Injection Fault & STOP 1.5 DCI

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Re: Injection Fault & STOP 1.5 DCI

Postby triumph2.5man » Fri Dec 30, 2016 9:30 pm

Hi folks. This has been an interesting saga. To me these are familiar paths, having wrestled with level 1 warnings (check injection) and level 2 warnings (STOP - injection fault) all the years we have owned the car.( I look after all the family cars - see my profile, all high mileage, old, common rail diesels and the Meg 2 has caused me more aggro than all the others put together! Mechanics' couchemar!) For years I struggled without diagnosis, relying on yonks of experience (I am beyond my three score years and ten!) which proved almost impossible. I tried a cheap scanner from ebay - useless! Also tried ELM327 interface on a laptop, also did not work. However when I invested in CAN CLIP a year ago (well worth every penny of £80), all was revealed but a laptop with 32 bit software is essential. Luckily i had an old one with Vista running in XP mode.
Most starting and running problems are caused by fuel pressure problems but without CAN CLIP it is impossible to see them. It is essential to understand fully exactly how this CR system functions in particular the IMV (inlet metering valve also known as the flow solenoid or fuel flow actuator) which is on the rear of the pump. We all basically understand how a CR system works, but do we?
The IMV is a normally-open solenoid when the engine is not running. It is fed by battery voltage from plug PPM! (black) on the UCP but the facts are more complicated than that. Putting a meter on the two IMV terminals will show only around half a volt, the reason being that the return wire is controlled by the injection computer via pin M4 of the brown (centre) plug. Putting the meter probes on the white wire and an engine earth will show battery voltage but this is not the working voltage. Still with me? Capisce?
Ready to start the car. CAN CLIP shows that cranking speed must reach 200 rpm within 5 seconds, requiring a good battery or two batteries connected in parallel. The rail pressure must reach 200bar or the engine will not fire. Any leaks in pump, injectors, unions or pipes will reduce the pressure below this figure.
What happens next is very rapid. When rail pressure sensor reads 200 bar (provided of course that signals are also received from cyl position and crank sensors), the injection computer instantly increases the IMV voltage to around 3.7 volts, IMV solenoid restricts fuel flow to around 225 bar at the rail, injectors pulse and idle speed settles down to around 900rpm. CLIP shows that the voltage, rail pressure and idle speed are varying constantly.
Revving the engine in neutral will give about 600 bar at 4000rpm but under load the pressure is far higher, up to 1400 or more. Simples?
Were the IMV to jam open (unlikely) the poor engine would be a rattlng runaway. If the solenoid coil were to fail, the injection computer would stop the engine instantly with a level 2 warning.

Here are a few more (relevant?) comments if I may. Swarf can affect an injector in two ways. 1) keep the needle from the seat resulting in unmetered fuel entering the cylinder (clouds of smoke will indicate this) 2) interfere with the seating of the control valve (its working movement is only a fraction of a mm anyway) resulting in excessive leak-off.
When looking into the input hole of an injector, a cross-shaped device is visible. This is a case-hardened, spiral plug driven into the orifice and which is impossible to remove. If any swarf is trapped inside, this is a likely spot. Apply the airline to the centre orifice at the control valve end but do watch out for the small control spring and its packing piece!
Fitting a filter on the output from the pump to the rail? Sounds like a good idea but can such a device handle 1600 bar? Unlikely
Fitting a lift pump? Tried this - waste of time and no need. The suction from the low pressure side (5 bar) of the HPP is considerable.
Bubbles in the fuel lines? There should be no bubbles in the supply tube from the filter to the pump inlet but there will always be bubbles (or even foam) in the return pipes from the injectors. Leaking off fuel is how the injectors function.
Bubbles in the main line can result from the priming bulb itself. The one-way valves are easy to remove and clean but must be put back the correct way. They are identical but fitted differently for obvious reasons.
It is imperative when removing the leak-off pipes for testing etc, to plug the pipes or the low pressure circuit can deprime pretty damn quick requiring much unnecessary pumping.
Both our meganes, mk 2 and mk 3 have bubble in fuel lines and do not affect the running. Most cars have.
Regarding the HPP, buying from ebay is dodgy "the car was running fine when it came into the yard mate...". By coincidence yesterday I dismantled such a pump (£30 from ebay said to be low mileage). There was no detectable wear on any of the surfaces but the presence of rust indicated water entry at some point, probably "after it came into the yard mate...!" This rendered it useless sadly.
It is handy to obtain a spare IMV in connection with CLIP pressure testing. I have accumulated several of these. You will find an identical one on the delphi pump of a Mondeo TDCI, a few pounds at your local scrappy. Use of this enables the maximum output of the pump to be checked, and therefore its efficiency. If you disconnect your IMV, the engine will be dead and error messages appear. All the spare IMV does is tell the injection computer that is is connected and this lets the starter turn. Pump pressure at cranking speed should be more than 1050 bar. My pump delivery is a lot lower than this and I am still working on this, time permitting!
I could write much more (!) but will pause at this point for any questions or comments. If I have bored anybody or taught "granny to suck eggs", I do apologise.. What I have written here applies to an early 1.5dci Megane 80 bhp although others are likely to be similar.
Mike the old Triumph man!

