Injection Fault & STOP 1.5 DCI

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quaker@eircom.net
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Re: Injection Fault & STOP 1.5 DCI

Postby quaker@eircom.net » Fri Jan 13, 2017 12:27 pm

Hello there Steve......Just thinking about an interm measure before any cutting of pipes and the like.

I assume your filter is the four pipe type....the "supply" side ( one from the tank and one to the HPP ) and the "return" side ( one from the HPP and one to the tank). What about disconnecting the two "return" pipes at the filter and just join them together and blank off the exposed pipe spouts on the filter housing. This way all the return/overflow diesel is now going directly to the tank including the bubbles. Not sure what the diameter of the filter spouts are ( either 6mm or 8mm ) but its easy to blank them off temporarily. A piece of either 6mm or 8mm pipe would/should join the "return" pipes.
I know the fuel filter is now without its heat source but when you start off in the morning this is the case anyway. If there are issues all can be undone with no damage done.
What do you think?

Stevie67
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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Fri Jan 13, 2017 3:44 pm

Hi Maurice,
I did think of doing what you suggest, I also thought about using two basic inline filters, one to replace the existing filter but not have spare spouts, the second just as a straight connector for the return pipes. Both methods would work and would be easier to implement, but when the engine is cold or more accurately the fuel is cold the filter creates a sort of closed loop, where the fuel circulates between the pump and the filter. This small amount of fuel will heat up a lot quicker than if it is all returned to the tank, because otherwise all the fuel in the tank has to be heated. The amount of foamy fuel I will be returning to the tank will be minimal. I think that since the computer knows the temperature of the fuel at the pump, it will adjust the amount of fuel injected depending on the fuel temp, warmer fuel being combustible.
In a lot of places this may not make a difference, but I live in the north of Scotland, I am closer to the Arctic Circle than I am to London, the outside air temperature is never warm, even in the rare event that the sun comes out, during mid winter we get less than four hours between sun up and down, the temperature rarely makes it above zero. So cold air rushing under the car as it drives along the road will cool the fuel tank, not to mention the surface water/snow/ice getting thrown at it. Therefore I recon the fuel will never warm up, certainly not on the short runs that the car will normally be doing.
That's my logic anyway, unfortunately no parts arrived in the post today, hopefully tomorrow....

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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Mon Jan 16, 2017 11:39 pm

Below I have posted a collage of photos showing my plumbing modification. In the first two pictures you can see the olive fitting method that I described above. In the third picture you can see that the olive has deformed enough to grip the pipe but not crush it. The forth picture just shows the new pipe fitted to the correct socket of the tee piece. In the fifth picture you can see the new pipe fitted to the car. The 8mm O.D. 5mm I.D. pipe fits perfectly on to the tee piece of the return rail. The new pipe is 240mm long. The sixth picture shows the plastic return rail retainer with the original end cut off to allow the new pipe to be held firm yet exit freely. In the seventh picture the engine is running, a bubble from the injectors can just be seen at the new tee piece, nowhere near the pump. I was expecting to see foam in this pipe at regular intervals. In reality there is only a random bubble, no where near the amount of bubbles that where previously seen at the pump. And in the last picture you can see the new pipe discreetly sneaking under the engine cover.

Image

Having the plumbing set up like this makes bleeding the pump much easier, there is now no need to bleed the return lines from the injectors. A small piece of pipe fitted to the pump spout that the return rail used to be fitted to with a bolt stuck in the other end makes for a useful vent when bleeding.
The most important thing is that there is now absolutely no bubbles visible at the pump, therefore I am considering this modification a complete success.
At £3.45 for the tee piece and the tube, I think this is a cheap and reliable way of insuring the pump remains healthy, the injectors can now bubble away as much as they want and the pump is safe. I had a look to see if the car had any codes, there were none, while I had the reader plugged in I looked at the live data and noted it at idle, 806 rpm I had 230 bar on the high pressure rail. I don't know what the rpm and pressure are meant to be at idle, but I can refer back to these figures in the months to come to see how the pump is getting on.

