Is this a fuel pump problem? (YES & Resulted in loss of compression)
 

Hello,

I own a '04 231hp Rx8. The last year there was some minor problem appearing after covering long distances and becomes more frequent during hot days.

In the highway after 1hour + pressing the throttle deep, the engine will not rev up, instead will be reving down like it has no gas for as long i keep pressing the throttle. Letting the throttle will make the car act normal and pressing it really slightly will get the revs slightly up. If I try pressing it again deep, the problem will appear again.

The problem during a trip will appear at high revs first, 6krpm and above, but as the car gets going the problem can even appear from 3k rpm.

If the problem appears and I keep pressing the gas the revs will go down to turn the engine off.

If i stop the car, remove any gear from the gear box and press the gas deep, everything is normal, car revs up easy to the deep reds.

If I experience the problem, stop, turn off the engine then start it up again, then I can get a few minutes without the malfunction.

I also see the problem rarely in short distances & while hard turning the car.

Ok, now I have read in a long distance test (90k klm) of a magazine (Evo mag) that they where getting gas feed issues while testing in a race track and during hard turns. Eventually the problem seemed to be in the fuel pump, because it uses no filter resulting on gas leftovers to stay in the fuel pump and stuff up the feed to the engine, leaving it without fuel.

As i mentioned before the problem persists for a year now, but it was not appearing very often and only in long distances. Lately and for the 3 months to come I will be traveling every week so I am about to get it every time.

Some mazda mechanics I discussed this about also guessed it is a fuel pump problem. Should I get a new one then or you have a different opinion from your experience?

possible clogged car?
OD

errrr--i mean possible clogged cat!
od

nope,

i get the same issue every now and then. had it on the way home from rr. this was with semi new coils, and fuel pump.

am going to pull the fuel pump soon and look at it. that is the most likely cause, but the heat soak that causes it does not make sense.

btw, just replaced my fuel pump resistor to no avail.

beers :beer:

I have almost the same issue, rapid acceleration above 5.5k rpm might choke my engine off like nutz, if I let the gas go and step on it again slowly, It will eventually go up to 9k rpm, but if I keep it there the *choking* problem will come back.

I was at Wayne Mazda today, but my appointment was kinda late (like 11am, got there like 11:35am), so I didnt mention anything about Fuel pump, I might probably go back there next week Mad early just to see if I can get them to fix this problem.

Same Issue
 

I first noticed this on a long trip (5 hours) on a warmer day.

What I noticed is that it seems to happen RIGHT at the 4K RPM.

May have to do with the fact that the RX8 begins to adding a lot more fuel at that point?

Wonder if the lack of fuel flow (semi working fuel pump) cannot hand the load when its asked at that stage?

This car's fuel pump are known to fail. Especially if the owner does a lot of "fill it up only if the fuel light turns on"

This part shouldnt even have a problem until like 100K miles,mine has 42.8K miles and Im seeing the issue. Its still alive, but god knows when will it just die and force me to call Mazda RSA.

My father's old mini van (now sold) had a dead fuel pump at 130K miles.

my car is at 71k klm and 4 years old so i guess that any problem of that nature is pretty normal, since the fuel pump has failed in many cases.

Looking the car from bottom, i also noticed that the plastic cover of the L wire on the cat was melted. There is a slight case that the cat is responsible since heat does play it's role, though my thoughts point to the fuel pump since the problem appears while hard turning. I am also letting the reservoir dry at least twice per month so maybe that didn't add up good and my fuel pump got some gas left overs in from the tank.

I am going for a fuel pump change on thursday, ordered the part and booked the bay, will let you know.

I got a new fuel pump like 2 months ago, its just that I dont have the time to take care of it.

and I've been to Wayne Mazda yesterday, since their services are so good, Gave me All new plugs(all 4!) and all new coils without questions (I said there were power loss issue), it got me thinking that maybe they will fix it for me under warranty ? cuz this *choke* is really annoying.

if it is the pump they wont cAtch it--they done have atest for this problem---olddragger

How many miles on your RX8? They recommed you change your coils after 40,000 miles so if it is past that start there. Any modifications done to your car? Have you checked your spark plugs? Engine light on? I advice check all your wiring and make sure nothing is cut coming out or close to the exhaust heat. Are you only using 93 octane? Hope this helps good luck.

this fuel pump is known to have a short life.

I never expect it to be that short thats all.

I could just order a gasket and fix it myself. but I figure that maybe I can get it fix under warranty so why waste the money ?

You need some one like my dog. She will catch anything..

Melted sensor wire eh?

Have them pull the cat and look inside while its in the shop.

