Fuel Cut!!!

Ive been geting fuel cut on my car. i replaced the fuel pump just resently and that didnt help all it did was help it quit runing lean :S ... i have my boost controller turned off and still it fuel cuts... but not as quick. my boost tstill wants to climb to almost 25 psi... it cuts around 18-20 psi... i know they make computers to help override it (because its the computer that causes it to fuel cut... when you hit a sertian amount of boost the computer says to cut feul) but they dont make them for vr4s because as i was told "VR4s are know to be some of the few cars that dont ever fuel cut"... anyone know what to do?... i dount it will help but would increaseing the injector size help? i know they came stock with 450cc but mabey if i jump to a 550cc it might help...?
need feed back plz.

yes they do cut, it is built into the ecu as a factory setting at around 16-17 psi from memory (dont hold me to that figure) but they definately cut. what turbos you running? if they are the std 9b's you are heading for a full engine rebuild if you are boosting that much. you should never boost over 14 psi with the stock injectors and ancilleries. if your boost controller is off and you are still boosting at 25 psi i'd say you have a boost leak somewhere. get it fixed or you will be in for a very expensive rebuild.with the stock settings and your exhaust and intake taken into account, the maximum you should be boosting should be around peak pressure 12-14psi which should fall back and hold to around 9-10psi.

Also the stock injectors are 360cc not 450.

Agreed, if you are boosting anywhere aver 15psi on stock injectors you are asking to screw your car up. You need larger injectors, fuel pump, and A/F controller to handle that, and even then the stock turbos can't produce that much boost.

Upgrade the above mentioned stuff or turn your boost WAY down to where it should be.

are you going by an aftermarket boost gauge or stock

i'm assuming that its a aftermarket, but it seems that you have a boost leak, aftermarket bov do you?

i have all that stuff except injectors. i have a
S-AFC, aftert market boost guage, a walbro 341 fuel pump, and a wideban o2 sensor. And yes i have a HKS BOV. i have no boost leak because i checked very very thoroughly.
i have looked into geting a correctional computer but MVPmotorsports (if anyone happens to know who they are, im good freind with Dusty the owner) told me that vr4s are known not to fuel cut.

And ive also made sure my car isnt running lean and not detinateing... so im not looking into a rebuild im not that dumb...

Stock injectors are 360cc, DSM's have 450cc injectors.

So what are your A/F's when you are running 20psi. You may not be detonating now, but when the weather begins to warm up you can say bye bye to the motor.

also the atr downpipe doesnt get rid of the precats.

And ive also made sure my car isnt running lean and not detinateing... so im not looking into a rebuild im not that dumb...


without being rude or preaching, you ARE running lean, you've got to be at 25psi on stock injectors, and even for some amazing reason you are not lean, all you are doing is blowing hot air through the turbos after 15psi anyway.an AFC device is exactly what you need to stop fuel cut and if you have that fitted, you should not be cutting unless it is set up wrong or you are RUNNING LEAN.

and for all the other forum users who dont know what AFC means it is short for anti, fuel, cut.

as its getting colder now, your boost will actually rise even higher as the cold air is denser than the warmer air in summer time so you have been warned.

i completely agree with tallskinyguy, all might be well at the moment but continual use at 25psi or anything over 14-15psi in fact and its goodnight vienna. it will be just another fantastic machine at the scrap yard and your days of driving a great car will be over.

i gutted the precats... basicully geting rid of them... and im not running 25 psi anymore it cuts around 18 psi. and i do beleive afc means Air/Fuel Controller because that is what it does it controlls how much fuel or air you want into the engine. and a 3000gt is a DSM. DSM means Diamond Star Motor (Hint "Mitsubishi")

Most people on here that I've talked to think the DSMs are just the talon/laser/eclypse because of the exclusive joint venture plymouth eagle and mitsubishi shared for just that car. Nice avitar by the way, gotta love trigun.

Either way, 18 is still too high, you are correct on AFC's meaning, although I think Brian was simply joking about that...and by definition, a 3000gt is definantly not a DSM, go over to the DSM forum, and any true DSM owner will be happy to tell you the same.

Talon, Laser, Eclipses are DSMs, even the latest gen eclipse doesn't qualify as a DSM. Those have 450cc injectors, VR4s have 3600cc injectors...

well ive gone to www.dsmtrader.com and they include Evos, 3000gts, laser, talons, and eclipse...
DSMs meaning is Diamond Star Motor which is representing Mitsubishi, and i think most ppl say its just the eclipse and their counter parts because they are the most common. here in texas there is a club dsm and they hapily excepted me with my 3000gt. so i beleive 3000gts are dsms...

I Dont doubt yall about the injectors but look at it this way ok. Ive been told that they are 450cc. and when i look for bigger injectors every where i go they start with 550cc for the 3000gt ive never found anyone selling 450cc injectors for a 3000gt... nor have a found 360cc. so i thought well mabey seince they atock thats why that dont sell them... but if i was to go larger it would be the next step so i would want to go 450cc not 550cc...

Ohh well, maybe things are just bigger in Texas ;).

heh... no things just get hotter here... errr lol. plus its not just texas im talking about websites like dynamicraceing.com which i think are located in florida. oh well.

you said you have a wideband o2 sensor, i was wondering what your air/fuel ratio is at whatever psi you are running. No one sells 450cc injectors because they are soo easy to get for dirt cheep from a DSM. (when I say DSM I mean the cars built in normal,IL).

about 14.7 perfectly stoich (or however you spell that)

when WOT you sould be around 12:1, not 14.7:1. You only want 14.7 when crusing, that is considered very lean when in boost.

well ive gone to www.dsmtrader.com and they include Evos, 3000gts, laser, talons, and eclipse...
DSMs meaning is Diamond Star Motor which is representing Mitsubishi, and i think most ppl say its just the eclipse and their counter parts because they are the most common. here in texas there is a club dsm and they hapily excepted me with my 3000gt. so i beleive 3000gts are dsms...


diamond star motors is a cross between mitsubishi and chrysler, which has nothing to do with the 3000GT. DSMs are cars that were made at the DSM plant in ohio (i believe) which include the 1g and 2g eclipse, talon, and laser. 3000GT's were made in japan, not in ohio. This is a common misconception. A lot of 3/S people do hang out with the DSM people and get DSM discounts, but we are not DSM cars, and if i'm not mistaken, neither are evos or galant vr-4s

galants are but evo's and 3000gt's are not.

so whats the feeling your getting when you run into this fuel cut or whatever? is it a hesitation?

the plant was in normal,il galants technicaly arent, but since they were out the same time with the same drivetrain they are often included, which is the same reason the EVO is often included.