300E -- hard start
 

My '86 300E with 170k is taking much longer to start in the morning. It cranks about 3 to 4 seconds before catching then runs fine. On subsequent starts during the day it fires right up. Only about 10k since last tune, at which time injectors were replaced. I've been running 91 to 92 octane gas. Any ideas about the problem?

FWIW, I just spent several thou more than the car is worth to do some old-age related mechanical repairs. (Drive shaft rebuild, rear muffler, rear suspension carrier, yada, yada, yada.) It nows looks and runs great. I'm very happy I chose not to dump it. My only concern now is to stay out of any accident that would cause more than a couple thou worth of damage. :( Insurance companies aren't interested in my repair bills.

Hard Start
 

Sounds like you may have a problem with fuel loss from one of the following

1) Fuel distributor leaking fuel down into the intake causing un metered fuel to be dumped into the engine causing a hard start.

2) Fuel pump check valve at the fuel pump leaking pressure back to fuel tank.

3) Fuel pressure accumulator not holding pressure.

4) EHA not enriching the fuel mixture like it should at first crank.

5) Coolant temp sensor may be bad.

6) Low compression in the engine.



Hope this helps

Thanks, Benz Tek.

#1 thru #5 are much more palatable than #6. Appreciate the help.

2, 3 and 4 are more like it. But 4 should be the cold start valve, not the EHA.

Sorry I didn't put them in order..lol Just typing to get all of the ones I could think of off hand. The reason I stated the EHA is because at cold starts the EHA's milli amps have to rise or enrich by changing the pressure between the lower and upper chambers of the fuel ditributor. I have had great luck by just removing the EHA and giving the adjustment screw a 6th of a turn clockwise(enriching the mixture). After the car is started you may also want to check your amps going thru the EHA(+&-) and also check the duty cycle at pin 3 in the round diagnostic plug to make sure that you have nice oscilation around 50 percent at normal engine temp.