Hi, A friend of mine has an 01 360 and when it is cold it idles rough and throws code missfire on number 3 and number 8 cylinders. We checked the compression and swapped coil packs and swapped the injectors and changed plugs. After the plug change it ran a bit better when warmed up. Again, this problem only occurs when the car is first started in the morning (cold). When it is warm it runs perfectly, no skipping. I wonder if this is common with these cars? Any help would be appreciated!!!!! Thanks, John N.
Have the timing and the timing belt tesion checked. It sounds like you have a missifre at start up, which many times is caused by incorrect timing.
Do a proper load test on the battery and on the alternator then put a battery tender on it. If the alternator will not put out 140 amps below 3000 rpm have it fixed. Low voltage related engine management problems at startup are very common on 360. If the cam timing is off it is always off and will not make any difference hot or cold.
If you increase the throttle slightly, does the engine smooth out, or is the engine rough at all rpms up to some high level (e.g. 5000)?
I have seen cars not only idle poorly but throw random misfire codes that could stay off of long periods of time if reset. Then they could randomly appear again at any time. In general my guess first is suspect wiring perhaps in the alternator circuit rather than the alternator itself. Is that a valid idea and do you see that just about as often as an under performing alternator?
When the engine is cold, the ECU will go through an cold enrichment cycle. When the mixture is too rich and the engine is cold, it will run rough. Furthermore, as the mixture is overly righ, unburned fuel will be condensing on the areas just outside the exhaust valve and manifold. In many cases it can even pool and then combust as the hot exhaust gases come out at the next idle... What will happen is a near immediate smoothing out as the throttle is opened, and runs well when at a few hundred rpm's over the idle point. If that's the case, make sure all bypasses are set up properly and are not clogged, make sure the banks are balanced and that your throttle potentiometers are working properly and aligned. M
How would it get too rich. There is no mixture adjustment. What by bypasses? There are none. Throttle potentiometers? You have me there too. Where do you guys get this stuff?
Love it! I would assume with any FI/ECU equipped vehicle the first thing you would check is alternator float voltage and battery condition. For the price of a new battery, unless it has been replaced recently, a swap out makes sense and can cure many ills. The selespeed alfa's do all sorts of weird stuff when the battery is on it's way out. Even my sons 50cc motorbike had a missfire due to a old/faulty battery. Cheers
