Re: 88 e32 735i COLD starting problem

[alex.fadeev@xxxxxxxxxxx]

ebelmont@domain.elided wrote:
> 
>  I need some help with a problem I am experiencing with my 735i 
> during cold mornings. The car does not start when cold or left 
> over night for a long period of time. Moreover,  As soon as I 
> pull the fuel pump fuse out the car starts up and I place the 
> fuse in the car is ready to go. 

Emilio,
Sounds like your engine is over-flooded with fuel during cold startups. 
Have you checked the spark plugs? Are they bathed in fuel? The most common 
explanation would be that your fuel injectors are leaking. The longer you 
keep the car parked, the more fuel they leak that eventually will keep the 
car from starting. Attempting to start the car with a disabled fuel pump 
clears the cylinders and eventually the car starts.

> The remainder of the day the car will start regardless of temperature.
> I have since tried the following to remedy the problem. Complete tune 
> up. fuel injectors have been rebuilt, 

Hmmm, there goes my theory. 

> new thermo-time switch and fuel pressure regualtor? 

Not sure what thermo-time switch is, but a flaky fuel pressure regulator 
could certainly flood the engine. 

> I should also mention that once the car has started up it runs 
> fine and very smooth, also it starts and operates fine during 
> warm and very hot weather? 

But not recently, right (unless you are regularly commuting to South 
America)?
The only difference between cold and warm/hot starts is that one of your 
coolant temperature sensors tells the DME to enrich the fuel mixture 
during cold starts (to compensate for fuel condensation on cold cylinder 
walls). But if anything, most cold start problems are caused by that 
sensor going bad and the fuel being to lean to start cold engine in cold 
climate. But your pump fuse 
I would start by verifying which way it is: flooding or starving. Than 
keep digging from there.

alex f

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