rb25det falls on face around 3500rpms - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

ls14-panthers64 · 10-02-2012, 06:53 PM

Ok so im stumped on this one guys i have tried everything i can think of so now i come to yall for help. so my rb will run and hold a steady idle but when i rev it up it gets to around 3500 rpms(assuming my tach is reading correctly) and it just completely cuts out and will not rev higher, but will not die, the idle will just drop down to 300 or so then will bump back up around 700 or so and will maintain there.
i have boost leak tested my system and have sealed all the leaks i found. i have my timing set to 15 degrees btdc which is stock timing. all my spark plugs are new and are properly gapped. after all this i figured i would try unplugging my MAFS and it ran the same way plugged in or unplugged so i replaced my MAFS and still i have the same problem. the only thing left i could think to check would be the TPS which i will check later tonight when i get my multimeter back. also at idle my boost/vacuum gauge is reading ten pounds of vacuum and when i do rev it up untill it cuts out my gauge will read at 0 and not go into boost. i am also not throwing any ecu codes.
any help,advice, or input will be greatly appreciated as i am at a stand still

bkt808 · 10-03-2012, 04:05 AM

check TPS should be .4 - .5 volts throttle closed, also check MAFS voltage should be around .4ish volts ignition on engine off and according to fsm 1.1v during cranking but mine reads higher during cranking so i guess if its a little higher it should be ok, also check to make sure your getting MAFS voltage at the ecu

Sileighty_85 · 10-03-2012, 04:14 AM

are you using the correct MAFS?

ls14-panthers64 · 10-03-2012, 05:27 PM

yea im using the right MAFS and ive tried 3 now. i manually checked the ecu for codes last night and i am throwing a code for the MAFS i checked the conditon of all the wiring everything looked good and is correctly wired. i am going to check the mafs voltage later and see

10-02-2012, 06:53 PM	#1
ls14-panthers64 Join Date: Nov 2011 Location: memphis Posts: 29 Trader Rating: (1) Feedback Score: 1 reviews	rb25det falls on face around 3500rpms Ok so im stumped on this one guys i have tried everything i can think of so now i come to yall for help. so my rb will run and hold a steady idle but when i rev it up it gets to around 3500 rpms(assuming my tach is reading correctly) and it just completely cuts out and will not rev higher, but will not die, the idle will just drop down to 300 or so then will bump back up around 700 or so and will maintain there. i have boost leak tested my system and have sealed all the leaks i found. i have my timing set to 15 degrees btdc which is stock timing. all my spark plugs are new and are properly gapped. after all this i figured i would try unplugging my MAFS and it ran the same way plugged in or unplugged so i replaced my MAFS and still i have the same problem. the only thing left i could think to check would be the TPS which i will check later tonight when i get my multimeter back. also at idle my boost/vacuum gauge is reading ten pounds of vacuum and when i do rev it up untill it cuts out my gauge will read at 0 and not go into boost. i am also not throwing any ecu codes. any help,advice, or input will be greatly appreciated as i am at a stand still

10-03-2012, 04:14 AM	#3
Sileighty_85 Post Whore! Join Date: Dec 2006 Location: Misawa, Japan Posts: 6,815 Trader Rating: (8) Feedback Score: 8 reviews	are you using the correct MAFS? __________________ 後輪駆動車１番 1989 Built SR GT2871R -363whp 1998 S14 W/RB25- 250ish (For Now) 1986 SR86 - 200ish 1990 R32 GTR - 320hp Don't Buy Engines from JDM-Online http://zilvia.net/f/businesses/207457-jdm-online.html Don't Buy XS-Power or SSAC Shit

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

10-03-2012, 04:05 AM	#2
bkt808 Zilvia Member Join Date: Feb 2010 Location: Wailuku, Maui, Hawaii Age: 33 Posts: 245 Trader Rating: (1) Feedback Score: 1 reviews	check TPS should be .4 - .5 volts throttle closed, also check MAFS voltage should be around .4ish volts ignition on engine off and according to fsm 1.1v during cranking but mine reads higher during cranking so i guess if its a little higher it should be ok, also check to make sure your getting MAFS voltage at the ecu

10-03-2012, 05:27 PM	#4
ls14-panthers64 Join Date: Nov 2011 Location: memphis Posts: 29 Trader Rating: (1) Feedback Score: 1 reviews	yea im using the right MAFS and ive tried 3 now. i manually checked the ecu for codes last night and i am throwing a code for the MAFS i checked the conditon of all the wiring everything looked good and is correctly wired. i am going to check the mafs voltage later and see