Can KV Histographs indicate ignition module issue?

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  • Witsend
    Banned
    • Nov 2012
    • 2942

    Can KV Histographs indicate ignition module issue?

    Got a low mileage (under 50 K ) 93 V6 3.3 L Buick Skylark in the garage that seems to have a course idle and exhaust HC fumes that will make your eyes water. No codes. O2 seems to switch regularly from rich to lean on the old MT200 but fuel trims don't read in percentile like I'm used to viewing but some other numerical value like what I though was 128. No fuel pressure regulator leaking gas or obvious vacuum leaks . Compression (engine only luke warm) seemed low ranging from 150psi on the first 2 to only about 120psi on the remaining 4. I'm not sure if after testing the first 2 cylinders with150 psi the others might have got the ring seal washed from gasoline. I put 6 new plugs in , cleaned the throttle body and MAF but idle roughness and eye watering HC emissions persist. No vacuum leaks smoking the intake.
    I've had some old GMs like this give me a run for the money and it turns out to be ignition module. The KVs look ok but the KV Histographs show less Hieroglyphic activity on number 4 , so before I put a bomb in this damn thing and Run like an Egyptian, I was wondering if anyone that uses a Counselor2 has seen a bad ignition module cause this?
    Attached Files
  • Witsend
    Banned
    • Nov 2012
    • 2942

    #2
    Swapped a couple coils and slammed an O2 .

    I think the new O2 I installed is still hanging rich and lean for too long before switching .I tried unplugging the MAF sensor to see if it runs better but No Cigar. I'm still leaning toward slamming a new crank sensor and ignition module because some of the square wave signals at the ignition module wires dont look flat across the plateaus. I really wished to check for fuel pressure and leakdown , but don't have a sharp 90 adapter to clear a bracket on intake ,Arrrg. Looking at this Old Turd I think early 90s GM started to say FU to us when they pulled a Farfignuugen stunt by putting SAAB E8 headed bolts on rear wheel cylinders!
    I got the Pids of MT2500 displayed on Counselor Screen which looks real trick for Baffling people with Bullsh@t when you can't dazzle them with Brilliance. LOL
    I'm wondering why one of the Quad Drivers is reading low when the other 2 read Hi .All 6 injectors ohm out fine and patterns look normal. P@ss on it , I think I'm just gonna ship it and give the Techron time to work, or wait till it gets towed in for a no start . Any old GM guys see anything askew on the display other than the signature beer can missing on the top ? As far as Trim Cell reading 16 , if that is percentile number then it is too lean. I don't know what Long Term trim displayed as 124 means though. Exhaust smells of HC
    Attached Files
    Last edited by Witsend; 10-23-2014, 01:23 PM.

    Comment

    • badcoupe
      Senior Member
      • Jan 2011
      • 218

      #3
      Check the injectors resistance as well as current ramp check them.

      Comment

      • Witsend
        Banned
        • Nov 2012
        • 2942

        #4
        Thanks but car is gone

        I Ohm checked all injectors , 12.2 -12.4 within specs. Checked the patterns (volts) and they all looked basically the same with my Counselor 2 . I did not check current ramp , however I have a 10A low amp inductive probe I bought for it but have to figure out how to get it to work in Lab scope mode which displays things in volts. I think I did get it to show a pattern from the Low Amp probe on a different car by selecting vacuum waveform to view a fuel pump pattern . I found one of the coils for 1 and 4 had a bolt that was stripped when I removed them to Ohm out the primary circuits of all 3 coils (checked the same as one another) Cleaned the module spades and smeared dielectric compound beneath the module, put a slightly longer bolt in to catch remaining threads, changed the plugs and put a bottle of Techron in the fuel tank and let it go.
        I'm still going to have to figure if the LT fuel trim and Trim cell readings displayed is a lean condition or not and whether all the quad driver displayed should read Hi or Lo.

        Comment

        • Crusty
          Senior Member
          • Dec 2007
          • 2450

          #5
          The trim "CELL" is referring to the computer mapping where the fuel adaptives were stored. Initially there were 16 different blocks of data. That increased thru the late 90's to 22-Block-Learn Cells. I'm pretty sure there are more than that now.

          As for the trim showing 128 and 124, do some research on INTEGRATOR and BLOCK LEARN. Those are the terms for the Short-Term-Fuel-Trim and Long-Term-Fuel-Trim. Do some reading on codes #44 and #45 for that 1993 vehicle too.

          There are 8-bits to a byte, and 8 bytes to a baud.
          0 to 255 is actually 256 digits which is divisible by 8.
          (If you disconnect a CTS or IAT sensor the value you'll see is -255-!!)
          For Fuel delivery, the half-way point is 128, which is no fuel adaption from the computer base programming.

          The short term fuel trim INTEGRATOR being something that is higher or lower than 128 is meaningless without the long term fuel trim BLOCK LEARN value and how far above or below 128 it is.

          Comment

          • Witsend
            Banned
            • Nov 2012
            • 2942

            #6
            Thanks, Crusty, if my Baud rate gets too high , better than cutting my losses, I'm just going to shave my head and walk against Body Cancer on old cars.
            The Counselor 2 , shows all available MT2500 data pids for this 93 Buick , do you see something of concern ? Other than a Trim cell 16 (that I incorrectly thought was a +percentile lean , the 124 for LT Trim must be ok, I just see 3 out of the 4 Quad drivers displayed , 2 read Hi and one reads low, so I ohmed out the injectors because I've had some old GMs with injector problems, but usually not super low mileage time capsules like this Old Guy's Skylark with under 50K. My Guess is this guy probably fills it up with stale Premium gas that sits in a tanks underground at a gas station way too long where they don't move much premium, and I got off on a wild tangent because of exhaust fumes from stale premium.
            I tell my sister with her 2005 T-bird , she is better off filling up with regular gasoline from a high volume station and just put in a bottle of octane boost and some Stabil rather then filling up with old stale Premium.

