Moderator: Toolbox
snake skrev: ↑10 aug 2006, 16:55 Eftersom FI-lampan lyser så är det nästan garanterat någon sensor som temporärt ger felaktigt värde. Kanske glappkontakt eller jordfel. Dessutom så dör motorn, och det är inte många sensorer som är så viktiga för motorn att den inte längre kan gå.
De flesta sensorer är inte kritiska utan motorn kan hanka sig fram ändå. T.ex. lufttryckssensor, lufttemp sensor etc. Det blir bara lite fet eller tunn bränsleblandning. Det är några som är absolut kritiska, t.ex. ignition pulse gemerator och cam pulse generator. Utan den signalen så vet inte motorn när den ska skjuta av tändstiften eller spruta in bränsle. MAP sensorn är också viktig. Om du kör i 90 knutar och MAP sensor skulle ge 0V i utsignal så tror styrdatorn att motorns vacuum är otroligt högt (stängd trottel) den kan då blixtsnabbt dra ned på bränslet för att inte flöda motorn. Det kan upplevas som att motorn dör för ett ögonblick.
Kolla anslutningarna/kablarna till dessa sensorer. Cam Pulse sensorn sitter i främre cylindern högt upp till vänster. MAP sensorn bakom luftburken (du kommer åt sladdarna om du tar bort tanken).
Innan du skruvar sönder något ska du kolla ev. felkoder i datorn.
Gör så här:
1. Sätt stopp-switchen i läge "Stopp" och vrid tändningsnyckeln i läge av
2. Kortslut "servicekontakten" som sitter och dinglar under sitsen.
3. Slå på tändningen och sätt stopp-switchen i påslaget läge.
4. Om felkod finns så kommer FI lampan att blinka när du slår på tändningen.
5. Räkna hur många gånger lampan blinkar.
0 blink - Ingen felkod
1 blink - Kortsluten MAP sensor (Manifold Absolute Pressure, dvs. trycket/vacuum i insugningsröret)
2 blink - Avbrott i kabel till (glapp) MAP sensor
7 blink - Glapp till ECT sensor (vattentemp)
8 blink - Glapp till TP sensor (trottel/gasspjäll position)
9 blink - Glapp till IAT sensor (Insugningsluftstemperatur)
10 blink - Glapp till BARO sensor (Barometer)
11 blink - Glapp till hastighetsgivare
12 blink - Glapp till bakre insprutningsventil
13 bllink - Glapp till främre insprutningsventil
18 blink - Glapp till kampulsegeneratorn
19 blink - Glapp till tändningspulsegeneratorn
21 blink - Felaktig O2 sensor (Lambda sond)
23 blink - Felaktigt värmeelement i O2 sensors
33 blink - Felaktigt EE-Prom i styrdatorn (elektriskt raderbart minne)
/OrreHow Does the Oxygen Sensor Work?
This is the only sensor that makes its own voltage. The voltage signal is proportional to the amount of unburned oxygen in the exhaust. When hot (at least 600. F), the zirconium dioxide element in the sensor's tip produces a voltage signal that varies according to the difference in oxygen content between exhaust and outside air.
The higher the concentration of unburned oxygen in the exhaust, the lower the differential across the sensor tip and the lower the sensor's voltage output. The sensor's output ranges from 0.1 volts (lean) to 0.9 volts (rich). A perfectly balanced (stoichiometric) fuel mixture of 14.7:1, gives a reading of around 0.5 volts.
Some O2 sensors have three wires and an internal heating element to help the sensor reach operating temperature more quickly. The heater also keeps the sensor from cooling off when the engine is idling.
An O2 sensor's normal life span is about 30,000 to 50,000 miles. Sensors can fail prematurely if they become clogged with carbon, or are contaminated by lead from leaded gasoline or solvents from the wrong type of RTV silicone sealer.
As the sensor ages, it becomes sluggish. When the signal starts to lag behind changes in the exhaust, or becomes static, the engine experiences driveability problems (loss of power, rough idle, poor fuel mileage, or excessive emissions).
Sensor accuracy can also be affected by air leaks in the intake or exhaust manifold, or even a fouled spark plug. A misfiring plug allows unburned oxygen to pass through into the exhaust, causing the O2 sensor to give a false lean indication.
Most aftermarket replacement oxygen sensors are of a universal design which means some wire splicing may be necessary during installation. Graphite anti-seize compound should be used on sensor threads unless they are precoated. The rubber boot that fits over the sensor should not be pushed down further than half an inch from the sensor's base.
Some vehicles are equipped with a different type of O2 sensor that has a titania rather than zirconia element. Instead of generating its own voltage signal, a titania O2 sensor changes resistance as the air/fuel ratio goes from rich to lean. Instead of a gradual change, it switches from low resistance (less than 1,000 ohms) when the mixture is rich, to high resistance (over 20,000 ohms) when the mixture is lean.
The engine computer supplies a base reference voltage of approximately one volt to the titania O2 sensor, and then reads the voltage flowing through the sensor to monitor the air/fuel ratio.
When the fuel mixture is rich, resistance in a titania sensor will be low so the voltage signal will be high (close to 1.0 volt). When the fuel mixture is lean, resistance increases and the voltage signal drops down to about 0.1 volt.
Compared to the more common zirconia O2 sensors, titania sensors have three advantages: (1) they don't need an air reference (there is no internal venting to the outside atmosphere to plug up); (2) they have a fast warm-up time (about 15 seconds); and (3) they work at lower exhaust temperatures (they won't cool off at idle and they can be located further downstream from the engine or used with turbochargers).
Nu är det ingen irriterade FI lampa som blinkar. 