93 safari 4.3L TBI will not start

[Polt86]

Our family owns a 93 GMC Safari with a 4.3L TBI engine.

It has been running fine for the last few months. A few days ago, it started lacking power just after starting driving on the road. About a mile down the road, it just died. The was no coughing or rough running, only the lack of power. We have not been able to find the problem.

There is gas at the injectors, and sparks at the plugs. The fuel pressure has not been tested, but the injectors seem to be spraying correctly, so I doubt fuel is a problem.

As for the spark system, the coil was replaced only 4 months ago, and is functioning correctly. The distributor cap and rotor are new and installed correctly. There is spark at the plugs.

When starting, it sounds as if there is no firing in the cylinders at all.

Does anyone have any idea what might be the cause of this problem?

This van did have a problem with similar symptoms about 4 months ago. The distributor cap and rotor were both worn to the point of not functioning at all that time. Both were replace at that time, along with the coil and the ignition control module (the control under the distributor cap).

Any help would be appreciated.

[CD Smalley]

You need three things for an engine to run. Fuel, Air & Spark. Verify that you are getting enough of all of these. Check the spark first. Attach an inductive timing light to #1 plug as close as you can and crank. Verify the timing light flashes.

Next start with the fuel pressure. Must be 9-13psi for TBI engines.

[Earlyboomer]

You didn't mention the mileage on this 93. I have found and seen more than one set of timing gears quit doing their job under conditions you are describing. It was real common with the "silent" gear sets that Ford and GM have used. They have nylon gear teeth on the cam sprocket and these could wear, crack, strip, etc. and then it was time for the tow truck. I just changed a set in a 2001 Astro and they were not the nylon version but at 130k miles they were really worn. Who knows how much longer it would have been before it stopped. Don't forget the camshaft controls the timing of the valves and the firing of the plugs and they need to work together. I personally think timing gears are often overlooked. Maybe this is something for you to consider.