Kim Jong Illest

Was driving on the highway with about 30% gas left and the car starts stuttering, loss of power. I kicked the clutch in and it just died. I waited for 5 mins while checking the codes, Misfire 302 and p0171 system too lean. TRied to start it up to get it off the highway - it cranked very weakly I turned the key in for 8 seconds I didn't hear it ever turn over but it held rpm at 500. sounded like ****. I got it off the highway and let it rest. thinking the fuel pump is the problem. came back to it a day later at night (when colder) i was able to start it up but it still sounded bad and was misfiring along with p0506? code? Engine idle below thresh hold. I let it get up to operating temp before turning it off and next day I couldn't start it (sounded like it was flooded)

so my question is: did the engine die? or can a fuel pump die in this manner?

2007 MT
85,000KM on engine and body

plugs 5,000 km
wire coils, 30,000 km

thanks for the help

lucky7willow

iTrader: (1)

I don't think its a fuel pump issue since it starts. I recommend getting a engine compression test done. If you have good compression the next step would be to troubleshoot the misfire issue. Most likely you might have faulty ignition coils that will cause the engine to run on one rotor or wont start at all. If that's the case other check engine codes will come up because the engine isn't running properly. If you end up replacing the ignition coils use Mazda coils or upgrade to the BHR ignition

TeamRX8

iTrader: (25)

That's simply not true. There are numerous reports otherwise on just this forum alone.

lucky7willow

iTrader: (1)

Can also check fuel pressure. Search for the procedure here on the forums. I'm sure someone has a write up

TeamRX8

iTrader: (25)

That's correct; proper diagnose requires testing

Kim Jong Illest

I replaced the fuel pump.

Car is flooded right now. Will work on deflooding it tmrw (i almost started it today but I should clean the plugs anyways and put some 2stroke in the engine).

I got P0171 which only triggers when STFT goes over +20%


I have heard that's most likely fuel pump related or a vac leak. will update once I start car.

I have the d585 coils with about 25,000 km on em and like 7k on my plugs.

I no longer think it's a compression problem because I started it up hot after it died even though it ran poorly)

Kim Jong Illest

so a quick recap I'm still stuck.

from the beginning:
car died when I was on the road, I still started it up just to move it 20 meters so I could park. I was getting a flashing CEL and a STFT of +25 codes 0301, 0171, 0506.
came back next day started the car up, still running poorly. this stime STFT +15 (colder night) and no 0171 so I think it's a the fuel pump which gave me issues earlier so I ordered it.
let the car reach teh s3rd notch on the temp guage and turn her off
the day I get the fuel pump I go to the car, try to start her up so I can pull the fuse while it's running to relieve fuel pressure but no go, she's flooded. so fuckit I replace the fuel pump anyways.
then deflood, but the car still running bad, flashing CEL. 506 and 301 still with +25 STFT
I have d585 coils that have only been used about 25k KM and plugs with 5k KM on them.
Do coil issues present with high STFT? or should I be looking at something else.
the VFAD nipple is on there, I do have the MS CAI.


If it was a vac leak wouldn't I get misfires across multiple rotors?

TeamRX8

iTrader: (25)

well you could say f-it and replace the engine anyways ...

Kim Jong Illest

I sprayed contact cleaner and wd all around the engine bay could not get a small rpm bump. The car looks like it's running on 1 rotor from the uneven exhaust. I'm gonna try switching the position 1 and 2 coils to see if I can get her to run on both rotors

Lemme exhaust all my options before I say **** it on the engine

Kim Jong Illest

Yep, bad front rotor leading coil. Swapping cured everything

TeamRX8

iTrader: (25)

https://www.rx8club.com/series-i-do-...-wires-222641/

John N

A mechanic told me it might be my fuel pump failing but I'm not sure. My car will start right up no problems, but then after driving it for a bit it turns off and won't start. After about like 20 minutes it starts right up again, until it reaches normal temperature, then it starts to turn off again. Not sure what it could be, and Mazda couldn't fix it either. They kept telling me it was the battery at the dealership, but I replaced it and I still have the same problem. I drive a 2005 Mazda rx8 with about 116,000 miles.

