Been slapping myself this past week. While taking my 84 L69 valve covers off for the Nth time, I grounded the wire that grounds to the water neck. It touched the terminal on the back of the alternator for a moment. Enough to remind me I forgot to disconnect the battery.

Can anyone tell me what systems this ground serves?? I can't figure out what burnt up, because it won't idle or run well since. My timing light only fires intermittently on all the wires. The ignition module and coil were replaced and no change.

I'm crossing my fingers there's a fuse somewhere that took the brunt of it, but I have no idea what this is connected to.

 

Grounds to the water neck? Do you mean connects to the sensor on the water neck? That's the coolant temperature sensor for the ECM.

 

No, its not the CTS. It is a black wire that usually grounds to a bolt up on or near the water neck(I guess its a thermostat housing). The end of it has a ground-type connector, that goes under the head of the bolt.

 

That's your ECM ground.

There's no telling what all might be smoked. It might have got the ECM, the ESC module, or any other related parts that contain semiconductors.

I'd suggest you go locate a similar car in the junkyard, and start swapping stuff out, one piece at a time. Start with the ESC module; that sounds like the timing culprit. Hopefully it'll be something small and cheap that's at the root of it all. Start with the smallest cheapest things, and work your way up.

 

Sigh....that's what I was afraid of. Well, I'll get on it, but I don't think the 'maro's gonna move for another month or so. That sucks.

Is there a way to verify the signal coming from the ecm with a volt-ohm meter?? I know it's a long shot, but if I can verify something is wrong before replacing stuff, it would make me feel better.

Let this be a lesson to all who read this: DISCONNECT THE BATTERY!

Well, you guys have probably already learned that. I guess it's my turn.

 

Or you could just take this opportunity to get rid of the computer.

 

Well, I already plan to F.I. with a stand-alone unit. The only problem is I'm not ready yet. I'm still getting the fuel delivery parts. It'll be a month or so before I even get the parts, let alone time to install it.
Just to tickle my fancy...would removing the computer require a different carb to get mpg out of the single digits. A new distributor is a must, but a non-cc dizzy would be the wrong direction from my long term goals.

Just replacing a part or two is worth having it run for the best time of the year to drive it.

Can somebody tell me what ecm I have. 84 L69.

 

i did the same thing just yesterday, the car ran fine but kinda slumped when you mashed the gas, then today when i went to drive home from work i turned on my lights and the car died, and wouldn't start up again, i have no power to anything.

Edit: and oh yeah i drove to school and back and then to work and it was fine until after work

 

If you need it to run, and want it to for cheap, go to the junkyard and get a vacuum advance HEI and a regular Qjet. Should take a couple hours at the most to swap it in, and then you can run it w/o the computer just fine. Those parts are cheap too... could probably get the dissy and carb for $30

 

That's what I did, and I might recommend it. Short term, it'd be easier than fiddling with the ecm. If you're fairly confident on how to fix that, give'r. But finding an ECM for that car at the JY might be kinda hard. I know an LG4 carb and dist (from an GM vehicle with a 305, sedans are easy to come by), would work just great.

 

Any vacuum advance HEI will work... could be out of a 267, 305, 350, 400, 454... anything. As far as your application goes, they are all basically the same.

The Qjet, well, it just has to be off a Chevy V8 to work in your car. Pontiac, Olds, etc.. all had a different one that had (among other things) a fuel inlet in a different position. You'll need one off a Chevy V8 to be able to reuse your stock fuel line. It can be off a small block, or a big block, it doesn't really matter. The one from a big block should be an 800cfm unit, and the small block a 750cfm unit. Either would be more than sufficient for a 305.

L69 stuff, especially ECM related stuff, is a nightmare to find anywhere... junkayrds, Ebay, internet classifieds. I know, I've looked. I also got a small fortune for the L69 ECM that I sold a few years back on the boards here. I'd suggest just swapping the carb and distributor... make your life easy. Why not, eh?

 

I appreciate all of your suggestions, but I think patience is the answer here. It's not vital to have this car running, but it would have been nice.

I have a hatred for carbs that is matched only by my hatred of Fords. Trying to tune a vacuum controlled interface sounds like something out of my nightmares. Seeing as I've already studied fuel injection to an endless degree, I don't have a lot of motivation to figure out an antiqued fuel delivery system. No offense to you carb guys, but the potiential gain in mpg far outweighs any 'simplicity' a carb might offer. That would be the why.

Johnnyboy, if you grounded your ecm where it shouldn't of been like me, then you already know your answer. Replace the ecm. Oh, and disconnect the battery next time.

 

Well, if time isn't a factor, why not switch to a TPI setup? Most of the L69 will be the same as a TPI setup would use, plus a few more for the TPI setup. TPI computers and the hard parts are always for sale in the classifieds here. Lots of guys don't like carbs, so you're not alone