Brain damage?

AtomicDog · 12-22-2005, 06:44 PM

My alternator failed. The measured terminal voltage with the car running was 15.2 VDC at idle. I didn't bother to run it up to 2K to check the voltage again. The new alternator arrives tomorrow, and I have a new coil standing by. The battery seems to be fine...

Here's the 64,000 penny question:

When the alternator goes by failing high, what is the likelyhood that it takes the DME computer with it?

The car was misfiring badly when I performed the voltage test, and I suspect the coil suffered. What else should I look into before I leave the driveway?

TIA,

Chris

Joe Bob · Joe Bob's Garage

high voltage usually takes the battery out. The DME Relay is cheap and when it goes it not intermittent....it just doesn't run....

AtomicDog · 12-22-2005, 07:13 PM

So there's no threat to the computer???

Where the heck is SteveW when I have another dumb DME question. Shoot, I would like to know what Lorenfb thinks, too. Who am I kidding, he'll tell me that I should have read the rest of his website.

Just kidding, Loren.

Chris

dfink · 12-22-2005, 07:20 PM

Mine went way high last year 18+ volts. Computer is fine, battery compartment got nasty. Two boxes of baking soda later..........

wcc · 12-22-2005, 08:09 PM

If you got a lot of money laying around, sure change the coil, computer, regulator, etc, and everything else electric. But I think that's stupid! Wait to get you new alternator in and then check voltages. Don't start throwing money at your car for no reason. Well I've done that, but that's not the point here. Sure there is always a concern when the voltage from your alt gets up there, that's what you fuses and relays are for. I don't think you have anything to worry about IMO...

masraum · 12-22-2005, 08:24 PM

I realized at some point that I had a bad regulator. I was putting out 16-17.5V most of the time. I think I probably drove like that for 3-5 months (I put a Voltmeter in after that). I put in a new voltmeter(internal), bearings, and brushes and was back on the road. No other peripheral problems after that.

AtomicDog · 12-23-2005, 03:09 AM

Excellent news. I'll keep my fingers crossed then.

wcc,

The new coil was to address the intermittent misfire problem as suggested by some other guys here on the board. I also replaced the 1-wire cyl head temp sensor, plugs, wires, cap, rotor, fuel filter, and the original (1986) DME relay. The coil seems to be the only thing left short of the computer/chip.

All of the other parts NEEDED to be replaced. The misfire is making me crazy. I'm just out of options.

Chris

dfink · 12-23-2005, 06:20 AM

If your car is as old as mine 85' and you have replaced everything else and are still getting ignition problems you might have an issue with the inpulse sensors. When I pulled the motor and tranny the insulation on the sensors just crumbled off. In searches about this issue I found it can cause various problems. The impulse sensors are what tell the engine where it is in the revolution by counting the teeth on the starter ring gear. Not a good place to have to check however I think you have to pull the engine to get to them. These are two of the wires on the left (drivers) side of the engine below where the the O2 sensor plus in. The sensors are below the engine tin and protrude through a cutout in the tranny case. Just possibe last case senerio.

AtomicDog · 12-23-2005, 08:36 AM

dfink,

Interesting you should mention that. I noticed insulation damage on one of the two impulse senders when I replaced the CHT sensor. Based on what those bad boys cost, I hope that isn't the problem. It is something I will keep in mind.

Thanks,

Chris

BTW, it USED to only happen when the car was fully warmed up. The last time it ran, the misfire started within 5 minutes of a cold start (in mid 30s temps).

dfink · 12-23-2005, 10:25 AM

If you do replace them do not take the bracket loose that holds the sensors. A real pain in the butt to get set back exactlly to the .8 mm setting. I found this out after I already removed it. I must have gotten it OK though as my car runs great. There was so much gunk around where they pass through the tranny housing that I thought they had to come off to get the tranny off. the case is cutout around the sensor bracket. Just thought this might help you in the future.

kasi · 12-24-2005, 05:06 PM

I have seen it a couple of times and usually the computer or stuff like this does not suffer,if you are not driving !! As far as i know !!
check all your lights ,probably some bulb's are burned !!