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Leaky Injectors?


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Just a thought, but have you checked that you have a clear return pipe from MU to fuel tank. If it is partially blocked, you may have too much residual pressure in the MU forcing fuel out of the injectors because it has nowhere else to go. Hope you solve the problem.

Yours

Paul

 

 

Hi Paul,

 

Good point, i have covered this, the copper pipe has been pumped through with air and is clear, i also tested it all by connecting the rubber pipe into a bottle, so the copper pipe was out of the equation. No change.

 

You know sometimes with this i think i must be mad :mellow: or its a very long bad dream :lol: And i will wake up, the injection will be spot on, the sun will be out and i will be driving on a nice streched of French open road. :rolleyes:

 

Cheers

Guy

 

Guy

Edited by Jersey Royal
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Guy

 

Have you tried disconnecting the return pipe directly at the MU and running the pump to see if the outlet from thr MU is obstructed?

 

Just a thought!

 

Cheers

 

Bill

 

Bill

 

Yup done that and it runs down the Mu.

Injectors off car, now going to run them to Specialist here to check blow off pressures. I hope he can do it today.

 

Cheers

 

Guy

 

Oh p**, place is shut up, hes gone for a weekend break to the sun in Spain. so is booked in tuesday. Injectors back on car

Edited by Jersey Royal
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PS: Under idle conditions I would expect more than a trickle in the return pipe.

There are 2 fuel returns to the tank so it’s important to understand which one you’re referring to. Most of the fuel the pump delivers is returned to the tank via the back of the PRV & this should be around 1.2 litre/min with the ignition on but engine not running. This is what you can mainly hear & see returning to the tank & will, hopefully, be as above if your pump is in good condition. Start the engine & this return flow will reduce, depending on the amount of fuel the engine is using; if the fuel return is significantly less with the PRV correctly set, your pump is knackered!

 

Fuel returning from the metering unit is termed “back leakage” & has nothing to do with the main return flow from the PRV. Most cars (as mine) have a separate feed line to the tank, earlier cars, I believe, tee into the PRV return. This back leakage is necessary to equalise the fuel pressure within the rotor when the shuttle fires back & forth & is why pressure will build & the diaphragm will unseat if it’s blocked. If you remove the M/U pipe, the amount of fuel returning should not be significant, anything more than a steady trickle & your M/U sleeve & rotor are probably knackered!

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Bill

 

Yup done that and it runs down the Mu.

Injectors off car, now going to run them to Specialist here to check blow off pressures. I hope he can do it today.

 

Cheers

 

Guy

 

Oh p**, place is shut up, hes gone for a weekend break to the sun in Spain. so is booked in tuesday. Injectors back on car

 

 

Update:

 

Had a call from Speacialist, he says my reconned injectors are "all over the Place"

 

Am not impressed, cant be bothered with the grief of sending them back and the length of time it will take, the next lot may be the same.

Am getting them sorted locally, should be back in the car in a couple of days i hope

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Update:

 

Had a call from Speacialist, he says my reconned injectors are "all over the Place"

 

Am not impressed, cant be bothered with the grief of sending them back and the length of time it will take, the next lot may be the same.

Am getting them sorted locally, should be back in the car in a couple of days i hope

Lets hope that gets it sorted. They are dead easy to adjust with a suitably sized allen key, all you have to do then is have some means of mesuring the blow off pressure. Many years ago before I had a compressor I used to use a modified foot pump with a built in pressure guage; crude as hell but it worked well enough.

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Lets hope that gets it sorted. They are dead easy to adjust with a suitably sized allen key, all you have to do then is have some means of mesuring the blow off pressure. Many years ago before I had a compressor I used to use a modified foot pump with a built in pressure guage; crude as hell but it worked well enough.

 

Fingers crossed, the chap i am using has a workshop full of equipment, and has just fitted a Reconned Mu and injectors supplied by K Raven Smith, to a white Tr5 (ex Tr Bitz). Hopefully that owner will be joining the Register soon.

 

I am happy he will sort it.

 

 

Thanks Richard and thanks also to everyone who has assisted in this on going saga.

 

Cheers

 

Guy

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Lets hope that gets it sorted. They are dead easy to adjust with a suitably sized allen key, all you have to do then is have some means of mesuring the blow off pressure. Many years ago before I had a compressor I used to use a modified foot pump with a built in pressure guage; crude as hell but it worked well enough.

Hi Richard, can you give some more details of how you do this little trick by using a compressor so i can test spare injectors that i have myself,Thanks.

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Hi Richard, can you give some more details of how you do this little trick by using a compressor so i can test spare injectors that i have myself,Thanks.

