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Discussion Starter #1
hello.my 4.6 gems is having a bad time to start from warm.when hot no pro.no faults stored in ecm,had it checked using autologic.how can i know if it is the regulator or leaking injectors?thank you
 

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Discussion Starter #2
My mechanic said that i must replace the 8 injectors!!!! when i mentioned the fuel regulator he said that it is not the culprit !!! and it wouldn't do like that.injectors cost 400$ i asked him if they can be cleaned instead,he answered cleaning them won't fix the pro they must be replaced.any thoughts? no faults in the ecm.
Please help,what do u think?
thank you
 

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JACK'S GRANDAD
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Weird if all 8 injectors went bad at the same time.
So, just so I am clear. When it is cold you have a hard time starting it, but when it is hot it starts just fine?
If that's the case, when it is cold turn the ignition key to the "run" position but do not start. Leave it in the "run" position for @5-10 seconds, then try to start it. If it starts right up, then the check valve in the fuel pump has gone bad, allowing fuel to return to the tank instead of staying in the fuel lines.
So far as your fuel pressure regulator goes, what is the fuel pressure at the test port on the fuel rail? That is the way to test the regulator. If the pressure is low, then it is a bad regulator or fuel pump.

Martin
 

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Discussion Starter #4
leftlanetruckin said:
Weird if all 8 injectors went bad at the same time.
So, just so I am clear. When it is cold you have a hard time starting it, but when it is hot it starts just fine?
If that's the case, when it is cold turn the ignition key to the "run" position but do not start. Leave it in the "run" position for @5-10 seconds, then try to start it. If it starts right up, then the check valve in the fuel pump has gone bad, allowing fuel to return to the tank instead of staying in the fuel lines.
So far as your fuel pressure regulator goes, what is the fuel pressure at the test port on the fuel rail? That is the way to test the regulator. If the pressure is low, then it is a bad regulator or fuel pump.

Martin
hello martin,thank you,no it is the opposite way,when it is cold it starts right away,when it is hot sometimes it starts from the second time,sometimes from the first time,when it is warm it refuses to start,just cracking and crancking,i am deffinit it isn't electrical,starter motor sounds sane and good.
i told the mechanic the exact thing about replacing the 8 injectors,he said he can't find out which one is the culprit even if he listened to them using a stetoscope.they rn't registering any fault.now it takes just 2 seconds when key in pos 2 to the fuel pump to cut off,i can hear it,and i did press the shrader valve in the rails and it squirted fuel right to my face,reckoning it is a good pressure,but of course the way to test is putting a gauge on the shrader valve.
this issue is driving me crazy,Martin do u know a way to do a definit test on each injector to determine which one is duff???car has only 74k miles on the clock !!!
 

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2010-2012 Range Rover MkIII / L322
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Maybe the air temperature sensor, or one of the other temperature specific sensors?

Has the mechanic put the vehicle on diagnostics?

I doubt there is an injector problem. There is a pressure valve on the rail running around the plenum in the right hand side of the car. Just check the pressure there with a pressure gauge as you go through the start sequence.
 

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Discussion Starter #6
Rich998a said:
Maybe the air temperature sensor, or one of the other temperature specific sensors?

Has the mechanic put the vehicle on diagnostics?

I doubt there is an injector problem. There is a pressure valve on the rail running around the plenum in the right hand side of the car. Just check the pressure there with a pressure gauge as you go through the start sequence.
hi rich.autologic was put on the car,no faults are present,i wanna test the pressure,how much should it be while engine running?and when must i check the pressure at the start sequence?
 

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JACK'S GRANDAD
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Fuel pressure should be 34-37 psi at the fuel rail test port with the engine running.
If that tests ok, leave the gauge on the port and see what it reads in @5 minutes. It should leak no more than @5psi in 5-10 minutes.
Only way to test the injectors for leak down is to remove them. You can however use Noide lights to check for an injector pulse signal.
Remove the plug from on top of the injector and put the noide light on the end of the plug. Crank it and check for a flashing light. That means the injector is getting a signal to fire. Repeat on the other 7 injectors.

Martin
 

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Hi jorjiok
no need to spend money when you can do -it-yourself!
FWIW: http://www.noidlight.com/
Hope this helps you
cheers
 

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Discussion Starter #9
leftlanetruckin said:
Fuel pressure should be 34-37 psi at the fuel rail test port with the engine running.
If that tests ok, leave the gauge on the port and see what it reads in @5 minutes. It should leak no more than @5psi in 5-10 minutes.
Only way to test the injectors for leak down is to remove them. You can however use Noide lights to check for an injector pulse signal.
Remove the plug from on top of the injector and put the noide light on the end of the plug. Crank it and check for a flashing light. That means the injector is getting a signal to fire. Repeat on the other 7 injectors.

Martin
Cheers martin will do that.by the way if there is a prob in the injector pulse wouldn't it register a fault like injector open circuit?and if i remove and cleaned them in case of a leak,wouldn't it cure it?
 

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JACK'S GRANDAD
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I have seen a weak pulse due to heat breakdown of a connector etc that has not thrown any codes. I went and bought myself the noide lights, as they are pretty cheap and super handy!
The only way to truly clean injectors is with ultrasonic cleaning IIRC. And then they need to be tested before and after. See if there are any fuel injection shops around you if need be, and they should be able to test, clean, or rebuild as needed.
I still doubt that all 8 injectors took a dump though myself. I would be looking at sensors etc with a live reading via Faultmate etc.

Martin
 
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