1993 SC 300 Loses Main Power While Underway

[OLD GUY WITH SC]

Original owner of this 5-speed SC built in 1992.  90,000 miles. Recent incident occurred while underway at 65 mph.  Ambient temperature 90 degrees.  Vehicle had been sitting in sun for 3 hours.  Drove 10 miles from stopped position.  Complete loss of power.  Eased to roadside.  Waited 1 minute.  No power indicators.  Waited 2 more minutes.  Rough start.  Got underway.  Vehicle jolting and jerking and jumping, even while sitting and certainly while attempting to get underway.  After 3-4 miles, everything smoothed-out and next 25 miles without further incident.  Can vaguely remember this occurring once before in 1995 or 1996, but of a minor nature.  Vehicle has been maintained in excellent condition; always stored in a garage.  Advice requested.  THANK YOU.

[TrevC]

Hi Mark...welcome to the Club

Sounds like it could be bad fuel (water content, sludge) maybe change the fuel filter if it occurs again and/or change fuel supplier.

Let us know what you find 

Cheers   Trevor

[62Daytona]

I had a similar problem with my 92 SC400.  A simple check to see if the problem is the Fuel Pump ECU is to use a jumper wire at the diagnostic box on the engine.  Use a piece of copper wire bend into a U and plug into FB and +B.  Look inside the box's lid to identify connectors.  This supplies 12volts to the fuel pump when the Key is ON.  If this solves your problem then the Fuel pump ECU is bad.  They are about $380.  The Fuel pump ECU is located under the left rear passenger panel.

Give it a try, it is free.  A bad Fuel Pump ECU does not set a code. 

[OLD GUY WITH SC]

Ta, Trevor.  And my thanks to you as well, 62Daytona.  My friend/neighbor/mechanic will look into these suggestions.  So far, I am able to recall two incidents as I described earlier; and my nephew tells me this also happened to him once.  That's just 3 times in 24 years which makes me/us wonder if it is a "phantom" electrical issue which is driven by the ambient temperature.  More investigation needed.  More suggestions welcome.  

[OLD GUY WITH SC]

Here I am, 3 years on and the "phantom" issue has been resolved.  My friend/mechanic worked through the fuel system from the gas cap to the throttle body.  Along the way, we replaced the fuel pump and filter.  Thanks to some fellow "sufferers," we also found a work-around for eliminating the "Fuel Pump Control Module."  And, voila, I have driven it 100+ miles and all seems to be operating perfectly.  NOTE : we also installed an inertia-triggered cut-off switch in the left rear trunk area to ensure that the fuel system is cut-off in the event of a collision.  Hope my experience is of some help to others.  Stay Safe!