Why does my port and valve looks like this?

[Ryosuke takahashi]

So I overhauled the 4G63 NA motor in this Galant GTi. I think I'm running lean there's not much torque. I have new set of plugs, my ISC motor is not working. Any recommendations of what I should do?

Please help me guys thank you in advance

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[steve]

Was the engine doing this before the overhaul?
Are the MAF and ECU correct for the car?
Have you measured the ISC coils to see if any are shorted or open?
Has the ECU been rebuilt and had it's capacitors changed?
Have you checked the compression and the fuel pressure?

Just a few questions to help move this along.

 

[Ryosuke takahashi]

Was the engine doing this before the overhaul?
Are the MAF and ECU correct for the car?
Have you measured the ISC coils to see if any are shorted or open?
Has the ECU been rebuilt and had it's capacitors changed?
Have you checked the compression and the fuel pressure?

Just a few questions to help move this along.

Hello i have a bad isc and my maf seems to be bad also since when i try to pull the socket the car doesn't die and it revs much better than the socket is on I didn't do anything with the ecu i have good compression and new fuel pump and filters

 

[curt-s]

Can you get a side profile shot of any of those plugs? Unless my eyes are playing tricks, I'm not even seeing an electrode anymore. It's unrelated but it's still a thing
By socket do you mean the ISC or MAF plug? If you have a bad ISC and have tested the resistances across terminals, did it short or blow open? Shorts cause ECU damage.

 

[steve]

Everything depends on having a good ECU and that it's airflow metering is functional and correct. The ECU from this time period suffer from capacitors that leak and corrode the circuit traces. Additionally the metal cased ISC's with brown/tan tops tend to short out and when they do it burns up the driver IC's in the ECU so that even with a new ISC they no longer function. If you haven't had the capacitors replaces you should check the ECU before investing on additional parts.Disconnecting the MAF causes the ECU to enter limp mode. It should also cause the ECU to turn on the Check Engine Light.

There are three sensors in the MAF that disconnecting will cause those to fault. Airflow, Intake Temp, and Barometric Pressure.

Here's what the ECU defaults to in limp mode.

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For the ECU to know how much fuel to inject it has constants in it's code for how big the injectors are (in CC's at base fuel pressure) and what their deadtime is. The fuel system is designed to maintain fuel pressure across changing manifold pressure by a regulator that tracks it 1:1. If it doesn't the engine gets more fuel than programmed at vacuum and less as the manifold reaches atmospheric.

You need to measure the base fuel pressure with the vacuum line disconnected from the fuel pressure regulator and plugged.

Those spark plugs like like iridium plugs, the standard NGK copper plugs seem to work better, at lease in the turbo cars.

 

[curt-s]

On those plugs, I think you're right @steve

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There could be an electrode there as the dark part obscures the light under the ground electrode

The only time I've seen brown on the exhaust side is when it's really, really terrible gas or highly doped with "cleaning" agents.

 

[steve]

And too much "octane booster" will give you funny colors too.