stumbled across this site while researching a problem i am haveing with a 1983 winnebago built off a chevy p chassies with a 6.2L non-turbo diesel. thought i would post and see if any one could point me in the right direction on how to fix it. i bought the motorhome last winter and drove it quite a ways home. it looked to have been sitting for about 8 years. it died as soon as we got into the drive after a 100 mile trip. i was just happy we made it home. after the weather warmed up i dropped the fuel tank and flushed it and replaced all the rubber parts of the fuel lines. then i put an electric fuel pump in front of the tank to help push fuel through the system to help with bleeding it out(tank is in the back 20' away). i wired up a pushbotton on the dash to cycle the glow plugs an replaced all the glow plugs.I wired up a switch to turn on the fast idle and cold idle advance. also a new fuel filter , oil change, new belts and a gasket to fix a small coolant leak on the crossover plenum on top. now it runs. it always needs the glow plugs to start even though it is 90*F out. and it has no power. can hardly even move the coach a few feet. smokes bluish whiteish diesel smoke like crazy. if i hold the pedal to the rug it will not even rev all the way up. it will just start missing and sputtering and smoking. i took out the little check valve in the top of the pump and blew air back through the return line to make sure it is not clogged i also tried running it with the gas cap off because there always seems to be a vacuum when i pull the gas cap off. the fuel pressure as read off the vent line of the box filter with just my electric pump running is 3# and with the engine idleing it is 4#. i have plenty of fuel flow when i vent it off to see if ther is air in it. the fuel pump is tight and the timeing lines are matched up on it. where to go from here?????

 

Howdy and welcome to DB first off i dont think you have enough fuel pressure to you're injection pump correct me if I am wrong but I belive you need at least 7lbs or more to supply the IP second i belive you need to find another fuel cap vachum in you're tank is a bad thing makes LP and IP work harder so you will need a venting style cap you as you have probally figured out diesel parts are a little more money good luck and keep us posted

 

Sounds like you have injector issues. One or more are probly cracked, and is pouring oil in the engine. Won't rev up right because the injector is not working right. Just my .02 but I'm a rookie, so I'm just guessing

 

Compression test? Try that too. Definitely get injectors checked or just replace them. Thats where id start

 

check your ip timing. when i first got my rig running, it smoked like crazy and i had to hold the pedal a little to keep it running. and it had absolutely no power. i advanced the ip timing a little at a time until it ran the best. the bluish gray smoke didn't go away completely, but it smoked significantly less.

 

update: i replaced the lift pump, blew air backward throught the return line into the tank to make sure it is clear, replaced the fuel filter (even thought it is new), put a bottle of diesel 911 into the tank(even though the tank was just off and the fuel is only 1 month old), and pulled the gas cap right off. i bled the system out by running the electric pump i have installed right on top of the tank and got good fuel flow. then I tryed to start it. i had to used the glow plugs and it started and idled and runs but if you just hold it to the floor it will start missing and smoking like a rev limiter. the rpm at wich this happes is low enough that i can't get over 45mph if i try to go donw the road. like i can't wind it out if i am downshifting on a big hill. the engine is an 83 but because it is in a motor home it only has 68,000 miles on it so it is hard to believe the injectors would be bad?????????? what now????????????

 

Crack the injector lines one at a time while its running and see if that makes any difference good or bad if you get a miss when you crack one you will know its good no diference and its likely to be the culprit!!!

 

Check your fuel filter housing for cracks, and check your fuel lines

 

it only misses when it is at the high speed so cracking the inj. lines would be kinda hard to do. maybe if i put a brick on the pedal then crawled into the wheel well and reached out to the engine to crack the fittings. (rember its a motor home so the coach is built over top of the engine).
i replcaced all the rubber fuel lines and left the metal ones in place all the way back to the tank 23' away. i have good flow now but i am worried maybe air is getting sucked though the lines as they transition to a vacuum when the engine is running a higher rpm and the lift pumps is sucking harder. i am going to put a 5 gallon tank on the passenger seat and run it right to the lift pump just to make sure that fuel supply is not getting air into it because i am worried that is what it is.

 

i ran a new 20' long piece of copper tubeing today. between the lift pump and the fuel tank eliminateing the little electric pump. i bled it out and started it and saw no bubbles going throught the little piece of clear tubeing i put on top of the pump at the return line check fitting so i know no air is getting in. took it for a drive and it is the same. spits and sputters at higher rpm if throttle is past 1/2 way point. if i back off throttle it will smooth out and start to speed up. if i rug it it actually slows me down. any ideas?????

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triple post , i'm really on a roll here. anyway this is the last question then i'll leave you guys alone unless somebody has an idea. this motorhome is very rusty from the moisture of sitting parked in the grass for years. i am thinking maybe my automatic advance is not advanceing the timeing. could that get seized from sitting or is it all inside the pump away from the atmosphere? i found this diagram.

so is the big black plug in the bottom of the pump shown below the trimmer screw? maybe i could take it out and spray some kroil into it and tap on it and get the cam moveing with a brass drift. beats pulling the pump and spending lots of money on it.