Hi all, new to forum. Bought my 2nd MB (other is 97 e320 81k) - the "jolly green giant" - per the wife and kids - this week - 181k. New mb installed motor at 105k and rebuilt tranny at 174,000 (have docs, am 3rd owner). She starts right up, does not smoke at all, but idles a bit low (500-600 by looking at slighty bouncy tach) and really rough. Give her some fuel and it smooths out.

Changed air filter, just did purge, which came out almost as clear as it went in and changed fuel filters. Idle is a tiny bit better, as is acceleration (14-15 secs best estimate maybe a little slower) but idle is still a bit low and rough. Turbo sounds like its spooling up if I don't get on her hard, but does not seem to stay spooling nor does it seem to spool if at all when you accelerate on the highway - just slow increase with max pedal.

Had similar issue with a TDI which turned out to be soot blocked egr and intake. I'm leaning in that direction but have not started dismantling yet. Wanted to see if anyone else has had same issues? Am i on the right track? If so, how difficult was it to remove and de-crap the egr and intake.?

Any input would be greatly appreciated.

 

Thanks for the input. I'll take a look. I don't recall seeing a dial like the one in the picture you sent, but will take a look tonight after work. Was wondering how to adjust idle speed. +50 to 100 should smooth it out. Specs are 630+- 50. I think it's pretty close. Just rough. Also thinking mounts could be shot. Limited visual doesn't seem to indicate though. My local indie quoted about $320 to replace if needed. Don't have time/skills/tools to replace myself. Seems reasonable based on parts and time.

Any thoughts on what seems to be limited turbo boost? Still thinking some restriction within intake. Had an EGR and intake plugged with soot (down to about 3/4 inch diameter opening) on my 03 tdi that caused similar issues - turbo would just stop working (overload cutoff - thank god). Not sure how it even ran. Anyway, am considering pulling the crossover to take a look. It would plug there first wouldn't it?

Thanks for your help. Want to try the easier things 1st.

 

Thanks again for the info.

I took a look tonight for the ELR per your post / pic. not there. Looks like the mounting plate is there but no ELR. See pic.

Removed and replaced the 10 amp fuse in the OPR. Old one didn't appear bad. Idle was noticeably smoother, tach smooth and somewhere between 6-7 hundred, ac compressor kicked on which I don't think it had before, no more whole car shaking. Took it for a test drive. Pickup seemed smoother, pulsing when braking gone, overall much better... for about 2-3 miles.

Took it out on the highway and she became sluggish again, vibration when braking, idle rough when I came to a stop and really slow acceleration. Didn't time it but best guess around 20-25 seconds to 60.

Loose or corroded connection from OPR to harness? I didn't want to yank it out yet. Is there a way to test proper function? I pulled the fuse while running and the idle slowed way down and picked back up when I put it back in. Don't want to replace $50-60 part unless I need to.

Any additional thoughts would be appreciated.

 

Checked OVP relay at terminals 30 and 31 and tested within specs - fuse not blown. Was able to get another OVP from junk yard which tested ok as well and it runs the same. Am now leaning towards fuel tank strainer. It seems to run/idle smoothly for a few miles after sitting and then acts like it's not getting fuel, (slower and rougher). If the crud settles to the bottom after sitting and then gets stirred up after driving I'm thinking the strainer is getting clogged and slowing fuel, thus, slower speed and rough idle. There was slime in the pre-filter when I changed it. The car did not get driven much by PO. Let me know what you think.