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Damian94

Hard starting 1uzfe problems IAC?

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I recently put a 1uzfe V8 into a L200 using the G4+ extreme ECU

I’m having problems with hard starting as it’s taking around 30-40 seconds from cold I’m pretty sure this is to do with the IAC, it seems it is not getting a signal it is wired into ports ISC 1,2,3,4 but is not receiving any signal 

Is there anyone who can shed any light on this problem or any wiring diagrams would be helpful 

 

thank you 

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The stock 1UZFE IACV is a 6 wire plug. Two wires provide 12v (B1,B2) from EFI1 Relay, and the others are grounding signal wires from ECU for ISCV1,2,3 etc. 

Unlike the stock setup above, when you wire in a Link you only need to use 4 wires of the 6 on the plug. The Link is able to output 12v on ports Aux 5-8. Aux 5-8 will need to be wired to ISCV1,2,3,4 respectively.  When you wire it up this way, you no longer need to have 12v coming from EFI1 to B1 & B2. You can just leave them unconnected. You will need to configure Aux 5-8 as ISC Stepper, rather than ISC solenoid. 

Here is a useful website going into further details about this sytem and provides pinouts for the plug. Watch out as the order of pins do not match the order of IACV1,IACV2 etc. http://wilbo666.pbworks.com/w/page/42947521/M-REL - 6 Wire Idle Speed Control Valve (ISCV) Wiring

Once you are done with the above, you can now begin testing. 

I would set your Idle control base position tables to 0. Then open your throttle stop on the TB, allowing the car to start using the throttle body blade's opening, rather than the IACV.

Let the car idle and get warm for a few minutes. Then adjust your throttle stop on TB to give you around 650-700rpm idle. Make sure your fueling and ignition timing in these areas are good enough that it wont let the engine stall out etc. 

Now you can go back to your idle tables, start in open loop and slowly introduce %DC into your base position table. At some point you should start hearing your idle raise. Make sure you can adjust your idle higher and lower by increasing or decreasing the numbers in your base table. If you can then you are good to go, and you can follow the rest of Link's help guide on how to setup idle. 

If all the above makes no difference then you may want to attach your MAP and a log of the hard starting in order to diagnose from that. 

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