Rough idle has returned. 2 years ago I had engine harness replaced and one new coil, new plug wires and boots to plugs. 6 months ago I also had the alternator rebuilt.

I pulled the following basic codes: 2,5,6. I also tried for detailed codes on two pins and got on pin 8: code 1 (no code) and pin 14: code 3. Should I try any other pins for more detailed codes?

Another coil is probably bad (15.9 kohms instead of 6.5 and 6.6) and I am ordering two new coils, just in case the third one fails (plus new spark plugs). I assume the boots should be still good (2 years, 25k miles)?

Among the threads I searched I found the following one by eorossi; it has good info on the egr cleanout. E320 Rough Idle / Egr Problem

I will try to clean the egr opening to the manifold. There is a 1/2 inch x 5 inch flat steel plate in the way; it is part of the throttle linkage; can I pop it off to improve access? Speedo cable has been mentioned to clean out the egr pipe; can I pick up any cable from my local Carquest or NAPA or does it need to be a certain type for flexibility.

Last, where is the egr valve located? Also, I'll check to see condition of the vacuum line under the engine. Other vacuum lines seem ok (but they are rather hard to find and follow).

Any other ideas? Thanks!

__________________
TomO
94 E320 Wagon, 170k, totalled in 2006
2002 BMW 525i Wagon, 75k
1991 BMW 318is (two of 'em)

If you are getting no codes from pin 8, you do not have an ignition problem [ coils, boots, etc]

I would look for vac leak or stuck open EGR....
A blocked egr pipe does not cause rough idle , but a stuck open [ common on 104 early egr] does...as does any leak...

Thanks, Arthur. Can you help me with location of the egr valve?
Also, I should have mentioned that the rough idle is an intermittent missfire and that the check engine light has not been on since the alternator croaked this past winter.

__________________
TomO
94 E320 Wagon, 170k, totalled in 2006
2002 BMW 525i Wagon, 75k
1991 BMW 318is (two of 'em)

EGR is located at the rear of the exhaust manifold on the right hand side of engine.
It can be tested with a hand vac pump for opening/closing operation as the engine runs.
With vac applied, the engine will run rough at idle.
With no vac , it should close [ snap shut] and the engine should smooth out.
For those without a hand pump, you can just steal some vac off one of the intake lines and use the engine vac as a source to power the egr for testing....

I haven't had a chance to clean and check the egr, but here are the latest symptoms: now it is missing during acceleration to highway speeds, and the last mile or so it didn't shift until 4200 rpms at stoplights. Still no CE light, however.

__________________
TomO
94 E320 Wagon, 170k, totalled in 2006
2002 BMW 525i Wagon, 75k
1991 BMW 318is (two of 'em)

I now get engine code 7 as well (in addition to 2,5,6). I ordered a new coil yesterday.

I checked the egr valve. It clicked when I applied my hand vacuum pump (mytivac). I started the car and let it idle; when I applied vac to the egr valve the engine vibrated wildly, then smoothed out when I released the vac. Once the engine died when I applied vacuum. I could not see a red dot on my egr valve (supposedly red dot indicates improved valve).

When I get a chance I'll clean out the egr pipe from the valve end. I can't see anyway to access the egr pipe at the intake manifold except by removing the throttle linkage, and I'm afraid I'll never be able to reassemble it. I think I'll wait until I replace the head gasket to look at it.

__________________
TomO
94 E320 Wagon, 170k, totalled in 2006
2002 BMW 525i Wagon, 75k
1991 BMW 318is (two of 'em)

Code 7 is ignition system..so, you now want to go to pin 8 for specific ignition code fault.

If the car ran very rough and actually stalled when appling vac at idle, I doubt you have tube blockage. A block would show little difference when energizing egr..

Does your cruise control work? I had similar symptoms and lots of weird codes, although my CE light DID come on. I had to replace my throttle actuator. See the DIY link at the top of the page for my writeup.

Good luck!

__________________
D.H.

04 ML500
02 E430

Experience is something you don't get until just after you need it.

