95 Lesabre | No spark | VATS system bypassed | HELP!

READYTOSCRAPLESABRE

MEMBER
1995 BUICK LESABRE
3.8L
V6
FWD
AUTOMATIC
125,000 MILES

1995 Lesabre. 125k miles. 3.8L v6.

Hi my Buick brothers and sisters. I am at my wits end with my Lesabre. I have never been as baffled with a car as I am now. Here goes the explanation:

Background:
I have owned the car for about 5 years now, with no major trouble. My car will not start. At all. When I turn the key the engine turns over but the spark plugs are not getting any fire.

Progression of problem (3-6 days in between each progression step)

1. Noticed my Service Engine light coming on intermittently about 4 weeks ago. Car was running fine otherwise.

2. Went from intermittent to every time I drove the car. Still no problems with running.

3. Took a trip to Wal Mart and the car just cut off on me during the middle of commute. I dropped it into neutral and cranked it right back up without any further problems.

4. Went to take a buddy of mine to work and turned the key and it took multiple tries before it fired up.

5. Finally, went to go to work and the car did not do anything when I turned the key. No starter engage at all. I also noticed that my instrument control panel lights no longer come on when I turn the key to the START position, although I still hear the door chime.

Diagnostic steps taken up to this point:

1. Checked the battery. Battery is 5 years old but still holds a charge.
2. Checked the fuses/relays. Checked out OK.
3. Crawled up under the car with a screwdriver and jumped the starter. The engine spun over but did not start.
4. Grabbed a multi meter and found out there was no power coming to the starter on the purple wire when trying to start it with the key.

5. Did some Google research and it was suggested to find the starter enable/disable relay (buried under the dash) and bypassed it. I did that and now the car turns over when I try it with the key, but still no fire to the spark plugs.

6. At this point, I thought it could be the VATS system that was causing the issue. I went to bakerelectronix. Com and purchased a Dual Frequency VATS bypass module and installed it on the BCM on pin E of the blue 10 pin connector. Tried to crank the car but still no fire to the plugs.

This brings me up to current day. If anyone has any ideas or suggestions, or have ran into this issue and can suggest a fix, I would be very grateful. Thanks again for everyone's time. God Bless.

"A sluggard's appetite is never filled, but the desires of the diligent are fully satisfied." - Prov. 13:4 NIV

3 Replies

WRENCHTECH

MECHANIC
20,761 POSTS

You very likely could have a problem with the PassKey system. The issue could be the decoder module or the key sensor. The key sensor is very easy to bypass but the module is not. You would need a high end scan tool to be able to diagnose this properly and there should be a security light on or flashing when you try to start it. Get rid of the aftermarket module. It probably doesn't work.

Here is how to bypass the key sensor.

That sensor can be bypassed. You would need a digital ohmeter to measure the resistance of the pellet in the key. Now go to Radio Shack and buy a resister of the exact same value as the key pellet. Go to the base of the steering column and locate the two thin white wires that go up to the sensor. Cut the two wires and solder the resister between the two ends coming from the harness. This will permanently bypass the sensor but not the rest of the system.