fuel cuts off at 4000rpm

[xvr420x]

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]

What MAF does it have? Engine management? SAFC?

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

[cotbu]

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]

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]

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]

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]

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]

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