This is crazy (wd heres a good question for you)

[D1 guy]

Ok if you guys remember, I recently made a post asking why my car is running rich after I replaced my fuel pump and added a greddy type s bov. Well I recirculated the boc right between the maf and the turbo. I adjusted it pretty hard and made sure there are no leaks. It ran great with the new pump for about two minutes of driving. Then it started bogging. Then it died.....I knew it was running way too rich. I decided to try and fix the problem today. I tried a lot of different things. I learned that if I pinch the fuel line right off the fpr then it idles right. I thought it might just be the pump. I put my stock fuel pump back on it and guess what......still rich....undrivable. Its like it was getting more rich. I dont know what went wrong bc it was fine before i put the new pump on. It ran like a champ before the pump and for just a few mins after it was put on. Does anyone have any ideas on this. Im stumped and Ive actually lost sleep over it.

[IvanAtSPRacing]

If your pinching the return line off, then your adding fuel. Your motor is starving for fuel. Its running lean.

[Nismo_Freak]

Try replacing your fouled out plugs.

[D1 guy]

hmmm I also just put iridium plugs in the car. Its not the plugs. If its starving for fuel, why would it act like its flooding? It back fires and everything just like it has too much fuel. My supra did that when it was running rich.

[fiznat]

Can you describe your symptoms a little more? What do you mean it is acting like its flooding? What makes you think its running rich?

[D1 guy]

well, at idle, itll drop way down to about 200rpm then die. If I rev on the car it sputters until about 2500rpm. If Im driving it and go full throttle, it does fine like nothings up then I let off the throttle and it bounces around then dies. I dont know whats up with it

[240SicknessX]

arnt you running a 12:1 fmu? well you said until about 2500rpm it sputters and when your at wot its good. at these times are you in boost? with the postive boost pressure and the fmu, it will start to put more fuel into your engine, 12:1 disc.

what fuel filter are you running?

[Red-KAT]

Yeah you might want to check your FPR... If I lean mine out it will sputter and backfire the same way.

[Structure240sx]

you can idle just fine to about 10:1 afr, but if your around 17:1+ at idle it will run very rough and can die out being that lean. the only real way its going to run very rough at idle from being rich is if you have a leaky injectors and raw fuel is going into the system

[D1 guy]

Im running a 300zx fuel filter. Its not my injectors. I did have them out, but they were working just fine for a long time. Does anybody know why Id be running too lean then?

[AN89HATCH]

When I had my first kat, I had an 8:1, and my car ran way to ritch with that, Most likely the 12:1 is to much, which is causing your car to bogg out.

[Red-KAT]

You need to check your fuel pressure... it could be the FPR going bad.

You said yourself that you pinch the fuel line and it idles fine... all your doing is adding pressure.

I would also get a wideband... I know they cost a bit but it helps when looking for issues... then you can confirm you're rich or lean with a glance. right now its just a guess becuse you have no way to read it.

[hysteria]

yeah i think red and ivan are on to something. when i pinch my lines the idle goes up a bit because the added pressure... i think you're not building enough fuel pressure...have you ever disconnected your mafs and tried to run the car? it will bog stutter and run terrible and everything when you open the throttle because it's running super lean, but at idle (closed throttle) it just kicks up the fuel a bit and runs fine. try disconnecting your mafs to see if it will run at idle. if so then it's a good bet you're not getting enough fuel.

when's the last time you replaced your fuel filter? it could be clogged. your fpr is 1:1 and it could just not be restricting fuel enough (no pressure in lines)... your fmu could be broken also, but i doubt the fmu comes into play because it has trouble idling.

[RMiller]

Did you change your vacuum lines, specifically for the fpr, when you installed the bov?Definitely running lean. Did you wire the fuel pump sufficiently? Maybe the connections are weak.

[D1 guy]

Hey everybody I fixed my problem and everything is working great!! My fuel filter was completely clogged. I put a NEW 300zx fuel filter on it and now it runs great.

[hysteria]

i win

[240SicknessX]

i win

damn, i asked about the fuel filter first, just didnt check the forum earily enough, im glad you resolved your issue.

[D1 guy]

thanks everyone

[AZhitman]

Glad it was something simple.

Damn, you guys are awesome in this forum - Keep up the great (and helpful) work!

[WDRacing]

Definitly the best forum on NICO...Not to mention it has the best looking Moderator on NICO!!