hard start when warm
Thread Starter
Newbie
Joined: Apr 2004
Posts: 6
Likes: 0
From: Kirtland Ohio
MB 450SEL 4.5L
hard start when warm
I have a 79 450sel with a 4.5 L mechanical fuel injection (CIS) system. This car when it is cold starts with just a tap of the key, however, after it has warmed up to operating temp. if I shut it off and go to restart it turns over 4-6 sec before starting. Does anyone out there have any ideas where I should start for trouble shooting ? I have a Haynes manual it refers to nothing about hard warm starts...any advice would be greatly appreciated...
Humbley yours ... Chaindrive
Humbley yours ... Chaindrive
Super Member
Joined: Jun 2003
Posts: 595
Likes: 0
From: Middlefield, CT
1994 E320
Over time the injectors run poorly at high temps. Also the injector seals might be failing. With the engine running spray brake cleaning fluid around the injector seat. If the engine runs rough or chokes, the seal is leaking and allowing air into the combustion chamber, hence affecting the mixture.
Thread Starter
Newbie
Joined: Apr 2004
Posts: 6
Likes: 0
From: Kirtland Ohio
MB 450SEL 4.5L
I din't think of that and that is a good suggestion. I was talking with an old-timer mercedes mechanic this morning and he said that I might be experiencing vapor lock...he suggested buying a plus grade of gasoline or gasoline without ethanol. It certainly is worth a try but I'm not sure of the availablity of non-blended gasolines in northeast ohio... Chaindrive
Newbie
Joined: Mar 2002
Posts: 13
Likes: 0
From: Orlando, FL
500SL
I don't know if thi will also apply to you, but I had kind of that same problem on my 500sl, after spending a couple of bucks on my dealer, I discovered that my has couple of fitting on the gas filter which holds the preasure on the line, when they go you have to crank the car twice longer before it starts, try checking on that too. it was only a couple of bucks for the part.
