Checking injector flow...

[John Howe]

My Winter rebuild included the installation of new injectors. The first mile or so included lots of popping and banging from the HDTB's at between 3,000-3,500 revs... all of which mysteriously disappeared before there was 4 miles on the clock.

 

Thinking back, it has accured to me that there may have been dirt in an injector or that one is not functioning correctly.

 

It there any easy/safe way or checking out their flow rate?

 

JH

 

 

[DohNut]

I need to check this as well, I was just checking the plugs and I found a difference in the colour of the plugs, this indicates to me that some clinders are getting a different mixture to others, I have just bought some redex to try and disolve some deposits but delving deeper I understand that most injectors have a wire mesh filter inside the injector which is a good starting point. I have not checked this as yet as it would necesarily be on the pressure side of the fuel flow and the housing would have to be re-seated to withstand 5 bar fuel pressure. This is not something I want to get wrong.

I remember a long time ago when CCC Dave Walker was first playing with the injectors he recomended a company to ultrasonicaly clean injectors for as new performance.

As far as actual testing flow rate,

remove injector

start fuel pump

put fag out

apply CORRECT (dont know what) voltage to injector to open it fully

point into measuring cylinder for 30 seconds

etc.

one further aspect to worry about is that injectors of the same flow rate can give differing flows throughout the range (short opening times - long opening times)

I dont think that this variance is likely to cause any problems unless your map is leaned off to the point of detonation on part throttle running.

 

I have just bought Walkers management book I will see if it covers it in there.

Nick

smile.gif

[John Howe]

Nick... thanks!

 

That's what I like about this Seven's World we enjoy... ask a question and someone will most often make sense in a reply.

 

...especially the extra note about putting out the fag.

 

Awaiting your next input

 

JH

 

 

[Rob Walker]

John,

 

Do not check the injectors as per the above posting. The injectors should never have a constant voltage appied to them, also you need to know that all four injectors flow the same fuel within 1%. Its not accurate enough just to squirt them in a measuring cylinder. Take them to your local Bosch Service Center and have them properly cleaned and flowchecked then you know they are working correctly before you waste money on mapping and spoiling your new engine. This is not an area to save money be warned.