robotnix

I will say right away that I did it cold in my garage, KOEO

81 o - air diverter solenoid fault, intake air control circuit fault / air injection diverter
10 - I think this is to say that now we go to c
91 c - shift solenoid 1 (SS1) circuit failure
96 c - fuel pump secondary circuit fault / high speed fuel pump relay open

this is the explanation the book gives.

but I'm clueless so still not sure what it means.
can anyone explain?
thanks.

dawson1112

First off you cant do a koeo or koer test with a cold engine. It needs to be up to operating temp.

81 is secondary air diverter smog pump related, no worries it just diverts the smog pumps air to the atmosphere when the car warms up.

the only 10 is for cylinder balance test, and means it failed the balance test on cylinder 1... could be missing on that cylinder.

91 is not shift solenoid, the aod trans does not have shift solenoids its not electronic. I dont know where your coming up with the 91o maybe your scanner is fruit loopy lol , but code 91 on the fox mustangs is
o2 Sensor Circuit Indicates Lean -driver side(R), No o2 Sensor Switching Detected. always lean -driver side(CM),
96 =Fuel Pump Circuit Open-Battery To PCM.... this code will set if the fuel pump circuit is abruptly interupted at any time during drive cycle, could be a faulty relay could be that your inertia switch is on its way out or you hit a hard bump.


I would clear all those codes and drive it , let it warm up then do koeo koer , and a balance test. Then see where your at with codes.

robotnix

ok I went out for 20 minutes and did the tests hot and here is the result,

KOEO
81
10 on my tester it says it's the separator from KOEO and Continuous error code
91
96

KOER
I got
8 with symbol CYL I guess it's telling you it's an 8 cylinder
91 something with H2O sensor to be precise in the ford code reader it says
HO2S sensor signal out of range/always lean

in KOER I did not get 96 what does this mean??

I'll change the oxygen sensors but what else do you read from this result?

you think my idle issues at stops sometimes is related to the Oxygen sensors?

so far I've changed,
spark plugs,
spark wires,
cap,
rotor,
egr valve,
cleaned IAC and MAF sensor and installed a new filter.


I've never owned a mustang it's new to me but this car smells strong from the pipes not sure if it's normal or something is off... I've always owned Toyotas 4 cylinders and they smell flowers compared to my mustang

dawson1112

Im not to sure how those code readers work , I always just jump the test port and read the check engine light flashes.

Anyways it could be reading the fuel pump circuit open in koeo becasue the fuel pump doesnt run after a few seconds untill the car starts again.

I would check all the wiring for the 02 sensors before you run out and buy a new one, also check for an exhaust leak at the header and where the down pipes connect to it. A leak in the exhaust on that side will allow air in and throw a lean code.

and the air diverter is nothing to worry about at all. Most guys have removed all that crap anyways and always get that code.

robotnix

can o2 sensor cause stalling and rpm screw-ups?

dawson1112

yes they can. But so can a vacuum leak in the intake if its drawing to much air into that side it can throw that lean code.

Chances are its the drivers side 02 at fault but doing a quick check for exhaust leaks or vacuum leaks before commiting the cash is wise.