[Dave100]

I'm getting fault codes for running rich at idle, both banks, also rough idle which occasionally rises of own accord to 2000rpm then falls back. CEL light on, comes back after resetting. Runs fine otherwise. Cleaned the MAF and changed air filters, no difference. Thinking 02 sensors. I have had an oil leak onto the right bank exhaust sensor for some while (now cured) Will try cleaning these first Any other suggestions? Thanks

 

[jbanks15]

i would replace cps crank position sensor

pretty cheap

 

[jbanks15]

but our experts would say get any codes read/scanned

 

[i860]

In das you can test difrent componets like
maf
lambdas
injectors
I will look at those.

 

[Dave100]

Thanks all. Fault codes are 0745 self adaption of mixture formation for enrichment at idle for r Bank above permissable limit p0171
0749 same for L Bank. P0174
Lamda on cold engine both befores showing 1.25. BOTH

Both afters showing 200ish then warmed up both around 28mv. Seems to me this indicates they are working. Cleaned oil off and wiring not touched by oil.
At 62 degrees
Intake manifold pressure 470 hpa adc 1.75 v
Sensor heaters all on
Intake temp on off ratio .92%

Hot engine lambda after around 52-66mv

 

[Dave100]

Cleared codes and test drive. No CEL. Drives fine but still have idle problem. Its revving by itself to 2000 odd then dropping to 1200tgen repeating. Purge control rising to 30% then dropping to zero as reves fall.9.9% at correct idle. Temp 100 degrees consistent. Purge control issue? No fault codes now.

 

[i860]

How old is the petrol in the tank?
Try to fill it with fresh one.

 

[Dave100]

Thanks. Recent fuel. This feels too regular to be dirty fuel. It's also happening same time as purge Valve opening or closing. It's like a repeated cycle.

 

[Dave100]

Well I'm still getting nowhere with this. Tried running with filler cap off, purge control valve disconnected, air filters off, maf unplugged. Symptoms still the same. Looks like for once I am going to have to take it in.

 

[Dave100]

Had this looked at by my local garage. Star shows lean mixture. Smoke tested and inlet manifold leak. From under manifold so hard to tell if gaskets or split in manifold. I've ordered gaskets from Mercedes. New manifolds on ebay seem to be around £260. No used ones showing. Haven't asked Mercedes price! Are they repairable? Hopefully just gaskets but hope to strip it down tomorrow. Any pitfalls to be aware of when dismantling? Anything else I should do when in there?

 

[jbanks15]

i had this 2 weeks ago but was running lean
they replaced my old 15 year old pcv hoses.. my code was P2187

 

[Dave100]

Thanks Jeff. Think the smoke test would have shown of it was these?

 

[jbanks15]

they did a smoke test first on mine also..

here is my thread

CEL - Check Engine Light/Resolution (I hope) P2187

Last Thursday I got a cel... my luck So code was P2187 P2187 System Too Lean at Idle DTC The P2187 code indicates that there’s an issue with the air-fuel mixture ratio. Combustion engines typically require a mixture ratio of 14.7+/-2 parts air to one part fuel; if the system notices that the...

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