18g plenty fuel, car cuts off....hmmm

[tharussian45]

ok, i got an 18g, got 550cc's, afc, walbro 255, fp cams-like hks 272's. and when the boost goes above 20lbs, the car cuts off, alsmot like a misfire, but then keeps going... im pretty sure its not fuel cut since i have plenty of it...maybe ecu? if anyone has any input on what it might be feel free to write. thanks guys.

 

[GSX93DSM]

Maybe it is fuel cut cause you could be not getting enough fuel for the 18g. If your running over 20psi on 550s with an 18g. The turbo could be wanting more. The fuel pump is fine also with no way of tuning with that much boost could cause problems. I would suggest turning down the boost get a fpr and fine a way of tuning the car before running such high boost.

 

[JayRolla]

Fuel has nothing to do with FUEL CUT. It cuts the fuel because the maf gets overrun from to much boost and it cant read the air so the ECU cuts fuel to save the motor. The 2g maf should beable to handle way more than 20psi before fuel cut. One of the largest reasons for having fuel cut at only 20psi in a 2g maf is a boost leak. Fix all boost leaks and see if that fix's it.

 

[No_Skillz]

... the car cuts off, alsmot like a misfire, but then keeps going...

Although I have never experienced what misfire feels like, this seesm to describe fuel cut quite well. You're not doing any favors to your motor while running like this. Do what Jay suggested and also get an AFPR for that pump.

 

[JayRolla]

Dont tell me you are running that much boost without any way to control fuel. You are going to destroy your motor. You need to get a logger and Fuel management to control the injectors. You should take them out and run 14psi max with out EMS.

 

[tharussian45]

well, i had a shop tune it out for me using a wideband, and they tuned it to around 19psi, but when i downshift and get on it, it spikes up to a little past 20. like 21. i had the motor rebuilt, and got arp headstuds with a new gasket, and its a good gasket, not one of those cheap autoparts gaskets. also, i notice that when i am running that much boost that i still run rich as hell. i foul plugs like every week. bpr7es's. but my friends talon did the same thing i think, it cuts for a second, but then keeps going and makes power still. so i dont know where to start. run very rich. im also in illinois, and its like 50 degrees here.

 

[GVR4592]

Turn the boost down to stock levels until you get a datalogger, running that much boost with a shitty tune is just asking for trouble.

 

[No_Skillz]

You're fouling plugs because you are over running your stock FPR.

 

[JayRolla]

Ok, like I said you may have a boost leak. Do a boost leak test first and I bet you money you have a few leaks. Also with that huge pump and no Aftermarket Fuel regulator you are over running the stocker. So at WOT your ok but when you are cruising you are dumping fuel in the cylinders causing you to foul plugs.

 

[spyderturbo007]

well, i had a shop tune it out for me using a wideband, and they tuned it to around 19psi,

I'm still trying to figure out how someone tuned your car when you don't have a SAFC, ECU+, DSMLink, etc.

I would want my money back.

 

[perley03]

ok, i got an 18g, got 550cc's, afc, walbro 255, fp cams-like hks 272's. and when the boost goes above 20lbs, the car cuts off, alsmot like a misfire, but then keeps going... im pretty sure its not fuel cut since i have plenty of it...maybe ecu? if anyone has any input on what it might be feel free to write. thanks guys.

Says right there he has an AFC. You are running out of fuel on those 550's. You need more on the lines of 750's to handle that turbo and the amount of boost you are seeing. Get a logger and find out what your duty cycle is on those 550's. I bet you are seein 100% or even more. Also go buy an AFPR, you are overrunning your stock FPR with that 255lph pump, and thats why you are fouling plugs.

 

[JayRolla]

You can run 20psi on an 18g pretty well with 550's. The 18g does not push much more air than an evo16g. He may be getting close but he should beable to get a good tune.

Also about the SAFC he must have added it because it was not in his list unless we all where really blind.

 

[tharussian45]

it was there when i first posted it. i said afc, should say SAFC. sorry about that. well, i looked at the SAFC and the fuel is turned down alot. i'm not sure how this is working then. i ran my car tonight and it was like 35 degrees here. the boost was steady at 18 lbs. and there were no problems of it sputtering like before. then when i was in 4th gear, i downshifted to third and gunned it, the boost spiked up past 20 and the car jerked a little, then the boost dropped down and it ran fine. so the fouling plugs is due to the FPR. is it bad to run super rich? i know there wont be any detonation or knock, but is there any side effects to running rich?

 

[spyderturbo007]

Also about the SAFC he must have added it because it was not in his list unless we all where really blind.

Apparently it's just you and I that are blind.

perley03, how do you know that he is running out of fuel?? I'm just courious since I didn't see any airflow numbers.

 

[mavisky]

550's at 20psi will do just fine for an 18g. I've got the base pressure dropped on my 650's and it still comfortably runs 20psi.

Is the cutout hard or just a little stutter? Mine stutters above 20psi but I think I've got a coilpack going out on me that's causing it. I'd pull the plugs and take a look at them.

 

[me612]

First thing I'd check is plugs as well. Ensure they aren't fouled(hell I'd put in brand new ones since they really aren't that expensive), and ensure the gap is correct. Easy check that shouldn't take much more then 15 minutes.

 

[tharussian45]

ya, i am fouling plugs. i need to get some new ones. its just a little shutter, and then when it drops below 20lbs, its fine. i talked to my mechanic and he told me it was because of the bigger cams. also, im an idiot. i thought that when the SAFC was in the negative, it turned down the fuel, well its not, it means that its pulling fuel. so sorry for that confusion earlier.

 

[auto2wd]

550's at 20psi will do just fine for an 18g. I've got the base pressure dropped on my 650's and it still comfortably runs 20psi.

Is the cutout hard or just a little stutter? Mine stutters above 20psi but I think I've got a coilpack going out on me that's causing it. I'd pull the plugs and take a look at them.

To you, make sure you check your power transistor module or w/e its called, i spent a week or so diagnosing that same problem, it wasn't a coil pack, or crank angle sensor or anything, was the power transistor module that had gone bad.

And for the OP, if you have no way of telling what your A/F is then you are going to be in this forum with people shooting suggestions off into the night and you'll go through a huge headache. I'd get a logger, or even better, in my honest opinion i would get a DSMlink and save yourself some time.

 

[mavisky]

Yea, i'm going to be testing that first now as I can't find that spare coil pack I used to have.