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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Sat Dec 31, 2016 1:48 am

Hi Mike,
Good post, some nice reference data there, but as far as I am concerned, I find what you say about bubbles particularly interesting. I have spent a good few hours today looking at bubbles. I did a leak off test with four bottles today, and plugged the return pipe from the injectors at the plastic spigot on the pump, therefore removing the return rail all together, as I suspected one or more of the little pipes between the 't' pieces to be drawing in air. With the car set up like this we started the car and noticed a drastic reduction in the bubbles, to almost zero. So it looked like we were looking in the right area. This setup also let us see the results from the leak off test, considering I striped all my injectors down, in as clean an environment as I could get, but still in a shed, I wasn't expecting them to be perfect I just needed them to be clean enough to run. To our surprise three out of the four were pretty much identical with very little leaking, the forth (no.2) is issuing about double the amount of leak off compared to the rest. We didn't measure the fuel accurately but just visually, as experience tells you what is acceptable, we consider that the bad injector is probably still within tolerance or close to it, I mean it has a regular drip not a stream. But as you say leaking off fuel is how the injectors work, and bubbles/foam in the return is acceptable, so I am thinking that the system is sealed where does the air come from? Is it possible that the air in my return pipes is in fact gas from the combustion cycle getting forced back up into the injector via the holes in the nozzle, where else could it come from? One reason for making this bazzarish conclusion is that my return pipe isn't full of foam but rather the foam pulses along the pipe in blocks about two inches long and at idle there must be between two and three blocks a second. Could this be a side effect of having one injector with more leak off than the rest. I was thinking that we should buy some new leak off pipe and remake the return rail but use less plastic junctions, there are two right angle fittings that I feel are mostly cosmetic and can be bypassed reducing the numbers of junctions therefore reducing the risk of air ingress. But now with what you have written Mike, it hasn't made me suck eggs but it has made me rethink the problem. Now I think I will re-investigate No. 2 injector, did I miss some dirt or a stray filing? I will try to clean it again and see if we can get the leak off test closer to the others and see if that removes my foam. I am not so bothered now that someone with experience has said some foam is acceptable, because searching the net for answers was revealing very little, there is a few people asking how to fix the problem, but no real answers.
I don't think I have a problem with my bleed bubble valves, as there is no air in the pipe between the tank and the filter, I have a few occasional bubbles in the pipe between the filter and the pump, but these seem to coincide with the foam blocks coming back down the return. I haven't examined the filter housing yet, but it has the return pipes connected to it as well as the feed pipes. I assume Renault are just using this as a junction box, they cant be mixing returned fuel in the filter housing are they, shouldn't it go back to the tank for bubble removal?
On other points you raised Mike, we have now got a generic code reader that is kind enough to give us the output pressure from the HPP, so using that and a spare IMV plugged in, with the injectors electrically unplugged (to stop the engine starting) I should be able to see more than 1050 bar, it is nice to have a figure like that to work with. I am fairly confident that the pump we got is good, some things are best found in your local breakers, like the pump, we were able pick a pump that was obviously still full of fuel and keep it full of fuel until we primed it up after fitting it, a pump that travels through the post is unlikely to be full of fuel, but probably has got some moist air in there from the soggy scrapyard and then some condensation when it gets into the postie's nice warm van.
I am also not wanting to bore people, and I have dragged us slightly off topic with my ramblings, but my initial problem started with the dreaded " INJECTION FAULT & STOP" message, so far we have spent less than £100 and basically we have a car ready for it's Mot. Nothing that has been discussed here is beyond anyone with a basic toolbox and an air compressor, If we had put our Megane into a garage for repair, to get it to the stage we are at would have cost hundreds of pounds for labour and then there is the parts, more than the car is worth. I can't see a Renault dealership being happy to fit a pump from the breakers yard. I came on here originally looking for Megane related info since I wasn't familiar with them, I wasn't really finding the answers that I wanted, so I thought I would sort of blog about our Megane's journey and maybe help others in the future save some money fixing their faults.
Steve.

