Common Problem: warm/hot engine will not start - PeachParts Mercedes-Benz Forum

Duke2.6 · #1 08-11-2018, 09:33 AM

Parts I've replaced so far:

- crank position sensor(new)
- coolant temperature sensor(the 4-pin, new)
- auxiliary temperature sensor(the 2-pin, new)
- cold start valve(new)
- fuel pressure regulator(fpr), fuel pump and filters and the fuel accumulator are about 5-6 years old - no leaks here
- fuel injectors are about 4-5 years old - no leaks
- EHA no leak (original) - idle control valve (3-4 yrs old) - tested with spare, no change

- OVP works - tried spare but no change

- Ignition coils, plugs, caps, rotors all new

Fuel pump works well even when the pins 1-2 bridge. Fuel pressure is good, no leaks as far as I know.

I had a similar problem with my '88. It was intermittent, but got worse with time. I ran a simple on-the car-test and found that the fuel accumulator had an internal leak, which means it wouldn't hold pressure. Fuel just short circuited back into the hose from the fuel tank. With a new Bosch accumulator, starting behavior retuned to normal.

I documented the test along with a destructive failure analysis of the accumulator that clearly showed the internal diaphragm was cracked. Search for threads started by me and consider running the simple fuel accumulator test even though it's not that old.

Duke

lowesguy · #2 08-11-2018, 12:16 PM

My SL stalls on me , so frustrating and scary in traffic, I had a 91 300E that would do that, replaced tons of parts, still did it, turned out to be the dist rotor was bent a tiny bit, when it heated up it it would bend more and lose proper position killing spark, then bend back when cooled and all OK.

with my SL it is random stalling, didn't know if it was fuel or electrical, finally bought a cig lighter plug in Volt meter, cheap $16, Autohauz AZ has it, found my voltage was going below 12 volts killing power to modules , those can't run on low voltage and car dies, bought new alternator/ voltage regulator, better but still stalling, pretty sure its my ignition switch now causing issue, good luck.

Mike Murrell · #3 08-26-2018, 01:07 AM

Quote:

Originally Posted by Duke2.6

I had a similar problem with my '88. It was intermittent, but got worse with time. I ran a simple on-the car-test and found that the fuel accumulator had an internal leak

Been there - done that.

Faulty fuel accumulator - one of the more common causes of warm/hot starting issues as per countless threads here over the yrs.

lorainfurniture · #4 08-27-2018, 01:58 PM

Quote:

Originally Posted by javelin

.so no, it's not the MSD.

The cap and rotor are of Bosch brand and they are new - less than a month old. The one before that was also a Bosch brand about 2 years old - decided to replace anyway, but problem persisted .

I certainly don’t mean to beat a dead horse but I just want some clarity:

You installed the stock coil and AFTER that you replaced the cap/ rotor?

If not, there’s still a chance that you burned your rotor. I think it’s worth opening up and cleaning/ inspecting to see if that makes any meaningful difference.

Did you try warming the car up until it stalls and Try and restart while spraying gas in the intake?