Long story short, I had my engine completely destroyed by RedZone in Fremont,CA. I had it rebuilt by Tech3 in San Jose, which is a great shop. It's a stock engine right now, only mod is exhaust.

Tech3 did the bottom end and the head work, I was responsible for the fuel inectors/intake manifold.

Symptoms:
OBD2 diagnostics run - monitors set - no CEL - passed smog - leaving the smog station 5 minutes later= P0171 (w/P0170)

Bouncy/high idle when cold - Clean FIACV?

When started hot - the RPM's drop so low when you let off the gas that the engine almost dies, sometimes it does die. I have a Fidanza flywheel...Could be lack of rotating mass.

I'm getting close to 30MPG

What I have tried:
Running 2 tanks of gas through w/injector cleaner
Changed fuel pump
Changed FPR
Changed Fuel filter
Changed O2 sensor


What I think it could be in order:
Clogged/dirty injectors (the injectors sat for a year while I was running 310cc's)
Vacuum leak
Low Fuel pressure (unlikely)

Any ideas or suggestions? I want to check for a vacuum leak, but I can't find one anywhere by ear or starting fluid.
I could potentially borrow my friends injectors.
I was going to find an OBD2 scanner that reads the freeze frame data to get more info.
Sorry if this is already TMI.
Thanks HT

 

a clogged fuel injector will defitnatly throw that code. and ive been seeing this problem more lately.. what happens is u have one or more cloged fuel injectors so one cylinder isnt getting enough or any gas.. and it is just pumping air into the exhaust so then ur o2 sensor starts putting more gas in the other cylinders thinking that will fix the lean condition but the oxygen level will remain pretty constantly high if there is a cloged injector. unplug the injector and use an OHMs meter to check if they are within spec.

 

This makes sense as to why the lean condition, but wouldn't it give a misfire code if a cylinder was not firing? It runs great and gets about 30MPG...

I'm also leaning towards injectors, but I don't know how to flow test them. I might try swapping them out with my friend's injectors this weekend and see who gets the code.

 

long term lean would say that its tried to adjust your fuel trims by adding fuel and it still is lean so its not getting enough fuel i would assume or you have a vacuum leak. Check your fuel pressure at idle than drive it and see if it holds.

Sine youve change injectors you mite have destroyed the orings a way to check that is spray some carb cleaner at ur injector o ring spot and see if the idle fluxuates, if it does you have a vac leak right there.

you can also try unplugging injectors one at a time and see if there is a change, ive been told not to unplug while running because it can fry a injector driver but ive done it b4, that is up to you. Keep us posted

 

Still can't find any vacuum or exhaust leaks. Sonny from Tech3 says there is not one.
I got the freeze frame data. Can anyone help troubleshoot this:

RPM.........................2245
TP...........................15%
Speed.......................30
Load.........................33%
Bank1.......................Closed
IAT...........................117
Long term Fuel Trim...19%
MAP...........................10.34 inHg
Short Term Fuel Trim..22%

I do not know how to interpret the Long Term and Short Term Fuel Trim percentages.
Thanks for all the help!

 

Is it adding the long term and short term trims together? ...and running my injectors at 41% above the ECU's fuel map?

To add to the info, the CEL goes off every couple days, then comes back on again later. It must not be setting the code all the time.
I'm getting very frustrated with this code! The car runs great, WOT or cruising.

 

Check your exhaust manifold gasket. Its not as likely but with a leaking gasket it will trick the system by air getting into the system.

It is tossing a lot of fuel in the system cuz the st ft value against the lg ft but you were also at a slight load I'm assuming accel.

I would prolly start with check the manifold gaskets and doughnuts

 

This was already done. The shop checked and I checked, no exhaust leaks or soot around the manifold. New doughnut.

And I'm starting to think these injectors are from a non-vtec civic and not my original ones... That would explain the high fuel trim and lack of leaks or other problems.

Does anyone know what the impedance on the '00 GSR injectors should be? or how to tell if I have 190cc vs 240cc?

 

 

*** P0171 and P0170 fixed ***
I swapped my injectors with my friends GSR over the last weekend. It's been a tank of gas and 4 days, no CEL.

The fuel trim was +22%. 190cc * 1.22 = 231cc
This led me to believe that I had D16Y7 injectors in there.

 

Glad to hear you fixed it.

 

I'm surprised you passed smog like that!

 

I went as soon as the monitors were set. It threw the code as I was driving away from the smog test. I'm also surprised it passed the sniffer running lean.
Thanks for all the help and advice!

 

im having the same problem with my 98 GS-R...i cant figure it out and it aggrivating me....i did i resistance check on all my injectors and all is in line... as well as a vaccum test, map sensor test, ELD test, and w.e else you can think of....mayb i will just try n replace my injectors to see if it fixes it...

plus my st ft goes all the way up to 46.9% holds for 5 seconds and resets at 0...my long term fuel trim stays rite at 0%