SR hesitation, stumbling, breaking up.. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

DJ_Sunrise · 06-01-2007, 09:44 AM

hey guys.. under full throttle especially in 3rd gear, once my car hits 4500 rpm it starts breaking up and losing power. occasionally in 1st even with partial throttle, it breaks up real bad past 3k rpm. when i shift under full throttle into the next gear the motor hesitates terribly, then takes off again. to start.. here are my mods..
z32 maf
aeromotive fpr
apexi suction kit
apexi power fc
apexi n1 dual
hks w/g actuator
forge unos mbc
blitz fmic
tomei exhaust mani
mr turbo outlet, dp
4ply silicone coupling, tbolt clamps

i changed the o2 sensor and spark plugs(ngk iridiums, HR 7) 1 month ago. fuel filter was changed about 2 months ago.

i thought it might have been a boost leak, so i reinstalled all the couplings and clamps and have them tight as shit now.. everything checks out with the boost. i also had a similar problem when my mafs ground was kinda shitty.. so i redid the ground.. still having the problem.. cleaned the mafs sensor, and plug. the breaking up started a few weeks ago, right after i did the aeromotive fpr kit from enjuku, but i didnt think much of it. at first the pressure was too high causing my car to sound like a lawn mower. after i redid the couplings, vac dropped causing the pressure to lower.. so i raised it back to 45psi. fuel pressure is set around 45psi w/o vac. off of the intake manifold as a vac source, i have the FPR and boost gauge hooked up together. at idle, my vacuum reads .65-.68 bar, and for whatever reason occasionaly dips to .60-.62.

im at a loss here.. to the best of my knowledge everything should be solid. do you guys have any idea of what else i can try??? to test my aeromotive fpr, can i turn the pressure all the way up, hook up my factory fpr, and see what happens?? i dont know what to do =( someone please help...

-Bart

slider2828 · 06-01-2007, 11:07 AM

Swap out coilpacks... Your problem does look like a coilpack issue. Borrow a friend's known good one and swap out one by one. Try ti.

Chrischeezer · 06-01-2007, 11:22 AM

sounds like a MAF problem..
under a load.., anything above 50 % it brakes up? def MAF

*swayray* · 06-01-2007, 01:06 PM

did you tune your power fc yourself? or did you have it tuned by a pro? it soundsl like your fuel starts to be lean at 4500 rpms...

DJ_Sunrise · 06-01-2007, 01:43 PM

yea it was tuned a while back, before i did most of these bolt ons. im going to dentsport on the 16th. i didnt think the mods would cause such an adverse effect.. most of the problems occured coincidentally around the install of the fpr.. although other stuff could have gone bad since then. car ran great before.. maybe the aeromotive fpr is bad? do you guys think i should seperate the vac sources? damn pfc..is there any way to get this thing to spit some codes?? is there any way to test coilpacks? im swapping mafs and coil packs sunday to rule those out..

-Bart

johngriff · 06-01-2007, 01:51 PM

You can test continuity of the coil pack wireing. You can also use a infared thermometer to measure the coil pack temp.

Did you check the base fuel pressure after the install?

slider2828 · 06-01-2007, 02:10 PM

yah pretty much everything above mentioned will call you to the problem. BUt just becareful of blowing your motor if you run too lean.

DJ_Sunrise · 06-01-2007, 03:44 PM

yea i hope the motors not running lean

i can barely afford gasoline at the moment, much less a new motor lol. a technician over at my work was telling me to use a spray bottle.. mist the coilpacks while the motor is running, and see if there are any sparks on the coilpacks.. blaaahhh. can you guys give me any tips as far as the packs go? i was told to put dielectric grease inside the boot.. that and if theres gray powder in side, the spark is arcing. anything else anyone can offer into my motors issues?

you nissan and your distributorless shit!!!!
-Bart

EDIT: yea i checked fuel pressure.. i have it set around 45psi.. my dick head friend reset my power fc map so im back to the old one for a little while now. ive just been increasing inj. 10%... been running fine so far, till this bs popped up

-Bart

nisans13turbo · 06-01-2007, 03:47 PM

check all basic maintance first, ground, wired, plugs , make sure they are all nice and tight and connected. Then go from there.

I almost bought a new clutch, asumming my clutch was slipping and it ended up to be my loose TPS sensor. DUH, but yea doublecheck.

slider2828 · 06-01-2007, 05:56 PM

Wait FPR should not be at 45, it should be around 55psi. Secondly, turn off the boost controller to see if there is stumbling or buckling happening. If there is no buckling when mbc is off, then it is a tuning issue. Thirdly, read the tips off your spark plugs, powdery white = too lean, black/sticky = too rich, and oily means timing is off. You have no one that can lend you a coil pack?

*swayray* · 06-01-2007, 06:36 PM

stock fuel pressure is between 45-49 psi... how much are you boosting?

slider2828 · 06-01-2007, 08:14 PM

18 PSI lol....

johngriff · 06-01-2007, 08:19 PM

What is the Rate of the Aeromotive you got? If its like 2/1 you might have your answer right there.

