rubberduckie

I think my fuel pump maybe dying, but I want to be sure before I go ahead and replace it...

Near the end of last year (I park my car during the winter months) I would not be able to rev past 5-6k rpm after driving for 30-45min. This wasn't everytime and after a quick shut down it would seem to go away. It was abrupt and seemed like ECU limiting my engine. My battery was slowly dying so I thought it might be that.

Fast forward to this year, I replaced my battery and everything was fine for a couple weeks. I got stuck in traffic for a couple hours, yes a couple hours, and my engine just died. Felt like it just studdered slightly and just went out. Walked around the car sat around for 10-15 min and decided to start it up. Started like a charm and ran fine for 5-6 minutes... than the same thing again. I managed to limp it home like this as I was pretty close.

It seems to be good for 20-30 minutes than there starts to be a hesitation under a bit of load, than the engine just stops firing. No misfires or anything.

Car starts like a champ. Put in brand new plugs 5k ago and a week ago (just in case). Idle is solid and AFRs consistent so I don't think it is the MAF.

Car Facts:
07 Manual, 55000kms
Red lined a couple times a week
New Battery
MS Intake
Catless Midpipe + Exhaust
AP + MM tune
BHR Coils and Wires (10k old max)
New Plugs

Am I right thinking it is the pump?

What do I need to replace this? There is a AEM universal fuel pump on Vivid, or do I need an OEM replacement? Any suggestions?

Thank you in Advance.

04Green

iTrader: (1)

Full tank? If low on gas, pump can get hot. Full take keeps it cool. If problem goes away with a full tank, then maybe pump.

j9fd3s

i've seen clogged fuel filters do this, along with clogged charcoal canisters.

i think you should test the fuel pressure, and go from there. preferably hot

ShinkaEvo

iTrader: (3)

check your cat as well.

rubberduckie

It seemed to run longer and better on a 3/4 tank. Its at a quarter right now and seems to get into this condition more.

I was thinking about checking to make sure the mesh in the filter isn't clogged. is that what you mean by the fuel filter? How would one test the pressure?

04Green

iTrader: (1)

@ duckie,

Sounds like the pump. Could also be a clog in the sock, but that would not change with fuel level. And, to get to it you have to pull the pump.

I got a complete pump assembly, with the pump in it, from Advance Auto and installed it at the track.

The process for the ring is in this thread. Vice Grips work better than channel locks.

https://www.rx8club.com/trouble-shoo...change-234314/

peterlemonjello

Sounds similar to when my pump failed. I'm on my third one. Your pump is overheating and shutting down. Once this happens it's only a matter of time before it fails.

BigCajun

iTrader: (1)

Hello all, I'm not trying to hijack, but this overheating fuel pump issue seems to be fairly common. Does anyone have an opinion on how low you would let your tank get before it becomes a problem?

I read about avoiding hard left turns on low fuel, but I can't find a consensus on what is considered low.
Any opinions are appreciated. Thanks.

j9fd3s

i've read about the pump issue, but i've never seen it... none of my local dealers stock it either.

the hard left turns, the fuel pump is on the left, so a hard left = the fuel going to the right.... FD's do it too

BigCajun

iTrader: (1)

Thanks for replying.

Karack

check the pump for external leaks under the passenger seat behind the driver's seat, inspection cover is right on top of the pump.

check the fuel pressure with an inline gauge when the problem arises.

check your cat by rapping on it with a soft mallet, any rattles replace your cat.

peterlemonjello

Most people agree anything less than 1/4 of a tank. At this point the pump is more exposed inside the tank so there's less fuel to help cool. However, this is may all be anecdotal. My 2 pumps failed with plenty of gas in her. They both bit the dust after driving between 85-100mph for over 4 hours on a road trip.

BigCajun

iTrader: (1)

Thanks for replying. Much appreciated. When I first got my 8, I did not know of the problem.
I routinely let it get low because of a stoopid grocery store gas discount card.

Trying to save a couple of bucks could have cost me thousands from not knowing about the danger of hard left turns on low fuel. Thanks again!

04Green

iTrader: (1)

Issue with left turn is because pump is already bad. No issue (unless really low gas, like light is on) if pump is good. However, keeping above 1/4 tank is the best maintenance. My factory one lasted 100,000 miles or so. I have an Advance Auto Parts one in now, that seems to be doing fine. I will mod the factory one with whatever BHR is recommending when this one starts to go.

peterlemonjello

There are two different issues being described in the thread. One means the pump is bad the other is a design flaw.

1) Low fuel plus sharp 'sweeping' left hand turn = fuel pickup problem. This in no way indicates the pump is bad. It's simply a design flaw with the fuel tank and pump. Gravity moves the fuel away from the pump pickup creating this issue. There's several threads going into detail about this.

2) The other is fuel starvation problem due to a faulty pump. Once you start experiencing this it's only a matter of time before the pump goes kaput. This feels similar to the pickup problem above but isn't isolated to low fuel & left turns. There's also several threads discussing this. The series1 rx8 pump is designed poorly. This issue was addressed in the series 2 rx8.

nycgps

iTrader: (1)

although the fuel system has some design fault, the fuel pump is in fact the biggest problem. it was made with garbage thats snap together in the cheapest way. u seeing this aaram?

the s2 fuel pump is 100% better. too bad its not a 100% direct swap. it solves 90% of the fuel problems

BigCajun

iTrader: (1)

Hello, thanks to all for replying.
I have no issues yet, but I assume habitual low fuel driving may contribute to an early demise.
If a new pump were bought from the dealer now, do you think it would be same poor quality? Would an aftermarket pump be any better?
Any thoughts for future reference is appreciated.

nycgps

iTrader: (1)

mazda has been selling the same pump, they only changed for s2, s2 pump is made by denso which is a night n day comparing to Aaarm.

there are other pumps that will work, u have to remove the old pump out of the pump assembly, if u use a higher lph pump(stock is like 115 lph i think), for example, a 255 lph pump, u have to weld shut the valve, otherwise it will pop(read: broke) the moment the pump turns on.

BigCajun

iTrader: (1)

Thank you. I will bookmark, just in case I ever need one.

j9fd3s

the part number changes, but i'm not sure what they did.

the current Mazda part number for the S1 is N3H1-13-35ZG. they only have 35 pumps, so they obviously don't sell a ton of them... they have 740 sets of spark plug wires...

04Green

iTrader: (1)

@ peter, I had not issues with left corners on track, even below a quarter of a tank, with the old pump, until it started to go bad. Then it was a mess. I think a good pump, with fuel in the assembly, can suck it back from the other side at a high enough rate to keep things happy (fuel flow, venturi, then excess in the bowl from the pop-off). If the bowl empties, death, destruction, and the red vette on your *** does something magical not to join you in the car...

I have no issues with my Advance Auto Parts special, even below a quarter tank.

The interesting thing was the performance and mpg went up with the new pump, so it had been bad for awhile.

Mickh

So Iv bought an 2004 rx8 recently and Iv been having problems with the petrol tank it won't go down under half tank and also when I I fill up it. Barely goes up I have been spending so much money on petrol and it seems to not go more than a just abit over half

Loki

iTrader: (1)

I don't understand, the fuel gauge won't go over half way?

Mickh

nah it doesn't go below half tank and when it gets to half tank my car turns off due to lack of petrol

Loki

iTrader: (1)

About how many miles does it take to go from full to half? I mean the fuel level sender could have gone bad, but its possible your fuel pump is dying and overheats when there the tank is lower than half full.