Hot start conundrum - BIOSHAGFET

[MacMerc]

Dear Gentlefolk of the forum,

I wonder if you could help me please?

My W124 230TE 1991 is a pig to hot start.

Here's the story it's sad but true:- The engine starts within 2 seconds when cold and is slightly lumpy for 10 seconds or so then settles down with the hint of a misfire now and again. It then drives perfectly.

When I stop after a few miles and a bit of heat in it and turn the engine off, it becomes a complete pig to re-start. It will initially fire and die within 2 secs then It takes up to 10 seconds and sometimes a few goes (I give up after 5-10 secs each try) to start and when it does light I have to give it some gas to keep it going for about 15 secs then its ok.

I am worried that I'm going to ruin the starter and battery soon hammering it like this.

So by putting together suggestions from this forum, I have done the following:-

1. Changed - Plugs / leads / distributor cap (rotor arm ok) / air filter
2. Cleaned pins on OVP & fuel relay (not contacts inside)
3. Cleaned every connector I could get my hands on under the bonnet
4. Cleaned earth connections on top of LHS suspension mount position.
5. Disconnected the electrics to the cold start injector (thought it might still be injecting on hot start)
6. Lubed the throttle linkage
7. Checked the microswitch on the throttle -ok
8. Air inlet flap appears free enough.
9. had two tanks dosed with redex through it.

Things not looked at yet:-
Fuel starvation?
Injectors?
???????

Of course, my next question is can anyone suggest any other reasons why it takes an age to start when hot???

I would value your suggestions,

Thanks,
MacMerc

p.s. answer to conundrum when car starts :mrgreen:

 

[peterchurch]

I have just bought a 1987 300 E that was left standing for 3 years It showed the same sorts of signs as yours. I put 2 bottles of STP in with a tank of super unleaded and gave the car a good run. mine seems very much smoother now...

It might help

 

[MacMerc]

Thanks Peter,

I was a bit generous with the STP type stuff but not to that extent, I might throw in the rest of the bottle (and maybe another) & see what happens.

Cheers,
MacMerc :wink:

 

[pascal]

And I am presuming that you dont put your foot on the accelerator, whilst trying to start.

 

[MacMerc]

Hello Pascal,

No, I try not to but it seems to need some gas pretty quick once it has fired and keeping at 2-3000 rpm for a few seconds then it idles fine, no hunting, and drives fine.

It also smells of fuel in the cabin following the hot start, thats why I thought it might be over-injecting on the cold start injector which incidentally, is still disconnected. The smell soon goes.

Is there a possibility of some sort of fuel vapour lock once its hot?

Cheers,
MacMerc.