OK, I replaced the injectors in my buddies '89. The truck is running a lot better, when it runs...

The problem has to do with starting it in the morning, or anytime that it has sat for several hours. He is having to bleed ALL of the injectors to get it starting. They don't require a lot of bleeding, but none of them appear to be pre-loaded with fuel when trying to start it. So, where should I be looking? I know there has to be a leak somewhere, but where?

I will tell you a couple of observations that I had while changing the injectors. A couple of the injectors and bad quad gaskets/seals. I replaced all the copper seals with the ones that came with the new injectors.

Several of the injectors came right out with my fingers! Then there were several that required some serious coaxing to get out. The ones that needed a little extra muscle were all gummed up inside. The third injector from the front of the engine was by far the worst. It had so much garbage in there it looked like mud. I scrubbed and cleaned everything before putting the new injectors in.

I also noticed that each of the old injectors that I pulled out was covered in a black fluid. Initially I thought it was just fuel mixing with carbon, but I am not totally sure. It didn't seem like oil, and I can't imagine how oil would be getting in there, but maybe it is...

So what are your thoughts? What should I be looking at?

 

viper as a rule having to bleed an inj system means obviously air is getting in, id check all the lines, even the metal ones. theres short rubber hoses at the tank dont forget those. I'll prolly get yelled at but on mine i pressurized my fuel syatem to 25 psi and used a soap solution to find leak, it was not dripping but alowed air to suck in. On mine the fuel pump was leaking on the side.

 

How would one pressurize the fuel system. I heard someone make mention of putting an airline to the fuel neck, but I just can't envision that working...

 

That's exactly what you do. Just stick an airhose in there and stuff some rags around it. I don't think you need 25 psi. Probably only between 5 and 10 psi. You'll see the leaks, if there are any, right away...the diesel will come dripping out!

 

How far will pressurizing the system like this identify a leak? Just to the VE pump? Through the pump? To the injector?

 

Pretty much up to the pump. Anywhere after the pump, you should be able to see a leak--we're talking several thousand psi here, so you will see diesel weeping from a high pressure line while the engine idles. Always wear eye protection when looking for a high pressure leak--that fuel spray will cut through your skin if it hits you

 

Pressurizing the tank will identify a leak AT LEAST to the injection pump. I'm honestly not sure about the pump itself. As for after the pump any leak there would be identified easily when the engine is running. The lines after the pump are under VERY high pressure! Any leak there would show itself imediately.

 

Have you checked the condition of the lines from the tank? A lot of rubber connectors to dry and crack, and they don't necessarily show wetness when they go south.

 

OK, an update on this, and please let me know if you still think it is air in the lines.

As I mentioned we did the injectors. This weekend I finally got a chance to work on the truck again, but he wanted to work at his house, where I don't have an air compressor to pressurize the tank. I did tear apart his VE pump, did the 3200 Spring install, brought the Full Fuel Screw in a couple of turns, and dropped the starwheel 20 clicks down. We adjusted his valve lash and replaced all the valve cover gaskets to stop the oil leaking. I instructed him that I wanted the engine steam cleaned before doing anything else, as we should be able to better identify problems with the engine clean, it is a MESS!

So the truck now fires up and runs for a bit. As he lets it sit there warming up, the engine will start to struggle and then die. He then has to bleed a couple of cylinders to get it running again. If he stays in the truck and stays on top of the engine so it never starts to struggle, the engine doesn't shut off. It definitely is worse when the outside temperature is cooler, so it is a problem in the early morning and late evening.

Ideas?

 

What kind of injectors are the replacements? Stock replacements? POD's? Custom? Did you try and drive it down the road at all, and if so, what was the result? Low power, normal power, super powers, hehe? What's the smoke situation? Smoke color when cranking cold, when cranking hot, when running cold/hot, etc. The more detail, the better. Any fuel seepage at the pump itself? Internal pump pressure is key and a leaky seal (like the one that faces the block and is hard to see...) can cause some really poor running conditions.
Greg

 

Check the fuel lines from the tank to the fuel pump. you are pulling air in from somewhere.