I did try pin 8 again, and I still get code 1. Cruise control works fine. The car runs worst when it is cold--no power and wierd shift points--then it runs fairly well when warm. Next week I'll let you know how it runs with a new coil and spark plugs, and I ordered 3 new spark plug boots, too, just in case. The symptoms are very similar to the last time a coil went bad. (I also need to do some research into which wiring harness the dealer changed.)

__________________
TomO
94 E320 Wagon, 170k, totalled in 2006
2002 BMW 525i Wagon, 75k
1991 BMW 318is (two of 'em)

I installed a new Bosch coil in place of the defective MB coil, and also installed new spark plugs (gaps on old ones were about 0.9mm.) In conclusion, two bad coils in past two years: first at 120k miles and second at 145k. Car now runs well again.

At this point I'm happy, except I'm puzzled by codes I now get. I'll try to explain my procedure, here goes:

As I stated in earlier posts, before I installed the new coil I got detailed code 1 on pin 8 and code 3 on pin 14 and basic codes 2,5,6, and 7. After installing the new coil and spark plugs and driving the car several miles I got code 23 for pin 8 and code 3 for pin 14 and no basic codes. I erased all the codes using the 6-8 second press according to Arthur Dalton's instructions. I started the engine again and the CE light stayed on. I tried to drive the car but the engine wouldn't rev unless I pressed the accelerator to the floor. I shut it off, pulled codes again (same codes as before except now the basic code light wouldn't work at all--see note below). I started the car and it ran fine and the CE light no longer stayed on. I then cleared the codes using the "ECU memory reset/reactivate procedure that allows the adapt memory to get back to Mean", as described by Dalton on 05-07-03, thread named "Check Engine Light 94 E320". I started the car (CE light went out) and drove it several miles and checked the codes again: I still get code 1 for pin 8, code 3 for pin 14, and the basic code light still doesn't work at all.

NOTE: I would be more concerned about the basic code light not working except it did the same thing the last time I had a dead coil and I pulled codes--eventually the basic code light started working again.

Another Note: I ordered three new boots for under the coils but I was sent the wrong parts--the three Beru boots and other plug wires are almost 2 years old, with 27 k miles. Using a digi multimeter, boots and spark plug wires yield the following resistance values, starting with cylinder #1: 1.84, 1.84, 2.02, 1.83, 1.93, and 1.85 k-ohms.

Third Note: These past few days I have also been trying to fix my right rear window which won't go up. I have been swapping window switches to see if any are bad (all seem OK). Could this possibly have contributed to the codes and CE light anomaly?

Thanks for all the help.

__________________
TomO
94 E320 Wagon, 170k, totalled in 2006
2002 BMW 525i Wagon, 75k
1991 BMW 318is (two of 'em)

< >>


The DM module will not reboot until it has gone through all the self test . This takes several drive cycles.
You will know this has been completed when you get a 1 flash code [ No codes Stored]

<< I got code 23 for pin 8 >>

Code 23 is bad coil secondary..
You are looking for 5.2-8.5k...
I think that was just a pending code from the old coil , but watch for a return..

On your 3 at 14, that could be if you lifted the throttle by hand when working on the engine...

FYI.. the coil primary calls for .9-1.6 ohm spec..............

My two year old coil primary is 0.9 to 1.0 ohm and secondary is 6.5 kohms; the bad coil was 0.8 to 0.9 primary and 15.9k secondary (but my ohmmeter reads 0.5 ohm when I short the leads). By the way, I also swapped (but kept) the third coil, hoping to pre-empt the return of this problem in the next few years.

Thanks again, I'll check the codes in a few weeks.

__________________
TomO
94 E320 Wagon, 170k, totalled in 2006
2002 BMW 525i Wagon, 75k
1991 BMW 318is (two of 'em)

Change the meter bat so it can zero out...

Also, the coil problems are usually the early blue ones [ pre face-lift 104s... ]
The coil ohm specs were changed in both 94 and 96...