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  • #91
    No, hunting for a wiring diagram which has the correct colour coded wires on it...

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    • #92
      The factory diagrams are not always correct. There are a few errors in most of them.

      The only diagram I have is from 1992, but based on a 1990 schematic.

      As far as I can see:

      TPS: G69
      Pin 1 - Black - voltage reference ECU 6A (likely 5v)
      Pin 2 - Brown/Green - Earth
      Pin 3 - Black - Signal ECU 7A
      Idle switch: F25
      Green/Purple - Signal ECU 9A
      Brown/Green - Earth

      So with ignition on you should see 5v at pin 1 and a changing voltage between pin 2 and 3 when actuating the throttle valve.
      Panthero Coupé quattro 20vt
      Indigo ABY coupé
      Imola B6 S4 Avant

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      • #93
        Thanks Alex, this looks the same as the one i have. It is the two black wires i think 'might' be the wrong way round. It looks like the answer will be trace the correct plug at the ECU and check for continuity between ECU 6A and 7A and TPS pins 1 and 3... thanks for confirming the ECU pin-outs though. Wouldn't life be easy if the diagram mentioned the black with brown tracer that i do have!

        On an additional note; I opened up the joint to my cat bypass pipe to remind myself what size gasket it has before ordering another and noticed that my Tony Banks system has introduced yet another dubious working practise which will be put right on the 18th. The end of the tubular manifold has an internal diameter of 55mm but for some reason the bypass pipe has been made with an internal diameter of 50mm. Its not much but things like that annoy me - it should really match as what i have now is a definite step the gas has to flow over before it gets towards the silencers.

        One thing for sure though, i am learning a lot more about my car working through this and when i'm done i won't have any faults at all and the car will be finished. hah, finished indeed...
        Last edited by steve briance; 10 December 2018, 22:33.

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        • #94
          mine will also be "finished" one day.... yeah... right.. .

          Honda CBR 1100XX Blackbird Turbo....undergoing major changes.....
          S2 Coupe... bit easier off the line...
          '03 ZX12-R daily hack.... lots of nice bolt ons...

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          • #95
            Whilst it would be better to trace the wires back to the relevant ecu pin surely just disconnecting the plug from the pot and testing the pins should provide the answer.
            Only one will have the ecu reference voltage on so that must be from the ecu. It seems pin 2 is earth. From the diagram it looks as though pin 3 goes through a connector somewhere. It usually gives you a clue on the relevant page. If the wiring (wire) has been replaced perhaps that explains the tracer colour.

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            • #96
              Originally posted by steve briance View Post
              No, hunting for a wiring diagram which has the correct colour coded wires on it...
              The picture show everything correct cause you rotate the connector when you plug the connector into the TPS.

              Did catched your "ECM picture" correct - the "ti load" won't get 255 (12.75ms) that you "reach" the last line but this doesn't matter cause you should have a full load fuel table for that (at "ti load" above xyz it switches over).
              So I don't know what your issue is - what you are looking for.

              I'm pretty sure that a incorrect wiring at the TPS would cause a DTC but Motronic should run MAF sensing anyways..
              Leaning out could have several issues (fuel pump etc) but so far I'm sure you "play" in the wrong tables in your ECM...

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              • #97
                Acki.
                I don't know what xyz is but let me clear up some things that may have been missed...

                This is not a motronic ecu, hitachi is fitted to the 7A engine fitted in my car. It may well run the same way but who knows, there is not as much written about them.

                I realised the plug is 'reversed' when connected to the tps but the testing procedure takes that into account and states: disconnect plug and check for voltages between pin 1 and 2 and then pin 1 and 3. Both should be between 4.5-5.5volts. I got nothing between 1 and 2, 5v between 1 and 3 and 5v between 2 and 3. The results are a reverse of what they should be hence the checks done and further checks at ecu to do. Having found the previous repair, I wonder if the person doing that didn't realise the plug pins are reversed...

                Although this was found on Quattroworld forum relating to boosted cars, there was a diagram of the inside of the tps and there is no full load switch built into it.

