The "check engine electronics" warning has come on. Fault code said EGR problem. I understand this could be a carbon-blocked inlet, at the intake manifold/EGR pipe. This would be the cheapest to fix (before replacing the valve and/or line), so I would like to try. Is this a DIY for a reasonably-competent shade tree mechanic? Any advice would be appreciated.

Coincidentally, the fault appeared within 15 miles driving after I replaced the battery. I needed to disconnect the battery again, which cleared the fault, but it came back after another 50 miles of driving. I assume the battery disconnect is just a coincidence, since the fault code was read by an independent shop (I watched).

Your help will be really appreciated,

Best,

g

__________________
64 230sl, my daily driver
94 E500, sold
98 E320, family and dog hauler
04 C240, safe machine for teen drivers, but a poc
08 audi a4, yes we have gone to the dark side

A simple EGR flow test will verify tube blockage.
Pull the EGR open with a hand vac pump at warm idle. The engine will stubble when you open the EGR.. if it does not , then the tube is plugged.
Also test the the EGR closes with a SNAP w/same test.

Thanks, Arthur, I appreciate it. So if the idle does not stumble when I create vacuum I can assume there is a carbon block?

g

__________________
64 230sl, my daily driver
94 E500, sold
98 E320, family and dog hauler
04 C240, safe machine for teen drivers, but a poc
08 audi a4, yes we have gone to the dark side

..yes, as long you can hear the EGR manually open/shut...there could be the remote possible that the EGR diaphragm is not working, which will also give the code. You should hear it snap shut .

The ECU does not normally call for EGR at idle, so if you manually induce EGR air at an idle, what you are actually doing is creating a large vac intake leak..so the engine tries to stall [ same as if you were to pull off the brake booster vac line]
The engine will not completely stall b/c the Engine management will try to correct the lean condition, but it will run very rough. If the tube is blocked, then opening the EGR will result in no rpm change b/c the tube blockage allows no air from the EGR to reach the intake.
What code did you get? .. there are different flow specific EGR codes to pin-point the condition......

Thanks,Arthur, that makes sense. Unfortunately I don't have the code, never thought to get it after the readout said EGR flow problem (or something to that effect). And I just saw that the bolts are torx, and I don't have a set down here in FL, so it will have to wait until I get to Sears anyway. I appreciate your help, I'll post how it turns out,

Best,
g

__________________
64 230sl, my daily driver
94 E500, sold
98 E320, family and dog hauler
04 C240, safe machine for teen drivers, but a poc
08 audi a4, yes we have gone to the dark side

<

I see ..
Well,
The reason I mentioned manually opening the EGR with this simple test was this is a first step diagnosis before having to take anything apart.
If you do not have a hand pump to do the test, you can just steal a live vac line from any other SOV location and put it on/off the EGR port and you will immediately know what is going on w/flow.

A. Dalton,

Thanks, you have illucidated the diagnosis and my ignorance, I thought I had to remove the "hot" pipe to apply vacuum and perform the test you suggested. I will look again and I am sure I can find a vac. line to tap. It also gives me an excuse to by a hand vac. anyway.

As always, your help is appreciated. BTW, the 230sl is running so well I can hardly find things to fix anymore. I am sure that time and miles will fix that.

Best,

g

__________________
64 230sl, my daily driver
94 E500, sold
98 E320, family and dog hauler
04 C240, safe machine for teen drivers, but a poc
08 audi a4, yes we have gone to the dark side

ilucidate...

..anyway , the egr should have a small vac hose going to it . This hose simply supplies vac from the engine , through an ECU operated SOV [ switch-over-valve] . When the SOV is opened by the electrical sig from the ECU , it allows engine vac to reach the EGR rubber hose port, which then pulls the EGR element [diaphragm] open, allowing exhaust flow to recirculate back to the engine intake [ through the suspect blocked tube ]
The reason for this primary test is b/c this is the perfect test point in the system to seperate the egr valve mechanics from the Engine management electronic system. This test point by-passes the ECU signal, the SOV valve , and any other hoses in between. [ in other words, YOU and your hand pump are the ECU control side of the system.]
If the engine stumbles when you work the egr manually, then the suspects are BEFORE the egr valve ..meaning no vac TO the egr port , which can be any of the other vac source chain of parts on the EGR control side of the system.
There are many parts in the chain that will bring on the code, so the easiest test is to seperate the controls system from the actual EGR flow system.
Somewhat like like testing your 113 for a/f mix by taking off the venturi link and manually open/close the air flap to determine if your fuel mix is rich/lean before parts changing.