backfire from hell
 

so it starts out as a little "popping" noise im hearing at idle, then as i start driving the car just gives very interupted power and will bogg out untill i guess the other rotor fires and keeps the crank spinning.

Then i take it home park it for a night. Next morning i come out take out the spark pulgs (ngks) and discover very fouled black plugs. this means black carbon everywhere on them and on each leading plug there are some brownish residue that i chipped off. I clean the blackened trailing plugs as well then try and start the car.

The car starts up pops a few times then a huge backfire. and the engine dies.

my question for today is, why? :confused:

bump

sounds like a crossed wire

update from the dealership: they say taht the oil metering pump has went out and in turn killed my ECU together just from the junkyard those peices are like 900$ does that sound like it could be the problem?

Could the one pump actually destroy my ECU?

maybe if its an S5 with the electric oil pump.

The metering pump is just a stepper motor that allows oil to be sucked inthe engine at a controlled rate. They usually don't blowup killing the ECU but.....If they go faulty and the ECU detects it it will run in limp home mode and they run like a dog! I would see if you can get one of your mates to lend you a pump to try. The ECU shouldn't be able to kill the pump even if it is faulty as long as you don't leave the ignition on for hours while it is not running. Just replace the pump start it up and take it for a short run if it is OK. buy a new pump if it is still crook look at a ECU.
Michael Smith

Mine had a similar problem, but my water temp sensor blew and so it thought it was running REALLY cool all the time so it dumped alot of fuel into it all the time. Hence the backfire even at idle.

Bad oil metering pumps don't cause popping at idle. When the oil metering pump stepper motor fails, the ECU logs a code and goes into limp home mode. The check engine light will illuminate the entire time the ECU thinks the oil metering pump is bad and the car will not have any power. The code for a bad oil metering pump is either a 20 (bad position sensor) or a 27 (bad stepper motor). I've never had a code 20, but i have had a 27.

There are two plugs just left of the alternator. One is a six pin plug, while the other is a three. In the attachment I've included the instructions as to how the OMP is tested. All you need is an ohm meter to test it. It takes less than five minutes.

If your check engine light did not turn on, and the OMP is actually bad, then it's possible that the ECU is bad, but based on my experience, not very likely.

Check the water temp sensor, its easy to replace and inexpensive.

I remember a thread on here stating that the OMP had a 50:50 chance of taking out the ECU on a S5. I don't remember if there were conditions implied by the thread or what have you, but search.