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Thread: Car won't start question

  1. #11
    Senior Member Slimer86's Avatar
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    Sensor underneath the throttle bodies bolted on the block is the factory knock sensor.
    Solenoid with two hoses coming out of it with a three pin plug connected to it, located under intake of number 4 is the idle control (stock 20v).
    If one of the wires which you have covered is black with a yellow stripe, it is switched positive when ignition 2 is engaged. It connects to the alternator in a standard ae86 (check circuit continuity) I believe. The color did not change with the 20v alternator.

    Check the ae86 factory wiring diagrams I think in the technical sticky.
    Big up's for the North East Massiv'
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  2. #12
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    Hey Slimer86, do you think that the idle control is what's causing this issue of sometimes starting and sometimes not? because id love to daily this car and work on my left arm tan! hahaha

  3. #13
    Veteran LittleRedSpirit's Avatar
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    An engine that's cold and freshly started needs way more air and fuel than a motor that's up to operation temp. Therefore when you start you need the idle controller to let more air in for a while. The ecu should add up to 25-30 percent more fuel and this should taper down to the normal amount according to your tune at operation temp. Just like what you observed your Toyota truck does.

    Check the post crank enrichment, cranking fuel, and ignition setting while cranking, which should be controlled from the haltech. Also check your correction table for fuel enrichment vs temp. I suggest 14MS of fuel while cranking and 4 degrees btdc timing.

    Check your ecu base timing, buy a timing light if you have to its easy and provides proof the engine is going to be in time. Your ecu will have a timing lock to allow this to happen and an offset controller to advance or retard a degree at a time to correct any discrepancy.

    Make sure the timing is well handled in that there are timing vs temp correction tables that generally rookies will overuse, for the most part until you reach the finer edge of your tuning you may never need to add data in these, Ive seen people with terrible values in there whose cars run like shit cause they had a table that made the timing retard 10 degrees at operation temps and basically ignite after tdc. So wipe all timing corrections based on air and water temp if there are any to simplify your trouble shooting.

    ECUs will usually have a gauges readout and a diagnostic readout that shows voltages etc. Make sure you have entered accurate calibration data for your ecu temp sensor and that its working perfectly. In my car I installed an aftermarket gauge right next to the ecu gauge and I calibrated it at specific temps off the other gauge as it warmed up. You can also leave it wired to the car then boil some water on a camp stove and calibrate it as its temperature warms. It takes a while but is most rewarding when it works right.

    Make sure you have filled out your injector dwell time vs voltage table. Often referred to as injector lag. Otherwise you might be effectively injecting at a bad moment that fails to atomise fuel at low temps. You can usually google and find this data from large tables others have researched.

    With grounds, all your sensors ground back to the ecu and the ecu grounds to the motor usually. The engine itself requires that big heavy disconnected cable to pass the current from the electronics back to the battery via the body, so make sure you have adequately sized cable to overcome voltage drop if you have a boot mounted battery and that all the lugs on its ends touch bare metal in the bay and on the motor. Make sure the negative battery lead is connected from negative terminal to body to complete the wiring circuits. Again make it touch bare metal, rub back some paint if you need to.

    Old starters often stick, even my rebuilt one has stuck on me once before, so just belt it with something as you say.

    Get a hold of a battery charger and slow charge your battery as it will be under stress and it will need it if you often are forced to crank it for extended periods. Check its de mineralised water levels.

    Make sure your plugs are the correct colour to indicate clean running, if they are sooty and fouled then they may be not able to throw a spark so you can clean them in a number of ways, I use a hot flame like a map gas flame and heat therm till the electrode goes reddish then the muck just wipes off as they cool. Hold them in the plug spanner as you do this to save fingertips. If you find them fouled then ask why, I dare say you have more fuel then you need and the number one culprit is the cranking enrichment since it can run good once warm but starting is always a pain. You may simply in old terms be flooding it. Most ecus have a flood clear function if you hold 100 percent throttle they will; cut all fuel and you can crank it over to dispell the fuel and then release the throttle and start over. Before trying read about your ecu and make sure.

    Are your itbs synced nicely? There are vacuum gauges you can fit to test them all simultaneously. Also, there is a correct way of adjusting all the butterflies and stops using feeler gauges if you have uneven amounts of air from one cylinder to another. You need the original manual from the donor vehicle that gave up your 20v.

    I dare say your alternator is charging as the thing would be flat as without it, lots of cranking and a 2 hour drive would surely completely flatten the battery if it was not charging.

    Good luck. Start with the basics, the setup and the fundamentals and you will make a lot of improvements usually.

    Im more knowledgable about adaptronics but I'm sure if you post your haltech map, someone who also uses haltech might load it up and go through it for you to check what I've described above, but really if you intend to own and live with an aftermarket ecu, you really should be the one to study it. Tuners just want a quick buck, if you take them a car with fundamental problems then they will just tune it with those issues and you will have wasted your time and money, so get all the fundamentals right first!






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