Alfa Romeo Forum banner
1 - 10 of 10 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter · #1 ·
Hi all,

I hope you are well?
I still have a non starter after replacing the injectors and resoldering 4 plugs on my 2004 JTD m 16v. I bought a swankier meter and got continuity on 7 out of 8 leads tonight either side of the solder points. Pleased to find the blockage. I am hoping this will make it start now?

Also I tested resistance on the 4 injector solonoids and got the same reading on the auto ranging meter, please see attached?!

Correct me if I am stupid but is this 000.3 ohms, meaning all coils are shot as I think on bosch common rail low impedance they should be between 3 to 8 ohms ? (but all virtually the same) or does it read 3 ohms? In which case they are all the same and good?

Thank you for any help you can give

Simon.
 

Attachments

·
Registered
Joined
·
936 Posts
Yes that’s 0.3 Ohms, I’ve just measured two of my (working) injectors with a couple of very average meters: 0.0 Ohms with one and 0.5 with the other. Within the accuracy of these meters that’s the same as yours.
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #3 ·
Yes that’s 0.3 Ohms, I’ve just measured two of my (working) injectors with a couple of very average meters: 0.0 Ohms with one and 0.5 with the other. Within the accuracy of these meters that’s the same as yours.
Hello R.T.
thank you or taking the time out to measure your injector resistances. That is really good news! I genuinely thought they maybe shot as I rebuilt them myself. But if yours work at that resistance excellent! Here's hoping she will start now...

Have you ever tested the harnesses with noid lights? Do you know if they are supposed to flash whilst cranking? Or just when the engine is running? All the guides I see show engine running, not the initial start up.
Take care.
 

·
Registered
Joined
·
936 Posts
I use a magnetic field detector rather than the noid lights as that checks both the ecu and the injector, but yes they should flash during cranking. The ecu will wait until there is sufficient pressure in the rail before starting to open the injectors so there will normally be a short delay before they start flashing. If they don’t and you know that the fuel supply to the rail is good then it’s likely that one or more injectors has an internal leak and is sending fuel down the return hoses, so the HP pump can’t generate the required pressure. A leak-back test will find it.
 

·
Registered
Joined
·
2,251 Posts
To confirm what RT said. Just been out to the shed where I have an as-new reconditioned 0 445 110 243 I bought as a substitute while one of mine was repaired (nozzle damage after swirl flap failure). That measures 0.3R and definitely works perfectly.

It may be worth buying a Noid test light, which will show if the firing signal is getting to the injectors. They're cheap. But if your battery isn't good, the injectors are locked out from firing if the engine cranks too slowly, to prevent kickback. Allegedly the limit is ~250rpm, but it seems slower to me. Try a better battery!

Another issue is that if you have drained the HP fuel pipes and common rail, during work on the injectors, it takes a lot of cranking to refill and repressurise. I thought I had broken mine. It took about 2 mins, and then was fine just as I was about to give up. The far better approach (for the battery and starter) is to crank the engine with (at least one) fuel pipe not connected to the injectors, so trapped air can escape without having to go through the nozzles in tiny amounts. You'll need to place a rag to catch the fuel, but once fuel comes out of the pipe, connect the injector.

(EDIT: sorry for repeating points, crossed in the post :)
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #6 ·
To confirm what RT said. Just been out to the shed where I have an as-new reconditioned 0 445 110 243 I bought as a substitute while one of mine was repaired (nozzle damage after swirl flap failure). That measures 0.3R and definitely works perfectly.

It may be worth buying a Noid test light, which will show if the firing signal is getting to the injectors. They're cheap. But if your battery isn't good, the injectors are locked out from firing if the engine cranks too slowly, to prevent kickback. Allegedly the limit is ~250rpm, but it seems slower to me. Try a better battery!

Another issue is that if you have drained the HP fuel pipes and common rail, during work on the injectors, it takes a lot of cranking to refill and repressurise. I thought I had broken mine. It took about 2 mins, and then was fine just as I was about to give up. The far better approach (for the battery and starter) is to crank the engine with (at least one) fuel pipe not connected to the injectors, so trapped air can escape without having to go through the nozzles in tiny amounts. You'll need to place a rag to catch the fuel, but once fuel comes out of the pipe, connect the injector.

(EDIT: sorry for repeating points, crossed in the post :)
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #7 ·
Hello RT,

Hello Halftone,

Apologies for my lapse in contact, had the dreaded lurgy, fortunately man flu this time.

I thought about what you guys said and very much appreciate the advice, thank you.

The air bleed totally makes sense now…I had the front wheels on breeze blocks for weeks now, when it tries to prime it’s pumping air uphill as the car was nose up, nose down now, caused by putting air into the system from previous work with injectors and replacement of fuel pressure reg’ etc. No doubt helps as the car is on a flat surface now. Also resoldered the last wire plug today and got continuity, then charged battery, and another to hopefully get some boost if need be.

My plan for tomorrow…?

1). Back off 1 or 2 injector pipe nuts (a little) leading into injector(s). Should I stick close to the rail feed (nearside)?

2) Remove fuel pump relay and bridge with wire to keep fuel flowing once I turn the key to the on position to prime system.

