Fuel pressure drop

[joey]

Hi,

I have done some logs last night and when i got to work today and started reviewing the logs, i saw a fuel drop in every WOT run around 5k rpm to 5.5k rpm... Then it comes back to normal.

I have not upgraded my fuel pump yet, and I know i should(just waiting for some cashflow). Its next on my upgrade list. I bought my car from a dealer, so I have no contact with the previous owner. I have had a look at my fuel pump and it looks like it has been removed, as i can see some wear on the bolts keeping it in place. Is there a way of checking if the FP has been upgraded without taking it off the car?

BTW, our baro pressure is 101kpa and all the logs was done in 4th gear. See attachment.

Kind Regards
Jo

[skiptownmcat]

You could command a really high pressure and see if it will hit it, if it won't it's not been upgraded.

[mituc]

My stock pump has no problem hitting 1860PSI. But the FP pressure drops just right after shifting or around 4500-5000rpm. If I do a WOT run in 4-th or even 5th from 3000rpm to 6500 the pressure won't drop. So my conclusion is that with the high load map ideally you should have your FP upgraded because it's right at the limit of the stock pump possibilities... it may work with some of them, or in some conditions, while with some others you may experience this pressure drop which in time (and not too much time) may force some piston rods through the block.

later edit: that massive drop down to 800PSI'ish at 226.36/298.08 was pretty nasty. In your case it happens even at 1.75load, mine was dropping at 1.9+. You need new internals mate, and until then load the base tune or if your intake/exhaust is still stock stay with the stock tune. Don't do any further tests.

If you want the autotech internals I've got a set from EdgeAutoSport and as far as I know they still have some in stock. My dealer also recommended to acquire the fuel pump o-ring (part #L3K9-13-ZE5) and the 3 bolts holding the pump (part# LK9-13-366B).

[joey]

Thx for the replies!

I have a 3" TIP and 3" SRI Intake with a catless 3" full zorst, FMIC, ITV24's, Exell SSQ VTA, HDI boost controller, RMM and some more smaller goodies...

I will have to save up for the internals... And being in South Africa makes everything that I import so much more expensive.

[mituc]

A bit offtopic: even in the hot South Africa I would ditch those ITV24's and replace them with ITV22's. The ITV24's drive indeed the heat away from the cylinders a bit faster but in this case you don't really need it, it's actually counter productive with your mods. ITV22's should work better, keep you away from knock as the ITV24's do but you'd make more power with them.
I live in Romania and here the summers are even hotter than in South Africa, and the winters a lot colder (damn continental climate!). So I know.

[Steve @ VersaTune]

Usually when load > 2.0 is where the stock HPFP starts to fail to hold pressure. Every car is different though.

Check the manufacture date on the pump as indicated in this TSB.

http://www.o-m-g-w-t-f.com/stuff/Mazdas ... 5B1%5D.pdf

[Rich990]

Thx for the replies!

I have a 3" TIP and 3" SRI Intake with a catless 3" full zorst, FMIC, ITV24's, Exell SSQ VTA, HDI boost controller, RMM and some more smaller goodies...

I will have to save up for the internals... And being in South Africa makes everything that I import so much more expensive.

Yo Jo,

FRC in Joburg does the Autotech internals for R3400, steve got a set the other day and he said he's holding Fuel Pressure just fine

Cheap insurance dude

[joey]

Thx for the replies!

I have a 3" TIP and 3" SRI Intake with a catless 3" full zorst, FMIC, ITV24's, Exell SSQ VTA, HDI boost controller, RMM and some more smaller goodies...

I will have to save up for the internals... And being in South Africa makes everything that I import so much more expensive.

Yo Jo,

FRC in Joburg does the Autotech internals for R3400, steve got a set the other day and he said he's holding Fuel Pressure just fine

Cheap insurance dude

Thx bro! Will check em out!

[joey]

A bit offtopic: even in the hot South Africa I would ditch those ITV24's and replace them with ITV22's. The ITV24's drive indeed the heat away from the cylinders a bit faster but in this case you don't really need it, it's actually counter productive with your mods. ITV22's should work better, keep you away from knock as the ITV24's do but you'd make more power with them.
I live in Romania and here the summers are even hotter than in South Africa, and the winters a lot colder (damn continental climate!). So I know.

Thx man! I got a DTC yesterday going home after work... P2503 - Charging System low... Now my car is not running at all...

I will have a look at this 2nite when I get home. http://www.thaimazda3.com/svmanual/esic ... 00W02.html

I'm driving my fiance's Chana mini truck