Need help with the Fuel Pump Power Wire for MagnaVolt installation!

[done12many2]

Charlie,

I have had the MagnaVolt mounted in my trunk since we installed the supercharger, but it has yet to be hooked up.

We are seeing a substantial drop in fuel pressure before even getting to the area of 9lbs of boost so I need to get it hooked up and retuned. The problem is, I am not sure for certain, which wire to cut and which end to run where.

I talk to Stephen out at Haddad and he told me the area to hunt for the thick grey wire under the passenger side rear just behind the rear passenger seat. I have located that wire, but it branches off in a confusing way and I just want to make sure I have the exact wire and understand which end is which before I hook up the Magnavolt.

There is also a thick grey wire right under the rear passenger bottom cushion that drops down into the area of the fuel tank and I am almost certain that is it, but I wanted to check with you to verify.

I also want to make sure I am hooking the wires into that split in the right direction.

Thanks in advance for any help,

Bill

http://kfmoyq.bay.livefilestore.com/y1pfk7eHtcVGfqDcFQ6-r58vHlp1IBdiwEI5kmcnRNJA0isuLFpRRLFwS2id_RLErfez08 aR-7fOvNBmGgfDZLKIQ/Magnavolt.jpg

[wreckwriter]

I'm not Charlie but I've been asking a friend the same questions so I believe I can say that yes, the gray wire under the back seat is going to be the correct wire.

[done12many2]

I'm not Charlie but I've been asking a friend the same questions so I believe I can say that yes, the gray wire under the back seat is going to be the correct wire.

Where are you planning to tap power for your unit (the red wire off the booster)? In the trunk somewhere?

I have the MagnaVolt mounted in the spare tire well. I'll just find something for power in the trunk. I can ground it at the battery ground point.

I guess either you or I have to be to cut that grey one under the seat, huh? :)

[wreckwriter]

I have the MagnaVolt mounted in the spare tire well. I'll just find something for power in the trunk. I can ground it at the battery ground point.

I guess either your or I have to be to cut that grey one under the seat, huh? :)

Yea, one of us will do it, then the other will :)

Alex, the guy who has been helping me, wired his under the front passenger seat. Still trying to decide where to put mine; just got it a few minutes ago.

btw- ours are Kenne Bell units, not Magna-Volt but I believe its basically the same beast.

[done12many2]

Yea, one of us will do it, then the other will :)

Alex, the guy who has been helping me, wired his under the front passenger seat. Still trying to decide where to put mine; just got it a few minutes ago.

btw- ours are Kenne Bell units, not Magna-Volt but I believe its basically the same beast.

Yeah I have actually talked to Alex on the phone about it. Last time we talked he noted that his method of wiring did result in the Kenne Bell unit increasing voltage on the output side of the cut, but was not sure if his FP increased or changed. I would tend to think that if the output side increased voltage, it must be working, provided the car is still running as it should after he installed it.

I think he ended up cutting into it somewhere other than under the rear passenger seat though.

[done12many2]

Additionally, I will have not way of knowing if it worked other than a voltage check, until I get it back to my tuner. I vote that you make the first move. :)

[wreckwriter]

I'll try to do mine this weekend.

[GRRRR8]

It is the gray wire, make sure its the ONLY gray wire. Cut wire and hook the yellow to the one that has power with key on. Finish wiring and retest pressure and A/F.

[wreckwriter]

How hot do these things get? Wondering if it'll be safe to mount it under the back seat?

[GRRRR8]

How hot do these things get? Wondering if it'll be safe to mount it under the back seat?

I wouldnt. Make sure it gets some air.

[wreckwriter]

My options are going to be limited. This thing has a fixed length wire that has to go into the engine compartment, I don't think it's long enough to go with a trunk mount. Likely will put it under a front seat.

[1ChargedG8]

I installed mine under the passenger front seat. I will install the fuel pressure gauge this weekend and i will let you guys know. Also, if look at the instructions sheet that came with the BAP it tells you that one way to check if the BAP is working is by checking the output voltage from the BAP, it should be somewhere around 16 volts if i'm correct.

[1ChargedG8]

So far the car is running without any fuel pump issues. To make sure i was cutting the right cable i used that schematic diagram to trace the wire from rear fuse box (a thick orange with green stripe) to the fuel pump relay at the instrument panel area. Then from the IP i traced all the way to the back seat. NOTE: I removed the two front seats a lifted the carpet a bit to make sure i was tracing the right grey cable. Then removed the plastic side trim/cover from the left side of the car (if you are standing in front of the car) and continued to trace that wire all the way to the fuel tank. You can also try to remove the panel where fuel pump relay is located to look at which cables are attached.

[wreckwriter]

Did the front seats come out easily?

I'm thinking to cut the gray wire under the passenger seat at the point before it goes into the side trim or under the driver's seat. See any issues with that?

