Subject	Re: When it's idling and the manifold is in a negative
Posted by	Broke_as_**** on July 31, 2008 at 12:27 PM
	This message has been viewed 141 times.
In Reply To	When it's idling and the manifold is in a negative posted by Audioquest on July 30, 2008 at 06:09 PM
Message	It’s supposed to maintain a steady 43.4 PSI difference between the fuel rail and the manifold. So when the engine is in vacuum it’s helping suck the fuel from the injectors so the fuel pressure is lower, should be around 36-38 PSI depending on how much vacuum your engine pulls (usually around 15 in/hg). As vacuum decreases the fuel pressure rises in step up to 43.4 at 0. After that it increases at a 1:1 ratio with boost pressure because the fuel now has to push through the pressurized air.
Follow Ups	Fuel pressure issue: Day 153 - Broke_as_**** 10:45:18 07/29/08 Damn... I was going to offer you my ECU, but you have - 91Z32TT 10:58:22 07/29/08 ar you still prvr equipped (sorry dont want to read all old - gt300zxtt 11:13:36 07/29/08 PRVR is gone (n/m) - Broke_as_**** 11:14:49 07/29/08 Damnit I was just going to ask about prvr - since it's - 91Z32TT 11:21:31 07/29/08 Re: Fuel pressure issue: Day 153 - Chad M (CA) 11:22:04 07/29/08 You'd have to ask JWT about that one - Broke_as_**** 11:39:55 07/29/08 Re: You'd have to ask JWT about that one - Chad M (CA) 11:58:49 07/29/08 Re: Re: You'd have to ask JWT about that one - Broke_as_**** 14:21:29 07/29/08 Re: Re: Re: You'd have to ask JWT about that one - Chad M (CA) 15:37:20 07/29/08 Re: Re: Re: Re: You'd have to ask JWT about that one - Broke_as_**** 16:13:55 07/29/08 Ok I understand now.... - Chad M (CA) 16:51:35 07/29/08 It pulls around 15-20 inches at idle - Broke_as_**** 17:03:16 07/29/08 Re: It pulls around 15-20 inches at idle - Chad M (CA) 17:15:06 07/29/08 Thanks for chipping in - Broke_as_**** 17:37:19 07/29/08 Have you swapped gauges around to rule that out? (n/m) - Audioquest 13:36:55 07/29/08 Yes (n/m) - Broke_as_**** 14:05:16 07/29/08 Very odd how in that same piece of fuel line from the tank - Audioquest 16:13:13 07/29/08 That's why I bypassed all of those lines - Broke_as_**** 16:17:13 07/29/08 I think your gauge is suspect----> - Audioquest 23:35:03 07/29/08 I've done that - Broke_as_**** 00:36:12 07/30/08 Maybe you just got a weak pump? HAve a look at this - Audioquest 08:12:03 07/30/08 A "weak" pump? - Broke_as_**** 10:26:41 07/30/08 When it's idling and the manifold is in a negative - Audioquest 18:09:38 07/30/08 Re: When it's idling and the manifold is in a negative - Broke_as_**** 12:27:56 07/31/08 Replace the fuel rails? - LitlElvis 14:57:29 07/29/08 I did a few years ago - Broke_as_**** 16:00:15 07/29/08 If it is dropping from the back of the car to the front - Spddracer 18:03:04 07/29/08 Re: If it is dropping from the back of the car to the front - Broke_as_**** 18:28:53 07/29/08
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