QuestionHi Josh,
I'm hoping you might be able to take a swing at my issue here.
Just before total failure to start, the engine had idle problems where it would surge to 1500 rpm and then almost stall.
This would occur just after warm-up.
When cranking, the start spins, and the engine sounds like it is going to catch. If I were to guess, it's not getting any fuel. Jumped the rely described in the bently manual, and fuel pump sound like it is coming on,
Checked codes after total failure and got the following:
Air Mass Sensor
A/C Compresor (probably not related?)
Knock sensor cil 1-3
I replaced the Air mass Sensor, and this didn't fix the problem.
My next guess is either clogged fuel filter or O2 sensor. As you have noted elsewhere in the answers here, they can be expensive, so I'm hoping to have a second opinion before I replace it or have the old girl towed to a "professional".
Thanks for your help in advanced!...tw
AnswerTodd,
Did you replace the knock sensor? Knock sensors detect "pre-ignition", or the fuel combusting before the sparkplug fires. If you are running cheap fuel, or low-octane fuel, it will/can cause the knocksensor to change how the engine runs, to avoid spark-knock. If you are running less than 89 octane, you may have created a problem for yourself, if you have been running 89 or 93 (what ever you have locally) then you've been treating the car correctly.
Depending on what year you have, some of the M50-powered cars had two O2 sensors. You will have to check and see. It "could" be the problem, but it doesn't sound like an O2 sensor problem to me. Most of the time, the car will run a little funny, but it will still start and get you where you need to go.
First I would do the elementary thing of checking for fuel and spark. I know you heard the fuel pump, but I would rather see fuel squirting under pressure to be 100% sure. Remove a fuel line running to the fuel rail, and place it in a bottle or some other catch basin. Have someone turn the key and see if fuel squirts into your bottle. If it does, then you KNOW you have fuel pressure.
Next I would check for spark. This is a little harder with coil-on-plug systems, but remove one coil and pull the spark plug with it. Lay the coil on a grounded surface (i.e. the engine, touching metal to metal) and have someone turn the key. Look for spark from the plug. If you dont see spark, play with the possitioning some, and make sure that the coil is grounded, as with the plug in the end.
If you dont see spark... that's your problem, if you do see spark then you need to find out why fuel isn't getting to the spark. You know you have fuel pressure, but apparently the injectors aren't opening, allowing the fuel to squirt into the cylinders and be ignited by the spark.
Check fuel injectors and make sure they are getting signal.
Hope this helps,
Josh