DJ_Sunrise · 06-04-2007, 04:39 PM

unless enjuku sent me the wrong fpr, it should be 1:1 ratio. i thought stock SR fpr was 38 with vac, 44 without vac??

-Bart

slider2828 · 06-04-2007, 04:44 PM

I do 55 with vacuum.

SILVIA_KIDs14.5 · 06-12-2007, 10:13 AM

Quote:

Originally Posted by DJ_Sunrise

hey guys.. under full throttle especially in 3rd gear, once my car hits 4500 rpm it starts breaking up and losing power. occasionally in 1st even with partial throttle, it breaks up real bad past 3k rpm. when i shift under full throttle into the next gear the motor hesitates terribly, then takes off again. to start.. here are my mods..
z32 maf
aeromotive fpr
apexi suction kit
apexi power fc
apexi n1 dual
hks w/g actuator
forge unos mbc
blitz fmic
tomei exhaust mani
mr turbo outlet, dp
4ply silicone coupling, tbolt clamps

i changed the o2 sensor and spark plugs(ngk iridiums, HR 7) 1 month ago. fuel filter was changed about 2 months ago.

i thought it might have been a boost leak, so i reinstalled all the couplings and clamps and have them tight as shit now.. everything checks out with the boost. i also had a similar problem when my mafs ground was kinda shitty.. so i redid the ground.. still having the problem.. cleaned the mafs sensor, and plug. the breaking up started a few weeks ago, right after i did the aeromotive fpr kit from enjuku, but i didnt think much of it. at first the pressure was too high causing my car to sound like a lawn mower. after i redid the couplings, vac dropped causing the pressure to lower.. so i raised it back to 45psi. fuel pressure is set around 45psi w/o vac. off of the intake manifold as a vac source, i have the FPR and boost gauge hooked up together. at idle, my vacuum reads .65-.68 bar, and for whatever reason occasionaly dips to .60-.62.

im at a loss here.. to the best of my knowledge everything should be solid. do you guys have any idea of what else i can try??? to test my aeromotive fpr, can i turn the pressure all the way up, hook up my factory fpr, and see what happens?? i dont know what to do =( someone please help...

-Bart

check again you got a boost leak had the same thing wit my s14 was gettin like no pwr past 3.5k found the leak now runs like a champ

hope it helps

06-01-2007, 09:44 AM	#1
DJ_Sunrise Zilvia FREAK! Join Date: Feb 2004 Location: NJ Age: 38 Posts: 1,134 Trader Rating: (1) Feedback Score: 1 reviews	SR hesitation, stumbling, breaking up.. hey guys.. under full throttle especially in 3rd gear, once my car hits 4500 rpm it starts breaking up and losing power. occasionally in 1st even with partial throttle, it breaks up real bad past 3k rpm. when i shift under full throttle into the next gear the motor hesitates terribly, then takes off again. to start.. here are my mods.. z32 maf aeromotive fpr apexi suction kit apexi power fc apexi n1 dual hks w/g actuator forge unos mbc blitz fmic tomei exhaust mani mr turbo outlet, dp 4ply silicone coupling, tbolt clamps i changed the o2 sensor and spark plugs(ngk iridiums, HR 7) 1 month ago. fuel filter was changed about 2 months ago. i thought it might have been a boost leak, so i reinstalled all the couplings and clamps and have them tight as shit now.. everything checks out with the boost. i also had a similar problem when my mafs ground was kinda shitty.. so i redid the ground.. still having the problem.. cleaned the mafs sensor, and plug. the breaking up started a few weeks ago, right after i did the aeromotive fpr kit from enjuku, but i didnt think much of it. at first the pressure was too high causing my car to sound like a lawn mower. after i redid the couplings, vac dropped causing the pressure to lower.. so i raised it back to 45psi. fuel pressure is set around 45psi w/o vac. off of the intake manifold as a vac source, i have the FPR and boost gauge hooked up together. at idle, my vacuum reads .65-.68 bar, and for whatever reason occasionaly dips to .60-.62. im at a loss here.. to the best of my knowledge everything should be solid. do you guys have any idea of what else i can try??? to test my aeromotive fpr, can i turn the pressure all the way up, hook up my factory fpr, and see what happens?? i dont know what to do =( someone please help... -Bart

06-01-2007, 11:22 AM	#3
Chrischeezer Zilvia FREAK! Join Date: Jul 2005 Location: earth Age: 41 Posts: 1,406 Trader Rating: (2) Feedback Score: 2 reviews	sounds like a MAF problem.. under a load.., anything above 50 % it brakes up? def MAF __________________

06-01-2007, 01:06 PM	#4
swayray Premium Member Join Date: Aug 2005 Location: torrance Posts: 1,017 Trader Rating: (23) Rides Gallery: swayray Feedback Score: 23 reviews	did you tune your power fc yourself? or did you have it tuned by a pro? it soundsl like your fuel starts to be lean at 4500 rpms... __________________ http://www.thenismoshop.com

