WOuld like to express my thanks to tfb (Richard) for all his help with my 2.5crd.

Basically, it would not start without a squirt of easystart, even when hot stop engine and would not restart.
Once running it would run great.

The first time I visited Richard we were halfway through the diagnosis process when it started starting, making it hard to make any further diagnostic. It was decided that the fuel rail pressure sensor 'could' be faulty.

A few days later, and with a replacement £40 sensor, the issue returned, so I went back for a second round of diagnostics with Richard. Everything was pressure tested and No1 injector showed a drop in fuel rail pressure when connected, none of the other 3 injectures produced a drop in pressure.

Away I went again, a couple of days later an injector arrives from ebay for the grand sum of £45. I replaced the injector and it has been starting fine since.

Had I taken the car to a dealer (I couldn't afford to anyway) at the very least it would have cost me a set of injectors + labour, I would guess in excess of £1k!!

As well as being great at diagnostics, Richard also makes a great cup of coffee!!!!

Thanks again for your time.

Tony

 

Yes indeed, there's something funny about injector #1 -- doesn't it have some kind of pressure sensor in it that the others don't?

Leedsman.

 

Code 26.

Good for Richie, Deefer sorted, everyone a winner compared to stealer rate. Most auto engineers carry a 'known to be good' injector for #1 use, its a Q&D swap-out trick to eliminate 80% of the wont start issue reasons.

 

aww, you're making me blush

Nope, No1 injector is the same as the others.

Going through the diagnosis we found that the ECU was getting a reading of low fuel pressure. Not low enough to generate a fault code but too low for the injectors to be told to fire while cranking.

The diffiuclt part was deciding if it was really low fuel pressure or the rail pressure sensor giving a reading that made it seem low. After a bit of fiddling around with various stuff it then started to start without problems. Usually these self clearing faults are electrical in nature, hence taking a guess it was the rail sensor.

On the 2nd attempt with a replacement sensor fitted we were able to exclude the sensor as a potential failure.

Monitoring the pressure on a scope while cranking we tried with FCA disconnected and tried swapping the FCA out of my wife's car and still had low pressure.

Next we checked for leakage from the over pressure valve at the end of the rail, but that was dry. Then we removed the injector pipes and capped off the ports on the rail and immediately the fuel pressure rose to the correct level when cranking. Connecting the injectors back to the rail one at at time and monitoring the pressure we saw that No.1 was having the greatest effect.

What was a real bugger was that after re-connecting No.1 it would start, though still with low cranking pressure.

We did steal an injector out of my wife's car and fit that in number one on Tony's and the starting was greatly improved.

The reason Easy-start worked is that it would cause the engine to spin fast enough to generate enough fuel pressure and rpm for the ECU to then fire the injectors. Once at idle the injection pump could overcome the leakage from No.1 to keep the engine running.

Regards
Richard

 

--The Easy-Start acting as fuel for the engine, spinning it a lot faster than cranking speed, raising the fuel rail pressure thus enabling a start. Faultless logic.

Leedsman.

 

So to clarify this I take it the fuel was leaking off the pressure Through the inside of No1 injector into the drain rail. There are some engines with a wired No1 injector, something to do with the firing timing.
Good to hear of the result of this fault and its not air in fuel as has been prevalent in the past.

 

yep, pressure was either leaking back out the leak-off pipes or through the nozzle into the cylinder (though there was no increase in oil level or lots of white smoke on eventual starting, so most likely the leak off route)

Early pre CRD engines with electronic control injection pumps used a need lift sensor on one of the injectors to fine tune the pump timing. On a CRD it's timed via either or a combination of the crank and cam position sensors

Regards
Richard

 

Early CRD's were magnetic solenoid, we are now quieter friction-free piezo crystal wafers. I can't remember when Bosch made the switch but certainly it was before my old 05 was built.

NOTE [update] : I've just had a look and the BOSCH CRD timeline is -

1997: 1st Common Rail system in the world for passenger cars. Injection pressure: 1,350 bar. First production use: Alfa Romeo and Mercedes-Benz.
2001: 2nd generation Common Rail for passenger cars. Injection pressure: 1,600 bar. First production use: Volvo and BMW.
2003: 3rd generation Common Rail with rapid-switch piezo inline injectors for cars. Injection pressure: 1,600 bar. First production use: Audi.

The 3rd gen CRD's from Bosch were radid switch piezo-inline-injectors. Demands for low exhaust emissions and fuel saving led to up to 20 % lower emissions or up to 5 % more power or up to 3 % lower fuel consumption or up to 3 dB(A) less engine noise. So the move from petrol at 40psi to CRD at 23,200 PSI is essentially metered after being delivered by a very high pressure, common rail with an electric signal generated by a computer chip that changes the shape of [like squeezing the end of an air filled balloon] the piezo material. BTW our GV's are plug~and~pray injectors. Bosch already has their variable 2,500 bar CRSN3-25 injection in testing. which should filter down to cars unless their research money is directed to next-gen hybrids only.

 

One needs to be a bit careful with piezo-injectors. They ARE all they are cracked up to be, but with one BIG problem -- the cost.

The current VW Golf GTi diesel uses piezo injectors and they DO go wrong. The piezo stack shorts to the metal case. The drive power is around 400volt and possibly the insulation wasn't up to it given heat, vibration etc.

Nearly forgot, the cost. £600 EACH.

This is why I say the older GV CRDs (and others) with solenoid injectors are probably a better bet in a used motor. The best fuel consumption I've ever had, all factors being considered such as the dead-weight of the vehicle etc., was a Renault Megane with the mid-power 1.5litre diesel. I almost got 60mpgUK out of it in mainly town traffic. It used solenoid injectors. Good fig. for a comfy gen. four seater car with a proper boot/trunk.

Leedsman.

 

The speed of slow clanky mechanical solenoid valves makes them obsolete for all but petrol. Piezo injectors are a more precise metering of the amount of fuel injected and an improved atomization of the fuel in the cylinders, that could never be accomplished with mechanical solenoid valves. The rapid speed at which the injectors can switch makes it possible to reduce the intervals between injections and split the quantity of fuel delivered into a large number of separate injections for each combustion stroke. Diesel engines become even quieter, more fuel efficient, cleaner and more powerful. Each iteration giving us more MPG is stolen from us by the sandal wearing tree hugging technocrats who up the anti with even more 'eat you own $***' valves and emissions laws. I had a Citroën BX CRD in the middle 80's that would return 55MPG. Our current crop of cars are returning much more than 55MPG, its the interference of the green lobby that deducts 30% of MPG capability.

So I agree with you in principal Leedsman, but the clanky mechanical solenoid valves of the Citroën BX CRD in the middle 80's would never be allowed a return in a new vehicle with current binding target of 130 [g/km], and the proposed 2020 goal of 95 grams per kilometre [g/km] emissions laws.