[1ChargedG8]

They are not hard to pull out, i guess the only part that i had a little of trouble was to remove the seat belt bolt from the seat. That will be a good place to cut it.

[wreckwriter]

Any reason not to cut under driver's seat instead or does it branch after that?

[1ChargedG8]

No reason, but for me it was easier just to do the other side.

[wreckwriter]

Alex, the gray wire is under the rug, not up inside the seat, right?

[1ChargedG8]

yes under the rug

[wreckwriter]

Thanks. I'm going to try to get the seat out so I can get to it. Looks like back seat and side trim may have to come off too to get the rug up. I hate messing with the plastic trim pieces, always break something :(

[1ChargedG8]

Yeah i broke a couple of clips but not big deal.

[wreckwriter]

I think I'm going to change my plan. I'm going to install the BAP in the trunk and cut into the wire right before it heads downward to the pump (under passenger side back seat).

Pulling the front seats just looks a lot harder, I think my wire will reach.....

[done12many2]

I think I'm going to change my plan. I'm going to install the BAP in the trunk and cut into the wire right before it heads downward to the pump (under passenger side back seat).

Pulling the front seats just looks a lot harder, I think my wire will reach.....

This is exactly where I want to cut mine. Under the rear seat cushion on the passenger side.

Just to make sure, Alex has confirmed that the thicker grey wire under that rear seat cushion which drops down into the fuel tank area is indeed the right one???

I don't have a wire that needs to run to the engine compartment. The MagnaVolt does have a wire that can be hooded to the TPS, I believe, but according to Haddad Motorsports, this is not used. This leads me to believe that the MagnaVolt adds voltage protortional to boost.

Man, I wish I would have asked this question here a lot sooner. The responses to this thread have been great.

[wreckwriter]

If no wire to engine, how does it sense boost? My wire goes to a Hobbs switch.

[wreckwriter]

I haven't split the wire loom yet but if there's a big gray wire in the loom that goes down thru the plastic plug that has to be it.

[ronbuick]

Would it be best to relay the pump and use a boost or Hobbs switch to energize the
relay to pump when needed, and also run new wires from or to the engine compartment than cut or splice existing wires, I do not know a lot about the wiring for these cars, but I sure woulod hate to start splicing or cutting in to the existing harness, also what amps
does this pump draw under, you might just have to relay it cause the cars wiring might not be able to handle the xtra load, just a thought, do not know if this helps or not.

Ron

[wreckwriter]

Its basically a step-up transformer, it just boosts voltage to the stock pump. Only one wire is cut, the BAP is spliced into it. Mine does use a Hobbs switch, only ups voltage under boost.

[done12many2]

If no wire to engine, how does it sense boost? My wire goes to a Hobbs switch.

Via some hose that sends pressure straight to the unit. I plan on routing this under the vehicle to the spare tire well, which is where my MagnaVolt is mounted.

[wreckwriter]

Via some hose that sends pressure straight to the unit. I plan on routing this under the vehicle to the spare tire well, which is where my MagnaVolt is mounted.

Be sure you use quality hose going under the car.

[done12many2]

wreck, I just sent you a PM trying to clarify which wire I was talking about. When and if I get to it today, I will get some photos.

[wreckwriter]

I'm half-way through the job. Will report.

[wreckwriter]

I got it installed but its really hard to test because I have to put it into heavy boost. Good roads are few and far between, especially now....

[done12many2]

I got it installed but its really hard to test because I have to put it into heavy boost. Good roads are few and far between, especially now....


Well you are a lot further than me. I haven't even started. :hang:

I just got the kids to bed and am about to head out to the garage to mess with it.

I am to assume that we guessed on the right wire? If so, we may need to pass this word on because I know of one shop that is telling you to climb under the car to cut into it, which is a bit more work than under the rear seat :)

I may not be able to get the vacuum hose run tonight, but do you think that I will be alright wiring everything up minus the boost pressure hose (vacuum hose) and still driving it to the shop where I plan to get her on the lift? I would assume that if the unit is not recieving any boost pressure (with the vacuum not hooked up) that it would simply assume no boost and run it at stock voltage. What do you think wreck?

[-Ray-]

I got it installed but its really hard to test because I have to put it into heavy boost. Good roads are few and far between, especially now....

Good work Tom.

[wreckwriter]

Well you are a lot further than me. I haven't even started. :hang:

I just got the kids to bed and am about to head out to the garage to mess with it.

I am to assume that we guessed on the right wire? If so, we may need to pass this word on because I know of one shop that is telling you to climb under the car to cut into it, which is a bit more work than under the rear seat :)

I may not be able to get the vacuum hose run tonight, but do you think that I will be alright wiring everything up minus the boost pressure hose (vacuum hose) and still driving it to the shop where I plan to get her on the lift? I would assume that if the unit is not recieving any boost pressure (with the vacuum not hooked up) that it would simply assume no boost and run it at stock voltage. What do you think wreck?

