SR20-DET Breaks up at 5k rpm - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

crashedintowall · 11-18-2020, 09:12 AM

Hey guys,

I recently imported a s14 Silvia from Japan. The motor keeps breaking up at about 5k rpm. If you give it a little gas and just slowly raise the rpm in neutral it doesn't break up. I just did spark plugs and that didn't help. Any Ideas on what it could be?

S14rebuild · 11-18-2020, 09:20 AM

Check fuel pressure at 5k rpm, check for boost leaks.... ckil.pack condition and voltage

*2_Liter_Turbo* · 11-18-2020, 09:28 AM

What gap did you set the plugs to? Definitely check for boost leaks and fuel pressure as mentioned above. It sounds like you're either blowing out spark or getting a boost leak under full boost (typically a hole in a coupler or loose coupler clamps).

crashedintowall · 11-18-2020, 09:42 AM

Spark gap was set to .030 the coil packs look to be in good condition but I'll check them with a voltage meter. I'll check for anything obvious for boost leak and try and find someone with boost leak smoke machine. Thanks!

S14rebuild · 11-18-2020, 12:53 PM

Quote:

Originally Posted by crashedintowall

Spark gap was set to .030 the coil packs look to be in good condition but I'll check them with a voltage meter. I'll check for anything obvious for boost leak and try and find someone with boost leak smoke machine. Thanks!

Meant battery voltage at 5k rpm

U can make a diy boost leak tester check out utube for that... coupler, pvc, air fittings and compressor... soapy water. Done

LtSlayer · 11-19-2020, 10:20 PM

make sure your tps is set correctly. My buddy had an s14 or s15 sr that had other problems but one of em was that it would bog at ~3k then boost to 5ish but hang out around there. I knew this wasn't right since my7 s13 revs to over 7k. I cracked an arm but it happens lol. Look up a guide on the tps setting. It's something simple that's often overlooked. I know we did. Good luck.

Slideurmom · 11-24-2020, 09:17 AM

Check the timing chain , I had a similar issue with my vct sr. I was off a tooth and boom fixed

*!Zar!* · 11-26-2020, 11:54 AM

Have you changed the fuel filter?

Check the spark plug condition & gap?

Is your maf clean? Try a different maf.

crashedintowall · 11-30-2020, 08:51 AM

I just changed the spark plugs, fuel filter and put a new maf in. I still need to check for boost leaks and check fuel pressure at 5k rpm.

240boosted · 05-29-2021, 09:00 PM

Def check plugs and look for boost leaks mine had same issue

11-18-2020, 09:12 AM	#1
crashedintowall Join Date: Nov 2020 Location: Boise Idaho Posts: 3 Trader Rating: (0) Feedback Score: 0 reviews	SR20-DET Breaks up at 5k rpm Hey guys, I recently imported a s14 Silvia from Japan. The motor keeps breaking up at about 5k rpm. If you give it a little gas and just slowly raise the rpm in neutral it doesn't break up. I just did spark plugs and that didn't help. Any Ideas on what it could be?

11-18-2020, 09:28 AM	#3
2_Liter_Turbo Premium Member Join Date: Mar 2005 Location: Arizona Age: 37 Posts: 798 Trader Rating: (28) Feedback Score: 28 reviews	What gap did you set the plugs to? Definitely check for boost leaks and fuel pressure as mentioned above. It sounds like you're either blowing out spark or getting a boost leak under full boost (typically a hole in a coupler or loose coupler clamps). __________________ 96 S14: Grip Track Car 90 R32: Bucket List Car 92 S13: Just for Fun Car Instagram: @SS.Maxey

11-26-2020, 11:54 AM	#8
!Zar! Premium Member Join Date: Nov 2004 Location: North Korea Posts: 14,576 Trader Rating: (27) Feedback Score: 27 reviews	Have you changed the fuel filter? Check the spark plug condition & gap? Is your maf clean? Try a different maf. __________________

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11-18-2020, 09:20 AM	#2
S14rebuild BANNED Join Date: May 2019 Location: Florida-FAIL Posts: 2,497 Trader Rating: (8) Feedback Score: 8 reviews	Check fuel pressure at 5k rpm, check for boost leaks.... ckil.pack condition and voltage

11-18-2020, 09:42 AM	#4
crashedintowall Join Date: Nov 2020 Location: Boise Idaho Posts: 3 Trader Rating: (0) Feedback Score: 0 reviews	Spark gap was set to .030 the coil packs look to be in good condition but I'll check them with a voltage meter. I'll check for anything obvious for boost leak and try and find someone with boost leak smoke machine. Thanks!

11-19-2020, 10:20 PM	#6
LtSlayer Leaky Injector Join Date: Jul 2020 Location: Norco Posts: 68 Trader Rating: (0) Feedback Score: 0 reviews	make sure your tps is set correctly. My buddy had an s14 or s15 sr that had other problems but one of em was that it would bog at ~3k then boost to 5ish but hang out around there. I knew this wasn't right since my7 s13 revs to over 7k. I cracked an arm but it happens lol. Look up a guide on the tps setting. It's something simple that's often overlooked. I know we did. Good luck.

11-24-2020, 09:17 AM	#7
Slideurmom Leaky Injector Join Date: Sep 2009 Location: Dumblando, Fl Posts: 89 Trader Rating: (0) Feedback Score: 0 reviews	Check the timing chain , I had a similar issue with my vct sr. I was off a tooth and boom fixed

11-30-2020, 08:51 AM	#9
crashedintowall Join Date: Nov 2020 Location: Boise Idaho Posts: 3 Trader Rating: (0) Feedback Score: 0 reviews	I just changed the spark plugs, fuel filter and put a new maf in. I still need to check for boost leaks and check fuel pressure at 5k rpm.

05-29-2021, 09:00 PM	#10
240boosted Leaky Injector Join Date: Nov 2010 Location: NYC Age: 31 Posts: 146 Trader Rating: (2) Feedback Score: 2 reviews	Def check plugs and look for boost leaks mine had same issue