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  #1  
Old 12-06-2015, 10:02 PM
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Pulling onto the freeway woes

I have a 1987 300 TD and It is an incredible car, except initial launch. Getting onto the freway can sometimes be a butt puckering experience. Once I hit 25 mph or so the car launches and I just drive off with no problems. BUT until I hit 25, I just wait for someoe to slam into me from behind.

It is my understanding the my car starts in 2nd gear. Is there a way I can change the gearing to start in 1st or just get it to pull away faster? I don't wanna 'roll coal' I just want to take off faster. Any ideas?
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  #2  
Old 12-06-2015, 11:15 PM
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I did a fair bit of searching for a 1st gear start for a 300SDL I had, and there wasn't really any solid options apart from getting the valve body reworked. From what I remember.

However, you should be able to get some adjustment out of your ALDA to increase your preboost fueling. It has helped on all of the engines I have had. No roll coal effect, even with it removed on the Jeep.

If everything is working like it should, you should get 1st gear starts if you give the skinny pedal a good stab. Something to check into, might just be a not working kickdown switch.
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Old 12-06-2015, 11:58 PM
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I will check onto fiddling with ALDA. Any links wpuld be appreciated. I replaced the kick down switch this summer. When that went out, the car wasn't much fun to drive
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Old 12-08-2015, 03:56 AM
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Quote:
Originally Posted by Slow Joe View Post
I have a 1987 300 TD and It is an incredible car, except initial launch. Getting onto the freway can sometimes be a butt puckering experience. Once I hit 25 mph or so the car launches and I just drive off with no problems. BUT until I hit 25, I just wait for someoe to slam into me from behind.

It is my understanding the my car starts in 2nd gear. Is there a way I can change the gearing to start in 1st or just get it to pull away faster? I don't wanna 'roll coal' I just want to take off faster. Any ideas?
IIRC when at a full stop, if you quickly move the gearshift lever from D to 2 and then back to D, you force the transmission to start in first gear. This bypasses the use of the kickdown switch and allows a quicker takeoff.

If you then punch it when you take off you can move "briskly" with very little smoke.

This adjusting shift points thread link may also be of help.
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Last edited by Alec300SD; 12-08-2015 at 04:00 AM. Reason: typo
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  #5  
Old 12-08-2015, 06:17 AM
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Second gear start?

I've owned a lot of gassers with that "feature", but my 87 300TD was a first gear start car. I'm surprised that the W126 Om603 used a second gear start....

Your engine is NOT running like it should. A well tuned engine will literally leap as soon as you hit the fuel pedal. Before messing with the ALDA, you need to make sure that the linkages are adjusted perfectly, and make sure the pressure lines coming off the intake manifold are not clogged with crap.

Once you've done the above, then move on to adjusting the pop off pressure on the turbo, and adjusting the ALDA.

If you have not yet blocked the EGR, please do that as well. See archives for lots of info.

Jim
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Old 12-08-2015, 05:27 PM
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Quote:
Originally Posted by JimFreeh View Post
Your engine is NOT running like it should. A well tuned engine will literally leap as soon as you hit the fuel pedal. Before messing with the ALDA, you need to make sure that the linkages are adjusted perfectly, and make sure the pressure lines coming off the intake manifold are not clogged with crap.
+1

check/replace ALL your rubber hoses from fuel lines, turbo pressure and vacuum lines
That was ~100$ on my car just for rubber connectors but it fixed many problems!



Quote:
Once you've done the above, then move on to adjusting the pop off pressure on the turbo, and adjusting the ALDA.
check your turbo pressure and set it to 14psi,
after completing what is mentioned above (including turbo pressure) ALDA screw 1 turn out should be enough.



Quote:
If you have not yet blocked the EGR, please do that as well. See archives for lots of info.

Jim
+1

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  #7  
Old 12-08-2015, 10:26 PM
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I thought that the diesels were first-gear start.
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  #8  
Old 12-09-2015, 04:06 PM
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The 1987 300D should always start in 1st gear. So, should any 300SDL.

If it is taking off in 2nd gear, then you need to check all of the thottle linkage to make sure that it is not binding or that a part of it isn't disconnected. If all seems well with the linkage, then try adjusting the bowden cable for the transmission. It should not have slack at idle. Loosening it will make the transmission hold each gear longer and
tightening it will do the opposite.

Anyway, the car should hold each gear until 4500-4800RPM at full throttle. Although it is not uncommon for it to shift from first to second a little early, like around 4200RPM.

I borrowed the pictures from someone else, but they show exactly where the bowden adjustment is.
Attached Thumbnails
Pulling onto the freeway woes-20.jpg   Pulling onto the freeway woes-19.jpg   Pulling onto the freeway woes-screenhunter_13-nov.-02-01.53.gif  
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Last edited by BenzEnthusiast; 12-09-2015 at 04:20 PM. Reason: Add Pictures
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