2005 CDI limp no code - PeachParts Mercedes-Benz Forum

dieselbenz1 · #1 04-12-2020, 12:05 AM

Last Eve I drove home in limp. Ok to get to 100
Kph just took a far Bit of time. So cleanded the
MAF, EGR and all the electrical connectors so far is good ok.

chronometers · #2 04-12-2020, 01:00 PM

Is car still in limp mode after EGR clean?

dieselbenz1 · #3 04-12-2020, 01:28 PM

No more limp just not certain what fixed it since I did several items before restarting it.

dieselbenz1 · #4 04-14-2020, 04:44 PM

It drove fine for 3 days so last night I put all the covers back on and sure enough this morning the check engine lamp is on. Using the foxwell read the code MAF malfunction. Cleared the code then ran the EGR test, charge boost control and fuel rail tests. Haven't drive it since.

dieselbenz1 · #5 04-16-2020, 05:43 PM

Ran perfectly for 3 trips then as I merge onto the freeway it throws a code then limp. This time code is erg valve position, then clear that code. Now no codes and still limp.

So far 2 times no codes and limp
2 times a code MAF then EGR cleared then normal operation.

Hmmmm.

dieselbenz1 · #6 04-16-2020, 07:08 PM

Removed the EGR valve last time I had just cleaned the exposed valve portion but never tested the valve. You just unclip several retainers and both ends can be exposed. Sure enough the valve had 20% movement. Cleaned the valve stem and worked it now easy full range movement. I'm betting that's the issue valve stem packing leaks jamming movement.

engatwork · #7 04-17-2020, 07:55 AM

How many miles on it?

dieselbenz1 · #8 04-17-2020, 09:51 AM

230 km took a quick spin and check engine came on MAF out of range. Cleared that now.

chronometers · #9 04-17-2020, 05:27 PM

Possible clogged EGR valve. Throws car into limp mode but no codes are thrown. Can be a dangerous situation if you are on the road and expect power.

Confirm it is the EGR. Take your EGR valve out (back right of engine). If it sticks, that is your culprit. Clean it out and make sure it opens and closes on its own with the spring actuation. I had to do this several times over the first few years I owned mine....it would be fine and then the EGR valve would stick open.

After a while, I decided to install an EGR delete circuit:

EGR EGR AGR valve emulator

Now my car takes a little longer to warm up but no more EGR clogging and no more soot being thrown into the engine.

The alternative is to replace the EGR valve but if you keep the car, it will develop same problem:

Wahler OEM EGR valve for E320 CDI

It also costs a lot more than the EGR delete.

dieselbenz1 · #10 04-18-2020, 08:19 PM

Thanks chronometers I was heading down that path. I had ordered from Lithuania in the past but delivery was around 6 weeks. I checked around and had enough parts so assembled a modified one as seen in the pics. I now have full power but a check engine lamp low mass flow so the power diode I used is incorrect. I'll see if I can find a more suitable diode or just tweak this circuit a bit.

dieselbenz1 · #11 05-17-2020, 11:33 AM

Just to update this thread it's been a few weeks since I had installed my version of the EGR emulator circuit. It's been working flawlessly without the engine lamp on, mpgs I would say improved a tiny bit and the black smoke is absent when I really gun it. I have parts to build several more circuits if anyone else needs one but only good for 05 and 06 CDI.

chronometers · #12 05-19-2020, 05:58 PM

👍😷 Congratulations. Welcome to the clean engine club!