to pressure changes cos I mapped it,
but if it is consistently over/underreading, then the fuel rail pressure may have to be qiute wrong to get the ECU the signal it wants from the sensor.

Under those conditions the ECU would control the injectors (partly) based on what is understands the fuel pressure to be, and that could make it lean or rich at idle when the engine is at its most "vulnerable". We shall see.
 
#36 ·
Fuel Rail Sensor

Blackadder, I have just copied your proceedures on my
CDT with Synergy 1 with Pierburgh Maf and a Mafam.
Not an identical test as you probably have a Synergy2?
Synergy OFF/disconnect fuel rail=almost stalled then returned to exactly the same idle.
Synergy ON/ disconnect fuel rail=almost stalled then returned to identical idle=no difference between synergy
on or off.
 
#37 ·
Aye, Wuzerk thanks for your assistance.

the engine cut-out is probably to do with the MAF signal going thru the Synergy, wheras your MAFAM is separate.

When I connect the MAF (NEW MAF!) direct; the engine doesnt stop when I unplug the pressure sensor, just the same as your car.
However, the idle still smooths out with the sensor unplugged.

Synergy is feeding the ECU a 0.13 v signal with the sensor unplugged, so I guess the ECU is going default.

Therefore it could be rail pressure sensor, an ECU fault,
or maybe just the Nut behind the steering wheel ! :cus:
 
#38 · (Edited)
signal

0.13V?? Is that correct? As I found when looking for my 'Tortoise' fault it is easy to finish up punch drunk, especially when you have to turn the ignition off each time you do an adjustment, but I assume that you have tried the Maf compensator adjustment in all positions and likewise with the Synergy range? The only encouragement I have is that the ECU doctor said that he had never experienced a fuel supply fault which was caused by the ECU. Unfortunately there is always a first time! I must say that the fact that you CAN achieve a smooth idle by whatever means suggests that there is nothing wrong with the injectors!
 
#39 ·
Yup 0.13v,
I looked three times because by chance its exactly 1/10th of the signal from the pressure sensor at idle when in circuit.

I think it isnt significant, its just what Synergy2 defaults to sending when its getting no input signal.

Looks like its time to visit the Bosch specialist at Burslem. <Sigh>.
 
#40 ·
Which is just what I did.

Despite all the evidence I gave them, incuding demonstrating how a good idle could be achieved by unpluging the rail sensor, all they did was read the ECU and put the injectors on a testbench to verify they are good.
'Course they are!

They said what Rover said, thet all the engine parameters are within spec. and injectors are fine.
I asked if they had verified the pressure sensors' output by using mechanical gauging and they looked embarrassed and said no they hadn't.
Wonderful diagnositic techniques, Mr Bosch. £190 down the drain.

£1200 and counting.

They did say that the injectors were "all over the place" (whatever that means) and suggested a wiring problem.
That's all they would venture.
Comments anyone?
 
#41 ·
This all happened from adding Millers right?

I had a rover 45 with this exact problem, when I turned her off she would idle nice for a little and then return to lumpy. Never affected the driving of the car.

I threw mega bucks at it trying to get it right and had no luck, the only thing that smoothed it out a little was adding 3 times the amount of millers to the diesel and giving her a real hard thrash in third down the bypass.

After using most of the fuel doing this and then changing the fuel filter it was much much better (still there but not much)

To this day its still doing it (only just though) and its so minor my parents have never noticed it.
(got so crazed with it I gave it to them lol)

I know this is not of much help but Its got to be a warning to people about this millers stuff!

I never realised that was the cause of my problems untill I had replaced every sensor and service item I could.

I really hope you get this sorted mate
 
#42 ·
Ta Garrett.

Perhaps Millers was pure coincidence. It happens.

"Injectors all over the place" was not what Rover said.

Wondering if it could be a genuine ECU or ECU wiring fault or incorrect fuel pressure caused by a faulty rail pressure sensor?

After the utter failure of Bosch; by the quietness of the Forum I guess everyones either as sick of this creaking gate as I am or equally puzzled.

Its back to trial and error or an ending of my Rover ownership.
Heads or tails?
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top