QuestionQUESTION: I have a 87 jag v12 that keeps flooding out .
I have been chasing my tail, can you please point me in the right direction. Thanks for taken the time.
ANSWER: Hi Eric,
You will have to explain "Flooding Out". What is it doing and how did you determine that it is flooding?
Howard
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QUESTION: Hi Howard , (Flooding out) I do smell raw fuel when I turn the motor over, also I can disconnect the fuel pump and the motor starts up, I reconnect the fuel pump and the motor cuts out, I have changed out a number of parts and still the some problem, even the ECU. thanks for taken the time. Eric
AnswerFirst thing to test is the fuel pressure. Connect a "T" in the fuel line close to the fuel rail and try to start the engine normally and note fuel pressure. You MUST have a "T" in the line so as to have the pressure regulator in the circuit. You should see from 28 PSI to 31 PSI.
The injection system has several components that are major factors in fuel to air ratio. First is fuel pressure. Next is the coolant temp sensor for injection (not the temp gauge sensor).
You can test the sensor with an ohm meter.
68 deg F = 2.5 K ohms
86 deg F = 1.7 K ohms
104 deg F = 1.18 K ohms
122 deg F = .84 K ohms
140 deg F = .60 K ohms
The throttle potentiometer is also a major factor.
You can test it to see that it is powered up on the green wire (color at the pot not in the harness) The yellow wire is the sensor ground but that is tied into the coolant sensor and air sensor so you may not be able to get a usable reading. The red wire is the wiper controlled by the throttle.
Sorry, I don't have a test procedure but you could at least test it's connections by disconnecting the three wires and test between the green and Yellow wire for some resistance value to prove the coil is at least connected and to test from red to the green and move the throttle to see a resistance value change and do the same from red to yellow.
There is also a full throttle switch separate from the throttle position sensor on the throttle linkage and that is a major factor in mixture control also on the right bank toward the rear is a vacuum switch that also detects full throttle so it is major also.
The O2 sensors are not major factors nor is the air temp sensor.
Keep in mind that the cold start valves can stick open or can be electrically held open thus flood an engine. Check you color of the spark plugs on each bank to see if they both are rich (flat black carbon) this would tell you if it is likely a cold start valve problem because it would be unlikely that both would fail in the same manor at the same time.
I would check all plugs to confirm it is something affecting the whole injection system and not just part of it.
Howard
