Fuel Pump? Data Logs Inside...

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Element

Member
I just received my dashhawk in the mail today and decided to do some data logging. I installed a Corksport DP yesterday and the car is running quite strong, however I did notice what appears to be fuel cut.

From what I can make out, as my boost pressure reaches it's peak, the fuel pressure drops and then comes back up slowly. I'm assuming that this is a sign that I need a new fuel pump.

Ok here are some new logs which are cleaner.

3rd Gear, Car did have some sort of cut:
3rdGear.jpg


4th Gear, Car did have some sort of cut:
4thGear.jpg


3rd and 4th Gear, Car did have some sort of cut:
3rdand4thGear.jpg


Any input is welcome. Thanks!
 
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dude, fuel cut would shock you. you'd really feel it, trust me. from what has been described, it's like hitting a brick wall. i've never experienced it but it certainly makese sense.

hmm, i wish you could stretch them out a bit. on the top left, there are the buttons. you can see the first one is depressed. click the one next to it, and then go down to the bottom axis and stretch out the time on the pulls so we can see them less compressed.

anyway, my car drops fuel pressure at peak boost, then shoots back up to high fuel pressure asap. to me, it looks like yours does something similar, but it lasts a bit longer on yours; hard to say.

from what i've read, the immediate dip after peak boost is a function of the pump relieving itself of pressure...if it stays down or the dip continues, then the pump is a real problem. i can't see the a/f on yours, did you pull it from the graph?

the a/f is the real indicator of an issue. make sure you select from the mazda PIDS- mazda > a/f ratio from sensor. the one you are using might be scaled right, might not be, but i know that they released the mazda specific PID later on.
 
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Ok here are some new logs which are cleaner.

3rd Gear, Car did have some sort of cut:
3rdGear.jpg


4th Gear, Car did have some sort of cut:
4thGear.jpg


3rd and 4th Gear, Car did have some sort of cut:
3rdand4thGear.jpg
 
typical of a DP upgrade....looks like cut to me. what did it feel like? must have been pretty sudden because everything drops mid pull on all of 'em.
 
builthatch said:
typical of a DP upgrade....looks like cut to me. what did it feel like? must have been pretty sudden because everything drops mid pull on all of 'em.
Click to expand...

It felt like a quick jerk and sudden loss of power, and then immediately after it would be fine.

Now what can I do to solve this? Is this a boost cut or fuel pressure issue?
 
Oh yea..you got some fuel cut. Notice how your AFR's really lean out when fuel press drops. Ever though of getting an Aftermarket BPV? Boost not holding too well.
 
what spring are you using? Winnepeg, that place is pretty cool. I went TDY to Grand forks, North Dakota and we went up there on the weekend.
 
mr_mazda329 said:
what spring are you using? Winnepeg, that place is pretty cool. I went TDY to Grand forks, North Dakota and we went up there on the weekend.
Click to expand...

Blue spring, 0 Shims.

Yeah it's really cold out now. I am wondering if that maybe has something to do with the cut.
 
mr_mazda329 said:
OKay... I put the blue and 2 shims in and I hold 15-16 PSI to 5500rpms
Click to expand...

I will have to try that. It's been a while since I got the BPV, but whats the next spring up?

So if this is fuel cut will it be solved with a new fuel pump or is it because there is too much boost being seen by the ECU?
 
Element said:
I will have to try that. It's been a while since I got the BPV, but whats the next spring up?

So if this is fuel cut will it be solved with a new fuel pump or is it because there is too much boost being seen by the ECU?
Click to expand...

I think Red is the next spring up. Shouldn't need it.

Fuel cut I think is caused by the ECU seeing too much boost. I'm still learning the ins and outs about this ECU.
 
mr_mazda329 said:
I think Red is the next spring up. Shouldn't need it.

Fuel cut I think is caused by the ECU seeing too much boost. I'm still learning the ins and outs about this ECU.
Click to expand...

I think I'm just going to put in a new fuel pump and the BCD as well just to be safe.
 
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