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Re: Injection Fault & STOP 1.5 DCI

Postby triumph2.5man » Sat Dec 31, 2016 9:05 pm

Steve you have done a jolly good job there. A lot of grease monkeys (even in the trade) will not touch Meganes especially the 1.5 DCI. Monitoring the Forum problems reveals that there are more issues with the 1.5 than the 1.9 or the petrol versions. I came to the conclusion long ago that the Bosch system in the 1.9 is superior to the Delphi system. Having said that, my everyday car, an elderly Mondeo TDCI is on 170k miles with the original Delphi pump, injectors and turbo and is the most reliable car I have ever owned. Mondeo injectors are similar to the Megane ones but the nozzle and the nut are a little longer. The "business end" (adaptor, control valve etc) are identical.

Now, back to the bubbles in the fuel line. I hate to say you are correct - fuel from leak-off is passed back to the fuel filter! There is good reason for this. Other and later models than ours have diesel heaters in the filter, ours does not. Incidentally, do you have a genuine Delphi/Renault fuel filter? The genuine ones rattle when you shake them as a ball bearing is contained within. This ball bearing is connected to a bi-metal strip. Why is this? Good use is made of the leak-off fuel for retaining heat. What happens is this. Start up, return diesel goes into the filter, complete with bubbles and foam (!) which is then transferred to the pump input pipe for recycling. At this point you will see bubbles in your input pipe! After some minutes (have never timed it) the oil in the filter will heat up, the bi-metal strip will bend down and the ball bearing will drop down and block the hole. Return fuel will then return to the tank and bubbles in the input pipe will stop. Get the idea? it's a good system, when it works. It does not work so well with non-original filters.
This leads me to one other point. Outboard engine owners know that when you pump the primer bulb, the bulb goes hard when the carby bowls are full. As you may have noticed this does not happen with your Megane. Once again it is because of that ball bearing. When the pump is full, pressure on the primer bulb dislodges the ball and fuel passes back to the tank. If you listen carefully you can hear it sloshing back down the return pipe and into the tank. Annoying, but it is not a problem. When I bleed my system i use the following method. Engine not running, carefully pull the return pipe from no 1 injector whilst squeezing the bulb. Release the bulb and at the same time refit the pipe. Repeat until neat fuel comes out of that pipe (usually a few strokes). You asked a good question, where do the bubbles in the leak off pipes come from? Probably pressure back from the engine somehow. You could also try this. Remove the leak off line from the venturi (where it connects to the pump) and plug the pipe. Put the leak off pipe into a jar (as if doing a leak-off test) then start the engine. The fuel in the return pipe should be bubble-free as it contains only the excess fuel from within the pump chamber itself (the leak-off will be going into a jar). This test should prove that the bubbles are only from the injectors. Interesting exercise!

Moving on now to pump pressure. I am glad to see you have got the gist of using a spare IMV and cranking the engine with injectors disconnected. Should exceed 1050 bar at 200rpm but in my case the test did not exceed 650 bar ie well down. Next test was to repeat but with a ball bearing tightened down beneath each injector nut (use a bike rear hub bearing 0.25") By doing this, the pump was able to reach 1299 bar. I then placed a ball under each injector nut in turn and repeated the tests four times to establish which injector was dropping the pressure because of leakage.

