Hey guys. So I have a 00 si im trying to get passed for smog. I swapped out my p28 for the stock p2t and now I've been throwing a p170 and p172 cel ( fuel trim malfunction and running to rich). As far as the fuel setup is concerned I'm running a walbro 255, golden eagle fuel rail, 310 injectors (swapped them out for the stock 240cc) and I even swapped in the stock fpr. My fuel pressure gauge is still reading 40-45. Any ideas of why I'm still throwing codes?!

 

Stop a block away from where you get tested and clear the codes

 

^^yeah I have an obd2 diagnostic reader that can clear codes. you can buy the scanner or find people to do the scanning for you. i charge 10 bucks to whoever wants it done. sorry, but i'm a little far from you.

 

I know testing systems may vary in other places but in CT. clearing the codes just before going to the test would not work, even your OBD2 scanner will only go from red to yellow and tell you that you still are not emissions ready. Before it will give you a green you have to put x miles on the car and let it do all its processes.

 

Yep just leading the codes throws it back into test mode for another 50-70 miles.

So i'm getting pretty sick of this CEL 45. In addition to putting the fuel system and intake side back to stock I've changed out the spark plugs and changed out the primary o2 sensor and bought another p2t ecu just to make sure that wasn't the problem. I'm pretty stumped at this point to what could actually be throwing the code. Any help would be greatly appreciated

 

Why has nobody pointed out he has 310CC injectors when they are 240CC stock. Your computer is tripping the code because it's sees it's getting more fuel than it's supposed to. So put the stock injectors in, clear the codes, and drive. I can bet you no more CEL.

Did you put the stock injectors back on? If you did, the HV walbro could be adding that extra fuel. If thats the case, which I wouldn't think so, then use your adjustable regulator to turn the fuel pressure down.

 

I put the stock fuel injectors, fuel rail and fpr back on but still getting the code.

 

 

Well before I changed everything back to stock I had a golden eagle fuel rail with a fuel pressure gauge. It was reading the stock fuel pressure

 

Up for the night.. Still have damn cel 45

 

The only two things I've read that will fix it are either a new O2 sensor, or turn the pressure DOWN since the extra fuel volume will add more fuel anyway.
EX: 40-45 psi with factory pump is equal to 30-40 with the high flow pump.... See what i'm saying?

 

I might try and throw another FPR on there and try to turn it down since mine broke. But the primary o2 is brand new but i never changed the secondary

 

The secondary O2 is purely there to detect if the cat is working. It does not control A/F ratio as the per the first one does.

 

Alright guys im fed up with dealing with this CEL 45 code..i've been messing with it for atleast the last few months on the weekends. Heres how my car was setup for the longest time before I needed to pass smog..

2000 Si
B16a2
dc sports intake
skunk2 throttle body
edelbrock intake manifold
dc sports header
greddy evo 2 catback
walbro 255 fuel pump
golden eagle fuel rail
some aftermarket fpr
310cc rc injectors
p28 ecu
and i think thats it.

Ever since i've plugged in the stock p2t ecu i've been throwing this code.

So far i've swapped out everything except the exhaust and intake with its stock counterparts and i'm still throwing this code.

It seems myself and everyone i've talked to has been pretty stumped about it as well. In addition i've also swapped out both 02 sensors.

any ideas?! it would be greatly appreciated!

 

also, after I drive the 50 miles or so to get the ecu out of test mode the code seems to be popping up on shortly after the next start up in low rpms/low speeds

 

bump

 

bumpity bump bump

 

did u ever turn down the fuel pump regulator?

 

you mean fuel pressure regulator?

 

Given you need to check to see what your fuel pressure is, but did you change the fuel pump and all fuel related items back to stock?

OH and the 2nd O2 does control Fuel Trim, given it needs to for cat efficiency.

 

yes all fuel items are back to stock. and both 02 sensors have been replaced.

it seems to run hard besides a little bit of a rough idle sometimes. the only other thing i can think of is that maybe one of the injectors is sticking or dirty. im just gonna clean them tomorrow and see what happens.

 

Do you have access to see the data stream from the ECU? Or a volt meter to read what the Primary O2 is doing?

I am going to guess your rough idle is part your issue.

 

no access to see data stream from the ecu

and i have access to a volt meter seeing as im an electrical tech

 

Ok so go put your Volt meter on the signal wire for the primary O2 sensor. Set it to DC volts and see what the numbers are. Should fluctuate from .1 to .9 volts if its good. My guess its going to be stuck on .7 or higher all the time. Disconnect 1 injector to see if it drops to .1v

 

so if it does all that then its good?