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Discussion Starter · #1 ·
Cobb wasn't kidding around with the disclaimer about fuel pressure. I did a brief pull tonight and logged it on the DH.



YIKES. :shock:

I'll be putting around under 3k until my CP-E pump shows up.
 

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Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

Yep..that's bad. Which exact map are you running?
 

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Discussion Starter · #3 ·
Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

[quote author=evo2ms3 link=topic=133955.msg2878667#msg2878667 date=1232503957]
Yep..that's bad. Which exact map are you running?
[/quote]

I believe the California 1.03 stage2 + SF + TMIC - 93 octane
 

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Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

What are your mods?
 

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Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

On a difficulty scale of 1-10, with 1 being 'slap a bumper sticker on the window' and 10 being 'omfg why didn't I get a pro to do this', approx. where is a fuel pump upgrade?
 

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Discussion Starter · #7 ·
Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

[quote author=Cataphract_40 link=topic=133955.msg2878856#msg2878856 date=1232507834]
On a difficulty scale of 1-10, with 1 being 'slap a bumper sticker on the window' and 10 being 'omfg why didn't I get a pro to do this', approx. where is a fuel pump upgrade?
[/quote]

I'm thinking it's around a 5. CP-E makes it a bolt-on from what I understand. Just time unclipping wires and hoses is all...
 

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Discussion Starter · #8 ·
Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

[quote author=evo2ms3 link=topic=133955.msg2878780#msg2878780 date=1232505884]
What are your mods?
[/quote]

cobb sf, rpmc inlet, ETS tmic, cp-e dp, stock catback, stock BPV.
 

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Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

[quote author=Sinitron link=topic=133955.msg2878879#msg2878879 date=1232508393]
[quote author=evo2ms3 link=topic=133955.msg2878780#msg2878780 date=1232505884]
What are your mods?
[/quote]

cobb sf, rpmc inlet, ETS tmic, cp-e dp, stock catback, stock BPV.
[/quote]

Can't get much closer than that for your map. I remember hearing way back when how v103's were gonna require a fuel pump. Looks to be the case for stage 2+ users at the very least. So far, I'm good on the stage 1+ final. Wish the built pumps weren't so damn expensive though, or I'd get one anyways.
 

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Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

looks like you are getting boost creep on that map, which is causing your fp to drop. I find that fp can keep up on the stock pump if you are holding 18 psi or less and your a/f ratio is 12.0 or leaner. If you add more boost or go richer the pump craps out. Your boost is building to 19 psi which is why the pump gives out. I would send that log to christian and see what he can do for the boost creep.
 

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Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

[quote author=aero_student link=topic=133955.msg2879229#msg2879229 date=1232515882]
What is our safety range for fuel pressure?
[/quote]

At WOT full boost, you should be AT LEAST 1400-1500psi
 

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Discussion Starter · #14 ·
Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

[quote author=evo2ms3 link=topic=133955.msg2879188#msg2879188 date=1232514781]
[quote author=Sinitron link=topic=133955.msg2878879#msg2878879 date=1232508393]
[quote author=evo2ms3 link=topic=133955.msg2878780#msg2878780 date=1232505884]
What are your mods?
[/quote]

cobb sf, rpmc inlet, ETS tmic, cp-e dp, stock catback, stock BPV.
[/quote]

Can't get much closer than that for your map. I remember hearing way back when how v103's were gonna require a fuel pump. Looks to be the case for stage 2+ users at the very least. So far, I'm good on the stage 1+ final. Wish the built pumps weren't so damn expensive though, or I'd get one anyways.
[/quote]

Yeah I never had a problem at stage 1, or even 2 up through versions 1/1.01/1.02... it held fine across the board with level fuel pressure.

Now it's falling off hard, and I'm watching the A/F wobble a bit when the pressure drops. Just waiting for my pump so I can re-log and make sure that's the solution.
I think it may also be the source of my random low-knock issue once I get into boost with partial throttle over 3k rpm.

As dread mentioned, it is getting up there in boost a little, but the PDF usually says +/- 1-1.5psi.... so... within range sort of. I usually hit 18-18.5.
If I switch to an aftermarket BPV, it used to reach 20(forge) to 21 or 22psi (hks) peak.
 

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Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

yeah the 103 maps are much more aggressive that is why everyone running stage 2 is having issues with fuel pressure. Too bad mazda didn't put a better pump in the car.
 

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Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

I don't seem to have a problem with 1.03 yet.

I need to run some more logs, but there have been no odd symptoms.

I am running the beta file for 1.03 - 93 octane + MSCAI2 + TBE.

My last logs in 3rd for fuel I was getting over 1600psi most of the run. Couple of dips but it bounced back up.

Is it the next step (fmic) that will cause me to need a pump?
 

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Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

[quote author=dread link=topic=133955.msg2879244#msg2879244 date=1232516375]
looks like you are getting boost creep on that map, which is causing your fp to drop. I find that fp can keep up on the stock pump if you are holding 18 psi or less and your a/f ratio is 12.0 or leaner. If you add more boost or go richer the pump craps out. Your boost is building to 19 psi which is why the pump gives out. I would send that log to christian and see what he can do for the boost creep.
[/quote]

fuel pressure drops, which causes pressure drop out of the injectors to drop, reducing the charge cooling effect of the DI, which causes egts to go up, which puts more heat energy to the turbo, which causes your boost creep. several people have said that the upgraded fp helped their overboosting issues.
 

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Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

[quote author=Strizzo link=topic=133955.msg2880579#msg2880579 date=1232569448]fuel pressure drops, which causes pressure drop out of the injectors to drop, reducing the charge cooling effect of the DI, which causes egts to go up, which puts more heat energy to the turbo, which causes your boost creep. several people have said that the upgraded fp helped their overboosting issues.
[/quote]

ooo...now THAT makes sense!

...and yes, i had serious overboost issues before my cpe hpfp. afterwards, things got a LOT better.
 

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Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

very informative strizzo. So the creep is caused by the fp not the other way around. Once the op gets his pump we will see what happens.
 

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Re: Cobb v.103 + Stage 2 = Fuel Pump Needed - Badly.

I was running Stage 2 v1.03 91+SRI+FMIC and monitored my FP and it never dipped below 1500 at WOT. I just didn't like the way my car felt. I kept getting a shitload of knock retard using this map. The car ran fine but the KR scared me. I went back to Stage 2 v1.03L 91+SRI+FMIC and knock retard is next to none, car runs great and strong and AFR holds around 11.75 at WOT. I may try v1.03 final later, but as of now i'm happy with the v1.03L beta map.
 
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