One other interesting check is Renault test 9 "injector sealing test", again using the spare IMV. Not certain if this can be carried out without CLIP but it is Renault's approved leak-off test, command AC029. Once started, the engine will rev hard four times (it increases voltage to the IMV). You then repeat the process then measure the leaked fuel. Any injector passing more than 35mm should be replaced. I had one that leaked 170 mm! Rather than upset the neighbours (very noisy!)I drove to the countryside for this! Got strange looks from a passing tractor driver!

Leaking injectors. The main cause of leakage is wear in the control valve. Did you spot the little wheel-shaped device? Sometimes these seize in the housing. The total movement of this device is 0.028mm - ie not a lot. It is probably prudent to replace one or more of these. They are around £42 each on ebay but you can get non-genuine ones from China for half this. Are they any good? Who knows but I have seen good reports. I am thinking about it!
When cleaning injectors I use cellulose thinner and this will dissolve all deposits. You can leave the nozzle soaking overnight but no longer as this stuff is surprisingly corrosive and will remove the surface finish. I end up with high pressure airline to ensure those minute orifices are all clear.


I will pause there and allow you to catch up with what I have written. Not certain if I have answered all your questions.
I have today carried out an autopsy on a non-working delphi pump but will include details of what I found in a new post rather than tag onto this one!

Glad to be of help.
Mike

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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Mon Jan 02, 2017 3:22 am

Wow Mike, some more excellent information, When I first started researching the Megane online, I was drawing a lot of blanks, I was finding a lot of people asking questions and not many getting answers. I think I said in an earlier post, that if I had known that these pumps where notorious for committing suicide, we probably wouldn't have bid on the car. But now I am glad that I have, I am enjoying the challenge of repairing the car, I am enjoying learning more about modern fuel injection systems, I have been working with cav pumps for years, but those things are so reliable that you hardly ever have to touch them, this is the first time that I have had to do anything with a modern diesel injection system apart from changing glow plugs and O2 sensors. As yet I have never had to turn anybody away and tell them to take their car to a dealership, and I feel this experience is just another tool to add to the old grey matter. Anyway, enough mumbo jumbo fuelled by a wee toddy or two, back to the matter in hand, Bubbles.
I understand the theory about the fuel recirculating to retain heat, it is almost a clever idea, but as soon as an injector starts to ware and produce foam, the pump is doomed. A tiny bit of air in the system could be acceptable if the fuel is returned straight back to the tank, but I don't like the idea of knowingly passing air through the pump. I understand that having the fuel at a constant temperature is good for the combustion cycle, and living in the north of Scotland where just before Christmas the temperature went from -10C to +15C in less than twelve hours, It is a good idea, but really how much of a difference would it make to have the fuel returned straight to the tank all the time. Eventually the fuel would heat up, you may loose a few miles to the gallon, but it is cheaper then replacing the pump every so often. The computer knows the temp of the fuel, measuring it just as it leaves the pump. So if I replace the filter with a simpler straight though setup and connect the return straight to the tank, the computer can adjust the fuel mix for the best emissions, therefore reasonable economy. I don't think it should throw up any faults, I could fit a heated fuel filter? Can anyone fault my logic?
I did try my leak off test with the whole return rail disconnected, as I had thought that the rail could have been drawing air, and the bubbles did virtually disappear, that is what made me think that the "air" was combustion gas, from either the compression stroke or the fire stroke. Tomorrow I hope to try the cranking pump test, as that is quick and easy, I don't know if I will get time to investigate the control valve in injector number two, maybe on Wednesday.
Steve.