I have a water separator/filter unit with quick relaese couplings fitted to the wall downstream from my compressor which also has a fairly accurate pressure regulator & guage. Take a very short length of air hose fitted with a quick release coupling on one end & a spare injector elbow (or equivalent fitting) at the other, set the regulator output pressure down to around 30 PSI, plug the hose with the injector fitted onto the output & wind up the pressure until the injector pops (do it quickly rather than slowly), making a note of the blow off pressure it popped at & adjust until you get the desired pressure reading; simple!

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Guy

 

Just as a matter of interest, who supplied the defective injectors?

 

I too have recently replaced injectors and suspect 1 or 2 aren't quite right.

 

It shouldn't be necessary to have to check pressures on the injectors before refitting, but with hindsight may be worthwhile.

 

AT

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Guy

 

Just as a matter of interest, who supplied the defective injectors?

 

I too have recently replaced injectors and suspect 1 or 2 aren't quite right.

 

It shouldn't be necessary to have to check pressures on the injectors before refitting, but with hindsight may be worthwhile.

 

AT

 

 

Pm sent

Edited by Jersey Royal
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Hi All,

 

Update.

 

 

Got my RE-recon injectors back today from local Specialist, have fitted and bleeding wasnt quite so easy to bleed this time.

 

Been for a run around the block, car runs brilliantly, and wait for it................ They still appear to leak. :blink: Although there appears to be small bubbles at the tips as fuel seaps, it may even be less than before, or maybe its wishfull thinking :blink:

 

Am going to give the car more of a run in the next couple of days just to ensure all air is out of the system, and test again.

 

:(

 

Boo hoo

 

Guy

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They still appear to leak. :blink: Although there appears to be small bubbles at the tips as fuel seaps, it may even be less than before, or maybe its wishfull thinking :blink:

Bubbles appearing around the poppet valve pip is an indication they are not seating properly, possibly due to fine debris or poor seating of the valve itself; you can lap them in using very fine grinding paste & Brasso to finish off but don’t overdo it.

 

If the bubbles are appearing between the poppet valve assemble & the injector body, the “O” ring isn’t sealing. This can be due to the wrong size/type being fitted by the recon. specialist or the inside of the injector body being damaged, possibly by rust; if so, it will never seal properly & will need replacing.

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Hi,

if the pump runs, the patrol express over the normal tolerances from the rotor to the valves and to the injectors ! This is a completely normal process.

If you want you can overfill the cylinders with petrol. About engine run !!!!

One step on the starter and bang. Our the con rods are bent !

I often used boschinjektors from the k-jetronic. When the petrolpump drive about engine run at some minutes you can hear when the injectors sprayed (iiiht). Please make the test all injectors in a glass, pump on and you can see that almost injector sprayed. Therefore, do not panic it is normally.

Regards from Germany :rolleyes:

Ralf

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Hi,

if the pump runs, the patrol express over the normal tolerances from the rotor to the valves and to the injectors ! This is a completely normal process.

If you want you can overfill the cylinders with petrol. About engine run !!!!

One step on the starter and bang. Our the con rods are bent !

I often used boschinjektors from the k-jetronic. When the petrolpump drive about engine run at some minutes you can hear when the injectors sprayed (iiiht). Please make the test all injectors in a glass, pump on and you can see that almost injector sprayed. Therefore, do not panic it is normally.

Regards from Germany :rolleyes:

Ralf

confused0068.gif Sorry Ralf I don't understand your comments let alone if they are relevant to Guy's problem! :unsure:

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confused0068.gif Sorry Ralf I don't understand your comments let alone if they are relevant to Guy's problem! :unsure:

From long experience of technical German, I believe Ralf is suggesting that it is normal for the injectors to weep, as their pop-off point is so much lower than the pressure from the M/U, but the weeping only arises when the pump is running and the engine is not, therefore it's nothing to worry about. :blink:

 

I think I see the point I believe he is trying to make, also of course after a run there will be residual pressure in the injector lines for a while which might weep out, but if the M/U is sealing properly, then I would have thought that unless the engine is running the pressure should not get to the injectors anyway. :unsure:

 

Certainly after reading all this saga, I have no intention of checking my injectors, ignorance = bliss. :P

 

Ivor

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Certainly after reading all this saga, I have no intention of checking my injectors, ignorance = bliss. :P

 

Ivor

 

 

 

Oh ... Go on Ivor, make me feel better. :rolleyes: You know you want too :P

 

 

Cheers

 

Guy

 

Nb Have ordered a set of injectors from a reputable source, they will be going on the car, they are going to be checked and sorted prior to depatch.

Thats going to be it, cant do anymore.

