flightline

Gather round, and listen to my tale of woe:

So this morning I go out and hop in my car and try to start it. Nothing. No lights, no click, nothing. Well, ****, it looks like I left my parking lights on for 3 days. That'll do it every time. Push the car out of my space, and try to hill start it on the mild grade that is the road I live on. I have high hopes, but it's really not steep enough to do the trick. So I park on the side of the road and call AAA to see if I can get a jump. Guy shows up and we spend about 20 minutes trying to get the thing going. First he tries one of those jump pack things, but it's just not enough juice. Engine cranks, but very slowly and I'm not surprised that it doesn't start. Hooks it up to the truck, and it's cranking a little faster; still no start. Let it charge for a few minutes, and try again ; no dice. It's cranking pretty fast now, and I feel like it really should start. We're all out of ideas, and the guy takes off.

Now my battery is still totally dead. I know it's on it's last legs, so a couple days ago I ordered the odyssey PC680 to replace it. It's supposed to be here tonight. So I can't just go out and buy a replacement battery, because I really don't want to spend an extra $100. Now I'm trying to figure out why the car's not starting, but because I won't have enough power to crank the engine until tonight, I can't really do much in the way of diagnosis until then. And even when the battery gets here, the terminals aren't the same kind as the original, so I'll be forced to jury-rig something up until I can mount it permanently.

Don't mind me, just venting

flightline

So I was just reading that the DME can be fried by using a "battery booster." Does this really happen, and how likely is it that this is what's going on? How would I know if that's what the problem is? If AAA fried my DME with their starter battery pack thing, do you think their liable? Do other cars have this problem?

Thanks

968-sjc

DME relay is a pretty common culprit on our cars - to the point that many people keep a spare in the glove box. Might want to troubleshoot with that in mind.

AKCJ

I think a voltmeter and a battery charger would be good to have at a time like this.

944_S_TYPE

+1 On the DME relay. I have had 2 fail. After the first, I keep a spare on board.

Napa sells them for about $26.00 Part Number ATM 99361522700

flightline

Very true.

I took the battery out and got it charged at an advance auto parts. Car now cranks at full speed, no start. I suppose it's possible that the dead battery, jump start, and subsequent no-start could be unrelated, but it seems unlikely. I pulled the DME relay and opened the cover on it.

This pic is from clarks-garage, but mine looks pretty much identical. The solder point indicated by the arrows looks as if the metal tab is just sitting on the bead of solder. Should I try re-soldering that joint?

Yarf

Yes

flightline

Re-soldered the connection, no dice. Tach doesn't budge when cranking. does this indicated something going on with the DME? The car has an MSD ignition system in it, and it doesn't look like I'm getting any spark from the coil. I'll try checking the injector voltage, but the LR fuel rail makes it tricky to get to the injector plugs.

Yarf

Check speed and reference sensors.
Info:
http://www.clarks-garage.com/pdf-manual/elect-19.pdf

flightline

Will do. I won't have access to a scope until this evening, is the resistance test considered sufficient to verify that they're working?

flightline

Did those checks mentioned and I think I may have a faulty speed sensor. Resistance was infinite when it should be 600-1600 Ω. Reference sensor measured 1 kΩ. I have +12 V on pin 4 during crank. Advance auto parts has a borg-warner equivalent (S8066), and can have it here early in the morning tomorrow. Any reason I should go with pelican parts' Bosch w/ Saturday delivery instead?

The copy on the advance auto parts website says "Advanced circuitry protects the system from stray electromagnetic fields and power spikes." I suppose this means that this is a part that normally might be vulnerable to power spikes, such as might be induced by jump starting. Fingers crosses that this is the only problem.

flightline

So it was simpler than I expected. The plastic plug on the sensor had fractured, and was separated just enough for the DME not to receive the signal from it. I pushed it back together and reinforced the connection with a zip tie. Then I tried to start it. Nada. Then I remembered the DME was still unplugged. Took care of that, and it fired right up. Free fixes are awesome.