fuel cuts off at 4000rpm - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

xvr420x · 09-17-2006, 04:28 AM

ok, first time poster here. Just got my 240sx with sr20det for 3000$$ car has fmic, hks blow off, and full exhaust. It also has 5XXcc injectors. The car will not rev past 4000rpm. The guy i bought it from said that the fuel cuts off at 4 grand because of the injectors, and all it needs is some stock ones. he also said i could get an fpr to fix it. i was just wondering if any of you guys have had similar issues. basically just looking for some input.

Thanks.

***S14DB*** · 09-17-2006, 04:37 AM

What MAF does it have? Engine management? SAFC?

Cut off like that is usually a sign of a bad MAF.

cotbu · 09-17-2006, 11:58 AM

The injector thing could be true, Why?How? over fueling then fuel cut...but ask yourself this. Am I running too rich? Then go find the answer. Or replace the injectors with stock ones. Or get something to control them. You still may have other problems but atleast you'll know if it's the injectors or not......maybe.

xvr420x · 09-17-2006, 01:20 PM

Its got the stock MAF, No engine management and it doesnt have an SAFC, but the previous owner said that he had one on it and it ran fine.

***S14DB*** · 09-17-2006, 01:48 PM

I would get some stock injectors and inspect how he removed the SAFC. I'm sure the MAF wires are fubar and the ECU is throwing a code.

datboibrad · 09-17-2006, 02:26 PM

check for rust in your fuel tank as well as the filter. rust + filter = no gas = lack of fuel pressure at wot = 4k break up.

xvr420x · 09-17-2006, 08:49 PM

no rust in tank or filter. i dont think my ecu is throwing a code, the led just stays on when i turn diagnostic screw counterclockwise and so forth. My car smokes kind of alot (black) and when the rpm's drop they go all the way to 500 then back up to 900 or so. Im pretty sure all these are symptoms of being rich, along with the fairly obvious smell it makes. My question is would larger fuel injectors alone cause a situation like this? why does it cut out? an Would a fuel pressure regulator fix it?

any help would be greatly appreciated. Also i will try to contribute to this site as much as possible

uthemofo · 09-18-2006, 01:15 AM

YES its running rich....you cant just throw some 550cc or whatever injectors on it and call it good....you need to ither 1) upgrade to a 300zx tt MAF and send your ecu to JWT and get it tuned OR 2) go buy stock injectors..... drop em in and check it out.....

with bigger injecotrs comes more fule but if ur not supplying enough air (MAF) its pointless....

get soem stock injecotrs and it will run

09-17-2006, 04:28 AM	#1
xvr420x Join Date: Sep 2006 Location: CA Posts: 40 Trader Rating: (0) Feedback Score: 0 reviews	fuel cuts off at 4000rpm ok, first time poster here. Just got my 240sx with sr20det for 3000$$ car has fmic, hks blow off, and full exhaust. It also has 5XXcc injectors. The car will not rev past 4000rpm. The guy i bought it from said that the fuel cuts off at 4 grand because of the injectors, and all it needs is some stock ones. he also said i could get an fpr to fix it. i was just wondering if any of you guys have had similar issues. basically just looking for some input. Thanks.

09-17-2006, 04:37 AM	#2
*S14DB* AFC #1 Join Date: Oct 2003 Location: 昨晩あなたのお母さんの家 Posts: 20,181 Trader Rating: (3) Feedback Score: 3 reviews	What MAF does it have? Engine management? SAFC? Cut off like that is usually a sign of a bad MAF. __________________ Comments should be taken as Opinions not as Statements of Fact

09-17-2006, 01:48 PM	#5
*S14DB* AFC #1 Join Date: Oct 2003 Location: 昨晩あなたのお母さんの家 Posts: 20,181 Trader Rating: (3) Feedback Score: 3 reviews	I would get some stock injectors and inspect how he removed the SAFC. I'm sure the MAF wires are fubar and the ECU is throwing a code. __________________ Comments should be taken as Opinions not as Statements of Fact

09-18-2006, 01:15 AM	#8
uthemofo Zilvia Junkie Join Date: Apr 2006 Location: san jose Posts: 425 Trader Rating: (2) Feedback Score: 2 reviews	YES its running rich....you cant just throw some 550cc or whatever injectors on it and call it good....you need to ither 1) upgrade to a 300zx tt MAF and send your ecu to JWT and get it tuned OR 2) go buy stock injectors..... drop em in and check it out..... with bigger injecotrs comes more fule but if ur not supplying enough air (MAF) its pointless.... get soem stock injecotrs and it will run __________________ My Feedback

09-17-2006, 11:58 AM	#3
cotbu Post Whore! Join Date: Sep 2005 Location: SWFL Age: 50 Posts: 3,318 Trader Rating: (3) Feedback Score: 3 reviews	The injector thing could be true, Why?How? over fueling then fuel cut...but ask yourself this. Am I running too rich? Then go find the answer. Or replace the injectors with stock ones. Or get something to control them. You still may have other problems but atleast you'll know if it's the injectors or not......maybe.

09-17-2006, 01:20 PM	#4
xvr420x Join Date: Sep 2006 Location: CA Posts: 40 Trader Rating: (0) Feedback Score: 0 reviews	Its got the stock MAF, No engine management and it doesnt have an SAFC, but the previous owner said that he had one on it and it ran fine.

09-17-2006, 02:26 PM	#6
datboibrad Zilvia Addict Join Date: Aug 2005 Location: tx Posts: 636 Trader Rating: (1) Feedback Score: 1 reviews	check for rust in your fuel tank as well as the filter. rust + filter = no gas = lack of fuel pressure at wot = 4k break up.

09-17-2006, 08:49 PM	#7
xvr420x Join Date: Sep 2006 Location: CA Posts: 40 Trader Rating: (0) Feedback Score: 0 reviews	no rust in tank or filter. i dont think my ecu is throwing a code, the led just stays on when i turn diagnostic screw counterclockwise and so forth. My car smokes kind of alot (black) and when the rpm's drop they go all the way to 500 then back up to 900 or so. Im pretty sure all these are symptoms of being rich, along with the fairly obvious smell it makes. My question is would larger fuel injectors alone cause a situation like this? why does it cut out? an Would a fuel pressure regulator fix it? any help would be greatly appreciated. Also i will try to contribute to this site as much as possible