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Idle or Stalling Problems - All Vehicles

461 messages,  Last post on May 31, 2013 at 3:53 PM

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What is this discussion about? Engine, Fuel System

Messages Page 47 of 47

#456 of 461 Re: idle problems [beckygr] by MrShift@Edmunds HOST

May 26, 2012 (5:48 pm)

Replying to: beckygr (May 26, 2012 1:09 pm)
EGR problems? Has those kinds of symptoms.

#457 of 461 91 S10 Blazer running rich, stalling on deceleration by rfletcher

Sep 15, 2012 (11:45 am)

91 S10 Blazer Sport, auto, 4X4, 4.3L TBI. 189000 miles. No trouble codes. Code 12 only. Recent post #171 in Chev. Blazer forum. No response. Guess no one is interested in dinosaurs. Since that post have learned more how to use scanner. The O2 sensor generates abt. .550v max. at idle. and does not reach necessary .620 [for closed loop in this engine] until operating at 2000 or more RPM for close to one minute. In city driving it rarely meets this condition so remains in open loop most of the time. I think this explains excess fuel and stalling at sudden deceleration. Much to rich in open loop. Runs great on the interstate and gets 22mpg there. Could be the exhaust gas not hot enough at low speed, for the O2, but cannot find why. The O2 is new [ third one ] , MAP new and test normal. Coolant sensor new and changed twice. Thermostat as well [ 195F]. EGR is new. Vacuum abt. 16 at idle abt. 22 at 2000RPM. Does have a little jitter. Should not be necessary but I am tempted to change to a heated O2. Might solve the immediate problem but may be a crutch. Hope one of you Super techs can solve where four shops and I have failed. I love this old lady.

#458 of 461 Re: 91 S10 Blazer running rich, stalling on deceleration [rfletcher] by srs_49

Sep 17, 2012 (7:32 am)

Replying to: rfletcher (Sep 15, 2012 11:45 am)
Is the O2 sensor a 3 wire unit, with the built-in heater? Maybe the heater circuit is open.

#459 of 461 Re: 91 S10 Blazer running rich, stalling on deceleration [srs_49] by rfletcher

Sep 17, 2012 (11:52 am)

Replying to: srs_49 (Sep 17, 2012 7:32 am)
Thanks, No, it's a new replacement O2 but the original one wire type. That's why I considered changing to the heated version. Real pain to do and a lot more expensive but would probably solve if not correct the problem. Seems a vicious circle. As I understand it, among other things, excess fuel will tend to cool the exhaust and non functioning / cooler than normal O2 will cause excess fuel. Maybe someone smarter than me can explain it.

#461 of 461 2000 Mercury Cougar stops when I stop. by free1913

May 31, 2013 (3:53 pm)

My 2000 Cougar will shut off without warning when I stop at stop signs and stop lights, but it will crank right back up, drive smoothly, until I have to stop again. I have replaced the MAF sensor, the O2 sensors on the left side, the IAC valve and motor. The alternator was replaced in December. The battery has been checked and is fine. I've had the fuel injection cleaned and replaced the fuel filter. The vacuum hoses have been checked and there were no leaks to be found. I'm going crazy!!! What else is there to fix, to stop this stalling???By the way, the check engine light does NOT come on, so there are NO codes showing up.

Messages Page 47 of 47

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