06-01-2007, 01:51 PM	#6
johngriff Post Whore! Join Date: Jun 2004 Location: Long Beach, CA Posts: 4,103 Trader Rating: (4) Rides Gallery: johngriff Feedback Score: 4 reviews	You can test continuity of the coil pack wireing. You can also use a infared thermometer to measure the coil pack temp. Did you check the base fuel pressure after the install? __________________ [email protected]

06-01-2007, 03:47 PM	#9
nisans13turbo Zilvia Junkie Join Date: Feb 2005 Location: Minnesota Posts: 485 Trader Rating: (13) Feedback Score: 13 reviews	check all basic maintance first, ground, wired, plugs , make sure they are all nice and tight and connected. Then go from there. I almost bought a new clutch, asumming my clutch was slipping and it ended up to be my loose TPS sensor. DUH, but yea doublecheck. __________________

06-01-2007, 11:07 AM	#2
slider2828 Post Whore! Join Date: Oct 2004 Location: San Francisco, CA Posts: 6,040 Trader Rating: (13) Feedback Score: 13 reviews	Swap out coilpacks... Your problem does look like a coilpack issue. Borrow a friend's known good one and swap out one by one. Try ti.

06-01-2007, 01:43 PM	#5
DJ_Sunrise Zilvia FREAK! Join Date: Feb 2004 Location: NJ Age: 38 Posts: 1,134 Trader Rating: (1) Feedback Score: 1 reviews	yea it was tuned a while back, before i did most of these bolt ons. im going to dentsport on the 16th. i didnt think the mods would cause such an adverse effect.. most of the problems occured coincidentally around the install of the fpr.. although other stuff could have gone bad since then. car ran great before.. maybe the aeromotive fpr is bad? do you guys think i should seperate the vac sources? damn pfc..is there any way to get this thing to spit some codes?? is there any way to test coilpacks? im swapping mafs and coil packs sunday to rule those out.. -Bart

06-01-2007, 02:10 PM	#7
slider2828 Post Whore! Join Date: Oct 2004 Location: San Francisco, CA Posts: 6,040 Trader Rating: (13) Feedback Score: 13 reviews	yah pretty much everything above mentioned will call you to the problem. BUt just becareful of blowing your motor if you run too lean.

06-01-2007, 03:44 PM	#8
DJ_Sunrise Zilvia FREAK! Join Date: Feb 2004 Location: NJ Age: 38 Posts: 1,134 Trader Rating: (1) Feedback Score: 1 reviews	yea i hope the motors not running lean i can barely afford gasoline at the moment, much less a new motor lol. a technician over at my work was telling me to use a spray bottle.. mist the coilpacks while the motor is running, and see if there are any sparks on the coilpacks.. blaaahhh. can you guys give me any tips as far as the packs go? i was told to put dielectric grease inside the boot.. that and if theres gray powder in side, the spark is arcing. anything else anyone can offer into my motors issues? you nissan and your distributorless shit!!!! -Bart EDIT: yea i checked fuel pressure.. i have it set around 45psi.. my dick head friend reset my power fc map so im back to the old one for a little while now. ive just been increasing inj. 10%... been running fine so far, till this bs popped up -Bart

06-01-2007, 05:56 PM	#10
slider2828 Post Whore! Join Date: Oct 2004 Location: San Francisco, CA Posts: 6,040 Trader Rating: (13) Feedback Score: 13 reviews	Wait FPR should not be at 45, it should be around 55psi. Secondly, turn off the boost controller to see if there is stumbling or buckling happening. If there is no buckling when mbc is off, then it is a tuning issue. Thirdly, read the tips off your spark plugs, powdery white = too lean, black/sticky = too rich, and oily means timing is off. You have no one that can lend you a coil pack?

06-01-2007, 06:36 PM	#11
swayray Premium Member Join Date: Aug 2005 Location: torrance Posts: 1,017 Trader Rating: (23) Rides Gallery: swayray Feedback Score: 23 reviews	stock fuel pressure is between 45-49 psi... how much are you boosting? __________________ http://www.thenismoshop.com

06-01-2007, 08:14 PM	#12
slider2828 Post Whore! Join Date: Oct 2004 Location: San Francisco, CA Posts: 6,040 Trader Rating: (13) Feedback Score: 13 reviews	18 PSI lol....

06-01-2007, 08:19 PM	#13
johngriff Post Whore! Join Date: Jun 2004 Location: Long Beach, CA Posts: 4,103 Trader Rating: (4) Rides Gallery: johngriff Feedback Score: 4 reviews	What is the Rate of the Aeromotive you got? If its like 2/1 you might have your answer right there. __________________ [email protected]

06-04-2007, 04:39 PM	#14
DJ_Sunrise Zilvia FREAK! Join Date: Feb 2004 Location: NJ Age: 38 Posts: 1,134 Trader Rating: (1) Feedback Score: 1 reviews	unless enjuku sent me the wrong fpr, it should be 1:1 ratio. i thought stock SR fpr was 38 with vac, 44 without vac?? -Bart

06-04-2007, 04:44 PM	#15
slider2828 Post Whore! Join Date: Oct 2004 Location: San Francisco, CA Posts: 6,040 Trader Rating: (13) Feedback Score: 13 reviews	I do 55 with vacuum.