Looooong time no post folks.

Everything has been going along fine with little to no time for computer time here...until today.

Long and short, wifey's CLK320 developed the hot start issue with daughter driving the car. Diagnosed as the crank position sensor, got the sensor and installed today so I could get smogged. Didn't know there was a check engine light on (instant failure) so I scanned and found it was the CPS error tripping the light. Cleared the code and went for a drive to get some drive cycles and reset the ECU. Just as I'm getting back to town a 4 x 8 sheet of plywood came flying from somewhere, quick reaction kept it from joining me in the front seat but lost the driver's side mirror and some paint in the process.

During the dodge/impact check engine light came back on. Checked the code while I was at my insurance agent's office and got the P0400 error. Cleared the code and took it for another spin (minus mirror) and the light came back on at the end of the interstate off-ramp. Again the P0400.

Now I'm sure it is purely coincidence that it came on at the time of impact. Soon as it cools off enough I will check the vacuum hose connections to ensure they are intact. I read about cleaning the EGR tube and will look at that if the connections are good. Anything else to suspect as the trigger for this MIL?

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Glad you dodged the plywood!

There are a host of possibilities. I would start simple. Inspect the vacuum lines as you've indicated you're going to. (Look all around, too, since you were just recently working in the back part of the engine...) If your model has the the little stub valve on the EGR, check that as well to be sure it's not leaking. If that's all okay, then put a longer piece of vacuum line on the EGR valve and suck on it. See if the diaphragm moves (you can see in from the back of the chamber), and be sure it holds vacuum (after it's fully moved put your tongue over the end of the hose). If it fails, replace it. If it passes, then pull the valve and tube and clean them. Some advocate cleaning the tube on the car, but if you do that you dump most of the crap that is in it into the intake manifold. Ugh.

Good luck.

Hey Mike, as soon as I saw your name I figured someone must have replied to a really old thread

I'd bet on a plugged tube but check the simple stuff just in case.

every egr code on a 112 motor I've seen is the tube and/or port. even after the dealer installed a new egr on an e320-funny! good luck, chuck.

Hey Mike. Other than your cel I hope you are doing well.

__________________
Jim

Jim and others,

Overall I have been doing fine, just busy, busy, busy. Shoot, my new car (the 2012 JSW) is only 3 years old and I've racked up 124K miles. Can't complain about that little diesel at all as I have a 42.25 lifetime MPG average with it.

I hope to jump on the EGR tube and connections early tomorrow. If lucky I may even be able to get it in to the smog shop before sending it off to the body shop for the plywood damage. It looked way worse this morning though. Left fender and A pillar also took a hit, door is creased from the mirror slamming into it and there is glass embedded in the paint.

Will be looking at any and all posts regarding cleaning the tube just to get an idea of the best/quickest way to clean.

Mike

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

The EGR code more or less started when the computer was cleared of codes. When you do that all of the emission diagnostic monitors are cleared. Look for a drive cycle instruction and you will find under what conditions the EGR is tested.

From what I recall the V6 had problems with the EGR passages in the head clogging. For most cars, if you manually operate the EGR the motor should stall / nearly stall at idle.

OK, it is hot out already but I got the EGR tube out. I almost had a little panic because I got the tube stuck trying to turn it out but managed to free and twist it out on the third try. Once you get all the peripheral junk out of the way the tube on the M112 is easy to get to.

Tube had hardly any crud built up and I think it may have been cleaned before we got the car. The fitting at the EGR valve was only finger tight ! I still did a little scrape job while the tube is out using a clothes hanger. I also checked the vacuum line at the EGR and it is pliable and intact. I did pull a vacuum on the valve, the valve opens and holds vacuum. When disconnecting the line you can hear the valve snap shut. Right now it is holding 22.5 in hg.

Now I am trying to think through where/what could be causing the MIL. Two possibilities come to mind - the loose fitting or the EGR pressure sensor at the front of the engine. With my luck the latter will be the issue. I can only see a little piece of vacuum line between the sensor and where it disappears in the maze, can't tell if it travels up under the intake.

For now I think I will start putting things back together while I look around and think through this. I'll check back in a bit.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Found the problem!

After getting the tube in and tightened down I decided to check everything one more time, even the pressure sensor up front. Well hell, the vacuum line to the sensor is, well, shot. The last inch or so is completely degraded and as soon as I touched it it crumbled. The line goes up inside the hard plastic sheath and I don't know where it connects at the other end. I need to splice in a piece of line and I should be good to go.

I guess I fall into that small category of folks who have something other than a plugged EGR tube causing the P0400 fault.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Hmmm...getting stumped.

Thought I had it, buttoned everything up and went for a drive. 20 miles out, stopped turned off the key and opened the door. Sat for a minute started up and headed back. Just as I got on the off ramp the check engine light came back on, pulled into the closest lot and scanned only to find it is the P0400 again.

Cleared it and went 20 miles out the other way and repeated the shut down, door open reset. Came back 20 miles but did not get the check engine light when getting off the interstate. When I got home I checked to see if the ECU had fully reset and it hadn't, probably because the traffic kept me at 65 rather than 70 (guessing), three systems are still showing incomplete - evap, O2 and EGR.

Scanner is reflecting the P0400 error again and says the MIL should be on but the light is off. I suspect it is because the EGR check is incomplete and the lamp will come on as soon as the EGR check completes.

It is too hot to mess with now but there can't be much left to check. It seems it could only be the EGR sensor or a problem in the vacuum line to the sensor deeper in the sheathing. I did cut that line back to good rubber before splicing in a new piece.

Any other ideas?

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

A quick update.

I had jury duty today but got released early, used the time this afternoon to dig into this EGR issue a little more. Found that the vacuum line to the switchover valve was also deteriorated. After replacing that I decided to pull the intake plenum again and recheck the vacuum lines at the EGR. Surprise, I missed one the other day!

I could actually see the line that goes to the EGR diaphragm and had to "look" with my fingers for the others. I only found one other line the other day but today I found the main vacuum line from the manifold to the solenoid. That line was holed at both nipples, literally crumbled at the touch. Now all the vacuum lines have been replaced.

Unfortunately I also found the return line nipple on the expansion tank broke off so I am dead in the water until the replacement tank arrives. Ordered the MB tank through Pelican and it could be here as early as tomorrow but wont be able to tackle it until Friday. Friday will be busy - replace expansion tank, install the breather box and plenum, clear the code and drive to reset the ECU, get smogged then get the car to the body shop so they can start on the damage from the plywood.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Final update:

Expansion tank received and installed, all vacuum lines replaced and codes cleared. Did the check ride last night to reset the ECU monitors, all reset except for evap and secondary air pump...suspect it was still too hot out to get a true cold start. Did a follow up check ride this morning, all monitors reset and checking in without fault. Passed smog and now the car is at the body shop to repair the damage from the flying plywood.

Feels good.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.