95 LeSabre | No spark | VATS system bypassed | HELP

rdy2jnkbuik

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

ray80

I believe the anti-theft system is fuel shutoff, so bypassing it not likely to help if there is no spark. Did you ever get the codes scanned for SES light to get a general idea of where the trouble may be?

imidazol97

The dropping dead quickly and restarting sounds like crankshaft position sensor. Sometimes these have to be cooled before they will restart as the gap and magnetic field fail more. There are checks to determine if the CPS is sending the signal to the spark control module. If I find those, I'll post them. They require some expertise with a volt/ohm meter if I recall.

I would check carefully on the positive leads from the battery. I believe yours will have two or more positives on top of the other. These's a lead cylinder between that carries current to the second one. The plastic covering can be pulled back to inspect that and be sure it's not crushed or covered with corrosion from acid. I would also check into each of the cables to be sure acid from the posts hasn't eaten into the copper. Slide the plastic covering to check the integrity of the copper wiring.

Check the other ends for good connections on the positives and negatives. Loosen and retighten if possible. Check the small grounds that go to the fender. Check the grounds from engine to anything else.

I would replace the battery with one that will fit in the holder that's known to be good.

Your VATS repair may be giving trouble. I still like the technique of finding the orange tube that looks like a hot orange wire that goes to a multiplug on the firewall and the orange ends and two fine white wires go to adjacent connections. Those are your leads from the two contacts inside the lock cylinder. So cut those high up and wire in resistors from Radio Shack (out of business?) that equal one of the 15 resistances in the tables for VATS--you'll have to check resistance on the chip in your keys to see which of those resistances you have. Solder the resistors in series to get within 5% of that and then solder to the ends of the white wires that used to go up to the lock. The white wires are very hard to strip because there are only a few strands of copper inside them.

The SES light? Was it flashing when it was on or just on a while and then off? If you didn't notice a misfire or poor running on the engine, I'd suspect it might have a meaning for another problem.

Does your fuel pump build pressure when key is on by running for a couple of seconds then turning off?

Are fuel injectors squirting. Touch one while cranking to feel the pulse. Or put a 194 light bulb's two wire ends into the power connector to a fuel injector and crank to see if you're getting pulses there.

Does someone you know have a code reader or scanner like Ray80 suggested--if you haven't disconnected the battery for a minute or more which might have cleared them.