129 SL500 only running on four cylinders

[LINDS HANSON]

My 94 SL is running on 2 cyls on each bank, I have replaced the engine injection wiring harness, both caps and rotors, I have read fault codes and there are 21 logged! Mostly relating to distributor timing advance limit and communication between injection and ignition problems. Any ideas? I cannot get the fault codes to clear

[deanyel]

I'd go ahead and list all the codes here. Certainly sounds ignition related, perhaps a bad coil. Are you getting code 15 or 16 on Pin 17?

[Daytonaman]

My 92' had the same problem. Don't run it on 4 because raw fuel might be going thru the catylitic. Glows red hot; may cause a fire. My problem was the SPARK CONTROL MODULE. Mounts on left front fender well. $2,500 new, $500 used part only. Hope that is not your problem. Good luck.

[aam]

Originally Posted by LINDS HANSON

My 94 SL is running on 2 cyls on each bank, I have replaced the engine injection wiring harness, both caps and rotors, I have read fault codes and there are 21 logged! Mostly relating to distributor timing advance limit and communication between injection and ignition problems. Any ideas? I cannot get the fault codes to clear

Check the adapters that hold the rotors.
You must check the part numbers on them.
They have been upgraded.
New rotors must not go on the old adapters, maybe that is your problem.
Regards.
aam.

[LINDS HANSON]

Thanks for replys everyone, here are the fault codes..
2 max retard acheived
3 coolant temp B1/9 from LH2-sfi implausable
4 load sensor in dist ign 1 (d11) N1/3
5KNOCK SENSORS 1 OR 2 A16G1/2
6 C/S postion sensor L5/1
7 Knock control analysis curcuit in dist 1 (d11) N1/3
8 Trans load protect switch S65 does not close
11 Ref resistor R16/2
12 TN eng speed signal output short curct
8108 unknown
8110 unknown
15 output stage1 dist ignition1 (d11) N1/3 ignition primary open
16 as above stage 2
18 magnets for crank post not recognised L5
20 DTC memory dist 1
21 load sensor dist 1
8210 unknown
8220 unknown
8240 unknown
28 no CAN reception from EA, CC,ISC
8303 unknown
The cap and rotors were changed after the fault occured but did not improve matters.
16 output stage2

[LINDS HANSON]

I forgot to mention I swapped the coils around only to find the same cylinders affected!

[moakesr]

That many fault codes is implausible.

Purely from a fault finding perspective, it seems to me you have a problem on the CAN bus which links the various modules and sensors controlling the engine.

Did you have an initial problem which made you change the wiring harness?

This is purely a guess, but I think you may have something on the CAN bus (sensor or actuator) which is blocking signals from/to other devices. Not sure how I would progress this, but I might be tempted to disconnect various sensors first and see if the situation improves, as in most cases the ECU will compensate for a missing sensor.

Other more basic things might apply, how good is the battery? is the voltage low?

Good Luck,

Richard

[LINDS HANSON]

Yes I have to agree that it couldnt run with so many faults, The battery is fully charged and all codes are there and unclearable with or without the engine running

[deanyel]

If the codes are there they've got to clear. What are you doing to clear them?

[LINDS HANSON]

Iam using a hand held diagnostic scanner, but the codes refuse to clear even after leaving the battery disconnected for 24 hrs. Is there a procedure for testing the EZL unit?

[LINDS HANSON]

The car drove faultlessly was left idling and then started to idle rough, that was when the wiring harness insulation was seen to be in poor condition. The harness and caps/rotors were then replaced to no avail.

[deanyel]

No way to test EZL without sending it out. But you need to clear the codes, drive the car, and read the codes again, to see what comes back. It's not hard to clear codes but you'll need to build the blink fault code reader - lots of info in the archives.

[lynns]

Originally Posted by LINDS HANSON

My 94 SL is running on 2 cyls on each bank, I have replaced the engine injection wiring harness

It appears that you are already aware that M-B had problems with the engine wiring harness in MY93-95. It is my understaning that there are two wiring harnesses to replace. Please read http://www.benzworld.org/forums/2568322-post5.html

1295402630 $177.00 Battery - Positive cable - Connector to starter

[deanyel]

Lower harness wouldn't likely cause the half-an-engine symptom. But while we're questioning the givens here how do you know you have 2 cylinders firing on each bank? Which cylinders is it that are firing?

[SPDMETL]

Loosen and clean all grounds ? It's free....