O2 readings questions

[wbzautocustomiz]

All of a sudden very low O2 readings on scanmaster like 052,128 etc. and no readings at all on A/F ratio gauge and when car drives then comes to stop it will shut off almost like as if it was a manual coming to a stop without pushing clutch in but no jerk then fires up fine idles good has all its power was just wondering if the low o2 reading and shut off could be a o2 sensor bad/going bad

 

[Raeban]

What are the other scanmaster readings? Do the O2 CC's go up?

 

[TurboBuRick]

If DFCO is activated it will kill the fuel on decel. The o2 numbers will be low or even 0. That's normal.

The car feeling like it's locked in gear when slowing down is a different story. That sounds like a bad torque converter solenoid.

Rick

 

[Raeban]

If DFCO is activated it will kill the fuel on decel. The o2 numbers will be low or even 0. That's normal.

The car feeling like it's locked in gear when slowing down is a different story. That sounds like a bad torque converter solenoid.

Rick

X2 on the TCC solenoid

 

[wbzautocustomiz]

Have to get other scan #'s will do that in few mins. As far as CC's I have the older scanmaster not sure if I can get that info. No car isn't locked in gear it just shuts off but if I hold gas pedal slightly it will not shut off "two footing" it

 

[wbzautocustomiz]

At about 55mph scanmaster #'s AF27, L8 58-65, INT 128-133, BL 142, ATS88, IAC99 then scamaster #'s at idle AF 05, L8 36, INT 128, BL 142, ATS 95, IAC85. when I did test drive a few min ago when I come to a stop either drive or neutral it will shut off but if a "two foot it" just a little bit all is good. Now maybe that I have the factory gauges out of car with Dakota digital in haven't put in the Dakota oil press sender or water temp sensor, but everything else is working on gauges (just fyi; have another thread about some gauge questions) I bring up the question about the factory gauges out of car since that's when I noticed car stalling out at a stop.

 

[Raeban]

BLMs are a bit high and indicate the ECM is trying to add fuel. Have you checked for vacuum leaks already?

 

[wbzautocustomiz]

I just did don't see any visible leaks not sure how to test for a vacuum leak other than finding one or hear one.

 

[Raeban]

I usually connect a regulated source of compressed air at 20 PSI to the hose going to the map sensor. With the car off you can find most leaks by sound or soap and water this way and I don't have to use aerosols or flammables. There are other tricks out there as well that can be found doing searches including making a fixture to connect to the turbo inlet out of a pvc cap and charging the system there.

The reason I suggested a thorough seep of vacuum leaks as this doesn't cost anything and usually finds something. Just because the BLMs are high doesn't mean you are lean, only that the ECM thinks you need fuel. I also noticed your IAC numbers at idle are a bit higher than typical. Stalling can be attributed to poor IAC response so I would clean that and make sure the IAC and TPS are set properly as well, again free. When troubleshooting I try to replace parts as a last option as too many aftermarket parts aren't worth a darn anymore and just stall troubleshooting in the long run.

 

[wbzautocustomiz]

Just when I read pvc and back of turbo in your post I had an aha moment when I was doing something the other day I did notice that cap is cracked on back of turbo but didn't fix right away and forgot. Will get on it tomorrow don't feel like messing with now more tonight you know how these cars are you lovem and hate em LOL after chang that rubber cap on back of turbo again will report back, is there an alternative to the cap that usally comes out of the" help section" in auto parts store ?

 

[wbzautocustomiz]

And 100% on buy part as last resort! Free is good

 

[wbzautocustomiz]

Changed cracked rubber cap in back of turbo but car still shuts off when I come to stop, can't find a vaccum leak yet anywhere, even though it was already doing it could the fact that I tapped into the factory sending unit wiring at the tank entry point wiring for Dakota digital gauge cluster fuel gauge on cluster programmed and reading good


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[TurboBuRick]

It's possible your IAC is stuck.

Rick

 

[wbzautocustomiz]

Thanks will check iac and clean it up I was banging on car pretty hard practicing 60 ft launches the night before I started having this problem so maybe on cool down it got stuck or something but it is fairly new only about 500 miles on it but not sure of the quality of the part itself


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[wbzautocustomiz]

Update ;pulled iac valve cleaned put back in same outcome, put a new one in same outcome, did the soapy water with 20 psi no vacuum leak found, still shutting off coming to a stop and SM O2 readings start up 440mv then drops to 000 reading lean on AF gauge. Maybe bad O2 sensor? Any more suggestions to try?

 

[dcfny]

I fought a low o2 issue last month, checked for vac leaks, ground strap, exhaust leaks, recorded several powerlogger runs, did fuel pressure checks at wot, and finally caved and replaced my 500 mile old O2 sensor and poof everything was perfect again. 20/20 hindsight, didn't want to buy a new sensor and probably spent that in gas. Thing is I'd probably do it the same way next time too.

 

[wbzautocustomiz]

Yeah 02 sensor $30 maybe IAC valve $50 return = $20 back in pocket and if its better sweet.

 

[Eric Stage I]

If the O2 sensor is good, and it's truly lean, then either there is a vac leak somewhere, or the MAF may be bad, or fuel pressure is way lower than it should be. My guess is the MAF, or maybe the Translator settings are incorrect. Look inside the Translator box, check settings, make sure some water didn't get in there.
Eric

 

[wbzautocustomiz]

I'm going to change o2 sensor since it's not too bad on price and will check for water and if dip switches are correct and the translator been on car for couple years unless vibration moved a switch. I did check fp all seemed to be correct. I want to kick myself in the a## car was running top shape then I wanted to put in Dakota digital gauges now this happens go figure.


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[wbzautocustomiz]

UPDATE, I went ahead put a new o2 sensor in it was helpful now my o2 readings on SM are back to normal and my A/F gauge back reading properly but car still shuts off when I come to a stop my BL is reading 132 cruising 50-60 when I let off its 138ish then when I come to stop its 142. Ran out of time to check translator box will check that out tomorrow and report back looks like Im going in a better direction.