Can VATS problem cause engine to stop while running or JUST no-start?

[HallenTi]

This has happened just once to me luckily. The engine on my 1990 L98 had been running for several minutes and was at the normal operating temperature. In city driving, the engine died just as if I had turned off the ignition. Lights, heater fan, and all electrical still worked. Tried to restart and it would not (it did turn over just fine but would not fire). Coasted over to the side and opened the hood to look for loose wiring to distributor, water splashes, etc. Several minutes went by and it restarted and has run fine since.

I replaced the ignition module several days ago (got a code 42 recently) and installed it correctly with dielectric grease, cleaned the connectors, etc. Replaced cap and rotor at the same time. Checked and cleaned all ignition connectors with electronics cleaner. Just checked the CCM and ECM codes, and the only code besides the "12" code was a "74" (deals with the LED dimming circuit).

I have changed the fuel filter about 4 months ago, always keep the tank filled rather than running it way down.

I searched here for "VATS" and checked out most of them, and only in one did I find any mention of whether the VATS had anything to do with a running engine vs. the starting sequence, and the person said that the VATS only controlled the starting sequence (fuel and ignition cut-off) and would not affect the running engine. I checked the Chevrolet 1990 service manual regarding the VATS, and he various descriptions didn't mention anything once the engine was running.

I checked the resistance on the standard ignition coil as outlined in the manual, and the coil seems to be within specs.

So, does anyone have an idea where I might look for this very intermittent problem? Thanks, Tim

 

[LT4man]

I would check every electrical connection under the hood that deals with the ignition system. Take the connections off of the ignition coil and inspect them very carefully. These connections will look like they are tight, but believe me, they can be anything BUT! If your engine stalls again, use a test light to see if you have current at the critical places. What happens in some instances, is that the metal spade inside the connector actually moves and stops contacting the clip that it is in. GM and parts stores sell most of the connectors that you can easily replace. Good luck!

 

[vigman]

VATS stopping the engine

Simple answer, NOPE
The Vats is ONLY part of the start sequence...If she cranks the Vats is OK
I would first verify that you have spark,, I have a High output coil and a standard ign module and it cooks from time to time ( but it has a 5 yr warranty he he he ).. but usually when it's REALLY hot outside.

Then I would VERIFY fuel pressure... with a gauge on the fuel rail.

Do a search for Bro-Ken fuel system that I did many moons ago that will tell the story.

Good Luck & Happy new year~

Vig~

 

[slapshot]

I've heard of some ground connections going bad. It sounds like some type of electrical problem, loose wire, connector, etc. They can be a bear to track down if they are intermittent.

 

[jmccloud]

Engine died

If your oil quantity is low, the oil level sensor will shut down the engine. Or, if the pressure drops (you mentioned city driving) the oil pressure sensor will shut down the engine. What is your oil level (or condition) like?

 

[HallenTi]

Thought about level after posting the question so I checked. It was about 1/3 quart below the full mark, so that didn't seem to be an issue. I have very good oil pressure at all times (I watch the gauges often). The oil itself was changed about 2,000 miles ago (10W-30). I removed and checked all the electrical connectors that I could find that related to the ignition system and cleaned them with the electronics cleaner. I mentioned before that the coil measured the proper resistance when tested, but I am wondering if it might be the original (I have 135,000 miles on the car) coil, and possibly heat and/or vibration might cause an intermittant short/open after years of use???

 

[G Winter]

Bad coils can tend to show up under heat. The work fine till they get hot then the insullation on the windings will break down and short.If your coil is that old it probably wouldn't be a bad idea to install a new one. You could take the car for drive to get some heat under the hood and then check the ohms on it. Or you could find some other controled way to heat the coil and check it.

 

[govette]

check fuse block on passenger side dash,water can get in there and mess things up.....ask me how i know:cry

 

[HallenTi]

Replaced the coil, and checked for water. Luckily, found no water anywhere that it wasn't supposed to be! So far, I've gone several days with not a lick more trouble. I have my fingers crossed!

Thanks for all the replies and the ideas...