S13 KA24DE dumping fuel

[DanDriftS13]

As of right now my car is pretty much dumping fuel into the motor. I am getting horrible gas mileage and when I floor it I can look in the side view mirror and visibly see a black smoke cloud coming from the exhaust of my car. It also does not like to idle properly anymore.

My setup as of right now is an ebay metal intake pipe, s14 ebay header to custom 3inch downpipe back exhaust, walbro fuel pump, and an adjustable fuel pressure regulator.

Now the over fueling problem started when I put in the walbro. Now yes i know that you are going to say well then taht is your problem. Well I'm not too sure of this I am currently waiting on a friend to let me know if he has a good stock fuel pump to test this out but in the mean time I am lookin for other possibilities because of how many other people run walbro on their stock ka's without this problem.

Before the fuel pump change the car wasnt running properly and would not pull smooth through the rpm rang and above 4k rpm the motor would sputter really bad and not rev anymore. I checked codes on the ecu na dit was not reading the knock sensor nor was it getting a good reading from the tps. After changing the knock sensor (i had a brand new one at home already) I found out that the wiring was bad and had to rewire the knock sensor to the ecu. After that I diagnosed the tps and determined that it was bad so I bought a new one and replaced. When I installed the new I got the voltage at idle to be at .54 volts. A little high but still in the proper range (one of my thoughts as to a possible issue). At this point the ecu started reading a good signal from the tps but the problem was still not resolved. Next I checked the fuel pump to see if the pressure was good. To do this I put on my adjustable fpr and upon doing so found out that the pump was bad pushing not even 1lb of pressure.

Once I found the pump was bad I installed a brand new walbro that I had at home already. Upon doing so the car will now rev fine through the whole rpm range and will pull smooth while in gear also. But now the car no longer wants to idle and it is dumping mass amounts of fuel into the motor. To the point that it seems like I am getting close to or even less than 10 mpg. When I first turn the car on when it is warmed up the idle is very eratic bouncing from 500rpm to 1500rpm and sounding like it is going to die and eventually if I dont hit the gas it will stall out. Once the car has been driven for a couple minutes the idle will even out around 1500-1700rpm and sometimes when i clutch in when coming to a stop the motor will just stall out completely. When the motor doesnt stall out when I clutch in it will idle smooth around 1700rpm for about 15-30 seconds and then will drop to around 500rpm and quickly shoot back to 1700rpm or sometime stall out completely. I have also notice a slight misfire around 2500-3000rpm that only happens if I let off the gas a little bit in that range. It almost feels as if the motor has dumped a little too much fuel when I let off and it misfires a couple times because of it. Before all this the check engine light never came and now it randomly comes on but never stays on for more than about 5 seconds at any given time and the ecu shows a code 55 which means no known codes.

Any help is greatly appreciated.
If there is any other info that you may need to help me diagnose the problem let me know and I will be glad to supply the info.

-Daniel

[ericcastro]

ummmm, dont those fuel pump upgrades pump more fuel into the car?.................
Whats the fuel pump upgrade for if you dont want to be shoving mroe fuel into the engine?

[DanDriftS13]

Originally Posted by ericcastro

ummmm, dont those fuel pump upgrades pump more fuel into the car?.................
Whats the fuel pump upgrade for if you dont want to be shoving mroe fuel into the engine?

Well yes more fuel is understandable but this is ridiculous amounts of fuel and my last car never ran this rich or got this bad of gas mileage with pretty much the exact same setup. I am literally getting less than 150miles to a tank of gas and that is from completely full to my gas light coming on.

[orion::S14]

What is your base fuel pressure right now?

Should be 43.5psi with the vacuum disconnected from the FPR...and should drop ~8psi or so with vacuum applied (assuming normal idle, and 20in/hg vacuum).

- Brian

[DanDriftS13]

I'm not sure of the exact psi that it is currently set at but it is lower than 43.5 this I am sure of because I decreased it because of the over fueling issue. I will check tomorrow morning and get back to you on the exact psi and ill also crank it back to 43.5 just to see what happens because I dont think it was ever set exactly there since I put the fpr on.

[oero_ballin16]

hey, did you ever figure out what was wrong? cause i have the same
problem