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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Mon Jan 02, 2017 6:09 pm

So, today I did a cranking high pressure test on the pump, the result was 1410 Bar. Since Mike recons that the pressure should be 1050 Bar or more, I am very pleased with this result, I think we have found a good pump. Armed with the information that we now have, I think it is reasonable to say that worn injectors leak "air" back into the system, this "air" travels back to the pump, therefore shortening the life of the pump, that, and the possibility that the car had been run out of fuel. I obviously want to protect the new secondhand pump, so I need to service again or replace the metering valve in injector number 2, but I also want to protect the pump so that this doesn't happen again. I can see two ways that might achieve this, firstly, remove the stock fuel filter and fit two simple inline fuel filters, one on the flow and one on the return. The up side is the fuel will go straight back to the tank for bubble removal, and you can probably get filters that will plug onto the existing pipe fittings. The down side is that the system will take ages to bring the fuel temperature up, especially if the tank is full and cold. My second idea, I am almost exited about, I am not sure, it might even be an epiphany. Seal permanently the spigot that the return rail connects to on the pump, connect the return from the injectors via a 'T' piece to the return pipe on the tank side of the fuel filter. Fuel that is being returned from the pump will travel along the existing pipework in the normal manor and recirculate through the filter housing, keeping the fuel a little warmer at the pump, and all the leaked off fuel from the injectors will always return to the tank. I think this should protect the pump and is cheap and simple to do. I also don't think the computer should even know it is happening, therefore it wont have a problem with it.
I would really like to hear if anyone has come up with this idea before or maybe even tried it.
Steve.

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Re: Injection Fault & STOP 1.5 DCI

Postby triumph2.5man » Mon Jan 02, 2017 8:07 pm

Wow Steve that is a hell of a pressure! Made me feel jealous! You had a great find there!!
I like your suggestions for returning the leak-off fuel to the tank thus by-passing the filter. As you say, leak-off fuel from the pump cavity will heat the fuel and the longer heating period should not be an issue. I am not sure if later models of DCI have diesel heaters but I know the 1.9 has. Some models have "water in diesel" sensors but mine does not. I did contemplate obtaining a fuel filter and fittings from a 1.9 but these are less common in scrappies than 1.5 and in the end I did not bother.
One final opinion - about glow plugs. My experience is that these engines will start OK on all but the coldest mornings even with dud glowplugs. Most have dud glowplugs. When I checked our mk 2 - all dead. When I checked our mk 3 -all dead!
Best of british mate - and thanks for the feedback. Nice to hear that somebody appreciates what I do. It is obvious that my priority now is to latch on to a decent pump at a local scrappy - one with fuel in and not water.....
Mike

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Re: Injection Fault & STOP 1.5 DCI

Postby quaker@eircom.net » Mon Jan 02, 2017 9:41 pm

hello there...

Just to clarify the steel ball testing method....did you put a steel ball into the top of the injector and then screw down the high pressure pipe nut on top of it? ( one per injector for 1st part of the test)?

If the resistance of the IMV was measured then could a dummy resistor be used to simulate a connected IMV ?

Re measuring the cranking HPP pressure......Steve, how did you arrive at a figure of 1410 Bar?....was it from the value on the signal wire of the fuel pressure sensor?

I definately have big bubbles in the low pressure fuel pipes but seeing that they are most likely coming from the injectors....I'll have to do something soon....the engine starts bang on everytime though.

rgds Maurice

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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Mon Jan 02, 2017 10:32 pm

Hi Maurice,
You picked up Mike just fine, the ball bearing acts as a pipe plug and the injector is isolated.
The IMV is just a solenoid, I am not sure what the book figures are, but I just measured my spare one at 6.8Ohms. I might be wrong but it is worth a try, using a resistor, interesting to know if you have any success.
For the cranking HPP test ,
I unplugged all four injectors electrical plugs,
I unplugged my IMV and used a spare IMV as a dummy load, (a resistor might work)
I then used an Autel MaxiScan generic reader to view the pump pressure live data.
The first turn of the key so to speak registered 17,585psi and the second attempt took the reading up to 20,450psi which converts to about 1410 Bar.

I am convinced that these bubbles will be responsible for a lot of damaged pumps, because of this I am going to post a picture with a description of my proposed modification, if the connections are well made there is no way that injector foam can damage the pump, and it may save your pumps life.
Steve.