            Comment

            • Witsend
              Banned
              • Nov 2012
              • 2942

              #7
              Thanks again , that's good info to get to know . I think if I decide to get L-1 certified I need a much better handle on GM

              Comment

              • Crusty
                Senior Member
                • Dec 2007
                • 2450

                #8
                Up here regular fuel can have 10% alcohol. Mid-grade can have 5% alcohol.

                The Top Tier gasoline is the better product to use and I find that vehicles get better mileage with the Top Tier PREMIUM fuels and a more complete burn so thete are lots of benefits to the better fuels.

                The Integrator and the Block Learn both start at 128 and then if the oxygen sensor feedback sees too rich a mixture the short term INTEGRATOR will go down. If it goes down far enough the long term BLOCK LEARN will adjust down one tick to 127 and the Integrator will go back to 128 and start over. If it goes down again the long term Block Learn will drop to 126 and the Integrator will again start at 128 and adjust again.
                It keeps doing this untill it can maintain 128 in the Integrator and then we can see tje long term adjustment for thay engine in different LOAD conditions which will be different Learned CELLS.

                What did you find for the code 44 and the code 45-?? The numbers 127 and 124 are less than 1% from base programming.

                Comment

                • Crusty
                  Senior Member
                  • Dec 2007
                  • 2450

                  #9
                  I wish the website didn't automatically make the pictures that are uploaded TWICE as large as they need to be......
                  Some sort of automatic size filtering could be applied for images of all types that are uploaded.....

                  Comment

                  • Witsend
                    Banned
                    • Nov 2012
                    • 2942

                    #10
                    I Hear you Crusty , I push the keyboard Ctrl button and scroll the mouse wheel down to quickly zoom out , then scroll out to reach the text if it is too small to read. Guess I need to get a larger newer rectangular LCD monitor to be able to view a lot of things in their entirety on the screen now a days.

                    Comment

                    • jm43130
                      Senior Member
                      • Apr 2008
                      • 182

                      #11
                      QUESTION

                      I too have a Counselor 2 and never knew you could display scanner data. Any special thing to do? How did you hook up scanner and what screen did you use on Counselor2?

                      Comment

                      • Witsend
                        Banned
                        • Nov 2012
                        • 2942

                        #12
                        I too have a Counselor 2 and never knew you could display scanner data. Any special thing to do? How did you hook up scanner and what screen did you use on Counselor2?
                        I'm not sure it supports much newer scanners than MT2500, or anything with a Baud rate over 9600 but for my MT2500 the Baud rate is 4800 I bought a MT2500-500 cable online cheap.




                        I attached it from serial port A at rear of Counselor 2 to the recepticle at back of MT2500 that looks like a phone or ethernet recepicle . The scanner set up instructions are in the MT3000A user manual red binder start on page 24-5. It's pretty easy to do and with a 20 ft scanner cable leading to the MT2500 to the Car DLC , you can leave the MT2500 sitting on the counselor and control it remotely if you have the Counselor remote control. It's still pretty impressive to me and folk who see it ,even if it is obsolete. Comparing the Counselor 2 to a Verus Pro is like comparing a B52 to a Stealth Bomber, both impress me, Ones a lot lighter and faster than the slower heavier one , but you wouldn't want to see either one of them crash to the ground.

                        Comment

                        • badcoupe
                          Senior Member
                          • Jan 2011
                          • 218

                          #13
                          Quad driver runs things like the electric fans a/c compressor tcc lockup etc. It was a way gm used to run high current items through the pcm. Didn't last very long!

                          Comment

                          • Witsend
                            Banned
                            • Nov 2012
                            • 2942

                            #14
                            The injector clean didn't work and it's back withpoor idle quality

                            I changed the PCV valve, Checked fuel pressure and leak down ok. Checked for codes, none. Hooked up the Counselor 2 and checked the Crank Shaft sensor 1x and 3x signal to the ignition module and I think they look real poor, and I need to take a look at the vanes of the crank pulley. I also was able to use the low amp clamp on a fuel injector to see a pattern. I Think I had the low amp probe on the ground side of the fuel injector,I tested .
                            Attached Files

                            Comment

                            • Witsend
                              Banned
                              • Nov 2012
                              • 2942

                              #15
                              Update

                              Pulled the crankshaft 1X 3 X pulley and I'm embarrassed to say that the odd various sized squares of 1X signal are a normal built in design of the smaller circumference hall effect vane having different spacing. I changed the Crankshaft Sensor anyway because the plastic was cracking around the mounting bolt and put in a Duralast one that made a rubbing sound for a little while, but idle still kinda rough and exhaust fumes like a 68 Chevy
                              Die B@tch! Sorry , I need to brush up on my Farfiggnuegen, there.
                              Well I look at the tracky looking grime covering the 3 coils , and take the ignition module off and it tests good on Wells tester at autozone, so I drive 2 miles to local junk yard and find a Turd with 3 new coils and another Turd with a new module , slam the $35 of used parts and car idles pretty much the damn same. I quiz the customer whether he is burning regular and not some stale premium gas from Tu Buck Tim . He says No just regular, Why? I said because the idle isn't quite smooth as it should be and the exhaust fumes are nasty . He said that's because It don't have a Cat Converter on it anymore... DUH ! never thought of looking under there, LOL

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