Potential fuel pressure relief valve failure

[ms_3]

Hey fellas I've got an 07 ms3 and it's been down for the better part of a month now. After hitting a small pot hole my check engine light came on for a misfire in cylinder 3 and my fuel pressure dropped to dangerously low levels, between 200-300 while putting around and 50-80 at idle. I babied the car for the next mile until i could beach it and do a bit of diagnosing. I took off the hpfp and inspected the internals. Everything seemed to be in pristine condition. Since i really dont have time to work on the car that was pretty much the extent of the diagnosing that I performed. I then had the car towed to the mazda dealership where they diagnosed the issue to be a bad injector in cylinder 3. I found this to be strange as i had just replaced the injectors in april with new CS seals. After getting in touch with the folks at CS I had a replacement seal overnighted to the dealership and they replaced the injector with a new seal. Upon completing the injector install the car is still experiencing the same issue. 50-80 psi at idle and never builds up higher than 300psi if the throttle is blipped. After starting the car, turning it off, then powering on without cranking, there is no climb in pressure. While the car is running i also hear a whining/more pronounced clicking sound. I havent been in the car since prior to it getting towed to the dealer but im being told it still has a misfire in cylinder 3 as well.. If i had the car i could throw up a log but unfortunately im not able to do that at the moment.

Any help or input would be greatly appreciated

[monkey.bones.007]

Pressure relief valve? That's my guess.

crapatalk, yes it sucks for free.

[ms_3]

Originally Posted by monkey.bones.007 Pressure relief valve? That's my guess. crapatalk, yes it sucks for free.

My thoughts as well but I haven't heard of anyone having a misfire when the prv failed. I guess its not too big of an investment to replace it and go from there.

[doctavus]

That's the same symptoms I was having when my relief valve failed. However, I did not have any CEL's and I drove that way for about a week or two, drove fine, just didn't boost.

This was when I had the CS Turbo on too.

[michaelhanson96]

Originally Posted by doctavus That's the same symptoms I was having when my relief valve failed. However, I did not have any CEL's and I drove that way for about a week or two, drove fine, just didn't boost. This was when I had the CS Turbo on too.

So my speed is clunking from my hpfp and it is shutting off while driving sometimes after I rev not all the time but it happened twice, its running like shit, I'm thinking it's the to but I'm not sure .

[loak1er]

I am having the exact same issue with my car, 100% same symptoms. I have pulled my hpfp and inspected, I purchased a new prv, I just have to install it. My car was throwing cyl 3 misfire code, rich at idle previous to failure, shitty fuel pressure. I will post update when I install prv.

[GroceryGtr]

I may have a used good one in my parts pile if you want to save some change. those things aren't exactly cheap for "guess diagnosing".

I would be ok with saying its the prv, except those things dont just fail because of a hard bump. You sure the hpfp was fine? Did you check the spill vavle as well? I'd also check inj. 3 to see if its hung open. That would explain the misfire and the drop in fuel pressure. I could certainly see a piece of something breaking loose in the fuel system over a hard bump and getting hung up in the injector.

[Bramma]

Originally Posted by loak1er I am having the exact same issue with my car, 100% same symptoms. I have pulled my hpfp and inspected, I purchased a new prv, I just have to install it. My car was throwing cyl 3 misfire code, rich at idle previous to failure, shitty fuel pressure. I will post update when I install prv.

Any luck with replacing the prv? Experiencing the same issue.

[loak1er]

Yes it worked. But i had shit fuel pressure thats why I replaced it.

[Bramma]

Gotcha! My fuel pressure is between 50-120 at idle which has me terrified. Hoping that will fix the issue. How much did you pay for the relief valve? Were you getting bad gas mileage prior to the prv fail?

[loak1er]

125 I believe