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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Mon Jan 02, 2017 10:38 pm

Below I have posted a photo of my planned modification.
Disconnect and seal the pipe circled in yellow, possibly seal with some sort of bleeding device.
Totally remove the black plastic return pipe circled in orange.
Where the orange circled pipe was removed at the injector T-piece circled in blue, fit a clear pipe following the route of my red line to the black tank return pipe circled in green ( in the photo you can just see the black return pipe running over the engine mount below the air-con pipe)
I am going to research the best fittings to use and will post here so others can buy a sort of kit, if they want to try this. I am going to use clear pipe to see how much foam is coming from the injectors in the future.

Image

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Re: Injection Fault & STOP 1.5 DCI

Postby triumph2.5man » Tue Jan 03, 2017 8:34 pm

What a spotless engine Steve - and look at that pump. You could eat your dinner off it!
Good luck with your leak-off mods. I await the outcome with interest.

Regarding the ball bearing under the injector union nut, this is a trick I learned many moons ago. Some folk might be fearful of damage to injector, pipe or union nut (especially as Delphi recommend renewing the pipe every time it is removed) but I have never had a problem with this and tighten hard. This method is a good way of identifying a leaking injector without resorting to diagnostics.
I can give a good example of this. I apologise for referring to Henry Ford's products but the Mondeo does have a Delphi system with similar pump, pipes and injectors to the 1.5dci. The iMV and fuel rail sensor are identical - handy to know when swapping over for testing.
I had driven about 2 miles, parked for a short while but without warning the car refused to start. With the Mondeo, a flashing glowplug light is the equivalent to our "check injection" warning. Stuck away from home, late at night with no tool or even a torch, normally ultra-reliable, the old beast stubbornly refused to start despite repeated cranking. No option but to call Britannia Rescue! The thing about low pump pressure is that it won't stop the engine once running but can prevent starting as the pressure from cranking is lower than when running (pump turns faster.) I used the ball bearing method under each nut in turn and found that by isolating cylinder 1 (timing chain end on this car) the car would start and run on 3 cylinders. Trying the other 3 made no difference - still no start. Out with injector 1, stripped, cleaned in cellulose thinner after soaking the nozzle (care, not too long as this stuff is corrosive. All the cars I resprayed with cellulose could not have done my lungs any good!). A thorough blast with the airline with particular attention to the several minute orifices, reassemble and back in. Started and ran perfectly and continues to run so to this day two years later - with the same injector in place. I was so impressed with this, I gave the other injectors the same treatment. Also did the same to the Megane!
I hope this helps someone.
Mike

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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Tue Jan 03, 2017 10:44 pm

I must confess :( , this is a picture that I found online, I was looking for a nice clear picture to show clearly what I was banging on about, my engine has been cleaned, but it isn't as clean as the one in the photo. When I source the parts that I need and fit them I will post a picture of the finished conversion.

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Re: Injection Fault & STOP 1.5 DCI

Postby quaker@eircom.net » Mon Jan 09, 2017 2:50 pm

Hello,
Re the modified return pipe plumbing as described, would this make any sense......put a small metal non return valve into the section between the fuel filter and the proposed "TEE" fitting. This is in the fuel return pipe from the Fuel filter and the Tank but between the FF and the new Tee joining.
I just measured the outer diameter of the transparent pipe and this is 10mm. I assume its ID is approx 8mm. I assume a NRV with an 8mm barb might work here. I assume the same diameters of the pipe going from the fuel filter back towards the tank. Just saying.
rgds
Maurice.

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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Wed Jan 11, 2017 1:34 am

