The cold start injector in the intake sprays fuel directly on the hot intake glow plug which ignites it.

 

They're glow plugs.

 

No there aren't glow plugs as far as I did recognized by my research.

Preheating works pretty simple:
Inside that stubby is a small glow plug. Fuel is added by the
side fuel line. Inside the injector burns a small flame heating the inside air- thats it!


So you have the engine without an Intercooler.
ARH( thanks for the provided pictures!) you should:

- clean the connectors and the related screws at the preheat unit with a wire brush to get rid of corrosion. Check for proper connection with a multimeter.

- maybe change the preheat unit( You don't know how long it is already built in, right?Maybe since ever)That device doesn't look like touched ever( no traces of tools)- maybe the PO changed the injectors???

- change the fuel filter against a fresh unit because you don't know how long it is in- I wouldn't change it if I was the previous owner and would know that i would sell it.

white smoke is a sign of unburned fuel during the start process. Maybe the preheat unit doesn't work at all, because it is possible to start an engine with a good condition without plugs during the summer.


As far as I remember those units are around 50 to 60 €. If you want to start safe have them checked or change the unit.
Those units are avialable from Bosch or Beru- it doesn't matter which brand- both are excellent.
Just make sure the engine gets enough fuel, too.
Some feedback would be cool if advice helps!
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If you get rid of the difficulties, or as a summer project: That engine screams for an Intercooler! You already have the open air filter- just add an Intercooler and gain added 10 to 20hp and longer engine life.

 

So, you're saying there's an actual open flame in this unit? How is it lit?

I did check the voltage coming to it from the relay and it checks out with over 12 volts.

You mentioned 50-60€, where exactly can you get these things? Do you have a part #? And a part number for the diesel filter/water separator would be sweet.

I have been thinking of an intercooler, but I think the pressure pipe routing would be difficult with the intake manifold and turbo situated like it is. Do you happen to know how I can adjust the pump for some extra juice? Isn't there a filter in the pump, too?

Also, stumbled across this:

ATG Diesel-Therm - Fuel Preheater for Diesel, Biodiesel, SVO/WVO

 

I will answer your questions from bottom to top.

That diesel preheáter is nothing than a glow plug screwed into the fuel filter.
VW and Audi have an arrangement of three plugs to assist coolant heating- it's a weird solution.

There is a screw which is called amount adjustment screw on your injection pump. Be careful! Don't turn on any screw without knowing what it does. I will look in my data paper which one is the right one. The turret on top of your injection pump is the boost fuel adjuster- the more boost the more fuel is injected into the engine.

There is no filter in the pump, it must be external. The unit behind the radiator looks like the filter unit. Just open the unit and take unit to a part supplier. Make sure you get the right dimensions.

The preheater unit looks corroded.Disconnect the battery and loosen the upper nut of the preheat unit. disconnect fuel supply. After that unscrew the preheat unit and take it to a part supplier. As I already mentioned Bosch and Beru produces them. The part supplier will find the fitting unit in their catalogue with the car data you should take along with you to the shop.

To start the preheat process is simple the unit starts to glow as you turn the ignition key. fuel drips on that plug and it starts to burn. there is a kind of fleece around the glow plug which holds the fuel and acts like a candle string.
Start with tuning your car when it runs again!

You need your preheat unit because there are so many different units available, you will find all information on this side:

Glow Plug for Flame Start Systems (Type GF)

 

It starts now with temperatures around zero Celsius. Either, this flame-start unit is a piece of ****, or it plain doesn't work.

How do I go about changing filters and taking the diesel supply system apart without getting air trapped in the system? And if it does, how do you bleed it?

 

There are two possibilities:
Either you have a small pump in the engine bay. ( If you don have one, install it:made by Bosch or Hengst)or you fill up the filter and crank the engine.
But the second solution isn't that good- to much stress for the battery. Buy a small fuel handpump to get Diesel to the filter and injection pump.
You will be happy to have that pump in the future.

Starting at higher temperatures is just a sign for a non working preheat unit.
Don't worry about air in the preheat unit.

If you fill up the replacement filter with fuel you shouldn't have to much difficlties with trapped air. If you install the filter empty or drained, it will be a nightmare to start and to run the engine.

The preheat control unit has a fuse- check this fuse too! Sometimes a small reason gives you big trouble. If the fuse is ok- then have at least one spare fuse for that in the car.

 

Looks like a ve44 pump to me, lots of infor mation on this site about it in the dodge 1st generation forum.

after reading all this it sounds like the preheat unit needs replaced, or what relay or solenoid controls it.

 

Does this engine have a block heater? If not, I would add a circulating type block heater.