So, if your 1.5DCI has bubbles in the fuel lines at the pump, this could save you some costly repairs.
Steve.

quaker@eircom.net
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Re: Injection Fault & STOP 1.5 DCI

Postby quaker@eircom.net » Tue Jan 17, 2017 4:52 pm

Hello there..
Looks good Steve...I assume the original fuel return pipe ( from FF to Tank) is 8mm OD and 5mm ID.
rgds Maurice

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Re: Injection Fault & STOP 1.5 DCI

Postby triumph2.5man » Tue Jan 17, 2017 9:37 pm

Perfick! You have certainly got your teeth into this problem Stevie. And the leak-off from the pump goes into the filter as normal to heat the fuel in there. If and when the fuel gets hot enough, the bi-metal strip will bend, the ball bearing drops down and leak off will be diverted to the tank via your T piece.
As you pointed out, this could take time up in the north of Scotland! The idle speed and rail pressure seem to be almost spot on. Well done, Mike

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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Wed Jan 18, 2017 1:41 am

Maurice, the existing black return pipe is 8mm O.D. the I.D. is slightly bigger than 5mm, possibly 5.25mm, I still used the same drill bit and the olives worked as well as in the photo above.

Mike, you got it, and it works perfectly. The fuel heats up quite quickly, in a few minutes the fuel pipes are noticeably warmer, so I am super pleased about that. We have strange weather at the moment, we still have pockets of snow lying around yet the temp today was 12 degrees, I had a chance today to start looking at some other problems with the Megane, it was like a summer day out there. I am really happy that you say the data is good.

I have searched the internet looking for a suitable valve type thing to replace the bolt in pipe that I am using to seal the spout at the pump, where the return pipe used to fit. I could not find anything that I liked the look of, so I had a rake around in my shed for something usable. I might be on to something now, using a tyre valve. If it works I shall post my results.

quaker@eircom.net
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Re: Injection Fault & STOP 1.5 DCI

Postby quaker@eircom.net » Thu Jan 19, 2017 1:01 pm

Re tyre valve as air bleed valve.
Get a lorry/tractor tyre valve and cut the base off. You are now left with a cylindrical metal stem 8mm in diameter and approx 40 mm long. Also get 8mm ID fuel hose ( rubber stuff not plastic), a few pipe clips ( like jubilee clips ). Push the tyre valve into the rubber hose until the threaded area is now only visible. Cut a 100mm length of this hose and feed it down over the pipe where bolt is stuck into.( take out the bolt) It should overlap approx 40mm approx and put the clips on to secure the hose.Remove the actual inside valve and cap it off. You might need to put a pipe insert into the plastic pipe so that the pipe clips wont crush it when tightening.
rgds
Maurice

Stevie67
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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Fri Jan 20, 2017 5:58 am

That is the sort of thing I am thinking about, but I don't have any lorry valves, however I do have car valves. I will post my results as soon as I have done a few experiments.

Stevie67
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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Fri Jan 20, 2017 6:24 am

Check this out, my engine used to be like this.....not any more.

    

Stevie67
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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Sat Jan 21, 2017 12:25 am

So this is what I came up with, a normal car tyre valve, remove the rubber with a sharp knife, screw the cap on the valve and mount the valve assembly in the chuck of an electric drill grabbing it by the cap end. With some emery cloth polish the part that the rubber was cut from, to make sure all the rubber is gone and now there is a perfectly smooth (with no knife marks) round brass spout that is almost exactly 6mm in diameter. Take the valve mechanism out with a valve key, then cut about 3mm off the threaded end, so that when the valve is reassembled the end of the moving section of the valve protrudes by about 2mm. The off-cut of 5mm I.D.,8mm O.D. pipe that I had left over from the previous modification, is then forced over the 6mm end of the valve assembly. See the picture below.

Image

Then, reusing the original fittings from the pump that I am no longer using to return fuel from the injectors, I connected the other end of my clear pipe.
The original fitting is fitted back onto the pump, now I have a bleed tube. Using the primer in the usual way bring fuel up to the pump, each time the primer bulb is depressed, just before releasing it I tap the bleed button ( the 2mm of valve sticking out of the valve surround), then let the primer refill.
Usually when you prime the system, you can see the air being forced up to the pump, with my clear bleed tube I can ensure every last tiny bubble is removed from the pump. By having my tube vertical, the bubbles just rush to the top. I found every few pumps of the primer I had to push the bleed button whilst depressing the primer rather then waiting till the end, this is to allow some fuel to rise up the tube making it easier to see the bubbles. All the time the bleeding is going on I left a lot of air at the top the tube, so fuel doesn't spurt out the end each time the button is pushed. Then when all the air has been forced out of the pump, use the primer in conjunction with the button to push fuel right to the end of the bleed tube.

