Author Topic: VATS... BCM??? (Read 1923 times)

Donk383 · « **on:** May 16, 2011, 07:16:16 am »

K, I am at my wits end...
I have had a problem with my 94 TA just killing instantly with no codes... Seams to die after about 5 or ten minutes of drive time. I have replaced the following:
Optispark
ICM
Coil
Plugs
Wires
fuses (none blown)
This weekend took the little monster to the car wash (just to vacuum it out so water is not the issue) as I was leaving I made it to the entrance and died. It would crank but not fire at all. after about 15 minutes it started just long enough to get out of the enterence (ran for probably 30 seconds). So I left the car for a while and walked to the gas station for a drink. Went back and started thinking what the issue could be. about an hour and a half after it killed a solenoid under the dash clicked, she started right up and I made it home with no issues. So I am wondering could it be a VATS or BCM issue. VATS has been disabled with tuner cats, however from my understanding that only disables the the reading from the chip in the key. the contacts in the key are old and worn. Could it be my issue?

Any help would be greatly appreciated.
--Doug

Rockin C Racing · « **Reply #1 on:** May 16, 2011, 08:38:32 am »

It does sound like a VATS issue. Double check your program. Only read the program and see if it is still disabled and a check.

Donk383 · « **Reply #2 on:** May 16, 2011, 09:36:19 am »

That was the first thing I did... VATS is disabled... Do you think even being diabled if the is a lack of connection on the key chip it could still cause it? If I am not mistaken all disabling it does is make it ignore resistance not connection...
Thanks

Rockin C Racing · « **Reply #3 on:** May 16, 2011, 10:04:57 am »

I'm not sure, but that is a possibility.

Donk383 · « **Reply #4 on:** May 16, 2011, 10:35:40 am »

Here is my thoughts...
Knowing the key is worn turning VATS back on to see if it throughs a code. If so I replace the key.
If no code turn it back off and use my spare key (not the same resistence as per why vats was turned off in the first place) and see if the problem continues.
If it still continues replace the vats relay then retry.
next would be the vats module followed by the bcm.

BumpaD_Z28 · « **Reply #5 on:** May 16, 2011, 02:46:55 pm »

Instead of turning it off, wire the correct resistor in line under the column

Donk383 · « **Reply #6 on:** May 17, 2011, 02:34:29 pm »

Connecting the resistor is unnessisary work. It is little more then the click of a mouse for me. But I appricate the thought.
Update
I tested my vats system by turning it back on and using both keys. I do get my vats error when I use the spare. With vats disabled my spare works the same as the original. Still shuts down.
I am begining to worry that my new opti is bad

I went with a new Pro Comp one (yes call me an idiot for getting one of the ebay cheapies...). The darn thing started doing this about a week after putting on the new opti. But still, I through no codes. Every other opti I have heard of going out at least throughs the low res and or high res codes... I am thinking just live with then ten minute drive time till I can afford the msd. It will still get me to and from work as long as it doesn't get any worse.

NVMYZ28 · « **Reply #7 on:** May 17, 2011, 04:05:11 pm »

Sounds like its falling on its face when going into closed loop (hook it up to your computer to verify it goes into closed loop just before dyeing). Optical sensor in your opti is clouded over with dust

This sensor only gets used in closed loop... thats when they rear their ugly head if they're clouded over.

You can probably get it to stay running by forcing it to stay in open loop (disconnect the MAF). I'll bet it runs then.... not ideal but...

Donk383 · « **Reply #8 on:** May 18, 2011, 06:31:32 am »

I have been monitoring it using free scan. It makes closed loop for a few minutes. I really doubt it is killing out because the opti lens is clouded. The new opti has only been on the car for about 3 weeks.

Question on unplugging the MAF, That forces speed density mode and prevents closed loop right? Did the 94's have speed density? In tuner cat it showed being turned off. I can turn it on and try.

However from my expierence when an opti goes out if you loose High res (the little hashes in the opti) you run poorly but still run. When you loose low res (the four hashes used for crank position) you loose it all. To my knowalge closed loop activated high res, low res is alway in operation or the ECM could not tell the icm or injectors when to fire.

Even still I am haunted by the click I heard in the dash sunday.

Donk383 · « **Reply #9 on:** May 18, 2011, 01:27:09 pm »

Today it showed a possible new symptom. Idle was verry low, about 450 rpm. Any thoughts? Possible IAC or just spark?

Donk383 · « **Reply #10 on:** June 03, 2011, 12:45:06 pm »

This electrical stuff is killing me...
K lately the thing has been idling verry low... Now the battery is not holing a charge. Even at the 450rpm Idle still shows 14 volts on the dash... It is an old battery... Do you guys think it decided to just crap out, or could whatever is causing the stall be killing the battery as well? I have still yet to get a code when she stalls.
I'm lost, anyone have any ideas?
--Doug

Rockin C Racing · « **Reply #11 on:** June 03, 2011, 01:20:34 pm »

Eliminate the new problem as quick as possible to rule it out. If the battery is already old and now low, just go ahead and replace it because will have to sooner rather than later.

