jacko
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| posted on 30/9/10 at 03:40 PM |
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diesel engines injectors
Hi can any one tell me how to find a injector that is not working ?
If i block the injectors pipe one at a time then start the engine will this show it duff injector like taking a plug lead of a petrol engine
We have fitted a new injector had it programmed in but we don't think it is working its just open all the time poring derv in
Thanks jacko
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speedyxjs
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| posted on 30/9/10 at 03:42 PM |
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I normally just whip them out, take them to a place local to here and they put them on their test bed.
Is there not a place near you that can test injectors?
Just re-read the last bit (doh). Can you hear it clicking whent he engine is running?
[Edited on 30-9-10 by speedyxjs]
How long can i resist the temptation to drop a V8 in?
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coyoteboy
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| posted on 30/9/10 at 03:49 PM |
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by the "programmed in" question I'd say you're working on a commonrail. I'd not be going near the fuel system under
pressure with one of those - do you want hypodermically injected diesel? 
Seriously though, disconnecting the injector electronic feed will do as you expect (duff injector will make no difference to the running when
unplugged) unless you car chooses to throw a fit due to missing injector.
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jacko
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| posted on 30/9/10 at 03:54 PM |
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I don't know the engine is a pain it will not run at the mo because with a injector letting fuel in all the time it won't /can't get
enough pressure with the fuel pump to start it
we have been told it needs 130lbs -300lbs to start the dam thing it's only got 60lbs
dam French renault
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coyoteboy
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| posted on 30/9/10 at 04:06 PM |
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What engine/car is it? If it's a french one it's probably an HDi (modern) or the old PSA diesel with mechanical pump if not.
Assuming you have a jammed-open injector it'd be easy to find by removing them all and blowing (mechanically) through them all.
[Edited on 30/9/10 by coyoteboy]
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T66
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| posted on 30/9/10 at 04:07 PM |
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With the engine running, just open the fuel supply union to it. If the engine gets worse / lumpier there lies the faulty injector.
If you open it and the engine doesnt stutter any further than it already is, the injector is fine.
Worst you will get is a scoot of fuel from the open union, stick a rag near it when you open it. To collect the drips.
Ive cracked lots of injectors, and Ive never managed to inject myself with anyhting yet, nor have I got dermatitus.
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coyoteboy
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| posted on 30/9/10 at 04:11 PM |
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quote:
Worst you will get is a scoot of fuel from the open union, stick a rag near it when you open it. To collect the drips.
Ive cracked lots of injectors, and Ive never managed to inject myself with anyhting yet, nor have I got dermatitus.
You are aware that commonrail injector rails run at about 2500*bar* aren't you? Sticking a rag near it will do nothing but serve as an extra
material to be embedded in your flesh. As someone who HAS got dermatitis from it, but fortunately hasn't been injected with it (as it's an
amputation-requiring problem) I'd advise caution. Old-school diesels are somewhat simpler and safer beasts.
[Edited on 30/9/10 by coyoteboy]
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dilley
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| posted on 30/9/10 at 04:19 PM |
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If you have common rail injectors than you can perform a leak off test, when an injector is 'faulty' the fuel will flow through the leak
off (return pipe), if this is happening on one or more injectors then the fuel rail cannot build up pressure and the ECU will so NO!!! A leak of test
is performed with the leak off pipes removed from the injectors, a plastic pipe/tube is then pushed in to where the leak off pipes have been removed
from, 1 for each injector, each pipe is connected to a small bottle (upside down) you then crank/start the engine.....all the bottles should fill at
the same rate, If you have a faulty injector then the bottle will fill quicker than the others. Hope this helps!!!
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stevebubs
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| posted on 30/9/10 at 04:21 PM |
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try disconnecting each one in turn...
My dad had this on his R75 and it turned out to be a wire that had frayed and then shorted....
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coyoteboy
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| posted on 30/9/10 at 05:21 PM |
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Yup, best method is to check the leak-off rate of each injector and the faulty one will stick out like a sore thumb, and it'll all be done in a
safe and orderly fashion with bottles collecting your mess.
While my warning over the fuel pressures may seem a tad over-the-top, I'd be remiss if I did not give it suitable weight - it IS dangerous to
the DIYer.
A stuck-open injector will leak off less into the bottle than a normal one. A stuck closed will leak more. You should be able to spot this really
easily in your case.
Good luck, and take care with it - it'd be horrible to be taken out by a daily driver diesel!
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jacko
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| posted on 30/9/10 at 07:40 PM |
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Hi all up date to this injector problem
My son and I have just removed the injector pipe from the injector and blocked the pipe started the engine hay presto is started wich it would not do
before SO we need a new injector thanks for your help so far
Jacko
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