Gentlemen,

I have a crazy one after all this work. Idle is uncontrolled with a hot or cold engine. Here is a youtube of a friends car (M104 1995 SL320)

https://www.youtube.com/watch?v=rGJRLHrmiW4&feature=youtu.be

Nasty problem?

When it starts from cold it runs at 1,100 RPM(shouldn't the EGAS module limit this) for about 45 seconds - then drops to 1,000 RPM and then goes into the revving up and down and then stalls. Then you can start it again and it revs at 1,000 RPM for about 20 seconds and then revs up and down over and over - sometimes it stalls - sometimes it catches itself just before it stalls.

Also it is not very responsive to the throttle - I tried to nurse the rev's up but as soon as it gets to about 1,400 RPM it stalls.


The codes are: 4, 13, 24, 42, 45 :

4 - Hot film mass air flow sensor
13 - O2S (Lambda) control system operating at rich or lean limit
24 - CKP sensor or magnet for position sensor not recognized
42 - CAN communication from ASR, EA/CC/ISC module or diagnostic module (OBD II) faulty
45 - Fuel safety shut-off of electronic accelerator or cruise control active

Yet all this stuff was replaced?

1) Replaced engine wiring harnesses - included MAF
2) Replaced MAF
3) Had BBA rebuild my ETA
4) Replace ECU
5) Checked for vacuum leaks

Fuses okay, and the ones in the computer coffin.

My guess is a ground(s) floated, or feed-back resistive element from ETA is noisy like a scratchy volume audio control, yet that may be one of the problems, and maybe BBA did not possibly do a great job? Maybe the EGR valve is damaged? I'm pushing buttons here? The codes are wierd? maybe the switch on the accelerator(some cars have this)?

Some insight gentlemen..

Give me your thoughts and suggestions...

Something to chew on?

Thank you,

Martin

Double check your secondary cables are going to correct cylinders if that's ok , it sounds like 1 or 2 cylinders are shutting down due to misfires, on the bottom of coils the boots sometimes cause that, they are available seperate from coils, make sure plastic intake or hoses are not broken or leaking air.

Sounds like a throttle actuator/EGAS issue. I've seen this happen many times.

What codes do you get from DM pin 14? This would be the main link to the EA/CC/ISC on you car. Check voltage at DM pins 3, 8 and 14, should all be the same, if 14 is not providing you codes or is low voltage, I would investigate the E-Gas module or replace/test with known good.

__________________
Stable Mates:
1987 300TD 310K mi (Hans)
2008 Jeep Grand Cherokee OM642 165k mi (Benzrokee)

Gentlemen,

Thank you for your replies. I will look into everyone's suggestion.

Martin

Do not forget fuel pressure regulator disconnect the vacuum line and put your finger under vacuum port of fuel connector and if you can feel fuel from the regulator then the regulator is faulty,

I will check the regulator, thank you..

Martin

Put a volt meter on the MAF output and watch it. You should see 0 VDC with no air flow and maybe slightly less than 1 V at idle.

Also, the MAF used on a 97 up with Bosch ME 2.1 ECU has 2 power feeds. A 12V to power the MAF and a 5V from the ECU to power the output. Not sure what yours has. I do know that your intake air temp sensor is separate where the 97 up system is built into the MAF.

You could also try unplugging the MAF and let go into limp. My 97 C280 had the OE MAF fail and the replacement after a few miles, the 2nd replacement has been on there over a year.

listening to that video , again it sounds like your intake manifold may be broken due to backfire, crawl under and look at the runners, ive seen 3-4 engines do this 2 104s engines and 2 m112 engines, backfire cracked intake manifold, when you looked under or at manifold you could see it

SL320 and Nulu,

Thank you, more to feed the fire of the trouble shooting

Thank you kindly!

Martin