JaysinSpaceman
Veteran Member
First a big thanx to kajikidu for giving me a good deal on a Diesel pulse timing light adapter for my m-TDi conversion. It works great so far.
Now some info on the dynamic timing advance for those that go the m-TDi route. When I built my pump I went with the current info that I could find (at the time) and used the e-TDi timing spring. I have fought with one of two conditions when I changed the static pump timing. Either the engine started well with little glow plug and sounded rattly at higher speeds and loads (when I would advance the timing) or I had to use the glow plugs even when the engine was warm if it sat for more then a half hour but it revved smooth and didn't sound rattly at higher RPM and load.
Now that I have a timing light adapter I did a few tests. From info I have found on timing with a light, 12 degrees BTDC at idle seems to be the best setting for most everyone. So I set the timing to that with the E-TDi spring and the truck was very hard to start but revved nice and smooth. The I swapped the timing spring for the original stiffer Cummins 4BT spring I had and rechecked the timing (note: I did not move static timing at all) and it was now idling at 4.5-5 degrees BTDC. So I reset static timing to 12 degrees BTDC at idle with the new spring and now the engine starts great and it revs smoothly with lower EGTs and much less rattle.
Moral of this story is that the stock E-TDi timing advance spring is FAR to soft and advances far too soon/too low RPM in a M-TDi pump without the E-TDi's ability to lessen timing with the computer. The Cummins may not be ideal but it is much better then the E-TDi spring. I will be doing more testing at various RPM for more data so I can figure out the advance curve of the Cummins spring, and I will also test a E-TDi with my light and see how the two advance curves compare. I should then be able to compare the physical spring rates between the two sparings and find a suitable spring rate to get close to the stock E-TDi curve.
Anyway, I thought people should know what I have found. I will continue to add more M-TDi tuning info as I go. And unlike those that are trying to make a living with the hows and whys that go into M-TDi pumps and tuning I am happy to give you what I find as it is all just a means to an end to get my truck to run well get good MPG and pull like a freight train.
That's it for the Spaceman Radio Hour. Thanx for tuning in.
Jaysin
Now some info on the dynamic timing advance for those that go the m-TDi route. When I built my pump I went with the current info that I could find (at the time) and used the e-TDi timing spring. I have fought with one of two conditions when I changed the static pump timing. Either the engine started well with little glow plug and sounded rattly at higher speeds and loads (when I would advance the timing) or I had to use the glow plugs even when the engine was warm if it sat for more then a half hour but it revved smooth and didn't sound rattly at higher RPM and load.
Now that I have a timing light adapter I did a few tests. From info I have found on timing with a light, 12 degrees BTDC at idle seems to be the best setting for most everyone. So I set the timing to that with the E-TDi spring and the truck was very hard to start but revved nice and smooth. The I swapped the timing spring for the original stiffer Cummins 4BT spring I had and rechecked the timing (note: I did not move static timing at all) and it was now idling at 4.5-5 degrees BTDC. So I reset static timing to 12 degrees BTDC at idle with the new spring and now the engine starts great and it revs smoothly with lower EGTs and much less rattle.
Moral of this story is that the stock E-TDi timing advance spring is FAR to soft and advances far too soon/too low RPM in a M-TDi pump without the E-TDi's ability to lessen timing with the computer. The Cummins may not be ideal but it is much better then the E-TDi spring. I will be doing more testing at various RPM for more data so I can figure out the advance curve of the Cummins spring, and I will also test a E-TDi with my light and see how the two advance curves compare. I should then be able to compare the physical spring rates between the two sparings and find a suitable spring rate to get close to the stock E-TDi curve.
Anyway, I thought people should know what I have found. I will continue to add more M-TDi tuning info as I go. And unlike those that are trying to make a living with the hows and whys that go into M-TDi pumps and tuning I am happy to give you what I find as it is all just a means to an end to get my truck to run well get good MPG and pull like a freight train.
That's it for the Spaceman Radio Hour. Thanx for tuning in.
Jaysin
.... no way