Loki

iTrader: (1)

Mazda thought it was the battery? Oh boy. Find another Mazda dealer to go to.

Most common causes are: failed ignition coils, low engine conpression, failing fuel pump. Fuel pumps and ignition coils are replaceable, engine compression requires a new engine. Have the coils ever been replaced? Can you get a compression test at a Mazda dealer (ideally not the one you just came back from).

NotAPreppie

Does it die when you are cruising or just when idling?

TeamRX8

iTrader: (25)

Those symptoms can indicate a failing fuel pump, but it requires testing to confirm.

However, there’s a safety recall now for fuel tank inspection and possibly pump replacement. Funny that your dealer didn’t flag that to you ...

Probably a free repair for you

https://www.rx8club.com/series-i-tec...epairs-263809/

John N

Just when idling

John N

the only thing they did was replace the fuel pump rings for me.

TeamRX8

iTrader: (25)

Ok, well somebody needs to get a pressure guage on it that can be observed while trying to duplicate the problem to determine if that’s it or not. The pump motor overheating and dropping pressure or just stopping is a common failure mode.

Or if it’s an idling only scenario the fuel pump low speed resistor could possibly be doing the same thing.


.

NotAPreppie

Time for a compression test and fuel pressure test.

Mrdeep22

Hi guys

been having starting issues with rex while back and still havent managed to get it running, cars been dead 2 months now. Me and my friend removed the fuel pump and put it into a bucket of fuel. Bridged the pump of a jump pack and its starts to eject the fuel, however im unsure of the distance or pressure it was pushing the fuel out the top. Shoukd it fire the fuel far out the top? as id say pushed the fuel only few inches out top of the pump. I questioned this when i got the car to run of easy start but dies after you stop spraying it, when i removed the fuel line off the pump there was fuel coming from the pump but wasnt blasting out. Which got me questioning is my pump unit dead. Let me no guys need my car running now been to long not running.

NotAPreppie

Spraying fuel everywhere has got to be the most dangerous and least effective test a human could have come up with.

You need to connect a fuel pressure gauge to the fuel line in the engine compartment and make sure it stays between 55 and 65 psi.

Mrdeep22

Its not dangerous when its going into container and in a control environment. Also ive seen and read people testing the pump on if its actaully stronger enough to pump anything. Let you know that test been around for some time as my mate been in mechanic trade over 30 years.

single question tbh with out **** response. If the car wont start i cant test fuel pressure if my car wont start surely. I can see there isnt much pressure built when pull the fuel line off the pump after cranking over doesnt blast all over the place it just flows out, i also taken the line off the front of the engine and had someone crank it to see again the pressure if any. That didnt go far either just flowed out the line. I just would like to know is the pressure high in the lines and at the pump to actually no the pump is crap.

NotAPreppie

Just because he's been doing it that way for 30 years doesn't mean he's been doing it right.

The pressure in the lines should be 55-65 psi. Put an inline fuel pressure adapter with a gauge on it and then turn the key to "Run". If the pressure doesn't come up to that spec, you have a problem. Then, since you put an in-line adapter in place, you can crank the engine (and maybe even start it) and see if the pressure goes outside that range.

One thing to keep in mind is that the fuel pump might work just fine when cold but be below spec when it's hot.

TeamRX8

iTrader: (25)

The factory test is to install a tee connector in the fuel line and power up the pump to see the static pressure. However, this is know to be pretty much useless for assessing the overall condition. The only effective way to know for sure is to have it setup so that you can observe fuel pressure while driving the car. It could be fine for idle and light cruising, but too weak for full throttle when fuel flow demand is highest.

The test you did just confirms that it runs, but otherwise doesn’t provide any useful information like is it maintaining correct pressure & flow under all operating conditions. And as noted in another reply, a pump can appear proper when cold, but can be partially failing such that after running for a while will begin to overheat and slow down or stop. The method I suggested is the only real way to determine this

TeamRX8

iTrader: (25)

You need something like the fitting in the link below. It fits between the 5/16” (8mm) factory fuel line quick disconnect fitting and provides a threaded port to install a fuel pressure guage

https://www.aeromotiveinc.com/produc...6-access-port/