low 02's at idle and rough idle

[mikestertwo]

Is your P/N switch working and adjusted correctly?

 

[QUIP'6']

Is your P/N switch working and adjusted correctly?

whats that park and neutral if so yes

 

[QUIP'6']

went out and started it cold and watched numbers at idle they were 350 to 400 and climbing and then went to 500 to 600 then to 750 and locked on because the cross counts stopped then as the temp on scanmaster went to 160 they started to drop 600 500 450 350 230 100 90 33 11 00 then i put in park and they jumped to 780 and stayed then put in park and they started to drop. is this the coolant temp sensor

 

[Junior Samples]

whats your vac inches reading?

Also i was getting somthing like that before i swapped injectors, i did the old fashion way by idlen car and pulling injec clip one at a time and check for any change, i wound up having two bad but at idle when i put a load on it it seemed to just go away...hmmmm..lol

 

[QUIP'6']

whats your vac inches reading?

Also i was getting somthing like that before i swapped injectors, i did the old fashion way by idlen car and pulling injec clip one at a time and check for any change, i wound up having two bad but at idle when i put a load on it it seemed to just go away...hmmmm..lol

injectors new but you never know i did pull each clip and noticed a difference in idle my vacuum is 18 inches

 

[QUIP'6']

well i hope this is the problem!!!! went out when car was cold and unplugged the temp sensor and started up got a code 15 and the scanmaster showed -39* temp well the car idles like no other PERFECT no sputter and rough idle and when it got warm up to temp that was showing on aftermarket gauge i checked the ccounts and it was locked and the o2's were perfect 750 and when i put it in gear they stayed locked and perfect. WELL THEN I PLUGGED THE SENSOR BACK IN AND ALL HELL BROKE LOOSE THE IDLE WAS ROUGH AND THE O2'S WENT RIGHT TO SINGLE AND DOUBLE DIGETS. then i unplugged it and the o2's went back up and i purred like a kitten. W.T.F!!!!! is it the sensor or ecu

 

[mikestertwo]

If the temp on the ScanMaster matches the temp on your after market gauge then I would say there is nothing wrong with the temp sensor. Pulling the wire off of the temp sensor will richen the fuel because it will move your mixture on the temp vs. fuel table. Cooler engine temp equals richer mixture.

 

[QUIP'6']

If the temp on the ScanMaster matches the temp on your after market gauge then I would say there is nothing wrong with the temp sensor. Pulling the wire off of the temp sensor will richen the fuel because it will move your mixture on the temp vs. fuel table. Cooler engine temp equals richer mixture.

why would it be so extreme when i unplug it they go from 750's to 025's

 

[mikestertwo]

why would it be so extreme when i unplug it they go from 750's to 025's

I assume you mean they went from 025's to 750's when you unplugged it. You fooled the computer into thinking the engine temp was -39* so the computer will richen the fuel a lot based on the temp vs fuel table. -39* is pretty cold so the table will richen the mixture considerably. As to what the real problem is I have to admit this is a stumper. The odd thing is when you put it in gear the mixture returns to normal if I read the post correctly. It almost sounds like a load vs. fueling problem.

 

[unix_punk]

Compare your temp gauge to the temp on your scan tool. If they aren't close then I would replace the temp sensor. When mine went it stuck around 60F, which is enough for the car to run fine until it warms up...then it ran like crap.

 

[johnnyttype]

wouldnt the car run like crap in gear too then? his problem seems to be only at idle in park, in gear there is no problem. maybe take some readings in park and then put car in gear and take some more readings to compare.

 

[unix_punk]

Wont know until we see if the temp sensor is working or not. If I remember correctly the car was better in gear, still wasn't great though.

 

[QUIP'6']

wouldnt the car run like crap in gear too then? his problem seems to be only at idle in park, in gear there is no problem.

yes in gear the o2's jump up to 700's and smooths out. in park they are low and it idles rough when i unplug temp sensor the idle smooths out and the o2's are the same in park and is gear

 

[johnnyttype]

i read that car will default to 111 degrees F when sensor is unplugged, just thought i would add that

 

[unix_punk]

im pretty sure mine went to -39 or some random negative number. been a while though.

 

[johnnyttype]

im pretty sure mine went to -39 or some random negative number. been a while though.

the sensor display will be -39 but the computer will recognize that there is a problem, pop the code and then default to 111.

i read this on gnttype.org!

 

[unix_punk]

Makes sense, I only know what I saw on the sm.

 

[QUIP'6']

mine is showing -39 unplugged and idles like a charm could it be ecu

 

[johnnyttype]

it is possible, if u have a known good unit u could try that or if someone else has one u can try. like i said before though maybe u will see something if u compare ur SM readings in park and in drive. like LV8 should increase when put in gear, along with IAC counts, stuff like that. how much does vac. drop in gear?

other things u could check, pull the line off regulator and see if o2's go up to where they should be, maybe egr valve is leaking alittle bit.

 

[QUIP'6']

it is possible, if u have a known good unit u could try that or if someone else has one u can try. like i said before though maybe u will see something if u compare ur SM readings in park and in drive. like LV8 should increase when put in gear, along with IAC counts, stuff like that. how much does vac. drop in gear?

other things u could check, pull the line off regulator and see if o2's go up to where they should be, maybe egr valve is leaking alittle bit.

thanks lv8 increases and iac increases 4 psi vacuum drop 18 to 14 fuel regulator stays the same (o2's) and egr is dissconected