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injector diffusers cause rough idle ?

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Old Aug 23, 2015 | 12:53 PM
  #1  
imitek's Avatar
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imitek
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From: portsmouth
injector diffusers cause rough idle ?

Running 850s x4 just got it back on road have a larger set of 2200cc bosch but wanted to get it running all good first then i will upgrade injectors

Im currently idling at 1500rpm no
Idle control vale( as no aux output available)
I remebre i use to be able to idle at 1k

I diddnt bother putting in the diffusers
Im just wondering if any one has experiance with the diffusers

Car drives fine its just the idle i want to sort out when i reduce or increase idle ether by screw, timing, or fuel it wants to cut out
Seems fuel related
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Old Aug 23, 2015 | 04:20 PM
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is your fuel injector atomization line hooked up? It might help a bit if your running both larger injectors & no diffusers

That and stock 850s will never be the best for idle. They are old tech and fairly large. Should still work ok though
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Old Aug 23, 2015 | 10:23 PM
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The diffusers do an important job. Now that being said you are running 4x850cc injectors so it could be a tune issue as well. We need more info.
You could also have a vacuum leak or bad spark
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Old Aug 23, 2015 | 10:29 PM
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If you're running 850cc OEM side feed injectors with stock rails you need the diffuser plates for everything to seat properly in the LIM and center iron......
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Old Aug 24, 2015 | 07:25 AM
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Most importantly, the grommets need to be installed around the top of the injector hole. The fuel rail should also be milled down, to allow proper seating of the injector. Then the primary injectors should be set at 64.7% in the PFC.

Edit: another problem I see frequently is the black plastic spacer missing, causing the rail to damage the grommets and diffusers.

Last edited by Banzai-Racing; Aug 24, 2015 at 07:47 AM. Reason: more info
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Old Aug 24, 2015 | 03:18 PM
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imitek
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From: portsmouth
I forgot i put this post up it was late night lolol
Thanks for the information
Guys very helpfull as always
The rubber o ring that sits around the injector is on both injectors and the plastic spacer is also in
When i said the diffusers not in the top part is but u no the thin legs that snap that part is not in
Tuning wise its motec m2r ecu ive played with the enrichments anything above 1400rpm is perfect no hesatance or flatspots or anything
No problems croosing only when i drop the idle down on screw

Tell u what it does seem like an air leak the way it hunts

There was one place i was getting an air leak was them primry injector big o rings (brake cleaner spraying around then started choaking)
Took them out and silicone them badboys back in just to test made no diffrence same still runns lumpy when i drop idle down

Ill record it tomaro and upload if it makes it easyer

Last edited by imitek; Aug 24, 2015 at 03:24 PM.
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Old Aug 24, 2015 | 03:25 PM
  #7  
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imitek
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From: portsmouth
On a side note what sort of spray patern should i be getting out the 850s
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Old Aug 24, 2015 | 06:24 PM
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Originally Posted by imitek
On a side note what sort of spray patern should i be getting out the 850s

Water hose.

Hence the diffusers...
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Old Aug 25, 2015 | 11:07 AM
  #9  
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imitek
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From: portsmouth
Thanks again ^^^^^^^^^^


You cant realy hear it but you can make out the shaking of engine

https://www.youtube.com/watch?v=xK6l9qphG6w&feature=youtube_gdata_player.
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Old Aug 28, 2015 | 05:28 PM
  #10  
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imitek
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From: portsmouth
Little bit more on update
I have evrything but one item
A 180deg 6an connection
Lol always the way
So hopfully i will be starting up this week as soon as the connection turns up and i re adjust the new dead times and fuel table

I have removed all the diffusers


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