[nova801428]

Hey guys,

I have an '89 F350 with a stock '89 Cummins 6bt engine. I swapped it about 6 years ago and noticed its getting a lot harder to start. It tries to start quickly and dies but usually takes a couple tries before its running. After it starts it shakes pretty bad, runs rough, and sounds like its missing. There is a huge cloud of blue/white smoke and it eventually clears up after some time idling. It starts perfect when its warm and I just took it on a 4 hour trip and had no issues. No idea on the miles or history on this engine but I haven't done anything to it other a 3200rpm governor spring.

Do you think its time for injectors or could this be another issue?

Thanks!

 

[Blackduck596]

Sounds like it is misfiring, cold be injectors or fuel supply.
Do you have a fuel pressure gauge?.
Could check for air in the system before cranking, crack the bleeder and hand pump the lift pump and check for air in the fuel.
What is the outside temperature when you are trying to start?

 

[nova801428]

Sounds like it is misfiring, cold be injectors or fuel supply.
Do you have a fuel pressure gauge?.
Could check for air in the system before cranking, crack the bleeder and hand pump the lift pump and check for air in the fuel.
What is the outside temperature when you are trying to start?

I do not have a fuel pressure gauge hooked up. I will check for air in the fuel before I start it next time. The temps I've been starting it are in the low 40's. I do not have a grid hooked up either. I don't think my block heater works as I've never noticed a difference.

 

[char1355]

The grid heater was going to be my question too. If it starts good and runs normally in warm weather that sort of hints the issue is temperature related. Low 40's should not be an issue of starting on a Cummins if all is well. I'd suggest doing a compression check. Your smoke issue is indicative of a cold diesel. If the injectors in the engine are original, that would mean they are 34 years old. They don't last forever. Those would have the 9mm tips and those have been discontinued for quite some time. The replacements come with 7mm tips and an adapter sleeve to cover the other 2mm. You could pull the injectors and have them tested. Pop pressure on those should be 245 bar. If they are too much off that number your timing would be off. Unless you're planning some big performance change you don't need more than stock injectors. Some many companies advertise injectors with so much added HP. That is bunk. Stock injectors are capable of far more power than the engine is set up for. Just a matter of turning up the fuel at the injection pump. Probably would consider a better turbo too. The old H1C used on those early engine has long since gone away. A good HX35W would give far better performance. That was the turbo that they started using in 1995. Might also consider making the grid heater functional.

 

[Nascarmark]

The shaking, white smoke and missing is a clear indication of air in the fuel. Running & starting good when warm is a hint the injectors aren't worn out yet. Old fuel systems are notorious for allowing air to be drawn in.
Grid heater in the low 40's would only cause a slight haze....none of the other symptoms.

 

[Tomypop]

The fuel injectors on your car will typically last between 50,000 and 100,000 miles. The length of time that the injector lasts has a lot to do with the type of gas that is used in the car and how often the various fuel filters are changed.

 

[Blackduck596]

The fuel injectors on your car will typically last between 50,000 and 100,000 miles. The length of time that the injector lasts has a lot to do with the type of gas that is used in the car and how often the various fuel filters are changed.

Think your mileage numbers maybe for common rail injectors, not the old mechanical ones in these trucks.
And by the type of gas you do realize we are talking Diesel here