91 cummins in 69 crewcab dodge
I apologize if this is covered somewhere and Iím just not understanding. Iím stuck, at a loss, and clueless. help?
This will be long, because I want to make sure all the pertinent information is given.
I am in the process of building a 69 Dodge W250 crew cab with a 91 Cummins in it. This is not an engine that I bought and donít know how it runs. I pulled this engine from my 91 dodge D350 when the body had finally fallen apart to the point of uselessness. The engine was running great.
After several years, Iíve reached the point where the engine is mounted, wired, plumbed, and was ready to fire up. Iím using the stock 91 radiator, exhaust, and fuel pump. I have the one wire that used to power the coil running the injector pump, and I have the air heaters plugged to a momentary switch on the dash so I can manually operate them should they be necessary. I used a diesel fuel tank from a 93 Ford F350, which is presently held under the truck with bailing wire. the return line and main line are plumbed with rubber line to a steel line that runs the length of the frame rails, and then the main line goes into a large NAPA auxiliary fuel canister fuel filter and water separator.
I read a number of forums on how to bleed the fuel system, so I got fuel in the tank, and began to use the priming handle on the mechanical pump, cracking the bleeder valve every few pumps. Nothing came out. I disconnected and went straight to a fuel can, and still nothing came out. I poured fuel down the line with the bleeder bolt open and fuel came out. Figuring the fuel pump had died from sitting for 5 years, I bought a new one and put it in. Now fuel and air bubbles would come out of the bleeder bolt when I pumped. Reconnected the fuel line to the main tank and bled until I could do 3 sets of 8 pumps with no air coming out the bleeder bolt.
With that done, I turned the key on, and began bumping the engine over with the starter to bleed the injectors. Crank for a few seconds, and then go crack the nut on the injector closest to the back. repeat until diesel came out, then move onto the next injector. By the time Iíd gotten to the third injector, the engine started and ran very very poorly. I stopped it, and continues the process, only now Iíd have to crank it, the engine would start, Iíd kill it, and then open the injector. Once all injectors had fuel coming out, I thought it might run better. it didnít. When I try to give it throttle, it smooths out with just a little throttle at what Iíd guess to be about 100 rpm. if I try to rev it, it dies. if I try to hold it at a higher rpm, it dies. And on a whim, I opened the bleeder bolt and there was air there again.
Back to hunting through forums. A youtube video shows that I can bleed the injectors while the engine is running, but to be very careful. Next time, I went back out, did the priming handle on the pump until there was no air at the bleeder bolt for 3 sets of 8 pumps, and then cranked with the starter. the engine started immediately and ran poorly. I started at the back injector and cracked the nut very cautiously. it squirted small sprays of diesel all over the place. I did that with each injector in turn, noting that when I tightened the nut back up, sometimes the engine would smooth out. the 4th injector from the back and the front injector both cause the engine to run very badly when opened. The other injectors didnít really seem to have much effect, except that sometimes when I closed them it would run better for a bit. Nothing I did seemed to make it smooth out (or as smooth as a diesel ever sounds:-). Just to see, I checked the bleeder bolt again, and it spewed air. lots of air.
Back to the internet for help again. The general consensus seemed to point to thereís a leak in my incoming line somewhere. the leak doesnít have to be big enough to let fuel out in order to let air in. So I took the line off at the tank, and put 15 psi air to it while spraying down all the connections with soapy water. I found two leaks and fixed them, figuring that NOW I could bleed the thing and it would run good again.
Go through the same rigamarole: bleed the bleeder until thereís no air (which seems to take longer each time I do this), and then bleed the injectors. By this time, the engine fires up instantly, so Iím always bleeding the injectors while itís running. Still runs poorly. still dies if I try to give it throttle.
After reading forums again, it appears that thereís a possibility that the pickup in the fuel tank is allowing air to get in. So I disconnect the fuel line at the tank and put it into a fuel can full of diesel, itís buried 8 inches into the fuel, so there should be no air. But the same issue occurs, but this time it does somethings strange: when I open the 4th injector, the engine runs worse, like it always does, and then it dies. Thatís the first time itís died at idle. It wonít restart. I checked the bleeder and lots of air came out.
Then I removed the auxiliary fuel filter from the line, in case that was a problem. Same deal, only now the truck wonít start. I changed my process a bit: Crank the engine, check the bleeder, crack each injector, and then check the bleeder again. And I still wind up after a while with bunches of air in the line. the truck now runs for a second and then dies.
Iím at a loss. Am I introducing air when I crack the injectors open? I rechecked the lines with soapy water and pressure, and there are no leaks that I can find.
Any help would be appreciated.