Donk383 · « **Reply #12 on:** June 03, 2011, 01:26:41 pm »

I am planning on replacing the battery while I do my PM's this weekend, being if the cash is avalible. I am also going to inspect the battery cables and grounds at the same time.

Donk383 · « **Reply #13 on:** June 06, 2011, 12:09:10 pm »

So I replaced the battery.
While doing this I found a bad plug wire the was grounding out to the block (it was too close to the belt). Replaced the wire, cleaned ground connections and noticed I had no ground wire going from the ICM bracket to the chassis.
I have not done anything with replacing that yet (hopefully tonight)... Even still she shuts down and idle is low, but will restart after only 5 minutes instead of an hour plus. I am hoping that all of this is just lack of conductivity from my missing ground.
I'll updated after getting it done.

The Sad · « **Reply #14 on:** June 06, 2011, 07:14:33 pm »

Good luck!

Donk383 · « **Reply #15 on:** June 10, 2011, 06:47:00 am »

So I did the ground wire. Haven't driven it long enough to see if the darn thing is going to stall out still.

While I was putting the ground on, I took a closer look at the wiring for my ICM and coil... The white wire to the ICM has a small bare spot from a splice where a window switch for NO2 used to be. It was taped over, but it's still little corroded with a small kink in it, also the two grounds coming out of the wiring harness had kinks aswell. I believe the white wire is the signal wire that tells the ECM as well as the dash the engines RPM (anyone know for sure?).

That is one more potential cause

I'm gonna take care of that as well before trying to force it to stall again. I found a new connector at AZ for about $20. So I guess its time to break out the heat shrink and the soldering iron!

Donk383 · « **Reply #16 on:** June 15, 2011, 06:17:25 am »

Update,
I had to order the connector for the ICM (sould be in today). How ever I am starting to think this is not the issue. It has stalled twice this week only on me in the after noon on my way home from work, never in the morning. I am begining to think it is heat related.
Potentail reasons:
Maybe the budget opti I put on can't stand normal operating temp.
Wire losses connection at higher temps
ECT sensor is not accurate (was replaced a few months ago)

Anyone else have any ideas??

When I get in to doing my connector I am going to put my dummy thermostat. It is just hollowed out so the seal is still intacked. So I will run cool enough it should also keep me in closed loop and see if that makes a differance.

Donk383 · « **Reply #17 on:** June 15, 2011, 07:22:30 am »

Just read a thread on a different forum… About pretty much my same issue, they where saying that if the vent on the tank fails or is clogged it can create enough of a vacuum the fuel pump cant pump the fuel creating a no fuel pressure situation.
Any thoughts?
Regardless I am going to recheck my fuel pressure.

Donk383 · « **Reply #18 on:** June 20, 2011, 06:32:15 am »

K, fuel pressure holds 42 psi at idle and 48 under throttle, with no positive pressure in the tank. A little low but not concerning. After doing my pigtail for the ICM it still stalled, took me more then an hour to restart. After stalling I plugged in free scan, and noticed I had no read from the MAF and the MAF temp sensor showed -40 (it was about 80* outside at this point), could this explain my low idle? I undid some electrical tape on the MAF temp sensor and found the pigtail there needs to be replaced as well. So now I am ordering both pigtails (before replacing the MAF sensor). Guess I was running in speed density mode after all.

Donk383 · « **Reply #19 on:** June 20, 2011, 07:35:02 am »

Hey is closed loop possible with no MAF? I showed in closed loop at the same time... Maybe I have ECM issues.

NVMYZ28 · « **Reply #20 on:** June 20, 2011, 08:55:17 am »

Its possible if you're running a speed density tune. Otherwise, it shouldnt be.

Donk383 · « **Reply #21 on:** June 20, 2011, 10:47:23 am »

I do have speed density turned on in the switch table... So that explains that.
I ordered new pig tails for the MAF and the IAT off of Ebay ten bucks a piece! I can live with that. The guys at AZ couldn't find the parts.

Donk383 · « **Reply #22 on:** June 20, 2011, 10:49:26 am »

Sorry for the immediate responce...
Had a thought hit me. With speed density turned on would it not use the MAF??

The Sad · « **Reply #23 on:** June 20, 2011, 01:04:51 pm »

Quote from: Donk383 on June 20, 2011, 10:49:26 am

Sorry for the immediate responce...
Had a thought hit me. With speed density turned on would it not use the MAF??

If you are forcing it to run in SD then you are correct, it would not use the MAF. You could also unplug the MAF and it should make it run in SD.

Donk383 · « **Reply #24 on:** June 20, 2011, 01:23:27 pm »

This is the funny thing. With SD on my MAF does not show a read. With SD off if I unplug my MAF the engine dies instantly.

News:

Author Topic: VATS... BCM??? (Read 1923 times)