No power until warms up - PeachParts Mercedes-Benz Forum

kc kid · #1 04-05-2009, 06:13 PM

I know these old diesels (85 300SD) don't have a lot of power , but mine has none until it warms up . After it warms up its not bad and by the way I do get 30 miles to the gallon and little better somtimes . Its worse when its cold out . Could this be a trany problem , fuel , the guy behind the wheel . Does anyone have any ideas where or what I could check first ? The trany fluid has always looked good (bright red) and has not needed any in the 6 months (15000 miles) I owned had it.

Brian Carlton · #2 04-05-2009, 06:44 PM

Usually, the IP timing and camshaft timing are late and this robs power at all speeds. The fact that it's cold exacerbates the problem.

Additionally, if the valves haven't been set in 50K miles, that's another issue to address, but, you'd typically get starting problems if they are too tight.

Finally, if everything above is done, there is the possibility of increasing the fuel quantity at lower power settings by adjustment of the ALDA.

All of these recommendations are detailed in hundreds of posts........and you can search on those terms using the search function.

kerry · #3 04-05-2009, 06:49 PM

At 10 degrees outside, I figure I start out with about 50 horsepower and get an additional 10 horsepower for every 1/2 mile or so until I reach full horsepower. In my experience, it's worse without a turbo.

JonL · #4 04-05-2009, 07:03 PM

I'd suspect marginal injectors as well. Bad spray patterns will have more of a detrimental effect when things aren't warm enough to assist in atomization / vaporization of the fuel.

lietuviai · #5 04-05-2009, 07:49 PM

It's possible you have worn rings. As your engine warms up, your rings will expand, which increases compression sealing and then improving power. Check your compression when you have a chance.
Worn engines are known to get good fuel economy as well.

tobybul · #6 04-05-2009, 10:34 PM

How about the simple stuff first like fuel filters, or dirty/plugged up boost line. I would definitely check your boost line that goes from the turbo to the switchover valve to the alda, and the valve itself. Clean the line - and the valve - with brake cleaner spray to remove soot.

Messing with alda would be a last resort, imo.

kc kid · #7 04-05-2009, 10:55 PM

This has me baffled . I have put a lot of miles on this car in a short time . I have changed oil every 3000 miles and all filters (oil ,fuel and air). It acts like an old man getting out of bed. The first mile or so I could get passed by my little brother in his electric wheel chair but when it warms up it runs like hell and i would rather drive it than my 08 GMC . Call me sick everyone else does , this is the first car i have ever owned and i love it . I just dont want to tear something up that I could have fixed before it gets bad .

777funk · #8 04-05-2009, 11:05 PM

Quote:

Originally Posted by kc kid

This has me baffled . I have put a lot of miles on this car in a short time . I have changed oil every 3000 miles and all filters (oil ,fuel and air). It acts like an old man getting out of bed. The first mile or so I could get passed by my little brother in his electric wheel chair but when it warms up it runs like hell and i would rather drive it than my 08 GMC . Call me sick everyone else does , this is the first car i have ever owned and i love it . I just dont want to tear something up that I could have fixed before it gets bad .

I wouldn't (personally) worry about tearing something up. It's pretty normal for a 617 to be a little bit more sluggish when it first starts in cold weather. Every one I've owned has been that way. I think part of it may be that the turbo might not spin as freely before it gets a good HOT oil supply. It's got thick cold oil to fight against. This means less boost. But also as another member has said, the clear boost line that goes from the back of the intake manifold to the overboost protection valve on the drivers fender and to the ALDA on the top of the IP can get clogged. Take the banjo fitting off the back of the intake and take a look at it. If it looks remotely dirty, clean it. I'd clean out every part of that connection. Also, if you're ALDA hasn't had the cap broken (the little black top hat on the ALDA which is on your Injection Pump), you might adjust it a little. As Brian said, you can find the proceedure on that if you Search ALDA. Many of our members (including me) have both adjusted and removed the ALDA. After doing both, my recommendation is to adjust it (you'll get less black smoke when you floor it and it does serve a purpose as a feedback system from the turbo to the Fuel Injection Pump).

Anyways, hope that helps. I'm sure you'll get more replies.

MercFan · #9 04-05-2009, 11:39 PM

Quote:

Originally Posted by kc kid

... but mine has none until it warms up...

I feel your pain, mine acts exactly the same way... After the purchase, I did all the things that other members recommended (new filters, valve adjustment, even ripped off the ALDA cap and made as slight, careful adjustment, measured the timing chain stretch) - it helped with the overall acceleration, but still - when cold we're going nowhere...

