SACHs diesel poor starter

This topic has 5 replies, 5 voices, and was last updated 11 years, 1 month ago by charlie.

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March 15, 2014 at 7:40 am #6405

charlie
Keymaster

Can anyone give suggestions why a water cooled SACHs diesel on a Howard Gem wont start, nothing more than a puff of smoke.

March 15, 2014 at 10:05 am #6424

crawler
Participant

Hi Charlie, are you using some sort of igniter when you are trying to start it? See my Sachs thread, in the cold the best I could get was a puff of smoke without using an igniter.
Had it been running previously? The first day I went to look at my MG40 we could not get it to start even with the igniters. The seller and myself tried until we were both about to drop and all we got was some smoke and the occasional bark, you could tell it was close but it just refused to start. The seller said he would get the injector serviced, when I returned we removed the igniter holder and turned the engine over a few times, fitted an igniter and the engine started first pull over compression.

March 15, 2014 at 6:23 pm #6435

trusty220
Keymaster

Injectors can become blocked yet still emit diesel which will give a false impression that they are working. When an injector is working properly it should emit a vapour which is easily ignited, but when they have been used for a while they can become coked up by deposits from the cylinder- in extreme cases I have seen them only squirt a jet of diesel which will ignite if everything is hot, but will not ignite if the engine is cold.
To illustrate my point I once towed a Nuffield Mini Tractor around a cricket outfield for three whole circuits before the engine fired and ran. It was leaving a trail of white diesel out of the exhaust for the whole time, but because a jet of diesel has much less surface area than a vapour it simply wouldn’t burn. A recon set of injectors transformed the cold starting performance immediately.
Don’t try to do the reconditioning yourself because it needs specialist equipment to set up the injector once the parts have been renewed and/or cleaned. There are many diesel specialists about and it’s best to use one of these.

March 15, 2014 at 7:50 pm #6453

hillsider
Participant

On the subject of diesel injectors one way to test them and be able to see what is happening at the nozzle end is to remove the injector from the engine, reconnect it to the injector pipe then crank the engine over while observing the fuel delivery pattern from the nozzle.
All is fine so far but due to the high operating pressure of the injector care must be taken to ensure that the spray is not directed at any exposed skin or the resulting injection of diesel into the bloodstream will cause severe problems, this can be overcome by aiming the injector into an empty jam jar.

March 15, 2014 at 7:53 pm #6456

vhgmcbuddy
Member

When I had my diesel gem that was a pig to start & kept flooding the wicks!!

In the end I had the injector recon & it was money well spent as it started & ran a treat

Shame I sold it!!!!!!!

March 16, 2014 at 7:59 am #6477

charlie
Keymaster

Thanks for suggestions I will pass them on to owner of the Gem.
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