Sprinter 312 overfuel after start from cold

[markwilson8954]

Hi all,
After start from cold, van starts ok then after about 5 seconds runs very lumpy and bellows smoke out of exaust for about 5 to 10 seconds before clearing and running fine threafter as if its over fueling.
If started when engine is warm this fault does not occur.
Glow plug cuircuit is working ok and all glow plugs are checked and ok with 12 volts on them when started from cold and staying on for a couple of mins till vehicle is warm enough to run without.
have checked all earth and battery connections including changing battery.
Anyone any idea's

Cheers

 

[mattkh]

Hi
What is the mileage

 

[wireman]

!2v on the glow plug only indicates that a supply is available to heat the plug.
The current is what heats the plugs, each one should draw up to 20A on switch on and probably fall to 10 or so as they heat up.
Disconnect each plug and test it from the battery via an ammeter.

Your description is of an engine that ain't firing on all cyliders when cold, this is a bad thing the unburnt fuel will wash away all traces of lubrication from the cylinder walls and could if left unsorted ruin pistons, rings and bores.

 

[markwilson8954]

Hi, thanks for your replies.
Milage is 200K
Have checked current flow to each glow plug and all are about the 18 to 19 amp range on first power up and fall gradually to about 9.
Its strange how the van starts ok and runs fine for the first 5 seconds before this fault occurs and the fault only lasts about 5 to 10 seconds before clearing up and only re occuring after the van is left to go cold again? I would have thought the van would have struggled to start at all if the glow circuit was not working correctly?
Strange i think.

All help appreciated
cheers

 

[dava]

What year and is it CDI?

 

[markwilson8954]

Hi, year is 1996/7 and i dont think its cdi engine, just the usual 5 cylinder thing
Cheers

 

[dava]

Rack on the pump sticking, pulls in on cold starting and sticks there for a while. Common fault that model, wd40 it.

 

[dava]

Some more things to check.
Throttle rod from pump to block drops off or seizes.
The damper, looks like a shocker drops off and causes funny throttle problems.
Also the diaphragm at the back of the pump goes and gives funny acceloration etc probs.
Hope these help.
Ray