HEAVY breakup at 5500 rpms........

[DRIFTINIZ]

car runs strong and idles good....got all the essential upgrades for the sr swap (i.e. walbro pump and 300zx fuel filter).....got the boost up to 10 psi which is conservative...still no where near max w/the factory 370cc injectors and the t25 turbo

boosts all the way until i hit about 5500 in any gear i choose....then the car won't rev any more than that.....lunges forward and i have to let off the gas.....kinda feels like a fuel cut b/c the car bogs big time

done some research......is a bad tps maybe at fault???.......maybe injectors....maf???.....blown turbo????......car still spools and pulls hella like it should LOL

please any help would be appreciated!!!

[S13FASTBACKSR]

hmmm..this could be caused by many different things...it does sound like fuel cut and yes it is possible that it is a bad tps..it could be that at w.o.t. it does not have enough voltage going to it..i dont think your injectors are the problem here nor your turbo..if your boosting fine and the car pulls hard your turbo is not blown...the first thing i would do since there are many things that could be causing the problem is to check the ecu for any codes. also are you running rich at all? i know you probably arent at w.o.t. because if its fuel cut you obviously cant be running rich but are you at idle? let us know..check for codes first and let us know what you get

[Blown240sx]

Maybe even a boost leak that occurs around that rpm but I doubt it. Id say break out the multi meter and check the TPS. Could maybe also be a bad MAF.

[S13FASTBACKSR]

if he's running rich yes possibly bad maf..if hes not running rich then its probably not bad but maybe dirty. driftiniz clean your maf with electronic cleaner and also check the voltage of your maf..12v power (black wire with white stripe) and the white wire should be 5v. other wire which is black is a ground

[DRIFTINIZ]

if he's running rich yes possibly bad maf..if hes not running rich then its probably not bad but maybe dirty. driftiniz clean your maf with electronic cleaner and also check the voltage of your maf..12v power (black wire with white stripe) and the white wire should be 5v. other wire which is black is a ground

i'm assuming i am running a little rich b/c i'm running an open atmosphere bov.......also when the car hits the 5500 the turbo seems to shut off as the acceleration breaks up.....when it does it i get like a whine and no blow off sound....weird

when u say clean the maf....u mean the wiring or actually inside the unit??and to check the voltage i just connect the multimeter to an exposed part of the wiring right??

keep going fellas......i want this thing back up and whooping on honda civics asap......thats all u see here in Ohio LOL

[DRIFTINIZ]

also......i'm scared that whats going on can hurt the motor.........what does the tps look like and where is it located by the throttle body???

thanks

[S13FASTBACKSR]

the tps is under the coldpipe the lever that opens your tb butterfly flap also opens the lever on the tps to raise and lower voltage..it has three wires. maybe 6 if it is an automatic transmission tps but most likely 3. yes clean the inside of the maf you will see the wire in there...its a thermosister and also yes thats how you check voltage. your t25 is probably done and maxed out 5500 rpm but you should still here your bov and thats not why your car is breaking up...do you have a boost gauge? whats it reading at th break up point? check all those things and also check ecu for codes.

[DRIFTINIZ]

i forgot to mention that before i have been able to rev up 2 7000rpm....so this break up at 5500rpm is relatively new

could maybe my manual boost controller be faulty...not being able to hold boost........or maybe my wastegate actuator is going bad??? i installed my new boost controller about 2 weeks ago....n b4 that i never had this issue....maybe w/more boost i fried the maf or the tps???

i will check the ecu for codes....if i'm looking str8 down at the ecu w/the E5 emblem facing upward....on which side is the little red light??

[itsnever2fast]

can you rev over 5500 with no load? ei neutral...

