Fuel Pressure Regulator - Which one?

Post here for mechanical and engine topics such as fuel issues, transmission problems, rough idle, exhaust, electrical issues, etc

Moderators: GRNSHRK, ron, bfons

Post Reply
User avatar
603racing
Posts: 462
Joined: Mon Dec 20, 2010 5:11 pm
Location: Barry, IL

Fuel Pressure Regulator - Which one?

Post by 603racing »

1985 635csi (US model) with the m30b34 of course, 059 ecu.

Real OEM shows several different fuel pressure regulators, all but one of which are 2.5 bar. The other is the 3.0 bar FPR. Which one is the correct one for my car? I did quite a bit of forum searching and looking on parts websites most places show the 2.5 bar as the correct one, but I believe the Bentley says 43psi, which is 3 bar.

There does appear to be a changeover date in 1987 from 2.5 bar to 3 bar, but I have not yet been able to confirm this.

A lot of conflicting info out there. All advice welcome.

Thanks in advance
Justin
'85 635csi - Dark Shark
'16 F150
'13 Subaru BRZ
User avatar
603racing
Posts: 462
Joined: Mon Dec 20, 2010 5:11 pm
Location: Barry, IL

Re: Fuel Pressure Regulator - Which one?

Post by 603racing »

After additional reading and looking at a friend's '85 e23 with the m30b34, I have less clarity. I was almost sure that a 0280160225 (2.5 bar) was correct. But he has a 0280160249 (3.0 bar).

Can anyone confirm or deny that the 249 is the correct FPR for an '85 m30b34?
'85 635csi - Dark Shark
'16 F150
'13 Subaru BRZ
User avatar
hornhospital Online
Platinum Member
Platinum Member
Posts: 2931
Joined: Sun Jul 11, 2010 6:46 pm
Location: Silverhill, AL
Contact:

Re: Fuel Pressure Regulator - Which one?

Post by hornhospital »

My 85 635 has the 3.0 bar FPR. I don't know if it is original to the car, but it works.
Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'85 325e "Hazel Ann"; '95 M3 "Ashlyn"
User avatar
603racing
Posts: 462
Joined: Mon Dec 20, 2010 5:11 pm
Location: Barry, IL

Re: Fuel Pressure Regulator - Which one?

Post by 603racing »

Feedback appreciated, thank you.
'85 635csi - Dark Shark
'16 F150
'13 Subaru BRZ
User avatar
603racing
Posts: 462
Joined: Mon Dec 20, 2010 5:11 pm
Location: Barry, IL

Re: Fuel Pressure Regulator - Which one?

Post by 603racing »

The underlying issue is that the shark started running real rough out of nowhere. I believe it is very lean. It idles rough and will barely move under a load. I have to constantly blip the throttle and ride the clutch just to get the car to go 5mph. I have parts to build an inline fuel pressure tester, just got sidetracked by a small Jeep project. I will test fuel pressure report back.

I have already checked all electrical and vacuum connections. I may also replace the fuel filter proactively, even if the pressure is good.
'85 635csi - Dark Shark
'16 F150
'13 Subaru BRZ
User avatar
Brucey
6 Series Guru
6 Series Guru
Posts: 10077
Joined: Fri Apr 09, 2004 7:17 am
Location: Cambridge, UK

Re: Fuel Pressure Regulator - Which one?

Post by Brucey »

603racing wrote:After additional reading and looking at a friend's '85 e23 with the m30b34, I have less clarity. I was almost sure that a 0280160225 (2.5 bar) was correct. But he has a 0280160249 (3.0 bar).

Can anyone confirm or deny that the 249 is the correct FPR for an '85 m30b34?
it varies with which ECU and injectors are fitted.

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
User avatar
603racing
Posts: 462
Joined: Mon Dec 20, 2010 5:11 pm
Location: Barry, IL

Re: Fuel Pressure Regulator - Which one?

Post by 603racing »

I finally got around to fixing this issue. With an 059 ecu and 19 lbs (yellow top) injectors, the 3.0 bar FPR is correct. I replaced it and the car runs well.
'85 635csi - Dark Shark
'16 F150
'13 Subaru BRZ
Post Reply