Maxima Forums

General Maxima Discussion This a general area for Maxima discussions for all years. For more specific questions, visit one of the generation-specific forums.

Researching FPR problems, if you have a aftermarket FPR, look...

Thread Tools
 
Search this Thread
 
Old 07-08-2002, 10:40 AM
  #1  
'Trynna' is not a word
Thread Starter
iTrader: (19)
 
mtrai760's Avatar
 
Join Date: Mar 2001
Location: Seattle Area, WA
Posts: 7,081
Researching FPR problems, if you have a aftermarket FPR, look...
Okay, I'm having problems getting my AEM FPR to regulate pressure properly. Researching a bit on the internet, Ive found some problems with regulators that use a spring design, such as the AEM, maintaining a steady fuel pressure. Does anyone with an adjustable FPR know what regulates their pressure? Do you have a spring inside, or some other design. Thanks in advance, I'm trying to get to the heart of this problem...
mtrai760 is offline  
Reply
Old 07-08-2002, 11:30 AM
  #2  
Not DAVEB the parts guy
 
Dave B's Avatar
 
Join Date: Aug 2000
Posts: 8,555
As far as I know, adjustable FPR don't work with the VQs. Lots of guys have tried and failed. The fuel system will compensate and bring fuel pressure within factory settings.

Dave
Dave B is offline  
Reply
Old 07-08-2002, 12:52 PM
  #3  
'Trynna' is not a word
Thread Starter
iTrader: (19)
 
mtrai760's Avatar
 
Join Date: Mar 2001
Location: Seattle Area, WA
Posts: 7,081
Not true, they do work, well most of them do... I was running about 35-36psi with my Walborro, fuel pressure is controlled by vacuum, not by the ECU, the MAF and ECU control injector open time, I just pulled my codes... 0505, no problems... I'm gonna put the stock one back on and see if anything changes, and then order a SARD from Thomas...

Originally posted by Dave B
As far as I know, adjustable FPR don't work with the VQs. Lots of guys have tried and failed. The fuel system will compensate and bring fuel pressure within factory settings.

Dave
mtrai760 is offline  
Reply
Old 07-08-2002, 12:54 PM
  #4  
My other car is a Hybrid
iTrader: (1)
 
Chunger's Avatar
 
Join Date: Sep 2000
Location: SoCal
Posts: 3,825
Hopefully you can get reimbursed for the AEM?
Chunger is offline  
Reply
Old 07-08-2002, 12:56 PM
  #5  
'Trynna' is not a word
Thread Starter
iTrader: (19)
 
mtrai760's Avatar
 
Join Date: Mar 2001
Location: Seattle Area, WA
Posts: 7,081
Ive had it since September, so I doubt I'll be able to get anything for it. If your not gonna use your SARD, wanna sell it?

Originally posted by Chunger
Hopefully you can get reimbursed for the AEM?
mtrai760 is offline  
Reply
Old 07-08-2002, 01:52 PM
  #6  
Moderator running more PSI than all the boosted Maximas... combined
iTrader: (5)
 
1MAX2NV's Avatar
 
Join Date: Aug 2000
Posts: 6,345
Fuel pressure is not regulated by ECU at all. Yes, the ECU can change injector pulses, but fuel pressure is totally controlled by mechanical FPR.

Originally posted by Dave B
As far as I know, adjustable FPR don't work with the VQs. Lots of guys have tried and failed. The fuel system will compensate and bring fuel pressure within factory settings.

Dave
1MAX2NV is offline  
Reply
Old 07-08-2002, 02:06 PM
  #7  
Not DAVEB the parts guy
 
Dave B's Avatar
 
Join Date: Aug 2000
Posts: 8,555
Originally posted by 1MAX2NV
Fuel pressure is not regulated by ECU at all. Yes, the ECU can change injector pulses, but fuel pressure is totally controlled by mechanical FPR.
Okay. But either way, it doesn't work on the stock system. Correct? It's the same way with the F-Bodies. Lot of guys tried the adjustable FPRs and the ECU turned out to be smarter. What's the point of an abjustable FPR without forced induction?


