*UPDATED W/ PICS* Car stalls unless AC is on.

[white_dsm]

Well my car will stutter below 1000 rpm if the ac if off and die. But if I have the ac on 3rd setting it stays on. I'm thinking since the ac makes the idle a little higher my biss screw might need adjusting.

Is that the case?

 

[2point3Tsi]

start with the biss, if its all the way in it should be 1 and 1/2 turns out IIRC from tight. more than likely that would cause a hi, not low, idle. Check your ISC first, it takes 5 mins with a multimeter.

 

[greddyturbo19]

dude thats weird mine shuts off compeletly if i let it idle with the ac on i hate it. so yea wow never heard that before

 

[2point3Tsi]

the ISC moves in steps so possibly it could provide enough airflow to sustain idle in one mode but not the other, depening on which coils are functioning. Mine went back and forth from hunting 1k-1.5k [when cold] to an idle of 3-400 or not at all [when warm]

 

[kenamond]

From what I understand, the ISC will try to maintain a constant idle RPM. If you turn on the AC, that adds load to the motor through the accessory belt. That normally *lowers* RPM, but the ECU senses this and tells the ISC to open up a bit to bring the idle back up.

I have no idea why the AC would keep the car from stalling.

greddyturbo19: Check your ISC. The BISS just gets the base idle in the ballpark so that the ISC can do its job. The only time you should have to adjust the BISS is if the ISC is all the way at the end of its range and can't do anymore. In that case, you adjust the BISS to get the idle back into a range that the ISC can handle given its limited range.

 

[white_dsm]

Well I went to check it out this morning and my car wouldn't start. Something has to be draining the battery. Brand new battery too supposedly.

Terminals and connections seem fine, no corrosion.
Haven't checked it with a voltmeter yet so I'm still guessing.
No acc. turns on what so ever.
I found a MPI relay next the battery that was jumped with a regular fuse so I took that out. It's a 20 AMP. Maybe that drained it? not sure


I was gonna try to adjust the BISS and check the isc but dam battery.. Well lmk, need some help!!!

 

[appeartobelosin]

turn on your car. pull the neg battery cable off and if your car still runs that means your alt is still good. be sure to check all your grounds. i had the same problem and it was just a ground

 

[white_dsm]

I'm sure the alty is good. But just found out after I jumped when it died soon after my battery was reading 5.4 volts. So that's a good sign, easy fix. But lets see if that solves it the ac issue. If not I probably have a short somewhere, good thing I got a test light and the search engine on dsmtuners. Yeah!

 

[appeartobelosin]

are all your grounds good?

 

[white_dsm]

Ok, I got an update.

Got the battery charged, freakin thing was reading 1 volt. So before I started the car with the charged battery I used a test light to test the fuses, something was drawing power overnight. I ended up finding 2 shorts.

1.) MPI relay- The only pin that lights up is the black and red wire.
2.) Radiation fan relay- the left top pin lights up.


Here are pics for reference:

1.)

You must be logged in to view this image or video.

You must be logged in to view this image or video.

2.)

You must be logged in to view this image or video.

You must be logged in to view this image or video.

Now what? , none of the wires seem tampered with. Oh and btw, car starts and idles perfect. Even stays on with the ac off so fixed that problem!

 

[white_dsm]

BTW, in pic reference 1 the pin circled is the one lighting up the test light.

What do I got to do to fix this?

 

[white_dsm]

I'm not trying to bump it, but I need some peoples insight, my battery drained after a complete charge. RIght now it's a 3.5v. All the 30/40amp fuses on the main fuse box under the hood light up with the test light..And the WDO relay does too.what does WDO stand for anyway? window?