99 Buick Century P1441 system flow during non purge

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  • Witsend
    Banned
    • Nov 2012
    • 2942

    99 Buick Century P1441 system flow during non purge

    The purge solenoid can be actuated by scanner fine and holds vacuum, not stuck open , Freeze frame data showed fuel trims to be negative at the time (rich) and Baro reading was 35.4 psi! . Car drives fine and baro reads 14.5 psi now , but I'm thinking with all the rain and high humidity lately, maybe the MAF sensor might actually been malfunctioning and PCM is blaming it on the purge flow I'm going to take a TSB look at the wiring loom near the accumulator, because I also have an ABS code for a right rear wheel sensor that seems to be agreeing with the other 3 wheels speeds. So Why did Baro show 35.4 PSI during freeze frame event if not a MAF problem, unless the PCM just defaults to that value when running too rich , Any better ideas ?
    Last edited by Witsend; 06-20-2014, 07:57 AM.
  • Crusty
    Senior Member
    • Dec 2007
    • 2450

    #2
    Use the purge and seal function and check the fuel tank pressure sensor.

    Comment

    • maven
      Senior Member
      • Mar 2014
      • 269

      #3
      Yup, do what Crusty said....check the FTP operation. This code wont run if there are MAP codes set so the PCM though 35psi was ok. the 1441 is for FTP below -11" H2O during the evap diag test.This is over 4volts, make sure the signal and reference wires arent shorted together. The canister and vent valve are back behind LR wheel, make sure the vent isnt clogged or hose collapsing. Make sure the purge solenoid hoses arent swapped and that there isnt any canister carbon in it. Skewed/erratic sensors are fairly common, I do a few a month

      Comment

      • Witsend
        Banned
        • Nov 2012
        • 2942

        #4
        Solved

        Thanks Crusty and Maven , I went out this morning , pulled cold vehicle in my garage unplugged the purge solenoid electrical connector and Evap tube side hose off of the purge solenoid and put my finger over the evap side port of the purge solenoid and could feel vacuum where it shouldn't have it when solenoid is not energized.
        Also did a KOEO check with a noid light plugged into connector, and is not lit , so it is not getting a non pcm uncommanded ground anyplace , so the purge solenoid is NFG and must intermittently hang open and leak at lower temperature , because it held vacuum fine yesterday with my hand vacuum pump , however the vacuum was applied to the evap side port instead of the engine side of the the solenoid like it normally should. I will check and make sure the hose connections are not reversed because I did intake gaskets not very long ago but never make mistakes, lol
        Now I'm trying to see if I can get up my Counselor 2 to display a AC wheel sensor output , set it on AC scale , 2V range, tried different time MS settings , working off the white and black alligator clips on Counselor 2 but can't get a display

        Comment

        • Crusty
          Senior Member
          • Dec 2007
          • 2450

          #5
          SnapOn scanners graph really well.
          USE this capability....
          See if you can get the wheel speed sensors on screen in GRAPH.
          KEEP THE SPEED SLOW, as in under ten miles per hour.
          Drive the vehicle and see if one sensor is a little flakey at three or four or five miles an hour.
          If you keep the vehicle speed slow you csn save screenshots and movies and catch the glitch that sometimes is only there for a few revolutions.

          Heck....even a rumbling wheel bearing can set off codes.

          Comment

          • Witsend
            Banned
            • Nov 2012
            • 2942

            #6
            I cleared C1228 code for right rear wheel sensor, and should let it go as a no problem found .I couldn't feel any false ABS activations , the harness looks fine, the hub is smooth and quiet ,the ABS light is not on at this time but a code 1228 for the right rear wheel speed sensor was in memory. I have an old Snap On MT 2500 non graphing and a DS708 that I didn't catch any drop out of wheel speed graphing all 4 wheels.
            Just thought I would try the Lab scope function on the Counselor 2 to see if it is capable of displaying a low voltage AC sine wave on 2 volt scale turning the hub slowly by hand and compare the humps to an opposite wheel.
            Can't the counselor 2 display a low speed , low voltage , AC sine wave wheel speed sensor trace? Cars have had ABS since the late 20th century when the Counselor 2 was still having it's glory days . I think it's capable, it's got to be me not doing something correctly.
            Last edited by Witsend; 06-20-2014, 11:56 AM.

            Comment

            • Crusty
              Senior Member
              • Dec 2007
              • 2450

              #7
              AFAIC the money you spent on the counselor-II would have been better directed to a Solus-PRO or a Vantage-PRO......
              What you are experiencing with it doesn't surprise me...it MIGHT have worked 25 years ago but.....lol

              Comment

              • Witsend
                Banned
                • Nov 2012
                • 2942

                #8
                there truly is more than one way to skin a cat

                Well I figured out that I'm able to view a wheel speed sensor pattern after having a beer and selecting alternator waveform.
                Attached Files

                Comment

                • Crusty
                  Senior Member
                  • Dec 2007
                  • 2450

                  #9
                  Well thete you go.....LOL.....
                  Licking the batteries again.....LOL

