Headlights lower idle

[iBoostDSM]

Something weird just started happening with my car. When I idle without my lights on its steady around 1000rpms, but when I put my headlights on it drops a bit to the point where it almost dies. I don't no what's going on...please help.

 

[iBoostDSM]

I been on the hunt for the problem for a while now. I know I have a leak but I can't seem to find it, I've used soapy water to track down many others. When I get home from school today i was going to check the multiple ISCs i have and TPS(Would you check that the same way as the ISC?) And I'm pretty sure my stepper motor is fine same with the BISS screw cause I bought a new one not to long ago, but is there any way possible to check the ECU?

Thank you so much for the help guys

I watched the video on youtube of how it's supposed to behave and mine doesn't do that. My ISC shows the correct resistance. Where should I start for my search to find the problem.

 

[steve]

If none of the ISC's you have work (make sure they don't have any shorted windings before connecting them) then it's likely a wiring or ECU problem.

 

[iBoostDSM]

Ok I'll have to get a diagram and check the wires as soon as I have some time. Is this going to solve my idle lowering with the headlights and such or am I also going to have to get a new alternator?

 

[steve]

It should fix the idling problem, hard to say about the alternator since the 2G ECUs switch it on and off. You may need to replace it too given the voltage readings or you may have just measured when the ECU had it off.

 

[iBoostDSM]

Do you know of anywhere where I can find a wiring diagram for the ISC. I've been looking when I have time but I haven't been able to find anything.

 

[steve]

Do you know of anywhere where I can find a wiring diagram for the ISC. I've been looking when I have time but I haven't been able to find anything.

http://www.dsmtuners.com/forums/fre...stions/324090-download-2g-service-manual.html

 

[iBoostDSM]

Thanks again, I'll have to take some time and look through this.

 

[iBoostDSM]

Good news! I fixed my problem! The culprit was the ISC connector, I pulled it off and two of the wires were cut. This fixed the problems with my lights and many others.

 

[steve]

Great news.
Which wires were cut?

 

[4g63oncrack]

it definitely sounds like a bad ground and that diagram should me on the manual?

 

[iBoostDSM]

Wires 4 and 5 were cut right next to the plug. I already had another connector so I just cut the rest of the wires then put that one on. It runs sooo much better now.

 

[steve]

it definitely sounds like a bad ground and that diagram should me on the manual?

Technically there are no grounds at the ISC/IAC connector. There are two power feeds and four wires to the ECU, one for each coil in the ISC/IAC that the ECU pulls low to energize that coil.

The diagram is in the FSM, the ISC/IAC wiring is included with all the rest of the ECU wiring in the fuel section or under MPI/MFI heading in the electrical manual.