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Discussion Starter #1
Hey guys I'm having some problems and I've traced it to the injectors.

My symptoms are:

Extended crank times when left overnight
Hesitation under load
Terrible mpg
Surging when able to finally accelerate.
Rough idle.

I've done a leak off test and everything looks ok. What would be my next move?

Should I box up my injectors to be sent off for inspection and order some new leak off clips and copper washers? Or should I take it to a diesel specialist and have them check temps on each cylinder?

307 2.0 Hdi 136 RHR
Siemens VDO injection.
 

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Discussion Starter #3
It's a bit confusing though. I assumed listening to each injector fire and doing a leak off test would highlight something but I guess not.

The old owner changed the fuel pump and referenced a lazy injector and tried to offer me a tuning box. I assume the box has killed the injectors and the old pump.
 

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You should never run a modern diesel with an exposed injector nozzle.

Diesel being sprayed out at 1750 bar can do serious damage to you and the car. Injectors should only be tested in a test rig

Sent from my SM-G935F using Tapatalk
 

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Yep...I aggree (with windy)...get them tested by a diesel specialist and refit with new pipes..you can see the pressure the pump is at by looking a planet...that will eliminate the injector doubt..
 

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Discussion Starter #8
Fuel pressure is fine but fuel economy is really bad and there is no torque in the engine.

A tuning box is one of those cheap remap alternatives that plugs in and tricks your car into making more fuel pressure. Like a bleed valve but for fuel pressure.
 

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some of the ones I,ve seem just tell the ecu the car engine is colder that it is to incease the fuel injection time to inject more fuel as it thinks its a cold engine...my rhr has been remapped and still gived me around 50 mpg..but not on short trips..a 5 mile nip out=30mpg,,
so with your short test runs the average will be well low...average over a long trip 55mpg
 

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Discussion Starter #10
I average about 20-25 mpg. It's a little better on the motorway but it's that bad it even uses a decent amount ticking over. It's foot to the floor everywhere just to keep it drivable.

Put it this way. My 1.6 hdi 90. £15 each way to my mum's. The RHR, £35
 

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Discussion Starter #11
Like you said. Cold engine needs more fuel which mine seems to be lacking. Maybe the box damaged the injector coil or something. It doesn't smoke so it's hard to tell. My dpf is probably catching it all
 

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Discussion Starter #13
Looks like it. I try to do what i can on my own. But if its 2 injectors for example. I change one out at a time with my spare and get nowhere because 2 are faulty. I'd rather pay to have it checked out by a mechanic with a pyrometer but I read I could send them off to pe checked which also seemed like a good option.
 

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Have you had it code tested ?
Have you compared actual and desired fuel rail pressure whilst on the road ?
Is egr operating properly , does this have the dozer and inlet butterfly strangulation flap ?

Most of high rail pressure faults are low pressure issues , you need to clear pipe it up , clear pipe between line from tank to filter , clear pipe from filter to pump , clear pipe from pump to return line ....all this is needed to look for air ....if it’s already got clear pipes look for air ingress .

Does the vnt mechanism on turbo pull up to full position when engine is started .

With the extended crank , you need to watch fuel pressure whilst cranking to see how quickly it get to around 250 bar , injection commence does not start till this is achieved.
 

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Discussion Starter #15 (Edited)
Thanks for The advice but I've checked all this. Injectors don't need coding on these. Fuel pressure is up to around 350 within a few seconds but it doesn't start. Sits fine at 250 at idle. When I put my foot down it even makes the right pressure. 1200+ bar no problem. Turbo is spooling and trying but the fuel delivery at the injectors is bad.

It's just one of those cars that almost promises you an end and doesn't. The other day I did a leak off test and found 1 injector was leaking back a lot more than the rest. Ok job done. Swapped it out and no different at all. Which is why I suspect either more than one injector. Or something that wouldn't not highlight the issue during a leak off test.
 

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As I mentioned in my earlier post the spray pattern is essential for the fuel to atomise. Use something to allow the fuel to flow into like a thick plastic see through container with the opening sealed with tape to check or better still take to option 2 as I recommended.
 

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As I mentioned in my earlier post the spray pattern is essential for the fuel to atomise. Use something to allow the fuel to flow into like a thick plastic see through container with the opening sealed with tape to check or better still take to option 2 as I recommended.
I dont think you appreciate the large differences between a 'standard' fuel injection system and a high pressure direct injection system. It is highly unlikely that a home mechanic would be able to generate the pressure and flows needed to effectively assess the proper functioning of these high pressure diesel injectors. Safety is also a major concern with the pressures you are dealing with, so decent test equipment is essential.
 

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Discussion Starter #19 (Edited)
Yeah testing spray patterns on the car would be almost Impossible without removing an injector and turning it upside down haha. I have had them off before and opened the nozzles and sprayed through them with a can of contact cleaner and a nice star spray came out. But I'd need a real flow bench to test operation properly. As well as spray patterns.
 
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