Tirefire

iTrader: (1)

I've been thinking of purchasing EFI Live for quite some time now, and was wondering if this program can pick voltage readings from my fuel pump? I've been testinig the voltage at idle which seem ok, but the problem is when I go wot and the pressure drops. I would like to see what my voltage looks like during these runs to see if it's simply a voltage problem or I need to upgrade to a double pump. Any help greatly appreciated.

slow

iTrader: (7)

to my knowledge no, there is not a voltage wire that measures pump voltage on a gm vehicle (fords there is 99+ RFS systems)

Ryan

1999ssls1

iTrader: (71)

I dont think so.

brokenfly

there is a pid for fuel pump voltage...i haven't looked at it in action during logging to see what it shows...

jimmyblue

iTrader: (11)

The thing is, anything coming from the PCM is not going
to know about wiring / connector and chassis I*R drops.
What you could do, if you have an interface that supports
external inputs, is run a sense wire from the pump feed
(past the last connector, close as possible to the load)
and resistor-divide it to play nice with the 0-5V input of
the cable. You might also want to return a ground sense
and log that too, because the motor sees the local voltage
difference (local_hot-local_gnd) for its juice.

Then again the same two wires and a cheapo multimeter
would do as well.

RedHardSupra

iTrader: (1)

there is a battery voltage PID, and there's a generic voltage hookup (although it's probably 5v so you'd have to use a voltage divider) that you could wire up to the pump.

Doc

iTrader: (9)

Why not just get an autometer fuel pressure sensor and log FP with EFI Live?

http://www.efilive.com/download.aspx#downloads7

Isn't that what you really want to know?

bryancarz

.....why not just back probe a connector as close to the fuel pump as possible and run a jumper wire to the passenger compartment and monitor voltage available to the fuel pump with a voltmeter. Being sure to also monitor ground to the fuel pump as well since it needs power and ground to work.quite simple.

Tirefire

iTrader: (1)

Thanks for all the help, I guess the easiest way since I have a multimeter is to connect two long wires (ground/positve) and monitor the voltage that way.

TAQuickness

iTrader: (28)

What kind of drop are you seeing?

Tirefire

iTrader: (1)

TAQuickness sorry for not reponding sooner. Anyway I'm seeing my fuel pressure drop from 58 psi to about 48-45 psi at wide open throttle. I had my car tuned in Idiana and I'm thinking that the tune might be off due to the alltitude diffrence. (Indiana 5 ft above see level and here in El Paso, TX 3500 ft above see level.) I spoke with the tuner and he advised me that he never had a problem with it dropping fuel pressure when he was tuning it. So who knows whats wrong? Some people in this forum say that I'm running out of pump and others are saying I should be ok, Go figure.

EPP

iTrader: (22)

Hi Andy, you would not a pressure drop from the change in elevation, at least nothing as dramatic as what you have. I thought you got your fuel pressure problems resolved this Summer? You should only be seeing the fuel pressure drop from 58 to 60 at idle to 54 at wide open throttle. With your set-up only pushing 8.5 psi of boost, the Holley/Walbro fuel pump, Boost a pump and Racetronix hot wire kit should be way more than enough. We have done the 8 lbs of boost/GT2-3 camshaft and just a Boost a pump on the Caddy CTS-V's without having any problems.
If I remember correctly you have replaced the fuel pump, replaced the fuel pick up line, replaced the factory fuel regulator and checked to make sure your fuel pressure gauge is accurate. With your fuel pressure dipping down into the 40's, the air/fuel should be going dangerously lean, do you have a wide band gauge on it, I don't remember? Thanks. Bob

Tirefire

iTrader: (1)

Hi Bob, no the problems are still there, I did changed the factory fuel pressure regulator when I bough a new bucket from a salvage yard. As far as a wideband, I have the Innovate LC-1 wide band installed since last summer. The only thing is that when my fuel pressure gauge starts dropping the wideband does the opposite it goes rich and it hits 10.5 on the gauge(rich). So I did what any other person would do and I bought a fuel pressure gauge and connected it to the rail via the shrader valve. After a couple WOT runs it pretty much did the same thing it dropped to about 45-48 psi. I spoke to Jake a few months back, but he really didn't know what my problem might be. One other thing I mentioned to him, is that when I go WOT I get black smoke. I did as you advised and changed out my sparkplugs, but the problem is still there. At this point I'm looking to buy EFI live to see what its doing and see if I can fix it.

As far as the elevation I looked up where you guys are at and I believe you guys are right above sea level (I hate you) haha. So I was thinking that maybe since I'm at 3500 ft above sea level it would take that much more fuel to make it work.

Tirefire

iTrader: (1)

I just want to make this thing work right and get as much out of it before I buy my new block. Thanks Andy

ssheets

iTrader: (1)

Hah! I'm at nearly 5,000ft. and most of the nice twisty roads around here go up to 8,000ft ASL. I should have gone for a blower instead of 11:1 NA.

There is one pass South of me that takes you into Yosemite Nat. Park and is over 10,000ft. at the top!!!