SL/R107: 1982 380sl hot start issues
07-02-2015, 04:02 PM
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1982 380sl
1982 380sl hot start issues
I recently acquired a '82 380sl that is in fairly good condition. I would provide the mileage but the odometer is broken. Previous owner said it had sat around for 8 months with engine issues. I found a lot a vacuum leaks. I replaced all fuel injectors and gaskets, a lot of hoses, spark plugs, leads,and distributor cap. Check the fuel distributor and a number of valves. Everything seemed in order. I had someone I know hook up the necessary pressure gauges and set the fuel pressure of the warm up regulator. He also did the timing and it passed a smog check over here in Cali. Here's the problem: everything runs as it should when I start it when it's cold: good idle rpms, fuel economy, horse power, temperature... No problems whatsoever. But when I start it with the engine warmed up or "hot" it idles rough with surging rpms, terrible fuel economy, very little horsepower, almost stalls out. Good from cold start, all messed up from hot start. It's very consistent. I could start it cold let get to normal operating temperature, turn it off, then start it, and get the same problems. I'm not good with electronics, but from what I understand it could be the ignition control unit, temperature sensor, over voltage relay, even my O2 sensor, or something else. Before I start replacing random things I would like some advice. Anyone had this problem before? Is it worth taking to a dealership to run diagnostics and pay for them to assist in trouble shooting?
07-03-2015, 12:36 PM
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450SL
If you shut it off when warmed up and try to start within a couple of minutes does it do the same or run pretty normally? If after sitting for 10 to twenty minutes it does this it is probably the accumulator. It maintains pressure in the system for awhile to assist in hot starts.
Dealer with not be able to run diagnostics. There is no computer that stores error codes like modern vehicles. Most don't even have the Bosch unit to connect to the port anymore.
Dealer with not be able to run diagnostics. There is no computer that stores error codes like modern vehicles. Most don't even have the Bosch unit to connect to the port anymore.
08-17-2020, 12:17 AM
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280se 4.5 380sl 560SEL
I recently acquired a '82 380sl that is in fairly good condition. I would provide the mileage but the odometer is broken. Previous owner said it had sat around for 8 months with engine issues. I found a lot a vacuum leaks. I replaced all fuel injectors and gaskets, a lot of hoses, spark plugs, leads,and distributor cap. Check the fuel distributor and a number of valves. Everything seemed in order. I had someone I know hook up the necessary pressure gauges and set the fuel pressure of the warm up regulator. He also did the timing and it passed a smog check over here in Cali. Here's the problem: everything runs as it should when I start it when it's cold: good idle rpms, fuel economy, horse power, temperature... No problems whatsoever. But when I start it with the engine warmed up or "hot" it idles rough with surging rpms, terrible fuel economy, very little horsepower, almost stalls out. Good from cold start, all messed up from hot start. It's very consistent. I could start it cold let get to normal operating temperature, turn it off, then start it, and get the same problems. I'm not good with electronics, but from what I understand it could be the ignition control unit, temperature sensor, over voltage relay, even my O2 sensor, or something else. Before I start replacing random things I would like some advice. Anyone had this problem before? Is it worth taking to a dealership to run diagnostics and pay for them to assist in trouble shooting?
