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  • #61
    Originally posted by Lago Blue View Post
    Mike,

    You may be correct about the cause of the fault codes, did you disconnect all of those 4 items?

    You could next try erasing the codes; and then see which return.

    Q: - When you say "...the oil filter is new and closed great.", you meant the oil filler cap on top of the cam-cover, correct?

    Q: - What is the fully warm idle vacuum now?

    I saw your video, and:

    Q: - Did you adjust the "idle air screw" out in attempting to raise the idle speed? Did it help at all?

    Q: - When you cleaned the T/B, did you confirm that the two(?) small drilled air passages on either side of the throttle-blade which connect to the idle air screw passage; where in fact fully clear?

    Q: - Is the O-ring for the replacement MAF sensor itself present and in good shape?

    Q: - When was that air-cleaner last cleaned or replaced? Is it the type that requires oil?

    Q: - Did you try disconnecting the ISV at full warm idle and noting what happens?

    Q: - Because your engine appears to vibrate a good deal and idle slow, is it possible that one cylinder is not firing? (600 rpm divided by 4 cyl = 150 rpm. 150 + 600 would be 750 which is right where you'd want to be as a minimum). Perhaps try disconnecting each spark-plug one at a time to ensure all cylinders are working.

    Q: - In your post #36 on page 3 above, you say "...and the other line go to the Idle Switch.", however there should be no such vacuum line or any place for it to connect to there. What did you mean?
    i have disconnect this connectors yes before i can remove the throttlebody.

    yes i mean the oil cover.

    yes but there is no idle speed while i does not use the throttle the car fel out.

    yes i spray with carb cleaner in it and use some compressed air to clean it. in the intake was again that black fluid. i dont know why its in there.

    the New MAF sensor was complete with body. i place the whole thing into the car.

    yes but no response while i disconnect it. only while i open the pipe from the intake manifold the idle go higher.

    its difficulty to check the firing because the car have no idle.

    i mean the tube that going to the idle switch. i know there is no vacuum.

    the vacuum is about 10 inHG with warm engine. but thats because the idle is so low. when i give some gas to about the 700rpm its about 15/16 inHG but thats not higher because the throttle is open than.

    i have place all new sparkplugs why does one sparkplug doesnt spark? maybe the rotor bad?

    Comment


    • #62
      Or cap, or lead.

      Comment


      • #63
        Excellent find sir!

        "...why does one spark-plug doesn't spark?"

        Why indeed but - Bingo! There's one cause of your low idle. Bowie may be correct, don't condemn the rotor just yet. You can clean them up in place (they are glued on the shaft) quite a few times without having to replace it. Could be as simple as visible (and remove-able) carbon-tracking inside the distributor cap. One can meter all the ignition leads for resistance also. I had one lead fail that would visibly leak blue spark at night with the hood open.

        Testing ignition leads (including the SAE's suggested max. ohms resistance per foot of length: 12k Ω):
        https://www.championautoparts.com/Te...lug-Wires.html

        Although NGK advertises new leads with only 1,300 ohms per meter, when testing or shopping, perhaps best to aim for a target of 6k ohms / meter (and not more than 16k Ω / meter depending on materials / construction / age) is what one is more likely to find.

        Q: - After engine shut-down, was the non-firing spark plug wet or dry?

        Q: - Re code 2232: Did that code return? I am concerned about your hot MAF wiring, is there perhaps corrosion on the connectors? Is this old damage (previous MAF) or new damage (current MAF)? This code could be due to wiring and not the MAF. In your video I believe I saw the MAF wires loose and not fastened down to anything (not clamped in place). Is there any other visible physical damage to them? Are they fused just close to the MAF?

        Comment


        • #64
          Originally posted by Lago Blue View Post
          Excellent find sir!

          "...why does one spark-plug doesn't spark?"

          Why indeed but - Bingo! There's one cause of your low idle. Bowie may be correct, don't condemn the rotor just yet. You can clean them up in place (they are glued on the shaft) quite a few times without having to replace it. Could be as simple as visible (and remove-able) carbon-tracking inside the distributor cap. One can meter all the ignition leads for resistance also. I had one lead fail that would visibly leak blue spark at night with the hood open.

          Testing ignition leads (including the SAE's suggested max. ohms resistance per foot of length: 12k Ω):
          https://www.championautoparts.com/Te...lug-Wires.html

          Although NGK advertises new leads with only 1,300 ohms per meter, when testing or shopping, perhaps best to aim for a target of 6k ohms / meter (and not more than 16k Ω / meter depending on materials / construction / age) is what one is more likely to find.

          Q: - After engine shut-down, was the non-firing spark plug wet or dry?

