fuel pressure 1300PSI - should I worry?

zaka · Oct 22, 2009

Hi all!

I've got a 3 MPS (Switzerland) and I'd like to know fuel pressure drops about 1300-1400PSI between 4200rpm and 5000rpm is to low??

I've already tried 2x CDI and KMD v2 internals and all failed and few km. I don't want to spend money with this internals because I didn't get refund on these!!

When my pressure drops, my AFR doesn't change to much, I'm about 11-11.5

Mods on my sig

AutoEuphoria · Oct 22, 2009

I wouldn't worry about those numbers. As long as AFR is good, you don't get knock, and it's not dumping boost I wouldn't see where that would be an issue. I wouldn't base the health of your fuel pump on AFRs, though...the ECU will do everything in its power to maintain a good AFR even if your pump is dying. My fuel pump was putting out <300 psi around that RPM when I logged it, and to save the motor it was dumping all of the boost and probably doing other things as well (like closing the throttle plate). I thought I had a huge boost leak, but it turned out my fuel pump was going bad. Now I'm waiting for the backordered parts, but I might just cancel that order and get a full PTP pump instead of the internals from PG, since I have no clue how long it's going to take to get the parts back in stock and my pump is still no good.

mazdaspeed32007 · Oct 22, 2009

im also going to go with the ptp full pump very soon. let me know how it all works out via pm if you remember. ive heard very good things.

AutoEuphoria · Oct 22, 2009

I canceled the one order from PG and ordered the PTP assembly. I hated to cancel an order from PG, but without any clear answer as to when the parts will be back in stock, I really had no choice. There's no time to screw around when you're seeing fuel pressures under 400psi.

MS3Zoom24 · Oct 22, 2009

300psi is this when your at idle or jsut cruzing or when you get on it???

AutoEuphoria · Oct 23, 2009

~380 psi at idle
anywhere between 500psi and 1600psi when cruising around
and when I was getting on it (and logged it) it would go to 1500psi, then drop like a rock to 900 then to 700 then to 400 then to <300. I have posted the log before...it looks horrible.

I hadn't been monitoring FP before, so I thought I just had a boost leak or a faulty BCS (which is why I logged the WGDC%). Since then I've been constantly monitoring FP and have been driving w/o getting into the boost and avoiding long trips. I haven't driven the car into boost since this log was taken (about a month ago now). Which is why I couldn't wait any longer and had to order the PTP assembly.

essejkcamraw · Oct 23, 2009

AutoEuphoria said:
~380 psi at idle
anywhere between 500psi and 1600psi when cruising around
and when I was getting on it (and logged it) it would go to 1500psi, then drop like a rock to 900 then to 700 then to 400 then to <300. I have posted the log before...it looks horrible.

I hadn't been monitoring FP before, so I thought I just had a boost leak or a faulty BCS (which is why I logged the WGDC%). Since then I've been constantly monitoring FP and have been driving w/o getting into the boost and avoiding long trips. I haven't driven the car into boost since this log was taken (about a month ago now). Which is why I couldn't wait any longer and had to order the PTP assembly.

you and i are having the EXACT same problem. if your actually getting the PTP pump soon PM me and let me know how it works for you man. im going that route here VERY soon too.

zaka · Oct 23, 2009

Here's my datalog in 5th gears:

And in 3th gear:

What do you think?
No knocks

bykeryder4life · Oct 23, 2009

if your pressure is lower than 1600 at any time under boost, you should worry. Yeah sure its fine to drive around and your not getting knock and your afr's are ok, but if the pressure is dropping off that hard then the VOLUME (what matters) is significantly droppng and the performance of your car is suffering. OP you need a working pump. If you cant correctly install internals get a full pump from somewhere... this has been covered but fuel pressure doesnt mean s*** except your internals are failing. If it falls, theres an issue that needs to be addressed. Its about the volume your motor gets if you want performance.

mazdaspeed32007 · Oct 23, 2009

otherwise it feels like someone is choking your motor.

Darth Vader · Oct 23, 2009

Now, that's the part I don't get. Pressure and Volume are INVERSELY related. Some dropoff is to be expected when you get on it, you are, after all, consuming the fuel. Think garden hose. You get alot of VOLUME with the hose open but, if you up the PRESSURE, by putting your thumb over the end, the volume goes down. The question I want to put to a Mazda Tech is, what is considered and acceptable pass-test pressure at WOT, since that's the only thing we can test.

zaka · Oct 24, 2009

Darth Vader said:
The question I want to put to a Mazda Tech is, what is considered and acceptable pass-test pressure at WOT, since that's the only thing we can test.

+1, I'm wondering the same thing

Darth Vader · Oct 24, 2009

Here's the answer: If the pump doesn't make 1669 psi minimum at > 60% load PID, it is dead, period.

zaka · Oct 25, 2009

Darth Vader said:
Here's the answer: If the pump doesn't make 1669 psi minimum at > 60% load PID, it is dead, period.

Thanks

Sounds like I have to take PTP internal... I'd like to get the fuel pump but shipping to Switzerland is quite expensive and shipping back my stock fuel pump is not cheap.

How about the KMD from Protege Garage? Is still back ordered?

mr_mazda329 · Oct 25, 2009

zaka said:
Thanks

Sounds like I have to take PTP internal... I'd like to get the fuel pump but shipping to Switzerland is quite expensive and shipping back my stock fuel pump is not cheap.

How about the KMD from Protege Garage? Is still back ordered?

I wouldn't worry about it being backordered. The PTP pump is the best and i haven't heard of any failures.

240ka · Oct 25, 2009

go with the PTP.

and with you having a tune and intake. bring in more air, the OEM pump wont be able to keep up.

im going to be getting the PTP internals soon...

i know that some guys have stated they didnt get their core charge back. so id just buy the internals. that way you dont have to deal with any hassles that have to deal with not getting your core charge back.

lube the internals up with oil

bykeryder4life · Oct 26, 2009

Darth Vader said:
Here's the answer: If the pump doesn't make 1669 psi minimum at > 60% load PID, it is dead, period.

truth. You should be able to get high pressures just tapping on the throttle at idle. Anything low is fail for a cdfp.

zaka · Nov 30, 2009

I don't understand why Cobb saying that:

PLEASE use the AccessPORT to verify that your Camshaft Driven Fuel Pump (CDFP) is able to keep up with new fueling demands before you drive aggressively. The variable "Fuel Pressure DI" should not drop below 1300psi while at WOT. If your fuel pressure drops below this level while at WOT and while running an AccessPORT map, then you will likely need a CDFP upgrade in order to run the map.

Darth Vader · Nov 30, 2009

Me either...I asked Mazda but, what the **** do they know. (crazy)

ericrapp · Dec 16, 2009

I just got on this. I had my fuel pump replaced by Mazda long ago by an excellent service writer. My mods were significant but he obliged me as i fell into the correct build date (pre february 07 i think) I did not data log till this year when we hooked up the standalone and my pressure remained great at wot. My biggest fear was going lean at higher boost. Also my duty cycle read at 30 percent when we tuned. lucky me i guess. Mine is always at 1800 plus wot. Got fuel? I have enough for the bigger turbos. nice.

fuel pressure 1300PSI - should I worry?

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