Anyone ever see fuel pressure do this??

[kidglok]

-8 feed, -6 return dual fed champion rails. Racetronix dual aeromotive 340's. I verified both pumps come on at 200kpa as commanded by the xfi.

The middle green line is the fuel pressure, and the injector dutycycle and 02 correction both confirm that the fuel pressure was dropping then recovering at the bottom of the gear. Boost was constant throughout the run, and everything is wired directly off the battery.

 

[Nick Micale]

......... and everything is wired directly off the battery.

Even though the pump is wired to the battery, check the voltage to see if it drops when the pressure drops?

 

[kidglok]

Even though the pump is wired to the battery, check the voltage to see if it drops when the pressure drops?

I'm going to check the voltage just to make sure.

Would this make the pressure recover on the shift and drop at higher rpm tho?


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[Mike Licht]

it does not look like FP is tracking boost

 

[TurboBob]

post the log, that screenshot is too tough to read.

but yeah it looks like its falling off...

B

 

[kidglok]

post the log, that screenshot is too tough to read.

but yeah it looks like its falling off...

B

Here it is, thanks in advance for helping me out.

 

[TurboBob]

the log looks like the classic case of insufficient fuel pump. at low demand it tracks the MAP well (so your fuel pressure regulator looks like its working),

but above about 5200 it starts to "droop".

One other hair-brained idea is something wrong with the pressure signal to the regulator, how/where is that connected to the manifold?

Bob

 

[kidglok]

the log looks like the classic case of insufficient fuel pump. at low demand it tracks the MAP well (so your fuel pressure regulator looks like its working),

but above about 5200 it starts to "droop".

One other hair-brained idea is something wrong with the pressure signal to the regulator, how/where is that connected to the manifold?

Bob

its tapped off the front of the manifold with a pushlock vacuum fitting going to the regulator. It would be almost impossible for 2 aeromotvie 340's not to be up to the task.
We are going to run through some basics such as checking voltage/fuel filter/regulator...probably going to drop the tank and see if anything funky is going on there as well.

 

[kidglok]

Update

Just disconnected the return line at the tank and stuck the end in a 1 gallon jug.
Sent 12v to the pumps and it flowed 2 Litres in one minute on each pump. This is at 45psi

So basically each pump flowed 30gph???

Going to change the fuel filter and test again.



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[kidglok]

Changed the filter (was a little restrictive compared to the new one) and upped the voltage to 13.5 and got 1 gallon per minute, that's 240lph, not quite 340 but it's better


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