Fuel pump output and voltage (deatchwerks)

K

kidglok

Balls Deep
Joined
Oct 10, 2010
after reading a post about deatchwerks pump and it falling off i decided to look at some things a little closer, runnig razors alky with a single nozzle. I went out and did a short pull at 20psi and looked at the log:

6.5 ss.png

i noticed the pressure drop off at the top of the gear around 20psi, checked the voltage on the xfi and was reading 12.6. Also noticed the injdc around 67%

so pacecarta and i decided to try a volt booster to kick up the voltage a bit, and heres the log:

6.6 ss.png

injdc down to 60% and fuel pressure rock solid with 15.4 volts.

just food for thought on the importance of knowing whats going on with your fuel pump, im not pushing crazy horesepower at that level (roughly 600) and relatively low boost psi, but the pump seems to handle it well for now. Any thoughts??
 
What you did was a good idea. Even at 20 psi on the street which is where I run my car at, the pumps need solid voltage at all times.

Good move.
 
Yea, a single DW without any help won't be able to supply 83's at any large DC% and boost psi.
 
Reggie West said:
What you did was a good idea. Even at 20 psi on the street which is where I run my car at, the pumps need solid voltage at all times.

Good move.
Click to expand...

thanks reggie,

if i had not been using wideband correction, things could have gotten ugly real fast!!
 
I have a single deastchwerks pump running 80s with hot wires on everything. I have noticed I can't get a true 1 to 1 rise on the fuel pressure even though the AFR is now in line with what I need. I have thought about getting a boost a pump also. One thing I also noticed when testing the pump voltage was that even with a hot wire on the pump there is a .6 volt drop from front to back. I believe that the ground that is used is just not good enough. It grounds to the tank and gas tank hanger bolt. I am going to run a dedicated ground wire back To the battery from the fuel pump as suggested by Nick Micale. That would be something to look into even with the boost a pump.
 
I did a dedicated ground for the pump as well as one for the boost a pump. Haven't had a chance to test things out yet.but I am giving up if this doesn't work. I have been obsessed with getting that 1 to 1 rise as well.
 
TR Custom Parts said:
I did a dedicated ground for the pump as well as one for the boost a pump. Haven't had a chance to test things out yet.but I am giving up if this doesn't work. I have been obsessed with getting that 1 to 1 rise as well.
Click to expand...

At 44 base psi and boost at 24 psi I get about 63psi on an Ashcroft industrial gauge. Injector duty cycle sits at 66%. I don't lose fuel pressure BUT I never get 1:1 rise.
 
jpwalt1987 said:
At 44 base psi and boost at 24 psi I get about 63psi on an Ashcroft industrial gauge. Injector duty cycle sits at 66%. I don't lose fuel pressure BUT I never get 1:1 rise.
Click to expand...

Yea same here, I have 45 base but at 20psi as you can see its about 60psi. It could also be the accuracy of my gain settings for the transducer in the xfi, I was only able to get a base voltage at zero psi, and another one at 45psi when I let the car idle with the line off (checking against a mechanical)
 
kidglok said:
Yea same here, I have 45 base but at 20psi as you can see its about 60psi. It could also be the accuracy of my gain settings for the transducer in the xfi, I was only able to get a base voltage at zero psi, and another one at 45psi when I let the car idle with the line off (checking against a mechanical)
Click to expand...

Make sure your vacuum lines to the regulator have no leaks. I had a couple of pin holes and by fixing those I gained 3psi. Before that I could only get 60psi.
 
What kind of volt booster did you use and did it effect the akchy system at alll??Thanks

Kevin
 
SS/GN said:
What kind of volt booster did you use and did it effect the akchy system at alll??Thanks

Kevin
Click to expand...

we used a caspers volt booster, no noticeable difference with the alky system, judging by air inlet temps both went from about 114* down to 70.

also halfway through second gear where the fuel pressure stayed constant with each run, inj duty cycle was consistant at around 52.
 
I'm using a Kenne Bell boost a pump, it is dedicated to only boosting the fuel pump, nothing else. Don't have much time testing it yet though, just put it in.
 
TR Custom Parts said:
I'm using a Kenne Bell boost a pump, it is dedicated to only boosting the fuel pump, nothing else. Don't have much time testing it yet though, just put it in.
Click to expand...

Where did you buy it from and how much?
 
kidglok said:
after reading a post about deatchwerks pump and it falling off i decided to look at some things a little closer, runnig razors alky with a single nozzle. I went out and did a short pull at 20psi and looked at the log:

i noticed the pressure drop off at the top of the gear around 20psi, checked the voltage on the xfi and was reading 12.6. Also noticed the injdc around 67%

so pacecarta and i decided to try a volt booster to kick up the voltage a bit, and heres the log:

injdc down to 60% and fuel pressure rock solid with 15.4 volts.

just food for thought on the importance of knowing whats going on with your fuel pump, im not pushing crazy horesepower at that level (roughly 600) and relatively low boost psi, but the pump seems to handle it well for now. Any thoughts??
Click to expand...

The xfi displayed voltage is useless as a comparison unless you have rewired so it gets alternator voltage. The actual voltage at the pump is what matters. Voltage is critical to volume at high pressure
 
bison said:
The xfi displayed voltage is useless as a comparison unless you have rewired so it gets alternator voltage. The actual voltage at the pump is what matters. Voltage is critical to volume at high pressure
Click to expand...

So what voltage would the xfi be displaying?
 
kidglok said:
So what voltage would the xfi be displaying?
Click to expand...

Whatever goes through that little wire that comes off the positive terminal and goes through the ECM connectors and through the ECM which is grounded through another wire. Alternator output voltage has been higher on just about every one I've checked.
 
bison said:
Whatever goes through that little wire that comes off the positive terminal and goes through the ECM connectors and through the ECM which is grounded through another wire. Alternator output voltage has been higher on just about every one I've checked.
Click to expand...



in my case through the caspers box through the connecters through the ecm :eek:
 
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