When I bought my 1st Mercedes Benz, a C280 W202 2000 model, the last thing the seller told me was – “if you can, change the Mass air flow sensor or just wait for the car to warm up before moving”. I smiled and thanked him murmuring in my thoughts “that’s sure an easy task”.
Apparently, this was why we waited for the engine to warm up when I came for inspection a week before. So upon pickup, I waited a few minutes for the engine to warm up, then drove off into the unique ecstasy that only Mercedes Benz’s offer.
The next week I purchased a new aftermarket MAF sensor. We had tested a few and found one that kind of matched. However, at start ups in the morning, nothing changed, the problem continued. The car revved up nicely on idle always but it never ran smooth if you moved off while cold. This meant that you couldn’t get to your car cold and zoom off. You had to wait for it to get warm.
My efforts at overcoming this persisted. I wanted perfection. The challenge was, it had similar symptoms as a failed MAF sensor. Some experts recommended one to use an original foreign used MAF sensor. I purchased this by requesting they have the MAF sensor removed from used engines waiting to be sold off, but the problem persisted. Some online blogs advised you buy (Bosch brand) new and only from autohausaz.com. I couldn’t pursue this, as a new one was a set back of $130 (N65,000). It just felt bourgeois a price to purchase a little component. Also, I felt it wouldn’t solve the problem as some foreign used ones I had purchased were logically original parts too.
Then one day, I stumbled upon a write up. During startup the Exhaust Gas Recirculation valve had a lot of functions. The EGR valve allowed a portion of your exhaust gas to be recirculated into your intake manifold. This portion is controlled by the Engine’s ECU. Air is an important part of every internal combustion engine. Thus the ECU recommends the exact amount that matches the petrol sprayed in by the injector.
In clearer terms, at startup and early movements, the ECU may program only 65% fresh air to go into the combustion chamber and 35% exhaust gas air. So if your EGR valve is blocked with carbon and soot deposits, the intake manifold will never get the full 35% required from the exhaust gas. This means that your engine will run lean and be starved of air.
When the engine gets hot or warmed up the ECU can reprogram that the air required might be 100% fresh air or close to it. Because of the little or no exhaust gas required when warmed up your engine runs smoothly and you are happy again.
For me and other owners of a Benz with a M112 engine, the EGR valve is located close to the intake manifold at the back of the engine. When I got mine out, it was clogged and filled with carbon and soot. We were able to change it with a used one that was fairly clean. The EGR part is a valve controlled by the ECU, so you must test it to be sure it still opens and closes.
I still hope to get one that’s extremely clean and free of soot or carbon deposits. But for now, it’s been pure ecstasy afterwards!
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