3) Watch the air bubbles until they stop, and fuel only leaves the backed off nuts, and then re-tighten whilst fuel flowing to stop air leak back?

4) Or do I physically need to crank? Saw this guy do it on a merc’ on you tube, looked sketchy… as once enough air had escaped, the car started and continued to fire fuel out of the rail whilst he rushed to tighten 4 pipes at high speed whilst being hit by fuel!

Am I also right in thinking RT… The leak back test comes after I do all this, and if it still fails to start, then I have my answer(s) either way, as to whether 1 or more injectors are open?!

Hope you and yours are well guys.



Simon.
I use a magnetic field detector rather than the noid lights as that checks both the ecu and the injector, but yes they should flash during cranking. The ecu will wait until there is sufficient pressure in the rail before starting to open the injectors so there will normally be a short delay before they start flashing. If they don’t and you know that the fuel supply to the rail is good then it’s likely that one or more injectors has an internal leak and is sending fuel down the return hoses, so the HP pump can’t generate the required pressure. A leak-back test will find it.
Hello RT,

Hello Halftone,

Apologies for my lapse in contact, had the dreaded lurgy, fortunately man flu this time.

I thought about what you guys said and very much appreciate the advice, thank you.

The air bleed totally makes sense now…I had the front wheels on breeze blocks for weeks now, when it tries to prime it’s pumping air uphill as the car was nose up, nose down now, caused by putting air into the system from previous work with injectors and replacement of fuel pressure reg’ etc. No doubt helps as the car is on a flat surface now. Also resoldered the last wire plug today and got continuity, then charged battery, and another to hopefully get some boost if need be.

My plan for tomorrow…?

1). Back off 1 or 2 injector pipe nuts (a little) leading into injector(s). Should I stick close to the rail feed (nearside)?

2) Remove fuel pump relay and bridge with wire to keep fuel flowing once I turn the key to the on position to prime system.

3) Watch the air bubbles until they stop, and fuel only leaves the backed off nuts, and then re-tighten whilst fuel flowing to stop air leak back?

4) Or do I physically need to crank? Saw this guy do it on a merc’ on you tube, looked sketchy… as once enough air had escaped, the car started and continued to fire fuel out of the rail whilst he rushed to tighten 4 pipes at high speed whilst being hit by fuel!

Am I also right in thinking RT… The leak back test comes after I do all this, and if it still fails to start, then I have my answer(s) either way, as to whether 1 or more injectors are open?!

Hope you and yours are well guys.



Simon.
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #8 ·
Hello RT,

Hello Halftone,

Apologies for my lapse in contact, had the dreaded lurgy, fortunately man flu this time.

I thought about what you guys said and very much appreciate the advice, thank you.

The air bleed totally makes sense now…I had the front wheels on breeze blocks for weeks now, when it tries to prime it’s pumping air uphill as the car was nose up, nose down now, caused by putting air into the system from previous work with injectors and replacement of fuel pressure reg’ etc. No doubt helps as the car is on a flat surface now. Also resoldered the last wire plug today and got continuity, then charged battery, and another to hopefully get some boost if need be.

My plan for tomorrow…?

1). Back off 1 or 2 injector pipe nuts (a little) leading into injector(s). Should I stick close to the rail feed (nearside)?

2) Remove fuel pump relay and bridge with wire to keep fuel flowing once I turn the key to the on position to prime system.

3) Watch the air bubbles until they stop, and fuel only leaves the backed off nuts, and then re-tighten whilst fuel flowing to stop air leak back?

4) Or do I physically need to crank? Saw this guy do it on a merc’ on you tube, looked sketchy… as once enough air had escaped, the car started and continued to fire fuel out of the rail whilst he rushed to tighten 4 pipes at high speed whilst being hit by fuel!

Am I also right in thinking RT… The leak back test comes after I do all this, and if it still fails to start, then I have my answer(s) either way, as to whether 1 or more injectors are open?!

Hope you and yours are well guys.



Simon.
 

·
Registered
Joined
·
936 Posts
Am I also right in thinking RT… The leak back test comes after I do all this, and if it still fails to start, then I have my answer(s) either way, as to whether 1 or more injectors are open?!
Yes after that, but there are other reasons why the injectors may not be opened: a poor crank sensor signal or cranking too slow, so you need to run some tests to find the cause. Working on the principle that the last thing to be disturbed is a good place to start, I would do the leak-back test. If all the injectors are good then start thinking of other possibilities.


[Ps: Never spanner any part of the high pressure system while the engine is running. Stop it and wait for the pressure to decay - risk of fuel from a split pipe being injected through your skin with possibly fatal consequences.]
 

·
Registered
Joined
·
2,251 Posts
4) Or do I physically need to crank? Saw this guy do it on a merc’ on you tube, looked sketchy… as once enough air had escaped, the car started and continued to fire fuel out of the rail whilst he rushed to tighten 4 pipes at high speed whilst being hit by fuel!
I meant 'crank it' - to clear air from the pipework upstream of the injectors. It can't start with the pipe unions to the injectors loosened since pressure will be too low, but to make sure unclip the electrical connectors. Once you start to see fuel emerge, reconnect everything.
 
1 - 10 of 10 Posts
Top