Jump to content



Rewire fuel pump with Bosch style relay


  • Please log in to reply
3 replies to this topic

#1 81zfan

81zfan

    Established Member

  • Members
  • PipPipPip
  • 974 posts
  • Gender:Male
  • Location:KY
  • Interests:Wrenching,Fishing,Bicycling, and collecting old school vinyl!!
  • Model:Conquest

Posted 11 April 2019 - 07:21 PM

I've been wanting to do this for a few weeks since I noticed a slight drop in fuel pressure after running the car for a few minutes.
I tested the plug in the engine bay on the passenger fender and was getting 13.1V to it. I proceeded to check power at the pump and was only getting 11.7V.
So I figured I'd give it a shot.
I bought a SPDT Bosch relay and socket offline for around 7 bucks and already had enough wire to run to the relay from the Battery since I've relocated it to the trunk.
You'll only need to wire 4 wires from the relay
terminal 30 will be your feed from battery/I installed a inline fuse between the battery and relay
terminal 87 will be the wire going into the pump
terminal 87A will not be used
terminal 86 will go to the harness side of the car
terminal 85 will be a ground
I cut the large blk/ylw wire at the plug in the rear hatch and wired in the relay here...the plug is located almost at the very rear of the hatch on the floor.
This is probably one of the easiest mods I've ever done to this car.
After wiring everything and heat shrinking I retested the voltage going into the pump and it went from 11.7 to 13.2 volts
Well worth the hour I spent wiring and heat shrinking!!
After everything was finished I ran the car and it held a steady 38lbs of fuel pressure

Edited by 81zfan, 26 April 2019 - 11:15 AM.

88 conquest, .30 over block,Bs eliminated, M28 head ,17c turbo,Ottowerks shifter bushing, Lower Shores Braided lines and TB parts, Boostinmini TPS conversion kit,Optional Methanol Kit "when hooked up",Custom 2.5 Intercooler Piping,3 inch Downpipe, Gasket Ported Intake and Exhaust Manifold, Manual steering conversion,ACT HD clutch, Ebay knock off GReedy BOV,put car on a diet "lost between 590-620 lbs", Super AFC, AEM wideband, Glowshift Boost,Fuel Pressure, and Coolant Temp gauges, ARP Head and Rod bolts/Studs, Walbro 255.... In the process of adding more !





#2 importwarrior

importwarrior

    6 Quests and Counting......

  • Moderators
  • PipPipPipPipPip
  • 18,313 posts
  • Gender:Male
  • Location:Manassas VA
  • Interests:Boost = 2KWIK4U
    Starquests
  • Model:Conquest

Posted 14 April 2019 - 12:10 PM

good info Thanks for sharing.

B-71 87 TSI ~ RIP

Black 87 Starion ~ Mess SOLD!!!

Proud New 89 slightly Rusted Fiji Owner !!!




#3 psu_Crash

psu_Crash

    Advanced Member

  • Members
  • PipPipPipPip
  • 7,219 posts
  • Gender:Male
  • Location:Lawrenceville PA
  • Interests:400+ WHP 450+ WTQ!!... and curves with green eyes
  • Model:Starion

Posted 15 April 2019 - 08:47 PM

One of these years I should really check my pump voltage ...
'86 Starion, MPI with MS2extra, Ebay To4E 57 Trim (in testing), P&P head, OS SS Valves, Wiseco +.030, ARP head/rod, RPW Roller Cam, Crower Rods,AEM H2O/Meth Injection, Mighty Max CAS 4 Direct Fire Wasted Spark, BSE, Tial 38mm, JDL exhaust mani, HKS turbo timer and EVC3, AEM UEGO, 3" DP into 2 1/2" Dual Exhaust, 85# Delphi's, Magna modded by Chad, Accufab FPR, Walbro 255, D2 Coilovers, GNT Poly Bushings and mounts, Autopower 4 point cage, Funk-Lock, LED Tails and Dome ... etc^4
2016-17 SCCA Solo Glen Region Champion in Street Modified. Going for a 3-peat this year ;)
The Valencia Project
http://www.starquest...+golden +dreams
My Feedback Link
Posted Image

#4 81zfan

81zfan

    Established Member

  • Members
  • PipPipPip
  • 974 posts
  • Gender:Male
  • Location:KY
  • Interests:Wrenching,Fishing,Bicycling, and collecting old school vinyl!!
  • Model:Conquest

Posted 16 April 2019 - 06:57 AM

The only reason for me checking it was that I was losing a few pounds after the car had been idling for 10 min or so. I first thought it was the Bosch regulator as It's been on there forever seems like and the Walbro is basically new, and when I say basically new It's been in the car for a few years but only has maybe 2 hours total run time on it.
A gain of almost 2 volts at the pump is well worth the few bucks you spend on the relay and time to solder 4 wires.
BTW, The walbro really talks now with proper voltage :lol:
88 conquest, .30 over block,Bs eliminated, M28 head ,17c turbo,Ottowerks shifter bushing, Lower Shores Braided lines and TB parts, Boostinmini TPS conversion kit,Optional Methanol Kit "when hooked up",Custom 2.5 Intercooler Piping,3 inch Downpipe, Gasket Ported Intake and Exhaust Manifold, Manual steering conversion,ACT HD clutch, Ebay knock off GReedy BOV,put car on a diet "lost between 590-620 lbs", Super AFC, AEM wideband, Glowshift Boost,Fuel Pressure, and Coolant Temp gauges, ARP Head and Rod bolts/Studs, Walbro 255.... In the process of adding more !




1 user(s) are reading this topic

0 members, 1 guests, 0 anonymous users