Yep, it was definitely the fuel pump. Replaced it with a new one and problem vanished, pushed the car really hard and it didn't appear again.

The mechanic (also rx8 owner) advised never to let the gas tank dry out, and explained to me that the combination of dirt in the fuel pump (there was something like thin red dirt In the fuel pump when I emptied it) and the heat, results on that behavior.

Problem fixed, Thank you all for your time and take care.

Im having a problem with my 8 mayb itz the fuel pump! I was driving to work about 10min and came to a light and began to drive again and the car began to stall and turned off, i started it again but it would run for about 7sec and shut of, i when to the gas station a filled up half the tank i had about i quarter before, it worked fine after that when i got at work! After i left my job about 10min after the same thing happened, i stop in a bank and let the car run for a bit and rev the engine to about 6 rpms and the engined choked like no fuel was being provided and slowly rpms went to 0 and it shut off, i drove it for a bit on the way home and it didnt shut off but i wanted to know if it would shut off again at 6 rpms and yes it did! Help please!

getting ready to turn in but it sems like your fuel pump might be the cause.is it an auto or 6speed?

how many miles also. have plug and coils been changed. not enough info.

but a fuel pump will give those symptoms. but other thing will to.. :)

beers :beer:

Itz a 6sp RX8 with 37k, i dnt think the coils have been changed since i bought the car with 20k! Warrenty is over for my car so anything wrong with the car the money has to come from my pocket! I ussually use mid grade gasoline, could that be the problem by not using premium with high octane! Also i drove my car 2day again and tryed to rev it 2 8000 rpms and the fuel cut off and the engine light started blinking so i shift to 3rd gear at 3000 rpms and the engine light when away after 10sec, i got my engine to rev to 9000 rpms on 2nd gear but while atempting again the fuel cut off at 7000 rpms and had to shift to the next gear to lower rpms! So far im gonna buy some octane to rule out the the mid grade theory problem! Still need help guys! Mazda said it could be the fuel pump or some wiring!

sounds more like coils / plugs..

btw, you car has a powertrain warranty up to 5 yrs / 60 k miles from mazda if you are in the usa..


beers :beer:

Well the weirdest thing happened today, i filled my tank up with premium fuel and some lucas octane and the problem went away, i think my car has upgraded fuel injectors that plus gas just wont cut it! I rev my engine to make sure it doesnt cut off the fuel and it didnt, i rev'd it to 9000 rpms and its all good! Well mazda replaced my HID headlights and one tail light and told me i got it on time because my warrenty was almost over, is the powertrain different warranty then the warranty that was covered by my HID lights? and yea i live in the US in Indiana!

or maybe you filled it up with gas and dislodged the stuff on the fuel filter..

and yes the lights are not covered by the powertrain warranty..

got an idea. break out that owners manual and read it..

then maybe. read the stickys..

and here

best of luck..

beers :beer:

Well im gonna buy a new fuel filter because i really dont want this problem to come again!
Well funny story, i guess the previous owner used the manuel alot or something that it looks like a ancient book, all the pages fell apart and the words are not readable! Im take a look at the manual online better! Anyways the car was purchased in 2004 so i dont think its still under warranty! My bumper to bumper warranty ended a few months back so it ended with the powertrain! hahahaha funny vid, just saw 2sec of it and got bord! Thanks for the help swoope!

no such thing as a new fuel filter, just get a fuel pump.

Ok, heads up people, actually this got much much bigger than anticipated, i'd say it got as big as it could go.

The old fuel pump let dirt in the two champers. My results are 580,599,614 and 434,465,462, talking about compression of course. The coils where checked and they seem to be working fine, but nevertheless my 3rd engine is on the way under the mazda 'good will' warranty due to extreme loss of compression in a motor of 13k miles. Along with the block replacement with a new one, we are going to clean up the injection becks because there is a high probability that the whole injection system has dirt init. I am thinking of replacing more than the necessary parts just as a precaution. Right now I am thinking about new coils, new spark plugs, new spark plug wires, and a new exhaust system (cat + back), along with my already faulty radiator sensor.

Pics of the compression results
Rotor 1 (front):
http://boxstr.com/files/2761196_6uful/16072008355.jpg
Rotor 2 (back, takes more heat, closer to the clutch):
http://boxstr.com/files/2761197_gphbp/16072008354.jpg


Btw, below is the new fuel pump in case someone hasn't seen one. It goes under the back seat and the whole job will take you aprox 30 minutes. You can't replace it by yourself unless you are very very experienced, and you have the appropriate tools. Make sure when you change it, that your gas tank will be as low as possible.

http://boxstr.com/files/2760982_p937s/04072008322.jpg

3rd engine???? ouch!!!! good luck with everything