[bigrigger19]

i am rebuilding my 85 6.9 i have a fresh top end with new glowplug system and glow plugs, new injectors, timed the ip several times all timing is correct, new supply and return lines, but i still have a horrible time starting when cold. two to three cycles of th glowplugs is usually needed then when she starts she smokes white all of the time even when warm. i have no muffler on it now could that be part of the issue, not enough back pressure? i also have a pusher pump in the frame rail for fuel 4-6 psi. if i plug the truck in for 2 hrs she will fire right up, but still smokes white. iv got two 850cca batteries and a starter with the mitsubishi gear reduction kit in it. i am also positive i have no air in the fuel done several tests. any ideas? im stumped. its a ritch fuel smell not antifreze. my ip was recently tested by diesel injection service and they said it was fine. runs great just hard to start and verry smoky

 

[icanfixall]

These new injecters... Were they actually new or rebuilt and where did you buy them. What was the compression on the motor? Sounds like you really have a timing issue being a bit retarded. Hard starting and white smoke usually means no glow plugs working and retarded timing. How do you know the timing is correct.

 

[Joe Mc]

Diesels do not need or like back pressure.

Your symptoms sound like a timing problem.
Have you done a compression test?

 

[bigrigger19]

i had a tech at a local repair shop chck the gear timing , but my governer plunger was hanging u so i brought the truck home then fixed the problem and spent two days tweaking the ip's timing till i was somewhat happy. but she still smokes. compression was arround 300 in all cylinders. my injectors are brand new bought them from diesel injection service and i made sure they were not remans. i thought non turbo diesels needed back pressure to proporly run, while turo diesel did not need back pressure because they create their own.

 

[arthurgoboom]

You do not need back pressure in any engine, that is an old wive's tale. What originated that theory is when a smaller/more restrictive exhaust system would make an engine run better, but we have found out that the smaller systems maintain a higher gas velocity which aids in emptying the cylinder of exhaust gases more completely. It's about the exhaust system being sized correctly for the cylinder displacement and operating RPM. Bigger is not always better, especially for a street vehicle.

Regarding your white smoke, ensure that your fuel supply pump is only providing that 4-6 psi. The IP can vary the timing internally and those mechanisms are controlled by fuel pressure. Also ensure that your return line system is unrestricted as a restriction there can also cause a timing change. I thought that a restriction in the return line had the effect of advancing the timing, but your results act like retarded timing. Perhaps you had a restriction that finally loosened up after you originally tuned the timing to your liking?