Cummins 4BT & Diesel Conversions Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter · #1 ·
I have a repower that is getting close to the elusive first key on and I wanted to get some help on any checklist before first fire. The vehicle doesn't have the dog cage on so I can reach the engine which means no coolant and no air filter. The engine has sat for maybe 8-10 years so it is likely dry on top but has oil in the sump. Do I need to do anything about that or will it push oil quickly enough?

I will try priming the engine by filling the filter and tank then pumping the manual prime on the LP pump. Should I be cracking the lines anywhere during the manual prime?

Then I will crack the injectors at the engine and do a series of 5-10 second cranks until I see diesel at the injector. I will tighten the injectors one at a time until they are all wet.

Then I will crank until it fires and let it run a couple minutes to work out any air bubbles.

What am I doing wrong or what could I do better? I am not a diesel person so any help is appreciated and don't be afraid to talk to me like a child, I won't be offended.

Thanks.
 

·
Registered
Joined
·
12,179 Posts
Without coolant, you don't want to run the engine more than 20-30 seconds. If this is a full scale test you want to get the coolant connected. Be sure you have plenty of battery power available as this make take a while. Which injection pump do you have? If it is the VE pump you will need a 12 volt line for the pump solenoid. Make sure your battery cables are plenty big. The starter on these things pulls a lot of amps. You may want to open the connector where the lift pump feeds the filter to get the air out of that line and the main feed line from the tank. Then start cracking open the fuel lines at the injectors one at a time while cranking. If you get a little dribble and some air bubbles you know at least the fuel is getting there. When the air is out of those lines be careful because that fuel pressure is extreme. Can shoot through you skin so keep the hands safely away and use eye protection. Once you have fuel at each injector you can see if it will fire up. May run rough for a while and you can crack the injector lines open one at a time to help clear out any residual air. Most of what you mentioned is good. Do you have an oil pressure gauge attached? Need to know if you are building pressure. Engines that have sat for a long time can have injection pump issues because parts are gummed up. Just have to take it one step at a time.
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #3 ·
Thanks for the tips, last night I primed the system but I couldn’t get the plunger on the lift pump to work so I siphoned it up to the connector. I cracked the injectors and did some cranking, I got bubbles and fuel at injectors 2, 3, and 4 but only some wetting at 1. I did maybe 6 or 7 cranks with the injectors closed and heard a few pops but no fire yet. The battery is definitely undersized so that could be an issue, I do have 12V to the pump though. I let the battery charge some more over night so will do a few more cranks today. I have a mechanical oil gauge hooked up and after all the cranking I can see oil filling that tube but without a fire I can’t read the pressure yet.
 

·
Registered
Joined
·
12,179 Posts
Might need a squirt of starting fluid to get it to kick off. Don't over do that. Just a squirt will be enough. You probably need to run some additive in your fuel to clean up the system. I've used Power Service for year and find it to be good. Walmart is about the cheapest place to get it. The #1 injector could be a pump issue or a sticky injector. Having injectors tested is a recommendation on any used engine. If the pop pressure is OK then you're not out much money. If they are bad then you have to decide to rebuild or replace. You can often buy rebuilt units cheaper than having the old ones rebuilt. Yeah, plenty of battery power is a necessity. A 4bt can work with a single battery but it needs to be a big one. I used to have a Peugeot 504D and that thing had a huge battery. I had to use a hoist to lift that sucker out of the engine compartment. Dodge even used a single on some of the early 6bts and it too was a monster with 1025 CCA. They eventually changed to duals.
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #5 ·
I added some fuel conditioner to try to clean it up a bit, we’ll see if it does anything after it circulates a bit. I did get the engine to run on it’s own for a few seconds but as soon as I let off the throttle it died. It was running pretty rough so I imagine only 2 or 3 cylinders were firing. I’ll keep you posted.
 

·
Registered
Joined
·
12,179 Posts
Probably still have some air in the lines. The fact that it did fire up is good. Need to get a coolant supply hooked up even if it's just temporary so you can run it and get it to clear up. If the missing persists you need to pull the injectors and have them tested. A bad one can cause a lot of grief. Might also do a compression test at the same time just to be sure all is well there. I suspect that the injection pump might be part of the rough running due to having sat for so long. Old diesel fuel in the pump can cause parts to be sticky.
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #8 ·
Please don’t say pump issue, that would cost more to replace than the whole car cost! They sell a set of injectors on eBay for $130 from Cummins, I may go ahead and just replace them to be safe. I’m not sure how to do a compression check on a diesel, I have a gauge for gas engines, does that just thread into the fuel injector location? I may not do that though, this project has sat for a decade already and the last thing I want to do is pull this engine back out even if it is down to 40 hp. I just need to drive it for a while, even if it’s only a couple months before it gets rebuilt.
 
1 - 8 of 8 Posts
Top