PLease help with SMOG TEST CA
Nau
04-23-2004, 05:59 PM
1989 Mercedes 300SE, 6 straight cyl.
I've been out of the town for 4 months, and now my baby is due to smog.
When returned, I charged the battery - it was dead (bad one?), changed the oil(Chevron 10W-40), and when I started the car, it started ok, but in couple of seconds started to cough, rmp dropped to 500 (600-700 normal in idle). If I give it some gas, it dies immediately. Restarted, coughing again, dies. On the third time after ~1-2 min of coughing it returned to normal idle rpm, didn't die if give it some gas, and I drove alright. In a mile or so at the traffic light (gas released, brake depressed) it started to cough again, and when I started to move it died again. In parking it coughed but still kept running, and I noticed that oil pressure dropped from 3 (max) to 2, sometimes 1. If shift to D, it died immediately. Again, in P, coughing, I press gas pedal, rpm goes up, and above 1000 oil pressure goes back to 3, and stays there if rpm >1000. So, then pressing brakes hard, keeping rpm at 1000 I shift to D and drive afterwards like this - never let it go down below 1000rpm.
On the second day in the morning it coughed only for like 20 secs, drove no problems, third day - car returned to the state I left it before my departure. I checked vacuum (hmmm - just listened), didn't hear any unusual hissing.
So now as my smog is due, and something terrible happened to the engine (WHAT???) while I'm away, I worry if I can pass. Before it passed smog no problems, readings all way below average. Should I do something special to improve/clean the engine, like some additives? I filled it up with Shell 91(always ised it when smogged all my cars - always no fail). Please, any advice will be greatly appreciated!
Thanks!
I've been out of the town for 4 months, and now my baby is due to smog.
When returned, I charged the battery - it was dead (bad one?), changed the oil(Chevron 10W-40), and when I started the car, it started ok, but in couple of seconds started to cough, rmp dropped to 500 (600-700 normal in idle). If I give it some gas, it dies immediately. Restarted, coughing again, dies. On the third time after ~1-2 min of coughing it returned to normal idle rpm, didn't die if give it some gas, and I drove alright. In a mile or so at the traffic light (gas released, brake depressed) it started to cough again, and when I started to move it died again. In parking it coughed but still kept running, and I noticed that oil pressure dropped from 3 (max) to 2, sometimes 1. If shift to D, it died immediately. Again, in P, coughing, I press gas pedal, rpm goes up, and above 1000 oil pressure goes back to 3, and stays there if rpm >1000. So, then pressing brakes hard, keeping rpm at 1000 I shift to D and drive afterwards like this - never let it go down below 1000rpm.
On the second day in the morning it coughed only for like 20 secs, drove no problems, third day - car returned to the state I left it before my departure. I checked vacuum (hmmm - just listened), didn't hear any unusual hissing.
So now as my smog is due, and something terrible happened to the engine (WHAT???) while I'm away, I worry if I can pass. Before it passed smog no problems, readings all way below average. Should I do something special to improve/clean the engine, like some additives? I filled it up with Shell 91(always ised it when smogged all my cars - always no fail). Please, any advice will be greatly appreciated!
Thanks!
Automotive Network, Inc., Copyright ©2025