Edited by Jersey Royal
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From long experience of technical German, I believe Ralf is suggesting that it is normal for the injectors to weep, as their pop-off point is so much lower than the pressure from the M/U, but the weeping only arises when the pump is running and the engine is not, therefore it's nothing to worry about. :blink:

 

I think I see the point I believe he is trying to make, also of course after a run there will be residual pressure in the injector lines for a while which might weep out, but if the M/U is sealing properly, then I would have thought that unless the engine is running the pressure should not get to the injectors anyway. :unsure:

 

Certainly after reading all this saga, I have no intention of checking my injectors, ignorance = bliss. :P

 

Ivor

Ralf; assuming Ivor’s done a sound job on interpretation then I’m afraid I don’t agree with you at all! sad0020.gif I have little practical experience of the Bosch K Jetronic system but have spent some 30 odd years maintaining & rebuilding Lucas PI systems. I concede that the odd weeping injector is a fact of life from time to time, it’s unavoidable but acceptable in the short term. But it is in no way normal for Lucas injectors to weep with engine running let alone with the ignition on (pump running) & engine off; this will result in a sump full of petroil mix & quickly knackered engine! :(

 

What I do know about the K Jetronic is that it operates at much lower pressure than the Lucas & it’s a continuous injection system, so operating completely differently to the Lucas. The Lucas injection system is high pressure 100-108 PSI & is both timed by the fuel distributor rotor & pulsed by a rotor shuttle. When running, the injector lines will have a residual pressure of around 50 PSI (depending on the injector operating pressure); the shuttle delivers a measured amount of high pressure fuel, pressurising each injector line in turn taking it above the injector operating pressure, resulting in a timed fuel spray. Because of the internal rotor sealing & one way valves fitted to each fuel line, no engine running should = no injector spray; unless there is something wrong. :(

 

Residual pressure in the injector lines after the engine is switched off will dissipate after a couple of days, sooner if the injector or M/U non return valves are less than perfect.; the main reason correct starting technique is important with Lucas PI’s. ;)

 

Oh go on Ivor check your injectors, you must be tempted ! :lol:

Edited by Richard Crawley
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Hi Guy

Ongoing saga still :o Richard's advice is as you know the best but your suppliers must have some answers to this issue?. Not long now before you go to the other side ;) when was the last time you changed the fuel in the tank?

Edited by ntc
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Hi All,

 

David,

I am getting my injectors from a different source to the last two suppliers, and will see if there is any difference. Currently i have two injectors that do not seep :rolleyes: and the rest do. This new lot of injectors are going to be checked thoroughly. And well if there is no improvement, i will have wasted some cash and not got very far. Although the Reconned Mu performs well and the car hasnt performed as well for a long while, this will be down to being recalibrated to suit cam.

 

Neil,

I have checked and rechecked everything, followed advise from specialists and the forum, and combined with manuals and books, and yet the problem persists. Advise i have had from specialist is that it should not be occuring, i suppose its difficult to diagnose the problem unless you have the car infront of you. If the last lot of injectors dont make any difference to what i have now... as far as i see it i have two options.

 

1

Shut up and live with it :blink:

 

2

Join the dark side and tread unknown territory :blink:

 

 

This makes me wonder how many others are out there, with leaky injectors. <_<

 

Thanks to Richard for your ongoing advise.

 

Cheers

 

Guy

 

Oh yeah, ....... Fuel , i use the car regularly, thats when i am not waiting for parts, so the fuel is constantly being replenished.

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Guy

 

When you really start to scream......

 

Sat in a hotel in Southern Sweden, over breakfast, Friday morning last week, a Dutchman (no I kid you not) came up and showed us a set of brand new innards for a Lucas PI Injector which are being made by colleague of his in the Dutch TR Register. And rather posh they looked as well. Adjustment for blow off pressure is far easier as there is no need for concentric allen keys, just one allen key and a small spanner.

 

Price €200.00 for 6 + P&P.

 

I have further details but they are 1) at home and 2) in poorly photocopied Dutch (well that's what he said it is but it might as well be Greek for all the sense I can make of it)

 

If you want the contact e-mail address PM me.

 

Regards

 

Tim

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Guy

 

When you really start to scream......

 

Sat in a hotel in Southern Sweden, over breakfast, Friday morning last week, a Dutchman (no I kid you not) came up and showed us a set of brand new innards for a Lucas PI Injector which are being made by colleague of his in the Dutch TR Register. And rather posh they looked as well. Adjustment for blow off pressure is far easier as there is no need for concentric allen keys, just one allen key and a small spanner.

 

Price €200.00 for 6 + P&P.

Sounds like a nice idea, especially as decent injector innards are now getting thin on the ground but that's one hell of a premium! :o But the Dutch never did have much sense with money :lol:

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Guy

Shut up and live with it is not an option (especially as decent injector innards are now getting thin on the ground quote Richard)

This is why most suppliers are having problems not only with injectors they are trying to recondition units that have already been reconditioned many times :(

Edited by ntc
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