XFI caspers adapter harness grounding

[norbs]

I have a question, how can the XFI work properly with no main ground connected?, it even specifies a 10awg wire in the XFI schematic and with the caspers box we have no ground wire in that location? Can we get a pinout out of the caspers box? Just wondering?

 

[Cheeseburger]

Thanks for posting this Norbs, pinouts are A12,B7,which are main power grounds for the XFI which are in question, i'm also missing D12......

 

[HelloBozos]

Maybe thats why i'm over heating after 10 minutes of run time an shuting-off? I'm still hunting...

 

[HighPSI]

I asked that question when the adaptor harnesses first came out and was told they are connected internally in the xfi. There are hundreds of cars out there using it that don't have any issues.

 

[HelloBozos]

I asked that question when the adaptor harnesses first came out and was told they are connected internally in the xfi. There are hundreds of cars out there using it that don't have any issues.

Could my internal been shorted out?

 

[Nick Micale]

I have a question, how can the XFI work properly with no main ground connected?, it even specifies a 10awg wire in the XFI schematic and with the caspers box we have no ground wire in that location? Can we get a pinout out of the caspers box? Just wondering?

The FAST adapter harnesses I have on the shelf are wired with a ground cable which connects to a dash ground.

As you know the body is the ground plane for a GN, and has a ground wire from the battery to the fender.

When we use a FAST adapter harness we do not depend on just the body ground, we run a wire from there directly to the battery.

 

[Cheeseburger]

So the fast standalone harness also does not ground pinouts A12,B7,D12?
Why would they design it to have ground pinouts if they never get used, does not make sence?
Nick, yes the Caspers box has 2 ground wires, we are talking about the xfi pinouts.......

 

[norbs]

I think the XFI circuit board has all the grounds tied together at one point internally, so if you miss a few it won;t matter, but just guessing.

 

[HelloBozos]

I sent my box to F.A.S.T. over the Holidays to inspect it ,they where going to put it on a car they had there, But...."there car was having a wiring issue"...They sent my box back an said the settings where off,Wrong...,I'm calling them this week to ask them what/where there wire issues at. I hope to try again with different box soon,an see if it runs longer then 10min., XFI 1.34 i had no issues. My issues started off after sending it to F.A.S.T. the first time over 6 months ago for the 2.0/traction update. my box went from red to black, an that was that...heh

I went to F.A.S.T. web site an read this below

http://www.cpgnation.com/forum/fast-xfi-fuel-injection-installation-notes-811.html

 

[norbs]

The caspers adapter box may not follow this rule of thumb for grounding ECU;s I have spent hours figuring this out, and I will have to do some changes. Check out the link its not fast related but it gives you an idea.

http://www.msextra.com/doc/general/grounding.html


The caspers box brings the injector grounds and the sensor grounds to the dash ground......not an ideal design, which may bring noise into the system. Everything is not 100% verified so use caution.


BUICK SIDE .......................................................................................XFI SIDE

NO CONNECTION...................................................(6) INJECTOR GROUNDS BRIDGED AND CONNECTED TO CASPERS HEAVY GND
D12 TPS, CTS, ATS GROUND............................... A16,A17,A3 BRIGDED AND CONNECTED TO CASPERS HEAVY GND

B3 CRANK REF.LOW .........................................A13 DIST. RETURN GND (need to verify)
D6 O2 SENSOR GROUND .................................NOT USED
A12 ECU GROUND............................................ CONNECTS TO B8 DIGITAL INPUT GND
D1 ECU GROUND ..............................................CONNECTS TO B24 ANALOG INPUT GND


NOT CONNECTED ..............................................A12 MAIN PWR GND
NOT CONNECTED ...............................................B7 MAIN POWER RETURN 10AWG
NOT CONNECTED .............................................D12, D15 INJECTOR GROUND
NOT CONNECTED ...............................................B25 MAIN PWR GND

 

[norbs]

I still need to check where the map sensor is grounded and the crank IPU, cam IPU stuff more carfeully.

 

[kidglok]

how would it be any different if there was a stand alone harness instead of the adapter?

 

[norbs]

how would it be any different if there was a stand alone harness instead of the adapter?

It would have more grounds for the main power and the sensor grounds going to ecu directly ...Study the schematic..

 

[norbs]

I think it would be best to take the sensor grounds to the analog ground input on the ecu, disconnect them from the heavy grounds, and take the heavy grounds back to the engine block.

 

[norbs]

I think the XFI circuit board has all the grounds tied together at one point internally, so if you miss a few it won;t matter, but just guessing.

I verified this today, all the grounds in the ecu are connected internally.

 

[kidglok]

I verified this today, all the grounds in the ecu are connected internally.

can you measure the voltage going into the adapter, and out to the xfi? just wondering if there is a voltage loss.

 

[norbs]

can you measure the voltage going into the adapter, and out to the xfi? just wondering if there is a voltage loss.

I doubt there would be a voltage loss that I would be concerned about, its the grounding causing a ground loop is the issue, I'll move the grounds to the block and report back...

 

[kidglok]

I doubt there would be a voltage loss that I would be concerned about, its the grounding causing a ground loop is the issue, I'll move the grounds to the block and report back...

Then wouldn't it be an issue for everyone using it?

 

[norbs]

I don;t think anyone has voltage issues using the caspers adapter, if that is what your asking. However on my car I have a many do-dads grounded to my dash, so I think this is amplifying the grounding offset problem for me.

 

[kidglok]

I don;t think anyone has voltage issues using the caspers adapter, if that is what your asking. However on my car I have a many do-dads grounded to my dash, so I think this is amplifying the problem for me.

What happened to the KISS method norbsy?