1985 300D Turbo loss of power
 

A couple of weeks ago my super strong and powerful 300d tubor mercedes experinced a marked decrease in power. I cannot get above 70MPh on a flat surface. Here is what has been done: replaced primary and secondary fuel filters, replaced fuel tank strainer and replaced all 5 injectors and added two cans of lubo molly diesel purge all to no avail. What is going on here and how do i get my diesel power back? thanks for any help. BTW, the last speeding ticket i got in it registered at 105MPH.

-terrell

Check your accelerator linkage. If that's ok, check your lift pump or fuel pressure.

Shift linkage or tranny.
 

What's your tach read at 70mph? The reason I ask is, on the turbos, that's about the max out for third gear. Is the car shifting into fourth? Perhaps your shift linkage is loose and you've actually been running the car in S (slope) while the lever appears to be in Drive, thus negating the fourth gear which would allow you to drive at speeds over 70. Maybe check this first and take a look at your RPMs before getting into anything else.

@Kerry, thanks. How do I check lift pump and fuel pressure? @Npretar, thanks; the tach is reading about 3200rpm but will engage the 4th gear trying to go faster but it simply spins faster with no gain in acceleration. Even on take off I can feel a noticeable loss in power.

Check all the ALDA plumbing starting with the fitting on the back of the intake manifold.

Clean your banjo bolt. No pressure sensing = no fuel = no power.

That sounds like the transmission is slipping. Is that what's happening? More rpm but no more mph?

If it is engaging, then it isn't slipping. If it is slipping, then you should be shooting past 3200 with just a little throttle.

Do you mean the trans will downshift (take you from a lower rpm to a higher rpm at the same speed) to try to give you more acceleration, but then you get none? Is the pedal floored at that point?

Sure sounds like a boost issue to me...

"If it is engaging, then it isn't slipping. If it is slipping, then you should be shooting past 3200 with just a little throttle.

Do you mean the trans will downshift (take you from a lower rpm to a higher rpm at the same speed) to try to give you more acceleration, but then you get none? Is the pedal floored at that point?

Sure sounds like a boost issue to me..."

@JHZR2, yes, this is exactly what it is doing. I'm flooring it to get it at this point and then it downshifts with more rpm no more in acceleration.
Everyone thanks for your help with this matter. I really do miss my powerful diesel benz...

Thank you all! After examining the banjo linkage I noticed that it had broke from the appartatus on the firewall. Reconnected and was back in business with FULL diesel POWER. Shifting is smooth and power is endless. Thanks again. Now, go and check your banjo linkage.

_terrell