Image

Once priming is complete, replace the cap and rotate the right angle fitting at the pump through 90 degrees to fold the bleed tube away. The end of the bleed tube clips into a convenient clip that Renault left blank for just such an occasion. I believe the clip is used when the 1.5 dci is fitted into a Clio.

Image

quaker@eircom.net
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Re: Injection Fault & STOP 1.5 DCI

Postby quaker@eircom.net » Tue Jan 24, 2017 5:07 pm

Steve....there are a lot of bubbles coming from injectors and these are now going straight back to the tank. Before you did this modification, where did these bubbles end up?....Looking at the plumbing, these bubbles joined the overflow from the HPP and were ducted back to the FFilter. If the fuel was cold ( like when you start off in the morning), then the heating regulator within the FFilter ducted these bubbles forward to the HPP, into the inlet side of the transfer pump. Now did these bubbles get transferred to the high pressure side of the HPP or did they join the overflow fuel from the transfer pump back around the circle again? Were these bubbles causing driveabilty issues before the modification?
rgds
Maurice

Stevie67
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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Tue Jan 24, 2017 9:05 pm

Hi Maurice,
When I first got the car it was not even able to crank over, it was bought as a non runner. The HP sensor was missing, due to a lack of signal from the sensor the injection computer would not let the starter motor kick in. So all I have to go on, was what the seller told me, "it just stopped running, had to tow it to a garage". The garage must have taken the sensor out. I replaced the pump after diagnosing it as being faulty, then I noticed the bubbles once we had her running. I did not risk driving the car with the bubbles, I didn't want to damage the new second hand pump.
I don't think the bubbles were making it to the high pressure side of the pump, but the low pressure pump would have not been lubricated all the time, also the external rollers of the high pressure side would have had dry spells. The dry spells at the high pressure side is what killed the previous pump. By making the modifications that I have, there is now no bubbles in my pump, therefore hopefully elongating the life of the pump. However, if there were more bubbles, the pump could run low on fuel, possibly enough to start affecting performance. In the video that I posted above, there is enough bubbles that it must be affecting performance.
An interesting observation was made after all the pipe mods, after the car had been run up to temperature and the engine was turned off, bubble were seen coming up my new return pipe for about five minutes afterwards. My only explanation for this is that one cylinder must have been on its compression stroke at the point that the engine stopped rotating.
Steve.

quaker@eircom.net
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Re: Injection Fault & STOP 1.5 DCI

Postby quaker@eircom.net » Wed Jan 25, 2017 6:58 pm

Re bubbles coming from the Injectors:-
If one were to get the injectors repaired/refurbished/reconditioned or the like, should the bubbles dissappear?
rgds
Maurice

alanf
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Re: Injection Fault & STOP 1.5 DCI

Postby alanf » Thu Jan 26, 2017 1:18 pm

Hi Steve, slightly off topic but have you read anything about adding 2stroke oil to diesel, about 150/200ml to a tank full its supposed to lubricate the pump and injectors, a mate of mine does a lot on VWs and swears by it.

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Re: Injection Fault & STOP 1.5 DCI

Postby Stevie67 » Fri Jan 27, 2017 1:11 am

Maurice,
In theory the bubbles should disappear, but in practice there may be an acceptable tolerance, especially if they are reconditioned.
Another unknown variable is how long does it take for bubbles to start appearing, even on a new injector? What do Delphi consider acceptable, 20k? 80k?
The only thing we can be sure about is that these injectors over time do develop bubbles, considering the environment the nozzles are in, I wouldn't be surprised if all injectors produce bubbles. Is this why car manufacturers nearly always use black pipes for the return, bubbles on a brand new car wouldn't exactly be a good selling feature if injectors produce bubbles from new....
Alanf,
I did read about 2 stroke oil somewhere, I must admit I am somewhat sceptical, I know that in a 2 stroke engine the 2 stroke oil does not burn, it gets thrown out the exhaust in tiny droplets, so in a vehicle that has the cats, filters and EGRs where does the 2 stroke end up? I know that the cat gets up to temperatures that way exceed 2 stroke engines, but if it is getting burnt there, will the computer try and adjust the fuel mix because of strange readings coming from the exhaust sensors, would the MoT sniffer pick up on the 2 stroke oil? Again the theory is there, I agree with that, but I personally am not brave enough to risk screwing up the exhaust system/computer, I'd rather cut my pipes up and divert my bubbles away from the pump altogether.


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