                Fuel pump is now brand new and running from a thicker cable and its own relay. This gained me an extra 100ml of fuel per minute so it wasn't that weak before but now its as good as it can be.

                The second pic is the tuning interface for fuel map and 255 is on the far right of the table. While driving the blocks turn red to show which block is being used. The 255 block never turned red so unfortunately it looks like I never got there
                You do not have permission to view this gallery.
                This gallery has 2 photos.

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                • #98
                  http://www.20v.org/throttle.htm

                  Scroll down for your set up. I am wondering if this is a typo that has been repeated.
                  We know that pin 1 should be the reference voltage from the ecu (5V). Pin 2 is earth/ground. Pin 3 should be the signal back to the ecu.
                  As far as I can see you would only get something out of pin 3 when it is connected to the pot. Therefore you would have to remove the rubber boot and back probe the connectors. Whilst I can see how you can get the varying voltage between pin 2 and 3 as thats the purpose of the pot, I can't see how you would get a voltage reading between 1 and 3 when connected as both would have voltage on them. So basically I am suggesting that it should be 1 and 2 and 2 and 3 for voltage with the pot connected and throttle closed as thats the only time the voltage will be close.
                  That doesn't mean that the wires have not been transposed. But clearly you can check two, the reference voltage and ground. The other must by elimination be the signal.
                  Might be worth asking to see if someone with a similar era 7A can verify the wiring as a sanity check!
                  Last edited by twoqu; 11 December 2018, 11:09.

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                  • #99
                    Measuring this should be done in parallel - everything connected.
                    You are right that I don't know the 7A ECM - I would wonder if this ECM works much different than the Motronic.

                    Motronic detects an TPS failure when voltage isn't ~1V when power on, it never starts at 0 -> fail safe, disconnection detection!

                    Full load you have another table or is this done in one table?
                    Your picture is not helpful... I don't see anything helpful to be honest.

                    Other story, my V8 has only maximum "ti load" of 220-230 - I never reach 255, when I would I would have some issue with the MAF sensor, diagnosis can only work when you have room for derivations.

                    So again, what is the real issue at this vehicle?
                    You run lean - you change the ECM but it doesn't affect the lean out? (can the enrichment is causing issues? I made the experience only Autobahn/long Dyno runs will show you the real lambda in high engine speeds)
                    Sure you change the right table?

                    Does any 7A reach the 255?

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                    • "Might be worth asking to see if someone with a similar era 7A can verify the wiring as a sanity check!"

                      I came very close to sending a pm to the seller of the mint condition low mileage 7A loom on this forum (vorsprung durch teknic) but then re read his advert and it is for the earlier cars with a 4 pin tps. Damn.

                      I don't know any other 7A owners locally where I could pop round and check but if anyone does happen to have their 7A car in bits for winter work, it would be awesome to have a photo of what lies beneath the tps plug rubber boot.

                      Acki, interesting point about whether the car ever reaches 255 in a fuel block. I've no idea.but I see what you mean about diagnostics needing a bit of variation.

                      I think the next update will be a nice picture of a new back box maybe with video (we all like pictures and videos) and then after that, because I am running out of knowledge, wait until the revisit to tuning.



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                      • Any update

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                        • Any update ?

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                          • Revisit for tuning is 25th January.

                            I would measure the flow through the new rear silencer but testing the old one appears to have melted one of the fan blades off my airspeed meter, I'm not so sure it will work now! ​​​​​​

                            Will add a pic of the new backbox at the weekend as I'm dead pleased with it. I hung around at PD Gough and watched when it was being made and they did a good job. Its now properly straight through and 4 inches longer than the outgoing one, sounds no more noisy which is a result.

                            I've got nothing to back up the feeling of course but compared to the Tony banks box, the engine feels keen now from earlier in the rev range. I'm going to have to find a 4wd rolling road one day and do a power run. It's inevitable.



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                            • Good stuff .I can't wait to hear from you about results after 25th.Good luck

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                              • VRS at Northampton now have 4 wheel Dyno

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