1984 300D Turbo - WON'T START
 

My 300D-Turbo wants to start but never catches... Before I replaced the injector nozzles I could at least get it to start after the 6th attempt.

Below is a list of the tasks/tests I've completed.
1. Checked the battery charge and load capacity. (3+ Times) Now its on the battery charger while attempt new tests.
2. Checked and tested (Resistance and Voltage) the Glow Plugs 3 times. Replaced one Glow Plug.
3. Inspected the Glow Plug wiring harness.
4. Replaced the Bosch Injector Nozzles with Bosio Nozzles following Diesel Giant instructions. Installed new Heat Shields...
5. Replaced the leaking Hand Priming Pump with the new model.
6. Replaced fuel hoses.
7. Primed the fuel system a couple dozen times.
8. Primed the injectors by loosening the flare nuts to the fuel injectors, turned over the engine to purge the air from the system.

I'm ready to pull the injectors and install the old Bosch nozzles to see if I can get it to start.

I haven't checked the valves or performed a compression test on the cylinders...

What else can I check?

I'd have put a compression test at #2 or #3 on that list. It's quick, simple, inexpensive and avoids chasing down dead ends. None of the other things will make it start if compression is low.

How about some history of this engine?

It was very difficult to start prior to your work?

What temperatures?

When did the symptoms develop?

When is the last time the valves were checked and adjusted?

How many miles on the engine............what's the maintenance history?


Everything is just a random guess without this info. But, you'll get plenty of that.............

1984 300D Turbo - WON'T START
 

There are 105K original miles on the vehicle. It seems that the engine always idled rough when cold and vibrated at stop lights.

It was very difficult to start prior to starting work. At least 6 cranking cycles before it would start.

All temperatures have been running normally.

We don't drive the car much, about 160 miles on weekends. (We have 3 other vehicles) Seems like a couple of months ago everything was operating normally. Then, one morning it required a few cranking cycles to start. After that, about 6 to 7. Seems like we always had a fuel filter problem so I changed all the fuel filters.

Valves were last checked and adjusted a few years ago...

1984 300D Turbo - WON'T START
There are 105K original miles on the vehicle. It seems that the engine always idled rough when cold and vibrated at stop lights.

It was very difficult to start prior to starting work. At least 6 cranking cycles before it would start.

All temperatures have been running normally.

We don't drive the car much, about 160 miles on weekends. (We have 3 other vehicles) Seems like a couple of months ago everything was operating normally. Then, one morning it required a few cranking cycles to start. After that, about 6 to 7. Seems like we always had a fuel filter problem so I changed all the fuel filters.

Valves were last checked and adjusted a few years ago...

Check the fuel filters, you may want to do a purge, then change the filters.

At 160 miles a week, your valve adjustment interval should be a little under two years. If you're over that, I'd go ahead and do a valve adjustment. I don't think it's the cause of the no-start, but it doesn't hurt to rule it out. If you're sure of the mileage, that engine is very very young to be having compression troubles due to wear.

I suspect you either have a glow plug problem or a fuel problem. The only things you haven't done on the GP system are pulling and bench testing the plugs, and reaming the holes. Older glow plugs will sometimes pass a resistance check, but still not get as hot as they should in use. Also, carbon build up around the glow plugs can result in failure to transfer heat to the fuel as it's injected. On the fuel side, a change of fuel filters is never a bad idea. It's also possible you have an old brittle line that is sucking air somewhere in the system.

You checked the GP, did you check them through the plug at the GP module? Do you have power at the GP when they cycle.
Does it Smoke at all when trying to start it?

Lots of possibilities.

In order:

1) Ensure, yet again, that you have 12V at each glow plug during the glow cycle (about 30 seconds). After 30 seconds, the voltage at the plugs should go to zero.

2) Replace 80A strip fuse under cover of glow plug relay (just to rule it out).

3) Remove fuel filler cap and attempt to start.

4) Adjust valves to specification.

5) Check compression if 1) and 2) and 3) and 4) fail to give desired results.

1984 300D Turbo - WON'T START
 

Starting adjusting valves today. All had hard contact and zero clearance.

Removed the nozzles to gain better access. Cylinder 2, 4, and 5 had serious carbon deposits. (picture attached)

What causes the deposits on 3, 4, 5?

I'd do 5 before 4 just to confirm that adjusting the valves solved a compression problem if there is one.

Most folks don't have the equipment or the knowledge.

........as suspected.

That will cause a no start condition if the intakes are hanging open.

Do you have the specs for the valves...........004" on the intakes and .014" on the exhausts? Be very careful and use a chart so you don't mix them up.

All the intake valves had hard contact!

Adjusted, to .004in and she started on the first crank...

Thanks to all!!