[SOLVED] Need help wont go over 4500rpm

Dillon davis

Dillon davis

Greenie N00B Member
08 mazdaspeed 3
Fbo besides manifolds bnr s4 pd tuned
Having a weird issue where the car wont go over 4-4500rpm it just hard cuts it runs fine until i get to 4-4500rpm. But it happened out of no where and stopped for like 4 months but and now its doing it again.

i have replaced plugs, vvt and timing components, throttle body, gas pedal assembly, both clutch sensors and maf still no fix..
Im thinking maybe its spill valve, prv or pressure sensor?
Will at pd tuning said the tune looks fine its something mechanical.
I have two abs codes u2023 & c1277
 

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Damond dual setup with plate ect. Its a full bolt on car besides intake and exhaust manifold still di with a bnr s4 tuned by will at pd.. which is crazy he said the log looked fine ? it definitely is cutting i mean i cant go over 4500 rpm because it hard cuts like limiter. I have swas unplugged and also my lc and ff are aet to 9k

Mod listScreenshot_20240409_121917_Gallery.jpg

Here is a small video. Im just cruising easy in video. but i can wot and it runs fine just hits a wall at 4-4500rpm
 

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Row 189 your AFR tanks along with your HPFP pressure. Leading up to that you have some knock in the 5 range from row 178 until you are at 4130 RPM in row 189.

I'd look at bad fuel to start, considering you said this problem comes and goes. Do you have any E-85 near you?
 
Prv failure is what was looking for initially, as it cause weird issues. Didn’t see hpfp drop below 1600 when commanded though.
 
Well earlier it started not going past 3k then sputtered out and wont start now. I hooked it upto a actual good code reader and it says crank sensor and cam sensor. I swapped cam sensor out with one i had from a vc i bought and then only gave me crank sensor codes. When trying to start my injector duty cycle was 0. Also the knock showing up i would assume be from the cutting abd backfiring
 
Backfiring sounds like a new symptom. Maybe get under the car and clean the CPS?
Also, when you replaced all that other shit did you replace the crank sensor? If so, did you fully re-time the sensor when doing so?

Logs don't support this being a fueling issue.

Check all wiring for cuts/rubs/etc, and make sure there aren't a bunch of metal shavings on the crank sensor.
 
Check all engine and body grounds, make sure the connectors are solid, tight and no corrosion, may want to remove the bolts and give it a good cleaning too. Having seemingly unrelated ABS errors plus cam/crank suggests a common ground perhaps going bad?
 
Im going to get a new crank sensor today and try to get it home. I dont have the tdc peg but i heard you can use a coil pack bolt and then tdc and count back 20 teeth. I hope this fixes it or atleast gets it home to dig back into this
 
Dillon davis said:
Im going to get a new crank sensor today and try to get it home. I dont have the tdc peg but i heard you can use a coil pack bolt and then tdc and count back 20 teeth. I hope this fixes it or atleast gets it home to dig back into this
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Doesn't bode well when the kneejerk reaction is to spend more money. Check all the other shit first.
 
Well i have a crank sensor code and it will crank and no start. So i do need a crank sensor im not just buying something i dont need?
Also there was no oem crank sensors local so im going to grab a non oem one to see if it will atleast allow it to fire up. It dine this twice before but unhooked battery seemed to fix it both other times except this time so ill atleast try the sensor if it works ill order a oem if it doesnt work then ill return the mf lol my buddies high end scan tool shiws sensor not wiring but who knows. I know my ap didnt pick up thise codes so thats some bs lol
 
Easter Bunny said:
Crank sensors have a low failure rate on these cars. Usually just dirty
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Hall effect sensors in general have a low failure rate. Nothing really to fail so long as there's no physical damage to the casing or wiring.

Dillon davis said:
Best way to clean it? .. only code it has and cranks with. No start. Injector duty cycle 0 when cranking.
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Just clean it. Make sure there's no iron filings or anything stuck to the portion next to the trigger wheel on the crank pulley.

Paper towels and hot water will be fine for this, don't need anything special.
 
I have had other vehicles where the crank sensor have went bad so i personally know they do go bad. The wiring and plug are all fine looking so i would assume it is the sensor beings thats all the scan tool is picking up
 
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