Dave
Dave B is offline  
Reply
Old 07-08-2002, 02:29 PM
  #8  
My other car is a Hybrid
iTrader: (1)
 
Chunger's Avatar
 
Join Date: Sep 2000
Location: SoCal
Posts: 3,825
Originally posted by Dave B


Okay. But either way, it doesn't work on the stock system. Correct? It's the same way with the F-Bodies. Lot of guys tried the adjustable FPRs and the ECU turned out to be smarter. What's the point of an abjustable FPR without forced induction?


Dave
Dunno about the F-Bodies but... Any car that runs on open loop mode during acceleration will have it's A/F ratio 'adjusted' by use of an FPR (those that use fuel return lines that is).
Chunger is offline  
Reply
Old 07-08-2002, 02:36 PM
  #9  
Moderator running more PSI than all the boosted Maximas... combined
iTrader: (5)
 
1MAX2NV's Avatar
 
Join Date: Aug 2000
Posts: 6,345
I don't see why not. At WOT, ECU uses a preset air/fuel map. The ECU assumes that the fuel pressure will be at 43psi and makes the injectors pulse X amount. Now you increase the fuel pressure by 5 psi. The same exact injector pulse now yields more fuel. The ECU has no sensor to monitor fuel pressure.

Originally posted by Dave B


Okay. But either way, it doesn't work on the stock system. Correct? It's the same way with the F-Bodies. Lot of guys tried the adjustable FPRs and the ECU turned out to be smarter. What's the point of an abjustable FPR without forced induction?


Dave
1MAX2NV is offline  
Reply
Old 07-08-2002, 03:04 PM
  #10  
'Trynna' is not a word
Thread Starter
iTrader: (19)
 
mtrai760's Avatar
 
Join Date: Mar 2001
Location: Seattle Area, WA
Posts: 7,081
Because with a 255lph fuel pump, stock fuel pressure is raised 2-3psi at all ranges...

Originally posted by Dave B


Okay. But either way, it doesn't work on the stock system. Correct? It's the same way with the F-Bodies. Lot of guys tried the adjustable FPRs and the ECU turned out to be smarter. What's the point of an abjustable FPR without forced induction?


Dave
mtrai760 is offline  
Reply
Old 07-08-2002, 06:03 PM
  #11  
Member
 
RClyatt's Avatar
 
Join Date: Aug 2001
Posts: 66
Originally posted by mtrai760
Because with a 255lph fuel pump, stock fuel pressure is raised 2-3psi at all ranges...

Your ECu does not know how much fuel you are passing. But if you dumping a lot of fuel and not burning it off the O2 sensors will notify the ECu the car is running rich. Hence you arent burning off the fuel you are putting into the chamber. I changed out my regulator and actually had to decrease the pressure. Usually from the factory cars are made to run a little rich as that is a little safer than running them lean. As long as you can get a good reading on your A/F ratio and it is within range the car should do real well. To rich and the car is lazy, to lean and you may burn something up. Just my two cents worth...
RClyatt is offline  
Reply
Old 07-08-2002, 06:14 PM
  #12  
'Trynna' is not a word
Thread Starter
iTrader: (19)
 
mtrai760's Avatar
 
Join Date: Mar 2001
Location: Seattle Area, WA
Posts: 7,081
Well it's not the FPR, I now suspect the fuel pump...
mtrai760 is offline  
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Aftermarket transmission cooler for 7th gen Maxima
catalinvint
7th Generation Maxima (2009-2015)
2
09-16-2015 07:48 PM
Glove compartment creaking noise
thenewguyy
Infiniti I30/I35
0
09-12-2015 11:12 AM
Introduction, my 96 Maxima
A32goldylocks
4th Generation Maxima (1995-1999)
2
09-02-2015 06:39 AM
Back to Subforum
General Maxima Discussion
View Next Unread
New pic of my max :O)




Advanced Search
Quick Reply: Researching FPR problems, if you have a aftermarket FPR, look...


Reply Closed Thread Share

All times are GMT -7. The time now is 12:23 AM.