Car Bogs Out before 4k RPMS
#44
Ok so I checked the grounds at the AFM and they were not the best. I moved the grounds for the afm, cleaned everything, Blew it out with a compressor. Still bogging. Now maybe even worse than before. Every time I go into boost it will bog. I made sure to really watch the gauge and it seems like as soon as I go past 0 the car just cuts fuel. I am really beginning to think that it could be the FPR, Fuel pump, or Fuel filter. The fuel pump was squealing as it was on as well. I pulled the plugs and they were not wet at all. What would cause it to just bog any and every time I go into boost? I will post a video soon of the fuel pump noise.
#46
it was an old ground that is not hooked up. I think my FMU was backwards. Switched it and it ran even worse but I think it is right now. Fuel pump is squealing and knocking. injectors are 195500-1970 which i believe are stock from the search i looked up. I think it may be time for a new fuel pup and fuel filter? Thoughts anyone? definitely have a knocking fuel pump though...or fuel filter...? could be a clogged fuel filter? Thoughts?
#50
Can't really make much out from your video. The fuel pump should not knock or squeal. So, you should replace it along with the fuel filter. Note that if you're going to stick with bandaids, you might want to consider a Walbro.
I also can't really tell how your FPR is hooked up from the photos. Instructions for a Greddy install are here (some explicit instruction on the FPR on second to last page):
https://www.miataturbo.net/useful-saved-posts-8/greddy-turbo-install-instructions-852/
I also can't really tell how your FPR is hooked up from the photos. Instructions for a Greddy install are here (some explicit instruction on the FPR on second to last page):
https://www.miataturbo.net/useful-saved-posts-8/greddy-turbo-install-instructions-852/
#51
Ordered a Walbro 255, going to put a new fuel filter in it. And going to change my top to be black because in the cold last night my rear window cracked. :( I am hopin gthat my issue is related to the stock fuel pump just giving out and not being able to provide enough fuel. The knock that I can hear however is definitely coming from behind the seats and is coming from the fuel tank area. I hope this will solve my problem, but if you guys have any other suggestions please feel free to let me know as I have checked almost everything that you suggested on here. I also made sure to unplug the o2 sensor...you name it and I have done it. Once again I thank everyone for their responses and not this weekend but the following will be when i install the walbro 255. Hoping that will give me more fuel than I know what to do with. Another thing that is kind of weird...is that if I absolutely floor it...it doesnt bog out completely but will just be running lean but will sort of go...any thoughts on that? Am just going to leave it till I get the new pump in but any suggestions you guys have are always appreciated.
Thanks!
Tyler
Thanks!
Tyler
#52
I've had good luck with E-bay tops. Bought one with a glass rear window for cheap. Worked out great.
When you get the new pump and fuel filter in, hook up a fuel pressure gauge and route it so you can see it while driving. Make sure that you are getting the correct fuel pressure for the MAP. If you had a fuel pump die, it is likely that you've got crud in the FPR's. That would definitely cause fueling issues.
When you get the new pump and fuel filter in, hook up a fuel pressure gauge and route it so you can see it while driving. Make sure that you are getting the correct fuel pressure for the MAP. If you had a fuel pump die, it is likely that you've got crud in the FPR's. That would definitely cause fueling issues.
#54
I highly recommend getting a fuel pressure diagnostic gauge (they are cheap) and making sure your fuel pressure is suspect before throwing parts at it.
If they can be disassembled and cleaned, then have at it. I'm not sure the stock FPR can be disassembled, and that is likely the one with an issue based upon your symptoms.
If they can be disassembled and cleaned, then have at it. I'm not sure the stock FPR can be disassembled, and that is likely the one with an issue based upon your symptoms.
#55
WELL, prior to seeing your last post I had already ordered the Walbro. As i began to read about the symptoms of a bad stock fpr I read that it can cause your fuel pump to squeal... Interesting. I have since gone ahead and ordered a new FPR and will test that before I try the fuel pump. Also may not be bad to have the extra fuel pressure as the one in there is most likely old. Not sure but will look into it. I will also check for fuel in my vacuum like that is attached to the stock FPR. I will let you guys know in a few days (when im actually home again) and can check a few more things on the car. Hope this works and I look forward to seeing if these things will make the car any better.
Thanks!
Tyler
Thanks!
Tyler
#56
Holy crap. my miata finally runs right. Thank you to veryone that has helped me try to figure this thing out. I have finally figured out that it was the fuel pump. I put the walbro 255 in there and the thing finally finally runs right. It does some nice burnouts too May or may not have done a few of those. But the air fuel ratios are where they should be, The car finally sounds good and strong and healthy. Wanted to let everyone know that it is finally over. I am very happy and will just hope that nothing else goes wrong with the car. LOL. Now I can focus on putting my sparcos in it and making it a little bit nicer on the inside!
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