Ok guys a have searched a lot about this lately but everything I do doesn't seem to fix it.

I keep throwing a code P0170 and P0171 system too lean and fuel trim malfunction.


here's my deal.

97 accord lx f22b2 w/ 169,000 miles w/ custom t25 turbo setup
My car has been boosted for 20k miles and I do this every year come emissions time.

I take out my DSM 450 injectors and my p06 ecu out in favor of my stock 0bd2 injectors and ECU. also hook back up my EGR ****. (take off the block off plate and put the solenoids etc back in) and hooked my evap stuff back up, and disconnect my wastegate flapper.

I have been trying to pass emissions for the last two weeks. I keep fixing things and resetting my ecu.


this is what I have replaced so far
new dizzy cap and rotor
pulled the EGR service plate off and cleaned all the ports (they weren't clogged at all)
cleaned out the EGR valve.
cleaned my IACV and all of the IACV passages on the intake manifold.
got a new bosch primary 02 sensor.
since i dont run a cat I use the spark plug no fouler trick and works great, i haven't thrown a catalyst code.

I keep going back and it takes forever to be ready to test, (longer than in the past)
then it keeps throwing that same code.

I also feel a little quiver or hesitation during acceleration.


I think it may be a bad injector or clogged one so I ran some lucas fuel injector cleaner in the tank yesterday...still awaiting the results if that fixes it.

the only thing left i can think of is swapping the stock injectors w/ another set I have in the garage.


anyone else have any ideas?

 

damn i guess clear corner lights, body kits, cold air intakes, and people have know nothing about cars have priority over my post which is actually somewhat serious and technical.

 

I really don't know, but did you clear out the codes after you changed the parts?

 

yes i cleared the codes. then it takes forever for the car to be ready again because of the drive cycles, then it throws a CEL. same code every time.

 

ok damnit this **** is pissing me off. I swapped the injectors with another set of stock ones i had in the garage, i really can't feel the hesitation anymore. but tonight after a few drive cycles over the last few days the CEL came back on...damnit

does anyone know what might be causing this problem.

these are my fuel mods
walbro 255lph fuel pump
AEM Fuel pressure regulator
(stock injectors right now) I normally run DSM 450cc's

 

how have you moded the car for the 450cc injectors? just the other ECU chipped to run a different map? you don't have any kind of seperate fuel managment?

The only thing I can think of that would cause it to go lean or think it's going lean is the ECU, injectors, o2 sensors, possibly injector error (?) it's really hard to tell without hooking up a wideband, or monitoring your o2 narrowband with an o-scope.

have you tried another ECU?

 

^ chipped p06 ecu with most likely uberdata or crome.

 

sorry to hijack your thread but I keep throwing the same code in my accord 98 2.3L....I have been searching and I seem to find that its the fuel pressure regulator??

 

I did test my fuel pressure regulator vacum line last week and I did have a pinhole leak in it. however that was fixed two CEL's ago.

one thing I wasnt sure about tho, when i put a vacum pump on my fuel pressure regulator, is it suppose to drop vacum a little bit? or should it be holding vacum?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by raceACCORDingly &raquo;</TD></TR><TR><TD CLASS="quote">^ chipped p06 ecu with most likely uberdata or crome.</TD></TR></TABLE>

yep thats right, but i dont think the 450's are the problem since I'm not running them in the car right now, Im running stock injectors and my stock obd2 ecu. i guess I could test my fuel pressure since I haven't done that yet.

better not be a bad fuel pressure regulator, my AEM cost me like $140. I really dont want to have to buy another.

 

i dont know if aem has fixed this or not but back in my nitrous spraying days the aem fpr's were known to fail easily cuz of the diaphram breaking.

when you pull the vac off the fpr is there any fuel?
also do you have a fuel pressure guage? if you do check your fuel pressure with the car on, pull the vac and see if fuel pressure rises.

 

well i bought a fuel pressure guage today to test it but the brass adapter fitting I used stripped out so i'm gonna need to get another fitting.

i also replaced my fuel filter today....man that thing is a pain in the ***. I wanna know who's idea it was to put it there so I can slap them.

 

alright guys I replaced my fuel filter...threw the code again...

I changed out my FPR with my stock one today...we'll see how that works.


I was reading through my helms manual and it said the EVAP system could cause the code. It also said to check the valve clearance.

 

Well i'm officially stumped...


I changed out my FPR with my stock one which should richen up the mixture a little bit due the fact im running a walbro 255lph pump..


tonight I threw the system too lean code again.

 

Ok..so to sum it up...

here's what I have done so far
replaced 02 sensor
Replaced injectors
replaced fuel filter
new dizzy cap and rotor
ran lucas fuel injector cleaner thru a tank
ran 1/2 bottle seafoam thru IM and 1/2 thru the tank
cleaned out the Idle air control valve
swapped AEM FPR out and put my stock one back in
cleaned out the EGR valve and all the EGR ports.

I'm about to just pay somebody off to pass me, its just so hard to find people around here that will do it on OBD2 cars.

Im so paranoid driving around with an expired tag.

 

What's happening is your engine computer is not able to compensate for an extremely rich condition or lean. Basically it's maxed the limits on fuel trim for whatever problem you have. I would start with an intake leak (vacuum leak) somewhere on your engine because that will also cause the slight hesitation your talking about

ETA: check the vacuum line that goes to the FPR and EGR


Modified by JDM_DC4_Fanatic at 12:05 PM 3/4/2007

 

I have already checked and double checked for vacum leaks on my lines.