7mgte swap...almost to the finish line! - Page 3

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  1. #21
    CelicaSupra.com Member
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    Well I fixed the O2 sensor wire. Tries again and same symptoms. Threw a code 22. Efi temp sensor malfunction. The ECU coolant temp sensor connector was loose on thermostat housing. So fixed that. Then threw a code 52. Knock sensor so I dunno. My next step is to do a compression test and Leak down test. Go from there. The motor was completely rebuilt, metal head gasket. So really hoping it's not the motor.

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  3. #22
    CelicaSupra.com Member
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    Those locks on the ECU clips are there to lock the pins into position in the plug. Generally only used when replacing a pinned wire that was somehow damaged or defective. What can happen when you plug a clip in without the pins being locked fully in, is that some or many pins may not be in full contact with their mating pins on the ECU. Of course, any pins that you back probe will likely be pushed into making good contact with its corresponding ECU pin. But I would guess many aren't. Otherwise, if all those pins were making good contact, wouldn't all the error codes for everything the ECU detected be displayed at the same time? For example, you got a temp sensor code when the plug was loose. And then after connecting that, a knock sensor code. Why weren't they both detected and displayed at the same time?
    At the very least, you should probably disconnect your battery and check and recheck everything. And you should manually verify every pin is firmly seated after you insert any plug with the lock open before reconnecting the battery and retesting everything. You should probably recheck everything else too. Your symptoms all seem to indicate different issues. At least to me they do, and I've been doing this kind of stuff for a lifetime.
    ECU's have at least some amount of capacitance to maintain the keep alive memory for a certain amount of time. This is so that it takes a loss of sufficient power for a certain minimum time before it has to relearn things that would have been kept in memory. This can also be a good thing to force a reset after it gets confused or to reset error codes by removing power for longer than that. Suppose that 20 seconds was about that time. Does this then suggest the two things might be related? Poor power or ground can do exactly this type of crazy stuff. Remember that your meter has an extremely high input impedance and therefore puts essentially no load on anything when taking measurements. It's very possible that with any load at all, some voltages virtually disappear. And you can't measure everything at once so... check everything after following these recommendations again.
    By the way, certain sensor wires are shielded to prevent the wires from picking up any of the extreme under hood electrical noise and rendering their outputs completely unusable. Examples are: O2 sensor, knock sensor, distributor pickup (which you don't have), crank triggers, cam position sensors, etc, as well as other similar things. Typically these shields are only connected to ground at the ECU and not at the sensors themselves. These shielded wires are very similar to other shielded cables like audio and video cables and others. One important factor in the shield being effective and the desired signal getting through in a usable form is the actual shape of the shielded cable. So sharp bends and kinks can render them unusable.
    Hope this helps you figure things out. Let us know what you find or don't find. Good luck.

  4. #23
    CelicaSupra.com Member williamb82's Avatar
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    Sounds like fuel pressure is dropping to me. If compression is bad, it would have issues even starting, and wouldn't run 10-20 seconds before slowing down and stalling.
    william
    Hidden Content black 84 7mgte, MS2, truetrac, bbk, etc...soon to have 2jzgte and t56
    Hidden Content blue 85 beater
    Hidden Content black 86 triple weber 6m in the works!

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  6. #24
    CelicaSupra.com Member
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    Hey all just a quick update. While troubleshooting, I broke a few wires and then kept noticing loose and brittle wires all over the place. Clearly the whole engine harness had been torn into in the past, repaired probably countless times. Half the shit was either cut or spliced. I am fairly certain the motor issues were attributed to this harness. So I decided to buy a whole new replacement engine harness. I found one from a very nice dude on the 82-85 celica supra facebook group. He had a very clean, unmolested harness from an 89 car that also came with the ECU. SO I picked that up for a pretty good deal I think and there are only two wires broken which goes to the thermostat housing. One that controls the AC fan switch. That connector was completely missing. It's a big 'ol blue one that looks like a knock sensor. So i ordered one up from Toyota. The other is the water temp sensor for the gauge. Just need to re-solder that one and should be good to go.

    Anyway, so I'll have to do the wiring conversion all over again. I am following Lee's guide http://www.celicasupra.com/forums/sh...P-wiring-guide. Seems pretty straight forward. The cool thing is this new replacement harness came with the male B1 connector! I'll reuse the cutout plug from the 5m ECU from my old harness, and the K plug that was originally on the 5m harness. So the only male plug I need for the sub harness is the m1 connector. I picked me up one of those from a good dude from supraforums. I'm all over the place trying to piece this thing together. One of the steps calls to de-pin the blk/orange wire from the B1 and pull it all the way out of the harness so that you can plug into the mkii coil or injector resistor connector. The blk/organe wire is critical as it powers the 7m coils, injector resistor and a whole host of other sensors. Seems like a huge pain in the ass unwrapping the whole harness for one wire. I'm wondering if you can just tap into a switched 12v source from another place up near the ECU plugs. If I end up unwrapping the harness and pulling the wire through, i will probably re-wrap it with some expandable sleeving. Here's what i was thinking. http://www.corsa-technic.com/item.php?item_id=292.

    So the plan is to get the sub harness built, figure out what to do about that one wire (either pull it through and re-wrap everything or find another power source). Install the new harness on the motor, re-do the ignition timing and hope for the best. Hoping to make some good progress this weekend.

  7. #25
    CelicaSupra.com Member gamble's Avatar
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    Man you're gonna finish 2 harnesses before i finish one at this rate. Wires can be the worst, can't live without em though :P

  8. #26
    CelicaSupra.com Member
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    Gamble, I hear you man. Wiring is not my forte but at this rate I'm going to be an expert. Takes a lot of patience and research. Both of which I'm not the best at. Ha!

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  9. #27
    CelicaSupra.com Member
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    Over the past week or so I've been trying to source replacement terminals to complete build the subharness. My goal is to have no solder points. Mark Sherman over at Vancouver toyota has been a huge help pointing me in the right direction.

    Here's a couple sites that sells a plethora of Japanese connectors.

    http://cycleterminal.com
    http://www.corsa-technic.com
    http://www.bmotorsports.com/shop/

    I found the B1 and K connector terminals. However having trouble finding the terminals for the M1 connector. I've dug through these sites trying to find a match. No dice. Terminal is pretty small and slides into a locking type connector. Tip 1.0mm wide and accepts a 20-22 awg wire. .





    It would be super helpful to have a cross reference guide of common mk2 and mk3 connectors, terminal types and current mfg, size and where to buy. I may create one when I'm done. It's been painful sifting through the toyota wire harness repair manual, get an idea of the terminal size and type and then go try to match it up at one of the sites

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