My car is an 1987 300SDL that has 270,000 miles. I've had it for a year and have had 15,000 miles of trouble free driving.

Today I was on a 5 hour drive from Portland OR around Mt Hood. As I was reaching the summit of the pass which may
be 4000ft elevation, the road changed from one to two lanes in my direction. I held the throttle open (not clicked down) for about 30 seconds, accelerating up the incline from about 45mph to close to 65. The automatic was in forth, the car was pulling strong past the low 60's at about 3000rpm. I'm assuming the Turbo was at or near full boost.
All of a sudden I lost power as if the key was turned off. Slowing down rapidly I realized the engine was still running and making maybe 25-30 percent power. Within about 15 seconds the power came back strong and performance was restored.
A brief description of the problem would be as if the wastegate dumped all of the turbo pressure, and then the Turbo spooled up again. At least that's what I'd tell a mechanic. For all I know it could be a fuel pressure problem.

Could I have "overboosted" and demonstrated overboost protection? Without a good 8 percent incline I can't hold high boost pressure (full throttle) for a considerable amount of time without breaking the speed limit. So I rarely have the opportunity to subject the engine to these conditions (full boost for 30+ seconds).
I'd like to add the engine temp and oil pressure are both normal. No strange sounds during this strange power loss. The car ran perfect the rest of the way home.

Any similar experiences???

Thanks,
DZLPWR

DZLPWR,
Perhaps a silly question but are your fuel filters in good order? A filter in questionable condition may give reasonable performance under normal driving but under the load you described you may have exceeded the flow a dirty filter can maintain and by waiting the 15 or so seconds it may have been able to catch up with itself. Fuel starvation in a diesel often shows a dramatic loss in power. I may be wrong on this but I have not heard of a waiste gate taking any measurable time to cycle back. I hope this helps.

Rick

The inline filter appears to be clean. When I purchased the car the inline filter was black. I changed both inline and twist-on filters. Acceleration improved and the black smoke was gone. A few months later it started smoking again so I changed the filters again and the smoke was gone. I've come to this conclusion regarding fuel filters: Clean filters = no smoke, Dirty filters = black diesel cloud trailing car.

I added Redline fuel treatment 8 months ago and have changed filters about 4 times in the last year hoping to clean out the system. At the time of the mysterious power loss there was no visible smoke.

Thanks for the reply

Use half a bottle of Redline diesel treatment every time you fill up the tank. It does make a difference.

it does kinda sound like what would happen when the overboost protection solenoid shuts the fuel down momentarily.

__________________
Jim

I'm not as familiar with the six cylinder diesel as the five but you should still have a boost sensing line at the back of the intake manifold this might have become obstructed and limited fuel enrichment. especially if your EGR is still functional.


Bob D.

Even though I could see through the inline filter, and see very little contamination- only a few particals, the filter was blocking the flow. It looked as if the filter were 99% clear, but I could not blow through it. The contamination was basically clear. She's back on the road.