Blazer dies when slowing down

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Blazer dies when slowing down

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Blazer Forum >> Mechanical & Maintenance >> General Tech Help >> 2nd Gen S-series (1995-2005) Tech >> Blazer dies when slowing down

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Blazer dies when slowing down - 3/30/2008 6:14:30 PM

sffans

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I have a 95 4.3 that when you slow down to come to a stop or turn, It will die. It does this most the time when you drive it. It runs fine except for that. I have put new TPS, IACV, Fuel filter, and cleaned the EGR. I am stuck. Its my kids car and he is just wanting to get rid of it now. But it is a very good vehicle. Someone told me something about the torque converter.
Thanks and PLEASE HELP ME.

Post #: 1

RE: Blazer dies when slowing down - 3/30/2008 6:17:55 PM

swartlkk

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From: Waterloo, NY
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The first thing I would do run through the entire vacuum system, making sure that you do not have a leak.

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RE: Blazer dies when slowing down - 3/30/2008 6:23:49 PM

sffans

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I have also done that and there does not seem to be any. There are not alot of vacuum lines on the blazer , but there does not seem to be any that are broke.

*Combining Consecutive Posts*

Blazer now seems to want to surge a little bit about 40. When you give it gas it doesnt react to it. Once again this does not always happen just most of the time. Thanks

*Combining Consecutive Posts*

I forgot to add that now the check engine light comes on now. It says low voltage for the #1 o2 sensor.

< Message edited by swartlkk -- 3/31/2008 5:04:53 AM >

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RE: Blazer dies when slowing down - 3/31/2008 4:58:22 AM

swartlkk

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Please use the edit feature to add additional information to your post if another member has yet to reply. Consecutively posting is considered another form of double posting and is prohibitted. The only time that consecutive posting is warranted is if/when a post has fallen off the first page of the forum section it resides in and a reply has not been made, at which time it is permissible to 'bump' the thread with a post.

Now, low voltage sensor one could be caused by an exhaust leak ahead of the upstream O2 sensor (the one closest to the engine on the exhaust manifold). Do you hear any ticking? It is also possible that a plugged fuel filter could cause this, but that would have symptoms at higher RPM (higher fuel demand) as well.

How is the voltage at idle? It is possible that the voltage is dipping, causing inadequate voltage to the fuel pump, resulting in poor fuel delivery at idle...

I'm just throwing out ideas here.

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RE: Blazer dies when slowing down - 3/31/2008 5:20:52 AM

sffans

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Sorry for that,Wont happen again. I put a new fuel filter on. It also runs fine when I start it up and its in park. It now says both o2 sensors are bad.
My kid just told me that the fuel tank has a hole in it. He can only fill it about 3/4 full. dont know if that has something to do with it or not. Thanks again

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Post #: 5

RE: Blazer dies when slowing down - 3/31/2008 5:43:50 AM

swartlkk

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From: Waterloo, NY
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The rear most O2 sensor is a catalyst monitoring sensor only. The only sensor that has anything to do with the fuel system is the upstream sensor which, as I said, is the closest one to the engine. Being a CPI motor, you only have one upstream sensor.

What are the codes that it is giving out?

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RE: Blazer dies when slowing down - 3/31/2008 6:05:00 AM

sffans

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P1133, P0131, P0133, and P0140 are the codes. Thanks

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Post #: 7

RE: Blazer dies when slowing down - 3/31/2008 8:12:08 AM

swartlkk

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P0131 - HO2S Circuit Low Voltage Bank 1 Sensor 1

quote:

This DTC is designed to detect an HO2S voltage that remains at a low (lean) voltage for more than a specified number of seconds during the test conditions. This DTC is set under the following conditions:

* There is an HO2S circuit fault that results in a false lean exhaust condition.
* The HO2S is correctly detecting a lean air-fuel ratio resulting from either a vacuum leak or a fuel control system fault.

P0133 - HO2S Slow Response Bank 1 Sensor 1

quote:

This DTC is designed to detect an HO2S that is slow to respond to changes in the exhaust oxygen content.