                  Comment

                  • Witsend
                    Banned
                    • Nov 2012
                    • 2942

                    #10
                    Ok not sure if it's conclusive but I got a printout of the frozen Counselor 2 trace of the suspect right rear wheel speed sensor and one of the LR wheel speed while turning the hubs counting one one thousand , two one thousand , three one thousand . I think the printer hicupped and the trace proceeded after being frozen , but it looks good enough to justify replacing the right rear hub, though.
                    Attached Files

                    Comment

                    • Crusty
                      Senior Member
                      • Dec 2007
                      • 2450

                      #11
                      Well just for Shxxs & Giggles, I plugged in my Solus Ultra and here it shows the 4 wheel speed sensors at a peak of 5-MPH and then another one at 10-MPH. I just backed up, pulled forward and backed up again leaving the shop today and grabbed a couple of pics with my cell phone.

                      Diagnosis time....all of about 30 seconds once I was in the ABS data group.


                      I have used this slow speed technique to verify a sensor signal dropping out for several years....and the Solus-scanners are just a tad more portable than the Counselor-II....LOL

                      Had a Cadi in a few weeks ago and the wheel bearing rumbled and the sensor picked it up. The bearing was noisy so it got replaced and the Cadi didn't need a sensor (they come separately on the CTS).

                      The last shot shows AFTER the bearing replacement proving to Audrey that all she needed was the bearing and the sensor itself was OK.

                      The Solus-PRO will do the same thing as the Solus-ULTRA and they can be had at reasonable prices apparently.
                      BTW...I like the cold one in the corner...LOL
                      Attached Files

                      Comment

                      • Witsend
                        Banned
                        • Nov 2012
                        • 2942

                        #12
                        The 4th picture down you posted is awesome, I can really see the corruption of signal from the LR wheel speed sensor but I don't see the one posted reading 10 mph where the others are reading 5mph
                        I'm Just learning how to use The Old Counselor I have ,Ignition work it's seems decent, but the Lab Scope part doesn't seem to work worth a Sh@t, but so far was able to use the 10A optional low amp clamp I bought by selecting Vacuum wave form from menu and was able to view a nice pattern from the fuel pump circuit with a current loop fuse buddy , and today I figured out how to component test and compare a wheel speed sensor pattern to another selecting alternator wave form. I will resort to Couselor 2 If my DS 708 scanner graphing lets me down like it is known to do
                        I'm sure Snap On even had some software holes on 25 year old lab scope like this but it's still a good solid piece of hardware, and I was able figure out some thing to get around it and view something useful

                        Comment

                        • Crusty
                          Senior Member
                          • Dec 2007
                          • 2450

                          #13
                          The first two phone pics are from my own vehicle today....
                          Known good vehicle....no problems....just showing to keep the vehicle speed slow to get better resolution in the graphs. 1st pic was at 5-mph. Second pic was at 10-mph and you can see how the graph expanded....so keep the speeds down when your using this technique.

                          The other three are screen shots from the scanner. It flagged a wheel speed sensor code when all that was wrong was the bearing.

                          That 4th one that you like proved that the vehicle was correct in that it didn't like what it got as an input from the sensor. Again a fairly low vehicle speed capture. The ROOT CAUSE was the BEARING, NOT the sensor-!!
                          The ROOT CAUSE is far too often overlooked and the "symptom" gets treated and the underlying problem remains.....THAT'S WHY so many parts are tossed at vehicles these days.....
                          It never was the correct method and it's even more important today to find the ROOT CAUSE.

                          Then the bearing was changed and the last screen shot shows that the sensor was happy without a rumbling bearing....the sensor was OK. The customer was happy she didn't need BOTH components. In fact she was just in yesterday for a vehicle service....if there had been ANY kind of an ongoing issue she would have said so.

                          USUALLY they'll show up at lower speeds but if it doesn't THEN I will increase the vehicle speed so the graph doesn't expand vertically to accommodate the highest speed that it saw on that road test.

                          Always good to have another method of PROVING OUT what you suspect, so I'm glad you're having fun with your 25 year old "toy"...LOL

                          Comment

                          • maven
                            Senior Member
                            • Mar 2014
                            • 269

                            #14
                            I love tools new and old as much as all of us and more than some of us, but your determination to make this Counselor work in your professional life seems to me to be costing you money Wit...Am I right? how much time do you spend figuring out how to do tests with this thing? Everything seems like an adventure when you break it out If these all are side work vehicles or hobby projects I understand, the joy/challenge of using stuff like this is fun. But if these are cars your using to pay your mortgage Id sure as hell be working on getting a quicker/more friendly solution. You seem to like torturing yourself. LOL

                            A $200 Vantage wouldve found that WSS drop out probably ten times quicker than the Counselor. Just food for thought. Im sure we're all flat-rate or owners here and I just dont like to see guys (who arent my competition) wasting their time and money.

                            Comment

                            • Crusty
                              Senior Member
                              • Dec 2007
                              • 2450

                              #15
                              Hay Maven....
                              If your "competition" isn't wasting their time, YOU get to fix the vehicle sooner anyway-!! LOL

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