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Discussion Starter · #1 ·
Hi all, my girlfriends 08 mazda 3 has a starting issue lately. It will crank for several seconds before starting (after sitting for more than 30 min) but once running all is well. A quick run into the store and it starts fine. Im leaning toward a fuel delivery issue. My girlfriend took it in for a diagnostic and they quickly said crank poaition sensor and wanted 600 dolalrs to repair, but it doesnt seem like a cps issue to me. Theres no external fuel filter to check/replace. What say you, mazda community?

Thank you!
 

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First of all, don't go back to that shop. There is no way that it should even cost half that much to change a crank sensor. An easy way to check for this type of fueling issue (pressure bleeding down) is to cycle the key from "off" to "run" several times before starting the engine. If it starts right up then I would suspect that the check valve in the fuel pump assembly is bad.
 

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Wow! A crankshaft position sensor costs between $9 and $33 depending upon which brand you purchase, and literally takes less than five minutes to install (two easily accessible small bolts and one electrical connector. While I doubt that is your problem, I agree that the shop was trying to rip you off.
 

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Discussion Starter · #4 ·
First of all, don't go back to that shop. There is no way that it should even cost half that much to change a crank sensor. An easy way to check for this type of fueling issue (pressure bleeding down) is to cycle the key from "off" to "run" several times before starting the engine. If it starts right up then I would suspect that the check valve in the fuel pump assembly is bad.
Bingo bango. Cycled the key, starts like a charm. Embarrassed i didnt think of it. Thank you !
 

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Discussion Starter · #5 ·
Wow! A crankshaft position sensor costs between $9 and $33 depending upon which brand you purchase, and literally takes less than five minutes to install (two easily accessible small bolts and one electrical connector. While I doubt that is your problem, I agree that the shop was trying to rip you off.
My woman took the car in to have it look at, i told her to get only a diagnostic so i can take care of it. They quoted 1600 for all this other stuff thats unnecessary. They didnt diagnose anything. They took a quick glance at it, saw it was a little oily and sent it.
 

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My woman took the car in to have it look at, i told her to get only a diagnostic so i can take care of it. They quoted 1600 for all this other stuff thats unnecessary. They didnt diagnose anything. They took a quick glance at it, saw it was a little oily and sent it.
Like @madmatt2024 said about the "check valve", when I had this behavior (long cold starts but normal warm starts) with my 97 Mazda 626, it was the fuel pressure regulator. Unfortunately, with the 1st-Gen Mazda 3, it looks to be in the fuel tank:
Product Rectangle Font Line Parallel

If you're going to go to the work of dropping the tank, I think I'd just replace the whole fuel pump -- I can't get a clear picture online of whether the regulator is discrete or integral to the pump assembly. In any case, the service manual directs a proper diagnosis to measure and evaluate the fuel pressure after 10-seconds of fuel pump running, then after 5-minutes of sitting ("fuel hold pressure"). From that, you'd implicate the pump, the regulator, or line leakage.
 

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I would add to the above if you drop the tank to replace the fuel pump please replace the white ring lock that secures the pump in the tank. This part cracks after a number of years and creates an evaporation leak code. You have to drop the tank again to replace it because Mazda made the access door under the back seat cushion too small.
 

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Hi all, my girlfriends 08 mazda 3 has a starting issue lately. It will crank for several seconds before starting (after sitting for more than 30 min) but once running all is well. A quick run into the store and it starts fine. Im leaning toward a fuel delivery issue. My girlfriend took it in for a diagnostic and they quickly said crank poaition sensor and wanted 600 dolalrs to repair, but it doesnt seem like a cps issue to me. Theres no external fuel filter to check/replace. What say you, mazda community?

Thank you!
I have the same issue, mine is a 2006 2.3 with almost 300k, I have one pistion that is at 40% compression and I get 18.7 mgp when I used to get 24+. It happened because I had an injector that went bad, I cleared the codes myself and ended up hurting the pistion instead of fixing the issue. Lean Bank1 something or another... I still pass SMOG though so all is good lol
 

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My woman took the car in to have it look at, i told her to get only a diagnostic so i can take care of it. They quoted 1600 for all this other stuff thats unnecessary. They didnt diagnose anything. They took a quick glance at it, saw it was a little oily and sent it.
Sounds exactly like my stealership experience when my wife's rear hatch wouldn't go up and down. They quoted over $1500 in 'needed maintenance'. I paid the diagnostic fee and left. They also gave a wrong diagnosis, which cost me a $150 unneeded part. Anyone need a rear liftgate module for a 2018 CX-9?
 

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I have the same issue, mine is a 2006 2.3 with almost 300k, I have one pistion that is at 40% compression and I get 18.7 mgp when I used to get 24+. It happened because I had an injector that went bad, I cleared the codes myself and ended up hurting the pistion instead of fixing the issue. Lean Bank1 something or another... I still pass SMOG though so all is good lol
Time to start getting ready for a 2.5 swap and be rid of the garbage 2.3
 

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As others stated, fuel pump. It’s a common issue for just about every modern car over time where the mechanical check valve on the pump unit wears and no longer keeps the fuel rail pressurized when the ignition is chit off therefor the fuel drains back from the lines. Good news is, you can get a whole pump assembly online for under 100 dollars (check Amazon and verify reviews) and the pump is pretty easy to replace. You do not need to drop your tank as someone stated. The access to the top of your fuel tank is under your rear seat cushion and you swap it out right there. YouTube is your friend, good luck!
 

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Not quite. The first video you shared is a CX-5; the second clearly was cut larger -- the hole and edges aren't machined smooth, and two of the female retention clips for the cover are clearly missing (cut away to make the hole larger).

Edit: @Seanduncan1 , I'd love to see a pic of your cover or access port, if you're convinced the stock hole is large enough to pull the pump.
 

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Not quite. The first video you shared is a CX-5; the second clearly was cut larger -- the hole and edges aren't machined smooth, and two of the female retention clips for the cover are clearly missing (cut away to make the hole larger).
Interesting, perhaps mine was previously modified but as far as I could tell it looked original. None the less if it hadn’t been big enough I sure as hell would have made it lol I had almost a full tank of gas
 

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Interesting, perhaps mine was previously modified but as far as I could tell it looked original. None the less if it hadn’t been big enough I sure as hell would have made it lol I had almost a full tank of gas
Yeah, I chalk it up to Ford's influence at that time. I see that the 2014-2018 has a larger port to pull the whole pump through. If I have to replace it on my 2006, I would strongly consider a nibbler; living in the land of salted winters, I worry I'd be in for a headache of snapped fasteners if I have to drop the tank.
 

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I didn't read all the post but I just replaced my fuel pump on my 08 Mazda 3 last month. Save yourself a lot of time and effort take a pair of tin snips and cut the hole larger . I used a Sawzall blade to cut through the stiffener .I then used pipe foam insulation cut a piece of sheet metal in a circle,drill some holes screwed it back down and was done within two hours I did not drop the tank and I've had no issues whatsoever since I did that.
 

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Interesting, perhaps mine was previously modified but as far as I could tell it looked original. None the less if it hadn’t been big enough I sure as hell would have made it lol I had almost a full tank of gas
What emissions package does you car have? Federal and Cali emissions have completly different tanks and sending units. The Cali version could be small enough to squeeze through the hole.
 
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