P0140 - HO2S Circuit Insufficient Activity Bank 1 Sensor 2
P1133 - HO2S Insufficient Switching Bank 1 Sensor 1

quote:

This Diagnostic Trouble Code (DTC) determines if the HO2S is functioning properly. It checks for an adequate number of HO2S voltage transitions above and below the bias range of 300-600 mV . This DTC sets when the Vehicle Control Module (VCM) fails to detect a minimum number of voltage transitions above and below the bias range during the test period. Possible causes of this DTC are:

   * An open or a short to voltage on either the HO2S signal or HO2S low circuits
   * A malfunctioning HO2S
   * A problem in the HO2S heater or its circuit
   * A faulty HO2S ground

For now, I would ignore the P0140 code and concentrate on the B1S1 codes. This looks like it is a sensor failure if not a large scale exhaust leak. I would first check over all of the wiring for damage. Inspect the exhaust system for any leaks. If the wiring appears to be good and the exhaust system has no leaks, then I would change the sensor.

As for sensors, I would recommend only using the AC Delco sensors. The price and availability of some of the other aftermarket sensors make them seem attractive, but it my own testing of many of these sensors, they are not as active out of the box as the AC Delco sensor in the same application. Initial activity of a sensor is a direct measure of its life.

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Post #: 8

RE: Blazer dies when slowing down - 3/31/2008 9:47:22 AM

sffans

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Thanks Do you think the 1 o2 sensor can be causing all the problems. I will check the wiring and stuff when I get home. Thanks again

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Post #: 9

RE: Blazer dies when slowing down - 3/31/2008 9:56:23 AM

Private_Ops

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Not to hijack your post but, this holds relative information to my problem as well.

I now know that I DO have an exhaust leak somewhere around my muffler. My RPM likes to jump up and down about 45MPH and up yet, I'm not getting a check engine light. Can the erratic RPM jumps be caused by this?

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Post #: 10

RE: Blazer dies when slowing down - 3/31/2008 10:59:12 AM

sffans

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Well if you know the fix please let me know.Thanks

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Post #: 11

RE: Blazer dies when slowing down - 3/31/2008 11:34:56 AM

Private_Ops

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The fix for an exhaust leak ( in my case, it wasn't welded fully) would be to have it completely welded closed. Kinda like fixing a hole in a wall, if you get my point. (Mines leaking where my muffler was welded on (used stock pipe))

I know the fix, I'm just wondering if this can cause erratic RPM.

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Used, got it as a birthday present :)

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Post #: 12

RE: Blazer dies when slowing down - 3/31/2008 12:06:38 PM

sffans

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ok I see yea mine idles fine except when you start slowing down or come to a stop it will die. It does not do this every time just sometimes.

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Post #: 13

RE: Blazer dies when slowing down - 3/31/2008 2:41:34 PM

sffans

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wow my blazer now stumbles on accelretion tell it gets up to speed then it is fine. My check engine lights are now off and it does not die when slowing. Who knows. THANKS

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Post #: 14

RE: Blazer dies when slowing down - 4/3/2008 10:43:35 AM

sffans

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Does the fuel pump just go out or does it gradually go? My Blazer now stumbles on acceleration. It will eventually go it just takes some feathering. It still also dies when slowing down. Thanks For the help

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Post #: 15

RE: Blazer dies when slowing down - 4/4/2008 7:38:51 PM

sffans

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Does anybody know if the fuel pump just goes out or if they gradually go?

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RE: Blazer dies when slowing down - 4/4/2008 7:51:14 PM

swartlkk

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Many just die, but I have seen some get weak, but typically if they are weak, it will affect high RPM supply sooner than low RPM supply.

Do you have a voltage gauge on your dash? If so, what does the voltage look like at idle when you experience the problem?

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Post #: 17

RE: Blazer dies when slowing down - 4/5/2008 4:22:49 AM

sffans

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The voltage looks fine. I hooked up a fuel pressure gage up and when I turned on the key it went to 54psi. then slowly dropped to 40psi. But the car does start and run. I pulled the fuel tank off and I am replacing the fuel pump now. The top of the fuel tank was leaking where the lines go in. They were also very lose. Could this be the problem. Thanks alot

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Post #: 18

RE: Blazer dies when slowing down - 4/5/2008 3:24:23 PM

sffans

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Just replaced the fuel pump. My pressure is about 60 now but it does not hold there when the key is turned off. Is this a fuel regulator problem now? Thanks

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Post #: 19

RE: Blazer dies when slowing down - 4/5/2008 8:43:32 PM

swartlkk

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You probably need to pull the plenum off and have a look inside.

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Post #: 20