Next step on Check engine light
 

Hey all!

I have need of your collective thougths on the next step on my diagnosis of a check engine light. For those of you who know my previous post, know my motor runs 11:8-1 compression and has the whole PI swap done. My check engine light was constant and still is, but not as frequent. It is giving me P0172/175 System too rich codes. I have replaced the front o2 sensors, vac selenoid, taken off the upper intake plenum and put the stock one back on (both had codes tripped so, I am not sure it was a plenum), my fuel pump is 4 days old a 155lph holley, all gaskets and grommets for the fuel tank have been replaced as well, spark plugs are colder, gap is at .50 due to compression to avoid spark blow out. The car has been dyno tuned previously and tuned with an SCT X2. The plug wires are less than 2 months old and so for the most part everything is new minus the rear o2 sensors.

Anyone have any ideas on what to check next? I have emissions and inspection due no later than the end of march so I have to get the light and code fixed.

Fuel pressure due to the type of motor I run is at 40 psi. I appreciate your help and really hope I can get this fixed.

Thanks,
John:postwhore:

do you have a wideband or access to one? We need to check and see if it's actually running too rich. Do you know your AF ratio at idle/part-throttle/WOT?

I'll see if I can help... or if any of my wrench homies can help.

Also... if you're using SCT software for your tune, can you send me your tune file? I'll check it out and see if there's a problem in there that's obvious. It's probably a tune issue at this point.

Seems like a tune issue as well. With all the work you have done, you must be running rich and you may need nothign more then a dyno tune.

how do I send the tune file, and how do I get to it?

your tuner should have a copy of it. email is best...cburnss at gmail dot crumb

If I can't get him to send it via email, is there a way to pull it off the programmer or have SCT do it?

I was getting rich on bank 1 and 2 turned out to be base fuel pressue was at 50 so I turned it down and it went away. If its only on bank 1 you could switch O2 sensors to see if problem moves to bank 2 make sure to clear codes each time. Also switch 4 injectors from one side of the block to other to see if problem moves to bank 2. Im thinking if it was something that both banks share like FPR or pump he should have code p0175 as well(rich bank2).

I'm not sure... I'll check with the boys on the SCT forums and see.

the fuel pressure thing sounds like a good start. he is getting a p0175 with his p0172

i do have both codes. Po172 and 175. It does show both banks. I only turned down one pound of fuel in my regulator to 39. I don't want to go any lower with it running such high compression.

see... I'd be treating the static fuel delivery with a change to the injector slope... not to fuel pressure. Fuel pressure can be toyed with for certain things but it's not a solution in and of itself. Hell on 99+ you kinda deal with 1 fixed pressure setting and adjust pulse width and high/low injector slope. Do you have the Pro-Racer pak or just a handheld and a custom tune?

A hand held with a custom tune.

Just reread your post so you are having both banks runing rich which like others say may be a tune issue,FPR,pumps or a vac leak. You also want to check your MAF sensor to see if its oily as it may give a false reading if it is.

I think the pump is good since it is only a week old and has less than 100 miles on the new pump. Where are the most common areas for vacuum leaks then? I will see if my tuner will retune the car for me and see what can be done. Problem is there is only one shop I know of in Salt Lake City, UT or anywhere nearby. I am willing to travel within reason and moderate distance to have it professionally tuned again if needed. I am trying to get my tuner to send me the tune via email so I can have it looked at. :postwhore: