87 300TD Wagon power question - PeachParts Mercedes-Benz Forum

DieselinBlood · #1 11-15-2006, 08:34 PM

I've purchased a 1987 300TD wagon to restore. The engine and tranny run great. It has 112K with no smoke,or oil burning problems. I changed all the filters and took it for a 400 mile ride yesterday. The best I could get it to do was 75MPH on level road. I seem to have the pedal floored most of the time. Is this normal? I'm not new to MB diesel's having owned a 240D,300SD and 95 300 diesel. But this is by far the slowest. Its suppost to have the most horsepower. I took the Trap oxidizer off today thinking it might be plugged but there was no problem . It had been modified and the chamber was hollow - no restrictions. Any ideas? How do you know if your turbocharger is working without having a boost gage ? Thanks,Jim

R Leo · #2 11-15-2006, 09:02 PM

Quote:

Originally Posted by DieselinBlood

I've purchased a 1987 300TD wagon to restore. The engine and tranny run great. It has 112K with no smoke,or oil burning problems. I changed all the filters and took it for a 400 mile ride yesterday. The best I could get it to do was 75MPH on level road. I seem to have the pedal floored most of the time. Is this normal? I'm not new to MB diesel's having owned a 240D,300SD and 95 300 diesel. But this is by far the slowest. Its suppost to have the most horsepower. I took the Trap oxidizer off today thinking it might be plugged but there was no problem . It had been modified and the chamber was hollow - no restrictions. Any ideas? How do you know if your turbocharger is working without having a boost gage ? Thanks,Jim

Check your throttle linkages to make sure that a floored pedal moves the power lever on the IP to a full load position.

My SDL had a similar problem (same engine as the 87TD you have) when I bought it. One of the throttle pivots located under the intake had come loose and flooring the pedal only moved the IP about 50% towards full load.

68882 · #3 11-16-2006, 02:45 AM

You should check the boost pressure to the ALDA on the injection pump. I had purchased a w124 300TDt and had experienced the same issue, we found the boost overpressure protection valve on the firewall was plugged with soot, preventing boost pressure from reaching the ALDA, thus preventing more fuel to flow.

Ara T. · #4 11-16-2006, 02:54 AM

It seems to me that the engine wouldn't rev up to 4500 RPM if the throttle linkages were not adjusted properly. Correct? How does it "go" in 1st gear?

Jim Wickham · #5 11-16-2006, 09:11 AM

Seems to be a VERY COMMON problem with those 603's in the 87 model. I just purchased my 300D sedan and see exactly the problem you are, I have not had time to work on mine as we are building the house and I won't be driving it till spring. Please let me know what ends up being the fix to yours. It's so much more help if people follow up their problem posts with solutions. Makes the search button a worthwhile venture, otherwise you just see lists of problems and potential solutions.

riethoven · #6 11-16-2006, 09:21 AM

You can call Mercedes with your VIN and they will check on recalls. If your trap ox had never been done then you may be able to get an new exhaust system and if they deem that it caused the turbo to go then maybe a new turbo also.

aersloat · #7 11-16-2006, 01:42 PM

To answer one of your questions, this isn't normal. My 87 300TD can hit 90 without any trouble. What is your 0 - 60 time? That is one way to tell if your turbo is working. Should be in the 12-13 second range I believe.

babymog · #8 11-16-2006, 02:10 PM

Original spec on the '87 300D was 9.8seconds 0-55mph with the trap-ox installed. My experience is that if it runs right, should hit 60 in under 10seconds with no trap-ox installed. Should top out around 120-125mph.

- Jeff Miller
190DT

gsxr · #9 11-16-2006, 02:53 PM

Read this first - lots of info, applies to 1987 300D/TD, power is one of the issues addressed:

http://www.w124performance.com/docs/mb/articles/124.1x3_buying_tips.txt

0-60 time should be in the 10-12 second range. Slower than that, start tracking down the assorted possibilities... filters, IP linkage, ALDA signal line blocked, low/no boost, etc, etc...

swogee · #10 11-16-2006, 03:25 PM

My 1987 300TDT is not slow. I can get sub 12 second 0-60mph acceleration times without a problem. It also has no problems cruising at over 75 mph if I don't pay close attention to my speed.

My 1987 300TDT has about 185K miles on it. When I first got it I discovered that the ALDA had a bad seal so the acceleration from a stop was slower than normal. After I fixed the ALDA, the acceleration time from a stop improved substantially. I still think I am having soming issues with the injectors though since it gets poor fuel economy (21-24 combined with mostly fwy driving) and it is noisy at idle. My 300TDT doesn't have the trap oxidizer since it was a Texas vehicle. I'm still chasing a few other issues as well.

-Steve

DieselinBlood · #11 11-17-2006, 12:04 PM

Thanks for all the replies. I worked on the car today checking linkages and vacum lines. I found some soot in the lines connected to the alda and blew them out.I took it out for a drive and the car still does 0 - 60 in 35sec. Right now I'm thinkin its the turbo. It starts right up and takes off with no hesitation to 30 mh .Then the acceleration slows right down.
Next week I'll take off the intake pipe and see if the turbo is free.If its free mybe the waste gate stuck. I'll post the results. Thanks, Jim

lrg · #12 11-17-2006, 03:24 PM

Swogee,

If you have an '87 that was originally sold in the US then it at least had a trap ox because they were all "50 state" cars in '87. It likely has been retrofitted with the later Trap Cat that is located further down the exhaust. The original "football can" that was next to the manifold should be long gone (at least I hope so).

LRG

gsxr · #13 11-17-2006, 04:06 PM

Quote:

Originally Posted by DieselinBlood

Thanks for all the replies. I worked on the car today checking linkages and vacum lines. I found some soot in the lines connected to the alda and blew them out.I took it out for a drive and the car still does 0 - 60 in 35sec. Right now I'm thinkin its the turbo. It starts right up and takes off with no hesitation to 30 mh .Then the acceleration slows right down.
Next week I'll take off the intake pipe and see if the turbo is free.If its free mybe the waste gate stuck. I'll post the results. Thanks, Jim

Try disconnecting the overboost protection for test purposes... there is a round sensor on the intake manifold, with a single wire connected. Unplug the wire, go for a test drive. See if there is any change in performance. When running correctly, your 35 second time should drop under 12 seconds.

DieselinBlood · #14 11-20-2006, 03:09 PM

I took off the Alda today after reading someother posts. What a difference. The car does 0-60 in 13 sec. It used to do 0-60 in 35 sec. Jim

gsxr · #15 11-20-2006, 03:39 PM

35 seconds with an ALDA, and 13 seconds without, means the signal line to the ALDA was blocked. And also that the pump is WAY the heck out of spec.

On my white 1987 300D, with the ALDA installed but disconnected (no signal line), it went 0-60 in 14 seconds. With the ALDA line connected, it dropped to about 10.5 seconds. That's 3-4 seconds loss, not 20+....!!!