[S13FASTBACKSR]

if your boost controller was loosing effiecency it would not cause a break up in the rpm band it would just not hold boost any higher than its effiecency range. say the boost controller was good for 11psi...the turbo would not be able to exceed that. however i could be wrong so maybe it wouldnt hurt to disconnect the mbc and give it a shot. takes 2 minutes so why not..but i dont think thats it.

also 10 psi would not fry your tps or maf. ive heard of maf's breaking up after certain amount of boost but 10psi would not effect the stock maf. it may be dirty..just check the voltage, clean it, and check tps voltage. also the l.e.d. on the 62 and 63 are on the back..opposite side of the plug..idk if the e5 is the same..just look for it... do all these things and im sure you'll find your problem..let us know

[sr20detmaybe]

do a boost leak test bc i had this same problem exactly and i had a big @ss boost leak right after the turbo.

[DRIFTINIZ]

do a boost leak test bc i had this same problem exactly and i had a big @ss boost leak right after the turbo.

in the actual turbo itself or the vacuum line behind the turbo???.....or do u mean in like the intercooler piping?

[DRIFTINIZ]

bump.......i put new spark plugs in.......NGK BKR6ES11....could that be a reason i'm getting breakup at high rpms??

the old sparks were an 8 heat range...which is kinda cold.....not sure bout that

[DRIFTINIZ]

the spark plugs are the culprit....the new ones work like a charm.....rev freely to about 5800 and burn rubber!!.....

[sr20detmaybe]

should rev higher than 5800 or are u sayin once u hit 5800 the tires break loose? The coupler that connevts my turbo outlet to the 1st hotpipe was ripped along oneside but i couldnt see it.

[ngcharleshk]

car runs strong and idles good....got all the essential upgrades for the sr swap (i.e. walbro pump and 300zx fuel filter).....got the boost up to 10 psi which is conservative...still no where near max w/the factory 370cc injectors and the t25 turbo

boosts all the way until i hit about 5500 in any gear i choose....then the car won't rev any more than that.....lunges forward and i have to let off the gas.....kinda feels like a fuel cut b/c the car bogs big time

done some research......is a bad tps maybe at fault???.......maybe injectors....maf???.....blown turbo????......car still spools and pulls hella like it should LOL

please any help would be appreciated!!!

I have the EXACT same problem, except that my car only bogs at 5500, any rpm lower or higher than that, it runs perfectly fine. It is at a so specific rpm to the point that i wouldnt realize the problem when reving it up on a straight line, however, when I go driving in autocross or the canyon, I need to stay on the throttle holding at a specific RPM through long curves, I then realize the engine jerks in between the range of 5300 and 5700, and I tried to hold the rev at 5300, 5400, 5500, 5600..etc one at a time on the straight line to diagnose the problem, and I realize that the "fuel cut" feeling only happens at 5500. I am positive that it has something to do with the MAF sensor because at 5500, my AEM wideband gauge reads 10.0 A/F ratio, which tells me that i m running very rich compared to other rpm ON BOOST(usually 11.0), therefore, I took out the MAF sensor and cleaned it with MAF cleaner, then I tried it again, the engine doesnt bog anymore on first gear, and it feels much better on second gear too, ofcourse i m refering to at 5500rpm. Inductively thinking, I believe it is a bad MAF, and I m going to get a new MAF sensor for SR20det to see if it will truly solve the problem. Hope this will help, but try to change the MAF sensor assembly, I m pretty sure it is the root of the problem.

[DRIFTINIZ]

OK......sorry my last post was a mis-understanding LOL.........when i said rev to 5800 thats when i shift lol.......my spark plugs fixed my issue....no more breakup at 5500.....i also cleaned the maf

and yes i can rev higher, especially when u most need it in first gear when your tires are breakin' loose

clean your maf......change plugs.........n then if u have this same exact issue hopefully that'll fix it for you!

later on

[ngcharleshk]

Could you gimme the part no. of the spark plugs? What brand are you using? I am using 7 degree NGK plugs, would that be a problem?

[240sxdominos]

lol I am having the exact same problem with my car. It starts cutting out in the 5000 rpm range. Also my car is running rich and idles high on start up, so would these be factors in the malfunctioning of the MAF or are they messing up something else. Also, what would I want to use to clean the MAF? -John

[DRIFTINIZ]

Could you gimme the part no. of the spark plugs? What brand are you using? I am using 7 degree NGK plugs, would that be a problem?

BKR6ES11 for the spark plugs