Yea, I guessed on the wire, the one we discussed. I would say you'll be fine with driving it to shop before boost hose.

I gotta find a way to test this better....

[wreckwriter]

What's the procedure I hear about involving checking voltage? I assume this can be done without putting the car into boost (I sure as hell ain't hunkering down in the back seat checking voltage while this thing shitweasels down the road with someone else driving)?

[norm8332]

If you have a meter with peak hold that would do it.

[done12many2]

What's the procedure I hear about involving checking voltage? I assume this can be done without putting the car into boost (I sure as hell ain't hunkering down in the back seat checking voltage while this thing shitweasels down the road with someone else driving)?

That would be funnier than hell with no back seat cushion installed :)

[wreckwriter]

That would be funnier than hell with no back seat cushion installed :)

Not for me! Made any progress?

[done12many2]

Not for me! Made any progress?


No sir. Got the back seat cushion removed and the wife shut down all operations. I have to take care of a few things today and once I am done with those, I will hopefully make the cut!

Your selfless leap should make this a lot faster for guys like me! Thanks Tom.

[wreckwriter]

No sir. Got the back seat cushion removed and the wife shut down all operations. I have to take care of a few things today and once I am done with those, I will hopefully make the cut!

Your selfless leap should make this a lot faster for guys like me! Thanks Tom.

I'm still trying to verify that this thing is working so don't thank me yet. It's still possible I super-boosted my trunk release or left blinker.......

[99-LS1-SS]

I'm still trying to verify that this thing is working so don't thank me yet. It's still possible I super-boosted my trunk release or left blinker.......

LOL! The super sneak trunk mod!

[wreckwriter]

It's possible. Working off a schematic rather than a wiring diagram. I really wish I had a better way to test, street testing is dangerous and I don't have a meter that will hold highest reading.

[GeorgeInNePa]

1) Turn power on.

2) Jumper the switch.

3) Test voltage.

4) ?????

5) Profit!

[wreckwriter]

You mean jumper the Hobbs switch I assume? You sure that won't hose anything up?

[GeorgeInNePa]

I can't see why it would.

You just want to see what the voltage is going to the pump, correct?

[wreckwriter]

Yep, just did it. BAP is definitely boosting voltage.

[ronbuick]

Wreck, why would'nt those little led's that you get at maybe Radio Shack and wire in to the power side and when under boost if you are getting voltage the led would lite up, might be a good fail safe for things like a head gasket, just a thought.

Ron

[wreckwriter]

If I blow the engine I'm buying an old style with NO FUCKING COMPUTER.

[done12many2]

Wreck, I am finally heading off to the shop to get it in. I never got a chance to finish and hope I get the same results as you.

I know you confirmed that it did indeed increase voltage, but was it enough to completely stabalize the fuel pressure, or did it only help out a bit?

Do you mind if I call you if anything comes up? I still have the number.

[wreckwriter]

I never really fully tested it. My little bit of testing showed pressure drop to 50 instead of 40 at full boost. Now that I've changed pulley I should be ducky.

Sure, call anytime except late at night :)

[wreckwriter]

OK, got a better test. Not ducky. I still have a big fuel pressure drop. I'm thinking this this is not kicking in.

I'm thinking I either have a bad Hobbs switch or the place I tapped it in (boost gauge line) is not good enough.

[wreckwriter]

Wreck, I am finally heading off to the shop to get it in. I never got a chance to finish and hope I get the same results as you.

I know you confirmed that it did indeed increase voltage, but was it enough to completely stabalize the fuel pressure, or did it only help out a bit?

Do you mind if I call you if anything comes up? I still have the number.

Where are you tapping to get a boost signal?

[done12many2]

Where are you tapping to get a boost signal?

wreck,

Sorry about the late response but I got done with the install yesterday and went straight into prepping for work today.

With the MagnaVolt, Haddad Motorsports only calls for a total of 4 electrical wires and one vacuum line to be connected. There is a fifth wire is used for engine speed which is not used in the G8 application for whatever reason.

Red = Battery Positive

Black = Battery Ground

Gray = Adjusted (Increased) Voltage output to the fuel pump

Yellow = Input from original cut fuel pump power wire

Vacuum = Boost straight off of the supplied MagnaCharger output port (ran about 16 foot of vacuum line to the trunk to get this accomplished.

With this setup, according to Haddad, the boost is simply detected by the MagnaVolt via the vacuum line and voltage is automatically increased to the output side of the MagnaVolt to the fuel pump.

Whether or not this is happening is purely speculation on my part at this moment in time as I have no fuel pressure gauge.

I will say that I am fairly certain that it is, because the car is running better. There are fewer hiccups from the exhaust that seemed to be quite regular prior to this and the engine feels smoother under boost. Once again, this is purely my opinion and has not been confirmed.