突然看到的實用資訊：備份下來，也許改天幫朋友debug VW GOLF MK2 用得到
Ref: Commet on https://www.facebook.com/groups/vwcorradoownersclub/posts/1375206023484532/
Basic Steps to Troubleshooting Bad Idle on a Corrado G60, for Beginners
First, do this basics to eliminate some variables:
DEGUNK THE Idle Stabilizer Valve (ISV) - Pull it off, spray it full of brake/parts/carb cleaner. Shake it around with the cleaner inside, empty it out, repeat until the cleaner comes out clear. Remember, do not unplug the ISV with the key in the accessory or on position. THis is bad for the ECU.
Check for vacuum leaks. There are a load of vacuum lines on the G60. The stock lines are rubber wrapped in a braided cloth and can dry-rot and crack. I replaced all of mine, from the dealer, for less than $40. Just ask for the diameters and lengths, and they should be able to cut them for you.
Here are the sizes, courtesy of the G60 Forum FAQ:
3.5 mm size line: 34" (brake booster line) + 39.5" (1 meter ECU line) + 6" (FPR) + 55"(charcoal mainifold) + 30" (air box to brake booster line) = 14.3 feet
9 mm size line: 40" (throttle body to charcoal)
5 mm size line: = 23" (brake booster to charcoal) + 28" (fuel tank breather line to charcoal) = 4 feet 3 inches.
That one-meter throttle-body to ECU line is important. There are two vacuum lines that go to the throttle body, and the ECU line connects to the nipple closest to the passenger side.
Second, Look at the electrical stuff.
Make sure there is no interruption in the spark: spark plugs/wires...make sure they are in good shape.
There's an electrical switch on the throttle body called the "idle switch" that should click on when the throttle is closed. Not surprisingly, the car will not idle right if this switch is fouled. It might not even start. It shares its connection to the harness with the wide-open throttle (WOT) switch, and the plug is on the back of the throttle body.
The fuel injector harness is in a crappy place, between the head and intake manifold, where there certainly is significant heat. The insulation gets very brittle over time and there is the potential for electrical shorts. Check it.
Look for corrosion at grounding points. Particularly the ground on the coolant flange on the (transmission) side of the cylinder head.
Third, determine under what conditions idle is poor.
>Is it bad when the car is cold but better when the car warms up?
>Or is it good when the car is cold and worsens when the car gets warmed up?
>Or is it just crappy all the time?
>Idle Is Bad When The Car Is Cold:
If you disconnect the blue coolant temp sensor while the engine is running and it idles better, you probably need a new blue coolant temp sensor.
If that doesn't do it, then check the O2 sensor, check your timing and reset your idle*
>Idle Is Bad When The Car Is Warm.
If you disconnect the o2 sensor before or while the engine is running, and the car idles better, you probably need a new o2 sensor.
If that doesn't do it, then check the blue CTS, check your timing and reset your idle.* If the idle is set too low, then the ISV will attempt to compensate for it once the car is out of cold-start mode, and the idle will be bonkers.
>Idle Just Sucks All The Time. Either the timing is way, way off, or you didn't set the idle right (too low).*
*Remember, the idle won't set correctly using the idle screw if you don't have the ISV unplugged.
And remember the method for setting the timing: The car must be warm, with the blue CTS unplugged, and the motor must be at ~2500 rpm. Set it for 6-8 degrees BTDC.
If idle is still bad, ask the experts in the G60 tech forum and read through the G60 tech forum FAQ if you haven't already and be sure to tell them you've done the basics.
Google 翻譯：
初學者排除 Corrado G60 怠速故障的基本步驟
首先，請執行以下基本步驟以排除一些變數：
拆卸怠速穩定閥 (ISV) - 將其取下，噴灑煞車/零件/化油器清潔劑。將清潔劑倒進閥內並搖晃，然後倒出，重複此操作，直到清潔劑乾淨為止。記住，請勿在鑰匙處於附件或開啟位置時拔下 ISV 插頭。這會損壞 ECU。
檢查真空洩漏。 G60 上有許多真空管路。原廠管路是用編織布包裹的橡膠，可能會乾腐和開裂。我從經銷商處更換了所有真空管路，花費不到 40 美元。只需告知直徑和長度，他們應該可以幫您切割。
以下是 G60 論壇常見問題中提供的尺寸資訊：
3.5 公釐規格管路：34 吋（煞車增壓器管路）+ 39.5 吋（1 公尺 ECU 管路）+ 6 吋（燃油濾清器）+ 55 吋（活性碳總管）+ 30 吋（空氣箱至煞車助力器管路）= 14.3 英尺
9 毫米規格管路：40 吋（節氣門體至活性碳）
5 毫米規格管路：= 23 英吋（煞車增壓器至活性碳）+ 28 英吋（油箱通氣管至活性碳）= 4 英尺 3 英吋。
那條 1 公尺長的節氣門體至 ECU 管路非常重要。有兩個真空管路連接到節氣門體，ECU 管路連接到最靠近乘客側的接頭。
其次，查看電氣部分。
確保火星塞/電線沒有中斷…確保它們狀況良好。
節氣門體上有一個稱為“怠速開關”的電氣開關，當節氣門關閉時，它會發出咔嗒聲。如果這個開關損壞，汽車將無法正常怠速，這不足為奇。它甚至可能無法啟動。它與節氣門全開 (WOT) 開關共用線束，插頭位於節氣門體的背面。
燃油噴射器線束的位置很糟糕，位於汽缸蓋和進氣歧管之間，那裡肯定會產生大量熱量。絕緣層會隨著時間的推移而變得非常脆弱，並且有可能發生電氣短路。請檢查一下。
檢查接地點是否有腐蝕。特別是氣缸蓋（變速箱）側冷卻液法蘭上的接地。
第三，確定怠速不良的條件。
>冷車時怠速不良，熱車時怠速會好轉嗎？
>還是冷車時怠速良好，熱車後怠速變差？
>還是一直都很糟？
>冷車怠速不好：
如果您在引擎運轉時斷開藍色冷卻液溫度感知器，怠速會好轉，則可能需要更換新的藍色冷卻液溫度感知器。
如果這不起作用，請檢查氧氣感知器、正時並重置怠速*。
>暖車怠速不好。
如果您在引擎運轉前或運轉時斷開氧感知器，怠速會好轉，則可能需要更換新的氧感知器。
如果這不起作用，請檢查藍色冷卻液溫度感知器、正時並重置怠速*。如果怠速設定過低，ISV 會在汽車退出冷啟動模式後嘗試進行補償，導致怠速異常。
>怠速一直都很糟。要嘛是正時嚴重偏差，要嘛怠速設定不正確（太低）。 *
*請記住，如果您沒有拔掉ISV插頭，則無法使用怠速螺絲正確設定怠速。
請記住設定正時的方法：車輛必須處於熱機狀態，拔掉藍色CTS插頭，引擎轉速必須約為2500 rpm。將其設定為上止點6-8度。
如果怠速仍然不理想，請諮詢G60技術論壇的專家，並仔細閱讀G60技術論壇的常見問題解答（如果您還沒有閱讀），並務必告訴他們您已經完成了基本設定。