Hi Maurice,
I get what you are saying, and I get why you are saying it. The section of the return pipe that I am targeting for the tee piece is almost directly above the engine mount where it attaches to the inner wing, incidentally the pipe at that point is black and 8mm outside diameter. There is a couple of reasons for fitting it there, it is easily accessible and it is the highest point in the fuel system. Having the tee at the highest point hopefully will allow any residual foam in the pipes when the engine is turned off to gather there, I think with the engine turned off the return pipe will return to atmospheric pressure within seconds and the foam will then form a big bubble, the foam infested fuel will be in the pipes from the injectors all the way to the tank, some may rise up the vertical piece of pipe where it rises from under the floor pan to the tank, but the rest will rise to the tee. When the engine first starts the fuel pressure rises in the return pipe at the injectors first, it is at very low pressure because it is only leak off from the injectors, I hope this pressure is enough to force the air bubble to the tank. I want to use a clear pipe from injectors to the tee so the we can always see the foam and how much of it there is. I know when we do a leak off test the existing pipes are clear of air, so when we fit the tee, if we continue to see air at the pump we will need to fit a NRV, but in doing so I don't want to increase the pressure between the NRV and the FF, the NRV would have to be very easy for the return fuel to overcome.
As yet I haven't made much progress as other jobs have come first, I have tried to clean injector number two again but to no avail, it is still leaking considerably more than the others. As time permits, I hope to visit the breakers before the weekend to pick up a few old injectors, using the existing top half, to save re-coding, I will replace the metering valve and possibly the nozzle as well. Once the best combo is found, it can be refitted to the engine.
I am also hoping my tee piece will have arrived from ebay, I have opted for a brass compression fitting with olives rather than the barb type, the barb type are a pig to fit without the proper tool. The pipe is 8mm, if we use a barb type of fitting the internal diameter of the pipe will be reduced to about 6mm. The area of a 6mm circle is just above half of the area of an 8mm circle, I think restricting the pipe that much could cause problems, using a compression fitting will keep the internal diameter of the pipe the same, 8mm. We just need to be very careful when tightening the nuts up, I will try finger tight plus 90 degrees to start with, all we need to do is grip the plastic pipe firmly, if it leaks then increase the tightening an eighth of a turn at a time, we don't want to deform the pipe too much.
Another thing occurred to me, I was thinking the only place "air" can get into the injectors, was that the compression gasses are forcing the needle open for a few milliseconds, but the "air" could also be forced between the injector shell and the nozzle body. Therefore close examination of the machined faces at this junction is vital.

Steve.

alanf
Passed Theory
Posts: 47
Joined: Fri Apr 15, 2016 8:52 am

Re: Injection Fault & STOP 1.5 DCI

Postby alanf » Wed Jan 11, 2017 5:50 pm

Hi Steve, just read your thread about an 8mm comp NRV and crimping up the pipe work, in the plumbing world we use plastic or stainless liners in plastic pipe. I don't know if any will fit the ID of the fuel pipe but a trip to your local merchants may prove worth while,

Good luck with your project

Alan

Stevie67
Just Passed
Posts: 102
Joined: Sat Dec 10, 2016 2:25 am

Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Fri Jan 13, 2017 4:03 am

Hi Alan,
If I have to opt for inserts, it would be metal ones as they have a thinner wall than the plastic ones. But as you say will they fit??
I haven't cut the pipe open yet, but I suspect the 8mm pipe has a 5mm internal diameter, Since the return pipes take low pressure the olives only really need to stop the pipes rattling out. I am going to try an experiment with the new bit of clear piping. Insert the shank of a diesel coated (for lube) 5mm drill bit, through the straight of the tee piece into the pipe, making sure that the drill shank is past where the olive sits. Then gently tighten the nut, meanwhile checking that the drill bit can still rotate. When the drill bit becomes quite stiff, pull it out. I think that this should cause enough distortion of the olive to make a good seal and grip, but the internal diameter of the pipe shall remain virtually at the 5mm. If this works on my new piece of pipe I will try it on the existing pipe, just making one pipe end up at a time, because the drill needs to pass through the straight section of the tee. Then assemble the fitting with some PTFE tape. I don't know if anyone has tried fitting an olive on pipe using this method, but if they have I would be interested to hear their results.
Unfortunately I don't think my parts will arrive before the weekend, as at the moment we are in the middle of a blizzard, the snow is getting deeper by the minute and it is drifting with the 60mph winds. So even if they do arrive, I think I might wait for a lull in the storm before tackling my conversion.
When I do get round to it, I will photo the whole process, and if my olive method works, and I am happy that it has cured the foam problem, I will post some of the photos.
Steve.


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