Hey guys,
Im replacing a salvaged fuel pump to my 242 turbo because of some cutout under boost and bought a T-Rex pump by Vortech rated at 70 psi and 50 gal/hr.Anyway it came with a nice wiring harness and relay from Bosch and Im wondering if this harness/relay setup replaces my existing harness/relay setup? Anyone ever use this system?Im hoping the setupwill replace my scalded relay harness.The relay part no. is Bosch 0 332 209 150.It has 2 red wires,a yellow and a black with an unoccupied middle prong.
Any insight is appreciated.
Thanks,
RR

I hope you are not changing pumps because you have encountered the factory overboost cutout switch. This is not the solution. The solution is to adjust the overboost switch. Remove it, heat it up, take out the epoxy covering the adjustment screw, back out the adjustment screw, test new setting with a Mityvac pressure tester and a test light, and reinstall. That switch is normally closed. When enough pressure comes, it opens, breaking the ground for the fuel injection. If you want to bypass it, I think the following works: Splice a wire from the wire to the switch to the wire after the switch. This way, there is a ground regardless and the switch no longer does anything.

Join the Turbobricks Mailing List, contribute to the Turbobricks Message Board, the Brickboard Aftermarkt, the Badbricks Mailing List, for discussion of performance issues. Usually someone has been through it before. It looks like you are spending $200 to solve a $1 problem. If you really do have pump problems or need a new pump, then the TRex is a good one.

Philip Bradley

Hey Philip,
Thanks again for all the help.No.Im a faithful follower of Tbricks and your work and I feel My salvage work on an unknown pump was not helping my situation.I got an o'boost switch from an I'cooled car and feel like its working fine.MY #7 fuse was getting hot and cutout was intermittant.Felt like elim pump as psoo.After everything else ive done to me 242glti,seems this invest was worthy.
Once again,thanks again for all the help.
RR

One prong is main power, usually designated 30. Power from the battery goes here. Another prong is 85. Either 85 or 86 is the trigger; I get these mixed up. The other one is the ground. 87 is the power feed out to the new pump. The new pump will also have a ground wire that goes to ground. A good ground. Use your existing pump wiring to trigger the new relay and to ground the new relay. You'll have to look at another relay under the hood to figure out 85 and 86 using a test light.

87a in the middle is unused for your application. You use it only when using the relay as a dual pole relay. Dual pole means that one thing is fed and then when the relay is triggered that thing is no longer fed and a new thing is fed. For example, 87a would supply power full time to your stock fuel pump and then when a Hobbs switch sensed 20 psi of boost pressure, it would trigger the relay trigger terminal which would then switch off the first pump and switch on the new TRex. Or some use like that.

Use heavy gauge wiring from the battery to the relay and the relay to the new pump. Like 10 or 12 gauge. Use equally heavy gauge wiring for the ground from the pump. The gauge of the rest of the wiring is not critical. Use good terminals, either M crimp or soldered with heat shrink. Marine wire from a boat store is better than auto wire from the parts shops. More and finer strands.

Philip Bradley

Hey Philip,
Thanks for the reply.So if I read you right,I can replace my old relaY harness with this new one,right?I hope so because Im trying to elim this cutout and down to the fuel system and would love to rewire the entire fuel pump harness.Im not that elect inclined so I have to follow instructions to the letter,so the more detail the better.
Again,thanks for the help.
RR

You cannot easily eliminate your stock fuel injection relay. That would be advanced class wiring. It could be done, but I would not bother. What I am recommending is that you change only the pump wiring. The new relay will probably go in the car somewhere or in a protected area under the car, near the pump. The old wires to the pump will go to the new relay trigger and ground terminals. A new 10 gauge cable that you run from the battery will go to the new relay power. A new 10 or 12 gauge cable that you make will go from the relay to the pump power. A new 10 or 12 gauge cable that you make will go from the pump to ground. You should add a havey gauge cable fuse of the appropriate amperage in the new power cable to the relay. Leave the stock fuel injection relay alone. It is tied into grounds and things and it would take a while to figure out how to bypass it.

Philip