When I pull out of my subdivision and the engine is cold, I have to carefully time my merge into the traffic, or else I'll soon have a string of angry tailgaters behind me... once warm, the car is actually pretty zippy.

Always wondered if other owners have similar experience with their cars, or if it's just mine.

James

the heap · #10 04-06-2009, 12:03 AM

Remember, these are compression ignition engines, and the thing that makes the pistons go up and down and the crankshaft go round is the force of expanding gasses against each piston. When cold, a lot of the heat of combustion goes into the cylinder head instead of expanding and pushing the piston down. As the head and the rest of the engine gets hot, then more force remains and is applied to each piston. And because these are cast iron engines, which has a high heat content (takes a lot of BTUs to raise the temperature), a lot of energy goes into making the engine hot enough to make adequate power. Diesel engines like to run HOT. Commercial diesel engines sometimes have ceramic piston crowns and cylinder head liners so they can run REALLY hot. So poor cold weather driveability is the nature of the beast. I often modify my commuting route in the winter so when I leave my house in the morning, I avoid non-signal controlled intersections, I can't rely on any power to scoot me across 2 lanes of oncoming traffic and avoid getting tee-boned as I pull out onto busy streets.

'77 300D 355Kmi
'95 C220, 180kmi

whunter · #11 04-06-2009, 12:22 AM

Quote:

Originally Posted by kc kid

I know these old diesels (85 300SD) don't have a lot of power , but mine has none until it warms up . After it warms up its not bad and by the way I do get 30 miles to the gallon and little better sometimes . Its worse when its cold out . Could this be a trany problem , fuel , the guy behind the wheel . Does anyone have any ideas where or what I could check first ? The trany fluid has always looked good (bright red) and has not needed any in the 6 months (15000 miles) I owned had it.

Add one gallon of kerosene to each tank of diesel during cold weather, for easier start and quicker warm-up/throttle response.

Read the valve adjustment thread:
* The factory service manual calls for adjustment every 15k miles.
* If the exhaust valve adjustment is tight = you loose (unknown %) compression = more difficult to start and slower warm-up.
* If the cam/rockers have a little wear = they must be adjusted a bit loose, crank engine one revolution and re-check/adjust any tight ones...

Here are a couple of threads to help you..

Diesel Injection:
http://www.peachparts.com/shopforum/showthread.php?t=142405

Valve adjustment OM617 FYI.
http://www.peachparts.com/shopforum/showthread.php?t=107729

Diesel Fuel Delivery:
http://www.peachparts.com/shopforum/showthread.php?t=142399

Have a great day.

tobybul · #12 04-07-2009, 08:43 PM

Quote:

Originally Posted by kc kid

This has me baffled . I have put a lot of miles on this car in a short time . I have changed oil every 3000 miles and all filters (oil ,fuel and air). It acts like an old man getting out of bed. The first mile or so I could get passed by my little brother in his electric wheel chair but when it warms up it runs like hell and i would rather drive it than my 08 GMC . Call me sick everyone else does , this is the first car i have ever owned and i love it . I just dont want to tear something up that I could have fixed before it gets bad .

Thats why I suggested doing the simple stuff first. The ones that do not require tearing things apart or modifying factory settings.

kerry · #13 04-07-2009, 08:51 PM

It also makes a difference that you're a mile high.

disqo · #14 04-08-2009, 12:44 AM

My car does the exact same thing. All of my filters are good, my valves are properly adjusted, and the alda line has been cleaned. One of these days I will install a boost gauge and I might play with the alda to see if that makes any difference. My best guess for the problem has been my injectors. I get a slight nailing when the engine is cold. Last weekend I was actually trying to climb a hill at the camp I work at in the mountains and the car did not make it. I had to back down the hill, wait for te car to warm up a bit and then try it agian. My brother always cracks on my car and this little display with him in the car didn't help.

shadetreemechan · #15 04-08-2009, 09:14 AM

This thread sounds like its becoming a cold diesel support group

My Sd does the same thing, to the point that when I leave the driveway in the morning I cannot manage more than 5 mph up the gentle grade of my street. My neighbor wondered out loud what I was doing creeping past his house in the morning.
He isn't just paranioid. The thing about my car is that once I am past his house, the car takes off like a rocket, often catching second gear on the loose gravel.
I have cleaned and adjusted the alda, bypassed the overboost protector, changed all filters, and valve adjustment, and a diesel purge. My latest guess is that the spring is worn in the lift pump and/or the seals in the lift pump are hardened and need to warm up before delivering enough fuel.
Since spring is almost here, I won't have to worry about it again until Fall. The car has no symptoms unless the outside temp is below 50.