Engine light blinking

Steven_J_B · 10-18-2002, 07:16 AM

I've got a 92 325i with about 160K on it and I recently had a idle control valve failure. The valve was replaced without any problem, however the mechanic noted that the ECU was wet and was not sending the proper voltage to the valve (we had really hard rains for a few days). He dried out and reset the voltage and everything seems to be working fine idle, acceleration and performance wise. The engine light, however, blinks on every 15 seconds and is accompanied by a click (probably from that valve) from the engine compartment (sometimes there is a slight change in engine pitch, but no noticable deflection in tach). I can not pull up any codes from the OBD when I check it, so whatever the problem is it is very short-lived. The car is driveable, the light blinking is annoying but I can live with it providing it's not a symptom of a bigger problem. Does anyone have any experience in this area? Should I consider replacing the ECU, if so can I handle that myself?

thanks-SJB

M3Wizard · 10-21-2002, 06:57 PM

Very odd, as a fuel injection problem would trigger a code that should stay in memory until you check it. The code reader says all clear?

Steven_J_B · 10-22-2002, 04:22 AM

Thanks for the reply,

All I get when I turn the key and hit the accelerator 5 times is a blink on, then off-Nothing more. When I initially had the engine light come on and the engine starting to run really rough I was able to pull out the 1262 sequence which led me (and the mechanic) to the idle speed control. Here's some more information that may help, it's gotten colder in NJ and the blinking frequency remains the same (exactly 15 seconds), however the momentary engine speed pitch change has become more noticable, especially at idle (still no observable deflection in tach). There is definitely a click coming from the engine compartment, if it's not the valve, could there be a bad relay or the like? I can drive it this way for awhile, but I'd hate burn out another speed controller (or worse) if the computer is giving the thing the wrong voltage. How hard (and expensive) is it to repace the ECU? Can I just grab one from a wreck, or does it need to have a lot of engine specs and stuff programmed into it? I'd like to keep this car going as long as possible (my previous '86 325 my Dad is driving with 260K+ miles on it, I want this one to go at least 200K).

thanks again, Steve

Steven_J_B · 10-23-2002, 04:32 AM

Here's a little more info:

engine off, ignition on, 5 quick pumps of the accelerator gives:

one 2.5 second engine light blink, pause, 0.5 second blink, pause, repeat

hold down accelerator for 10 seconds (clear codes):

engine light stays on

shut off ignition, wait 10 seconds, turn back on (engine off), 5 quick pumps:

one 2.5 second blink, pause, 1444 sequence (codes clear).

restart car, engine light blinks ever 15 seconds for 0.5 seconds.

kill engine, switch on ignition, 5 quick pumps:

one 2.5 second engine light blink, pause, 0.5 second blink, pause, repeat .

So it seems that whatever the problem is, the OBD can't report it properly, leading me to suspect that the computer itself is at fault. I wish I had a good one to swap in just to see if it fixes it, I hate to buy one and not have it be the solution. I plan to check the output voltages at some of the pins this weekend, maybe I can see a voltage drop at one of them and know for sure what valve, actuator or sensor is clicking (hopefully it's a voltage drop, not an overage since that would be less likely to burn out something). I put on about 300 miles a week, so I'll check my gas mileage and see if it's really off, that should tell me if an injector is bad.

SJB