runing lean bank 2 after cpu replacement

[Raginstang]

okay, so when I was hiding my wires in the fender awhile ago I accidently shorted out the cpu, so I recently installed a new one, now the car runs pretty bad, I pulled the codes and I got code 91 system lean bank 2, no exhaust gas oxygen switching. since I just replaced the o2 sensors I don't see why that would be, I have a/f ratio guages and they are showing lean on bank 2, but I was also thinking, that if the o2 wasn't switching wouln't that only hurt performance once the car is warm, and the car is monitoring them, right now it is running bad all the time even cold. ?

here are the symptoms, the car does not hesitate or anything, just feels like its not all there. doesn't have the same audible tone it use too. feels like im a cylinder down, revs slow,

heres what ive done too check
set fuel pressure to 40psi, set tps voltatge to .98, checked for vacuum leaks, re-dropped the distrubutor, pulled spark plugs, checked for spark at all plugs, just installed 2 new O2 sensors yesterday.

any suggestions?
I am really getting frustrated because it seems like all is working right, but im missing a cylinder or somethin, and I have recently done a compression check and they were all around 190 psi.

 

[wht93gtEd]

I don't mean to insult your intelligence, but do you have the plug wires correct.

My buddy, who shall remain nameless, was having a problem with his car "not feeling all there" and he couldn't figure it out. It didn't really sound like it was missing either, but when we checked it out...the plug wires were on wrong.

 

[Raginstang]

ha ha, you aren't insutling me, all the help is needed, and sometimes the easies things are the ones overlooked, unfortunatley, I have already checked them and they are all in the correct firing order but thanks for the reply

 

[bobbys9350]

I think i really know the problem! Take the cover off the MAF and clean the two little wires, then reset the ECU. You Caqnt have ANY SPEC OF DIRT OR CARBON!!!! If it isnt our wires, i REALLY think this is your problem

 

[Raginstang]

well, I tried cleaning the maf and it didn't change it. still not reading the drivers side o2 very well or something, it always stays in the lean, and my pass side is workin fine. ?

 

[Raginstang]

well, I think I found the problem, I was using my stethoscope to listen to the injectors to see if they were firing, "clicking on and off," and they all were except the #5 cylinder. which is the driver side front cylinder, which is also bank 2, which too me seems like that would cause a lean condition. bummer though, fairly new injectors, I wonder if summit could help me out with replacing the one or if Im just screwed and have to buy a new set?

 

[h8louzn]

Swap the injector with another one and see if it is the injector or wiring.
Just a thought before you buy another set.

 

[Daggar]

Before pulling it all apart... Do a search for "Cylinder Balance Test". jrichker has a checklist proceedure for running that test. If you've got a bad injector, it will you tell you.

Edit: BTW... if you do identify a bad injector, you can replace just THAT injector. You don't need a whole new set.

 

[Raginstang]

yah, but I have ford racing 24lb injectors, not stock ones, I don't think I can buy just one from them, or summit where I got em

 

[cooter_11]

You definetly had the right idea about the lean condition that a dead injector would cause. Just think of it like the "corn theory." What goes in and doesn't get used comes out the same. I agree with the post above mine to swap a known good injector for that one and make sure it's not an electrical issue. Go from there and good luck.

 

[jrichker]

As requested...

Cylinder balance test:
Warm the car's engine up to normal operating temperature. Use a jumper wire or paper clip to put the computer into test mode. Start the engine and let it go through the normal diagnostic tests, then quickly press the throttle to the floor. The engine RPM should exceed 2500 RPM's for a brief second. The engine RPM's will increase to about 1450-1600 RPM and hold steady. The engine will shut off power to each injector, one at a time. When it has sequenced through all 8 injectors, it will flash 99 for everything OK, or the number of the failing cylinder such as 22 for cylinder #2. Quickly pressing the throttle again up to 2500 RPM’s will cause the test to re-run with smaller qualifying figures. Do it a third time, and if the same cylinder shows up, the cylinder is weak and isn’t putting out power like it should. See the Chilton’s Shop manual for the complete test procedure

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at Walmart.