Good Morning,

Usually when I started my car up it would idle kind of fast until it reached a certain temp, and then settle down. For about the past two year the fast & settle down is gone. In the summer it will idle pretty good, but no fast or settle down. In the winter it will not idle at all. I'm just tired of trying to keep part of my right foot on the brake while keeping the pedal down so she will run. Which direction should I go in to solve this problem? Merry Christmas.

Hugh Sr.

1984 190d (W201) 108,345

If the variation is summer - winter, my first suspicion would be lousy fuel quality.

Start here.
http://www.peachparts.com/shopforum/diesel-discussion/309367-warning-all-diesel-owners.html


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1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

Fuel is definitely a good starting point. Also, how long as it been since you've "overhauled" the GP system? Mine sure was happier at idle in the winter time during cold weather after I went and bought a new battery, new glow plugs, and most importantly in my case; added the new after-glow GP relay. Those things really made a big difference in how well my car would idle when cold (85 SD). Before I was like you and had to keep my foot in it for a good 30 seconds before it would idle on its own, but I no longer have that problem. I did adjust the valves as well, but I know that doesn't apply here.

1) Are you running alternate fuel, like WVO?
2) Do you have after glow modification or the glow plug relay is in good shape?

All I can think of is that after-glow circuit will cause the engine to surge at cold start with viscous fuel like WVO. When the engine is warmed up then it will idle smooth. It does not happen in summer because the fuel is not as viscous in warm weather. If I were you then I will try to measure the GP timing to see whether they are staying on or not after engine started. It could be by design if the relay is modified or by accident - the purple wire is disconnected or GP relay has an internal fault. After-glow circuit is good for alternate fuel in winter, more complete combustion and engine stays on running when cold.

Good luck.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

It's a little pain but you could adjust your idle up a little in winter time just so that it will stay running on its own beats having to keep your foot on pedal to keep running.

Na, I just use diesel available around the Nashville, and Middle Tennessee area. It's been doing this for about close to three years, so I don't think it's a fuel problem. How much are those glow plug relays? I appreciate your help.

Hugh Sr

1984 190d (201)

What viscosity of Engine Oil are you using?

Valve Adjustment?

If your Injectors have the stock Spray Nozzles in them:
w123 300d rought idle

Or the Injectors need rebuilding.


I read in one of the threads where some have had enough blow-by that it raised the crankcase pressure enough that it would effect the Vacuum Shutoff on the Fuel Injection Pump.
A little messy be easy to check; see if it idles better with the Oil Fill Cap off.

The Fuel Supply/Lift pump and the valve in the below thread could be having issues.
Long Fuel Pressure Relief Valve/Overflow Valve Thread
http://www.peachparts.com/shopforum/showthread.php?t=234609

__________________
84 300D, 82 Volvo 244Gl Diesel

Using a cetane boost will give additional diagnostic data regarding other possible fuel system issues.


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