          Q: - Re code 2232: Did that code return? I am concerned about your hot MAF wiring, is there perhaps corrosion on the connectors? Is this old damage (previous MAF) or new damage (current MAF)? This code could be due to wiring and not the MAF. In your video I believe I saw the MAF wires loose and not fastened down to anything (not clamped in place). Is there any other visible physical damage to them? Are they fused just close to the MAF?
          hello, i checked the rotor and the cap, yes there are carbon tracking inside the cap. all the contacts are black. does i need a new cap? https://ibb.co/VCkkdPP
          https://ibb.co/9tnk9f4 that scratches are from a sandpaper
          the cables are good and have 12k ohm what you saying and there are no cracks or damage on the cables.

          Q1: all the sparks are wet when the car shut down.

          Q2: the code is returning. the cable was smelted before i buy the car. i remove the black stuff that protect the cable because it was smelted. it was before i place the new MAF. only this cable is damaged i think it was come to the heatshield. no there is like 40cm before it comes to into the MAF, i have the same cable that i can place on it. can i soldering the cable into it?

          Comment


          • #65
            Your cap is fine.

            Have you replaced the plug(s)?

            Plug wires may have the right resistance, but may also have an insulation breakdown so they earth to the engine, and not through the plug. You could test this by swapping leads between plugs (both ends obviously) and running the car again, then check if your dead cylinder is now magically firing.

            Comment


            • #66
              Originally posted by Bowie69 View Post
              Your cap is fine.

              Have you replaced the plug(s)?

              Plug wires may have the right resistance, but may also have an insulation breakdown so they earth to the engine, and not through the plug. You could test this by swapping leads between plugs (both ends obviously) and running the car again, then check if your dead cylinder is now magically firing.
              yes i replace all the plugs but before changing the same problem was on it. there are two wires with some damage but its not big so i dont know if its a problem. how can i swap the cables they are all with there own lenght.

              https://ibb.co/M2DHV50
              https://ibb.co/x2VS50Z

              Comment


              • #67
                They are sort of custom length, but if you take them out of the shroud, you can hook them up temporarily.

                But I'm going to tentatively stick my neck out and say that lead is broken and very likely leaking electricity.

                Comment


                • #68
                  Originally posted by Bowie69 View Post
                  They are sort of custom length, but if you take them out of the shroud, you can hook them up temporarily.

                  But I'm going to tentatively stick my neck out and say that lead is broken and very likely leaking electricity.
                  All the wires have te same resistence and there was a corosion on the wire Connections I have clean it up now its better rpm but fluctuating

                  Comment


                  • #69
                    Same resistance means nothing other than there is no break in the wire.

                    If there is a gap in the insulation, and the spark is escaping to the engine block/head/anything else that is ground, it won't be getting to the spark plug, which means you get a misfire.

                    Comment


                    • #70
                      Originally posted by Bowie69 View Post
                      Same resistance means nothing other than there is no break in the wire.

                      If there is a gap in the insulation, and the spark is escaping to the engine block/head/anything else that is ground, it won't be getting to the spark plug, which means you get a misfire.
                      How can i test it, What wires wrong

                      Comment


                      • #71
                        Swap them between cylinders, and see if the wet/non-firing cylinder moves.

                        Comment


                        • #72
                          Originally posted by Mikemul View Post

                          How can i test it, What wires wrong
                          Look at it in the dark? Arcing should be visible .

                          Comment


                          • #73
                            Yep, very possible, unless it is leaking down the plug hole.

                            For the sake of <£100 I would just replace them, they are rooted.

                            Comment


                            • #74
                              Originally posted by Bowie69 View Post
                              Yep, very possible, unless it is leaking down the plug hole.
                              Very true.

                              Comment


                              • #75
                                Lago Blue has given some top notch suggestions and solutions for this lifelong problem. Amazing how into detail you are willing to go just to help a lost friend out. This thread is ready to be the "go-to" thread when 20v NA owners experience idle issues. lol

                                I had a funny solution to my idle issues with my 2.0-20V NM motor (lil brother of 7A). I had bought the car with a bad cold idle and after exploring countless hours in the engine bay, replacing all kinds of stuff and READING a sh** ton of info about 7A motors I finally noticed something that wasn't supposed to be where it was.

                                The PO had put a fuse on top of the fuel pump relay.

                                explanation to the unaware... a fuse is placed on top of the relay ONLY when setting the idle speed and CO-value. It locks the timing to 14? degrees advance and probably something else i can't remember right away..

                                The best part is i drove the car easily over 10 000km with the fuse in place and basically the car always in "idle setting mode". IIRC the symptoms were (1.) faulty idle most of the time (only not when engine was fully hot(of course, because the idle setting is supposed to be done with a warm engine)), and (2.) I think I felt the timing lock dissapearing and changing to normal upwards 2000rpm. The change was noticeable as the car was stuttering at around 2000rpm.

                                But that's all.. do check that you don't have a fuse in there... on the fuel pump relay...
                                1989 90 quattro NM

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