[winnie51189]

Got a stock salvage 3.8L dropped into the car as a temporary engine while I'm building my 4.2L.
Long story short the guy that dropped in the engine basically told my parents he would do it for a favor for free b/c my dad got layed off after the company he worked for got bought out. Then proceeded to do a half-ass job and charged my parents multiple times most for fixing mistakes he made that I pointed out in seconds. All in all he ended up charging my parents a total of about 700ish. Since finally getting it back, I've had numerous small issues that I've been fixing since this guy got his hands on the car. However the main issue is the battery.

Symptoms:
1.) Battery drains everytime I leave the car off overnight.
2.) Can't change the a/c from vent/defrost/ etc. (fan speed and temp work though)
3.) When the engine is running I hear a hissing noise coming from the vents. But air only comes out of the vents blowing directly on the windshield.

I can't stand the thought of losing my Optima red top b/c this guys piss poor work.

[ESG-642T]

Get the battery tested (1)

I had a red top that went bad and did that. Otherwise, the guy you told me about sounds like a common idiot I would go over everything he did!

[winnie51189]

Originally Posted by ESG-642T Get the battery tested (1) I had a red top that went bad and did that. Otherwise, the guy you told me about sounds like a common idiot I would go over everything he did!

I've put a different battery over the weekend just to make sure my red top wasn't the culprit... Same problem.
And yes the guy is a moron. I also pulled the inline fuse for my subs, as well as the fuse in my headunit, then checked all the ground just to be sure. All checked out A-O-K. just can't find wtf else this guy screwed up.

[mcqueen]

Originally Posted by winnie51189 just can't find wtf else this guy screwed up.

Pull the whole engine out. Put it back in correctly.

[Tang Stang]

1. Disconnect the negative battery cable. Hook one of your multimeter leads to the cable, and one to the battery post, with the multimeter set to read current flow (amps). If the reading is over 50 mA, you have a parasitic drain. Start removing fuses one at a time. The fuse that reduces the current flow is the circuit causing the drain.

2. & 3. One of the vacuum lines controlling the HVAC is disconnected.


As always, reps are appreciated.

[03stanggg]

Check the terminals too, make sure there isnt corrosion on the connections. Have you had the alternator tested? Im pretty sure pepboys or any other store like that runs tests for free.

[winnie51189]

just had the alternator and battery tested, both fine. Just need to find my DMM to do more electrical testing.

[winnie51189]

Finally found my DMM. Started testing things and narrowed it down to the PCM.

[SALEEN961]

The PCM will still draw a large amount of current for up to 15 minutes after the car was shut off. To test for a parasitic draw you have to wait until the PCM has completely shut itself down and then loosen the negative battery terminal and put one DMM lead on the terminal and one on the battery post, now you can remove the terminal from the post and test for parsitic draw.

By keeping a complete circuit the whole time you don't have to worry about the PCM powering backup after a power loss like they will in some cars (Not sure if Mustangs will do this, some cars do, others don't).

The parasitic draw spec listed for a '99 V6 is "less then 0.05A (50mA)"

[winnie51189]

Originally Posted by SALEEN961 The PCM will still draw a large amount of current for up to 15 minutes after the car was shut off. To test for a parasitic draw you have to wait until the PCM has completely shut itself down and then loosen the negative battery terminal and put one DMM lead on the terminal and one on the battery post, now you can remove the terminal from the post and test for parsitic draw. By keeping a complete circuit the whole time you don't have to worry about the PCM powering backup after a power loss like they will in some cars (Not sure if Mustangs will do this, some cars do, others don't). The parasitic draw spec listed for a '99 V6 is "less then 0.05A (50mA)"

I only got around to testing the fuses in the engine bay though, b/c it started raining. The only fuse I pulled that decreased the amperage was one of the 40amp fuses. When I looked up the fuses my workshop manual it listed Instrument cluster, PCM.
However upon further inspection the noise that is I continuously hear whenever the engine is running is definitely coming from somewhere under/behind the dash on the passenger side.

Hopefully at some point I will be able to test the fuses under the dash and see if the drain on the battery changes.

[winnie51189]

Update:
Started pulling the dash apart. Didn't get very far before I saw something suspicious. A vacuum T fitting that had only 2 of the 3 connections made. Connected the 3rd, fired it up to see if that fixed it and sure enough all is well. I'll be keeping an eye on it to see if I have any more issues. As for now it's back to work on the 4.2 stroker build.

[GUNBUNNY103]

I am having the same issue with the power bleed. I pulled fuse 39 (GEM) and it seems to have slowed but not stopped. So i have disconnected the GEM altogether (wires from the box) to see if this will halt the drain completely. From my understanding this is usually the culprit in most cases. Just need to know (if it is) do I have to get a new GEM "programmed" or is it just remove and replace item. But I would start with that one when you go under the dash.

[winnie51189]

I believe mine is resolved as I've had no issues with the batter draining any longer.