Where I landed for purge and run times

[lancaster,pa]

I have ended up with purge and run times set at 15 seconds and 83 seconds respectively. These settings produce smooth starts and smooth idling for my vehicle (00, F350). I maintained consistent conditions while testing with shut down occuring at ambient temps of 85F, sitting overnight for 12 hours and then starting the next day with ambient at 65F.

My vehicle may have been more sensitive to veg in the injectors at start up because of the partially hydrogenated soy I run in the summer and because of the cool ambient temps in the 60s upon start-up the next day. However, because of that, I feel confident that there is no veg left in the rails or injectors after purge. I will need to stay at the 83 second run since my 00 will not rev when in auto shut down.

Below are other settings I tried with results on starting/idling noted:
1. 11 second purge and 58 second run resulted in rough starts/idle
2. 11 second purge and 83 second run resulted in rough starts/idle
3. 11 second purge and 120 second run resulted in smooth starts/idle
4. 19 second purge and 83 second run resulted in smooth starts/idle

Again, this is what worked for me and my vehicle. May not be the same for everyone. - Patrick

[Marv]

Good info Patrick...thanks for posting that. I still need to adjust my run time - moved the purge to almost 13 seconds and that really helped.

I think with another 30 seconds or so of run time, mine will be doing fine.

[lamintdog]

Have you guys checked the amount of diesel that is returning to the tank when extending your purge times, say, by removing the return from the tank and putting it in a bucket or using a sight glass,etc?

When messing with my purge time, I put a short section of hose from the purge solenoid directly into a bucket under the truck. In testing shutdowns, diesel started getting to that point in the return at just about 6 seconds. I assumed that adding a couple extra seconds to that time would get a little diesel back into the veg tank, but never tested it beyond that. I guess I need to test more...

[Clay]

Have you guys checked the amount of diesel that is returning to the tank when extending your purge times, say, by removing the return from the tank and putting it in a bucket or using a sight glass,etc?

When messing with my purge time, I put a short section of hose from the purge solenoid directly into a bucket under the truck. In testing shutdowns, diesel started getting to that point in the return at just about 6 seconds. I assumed that adding a couple extra seconds to that time would get a little diesel back into the veg tank, but never tested it beyond that. I guess I need to test more...

Yep, i purge 7 seconds...diesel in the vegi tank won't hurt anything but your wallet. No need to pump a quart or more in there by purging longer.

[lamintdog]

Yup. I look at a little #2 in the VO tank as a good thing based on Jason's tests regarding polymerization... but I agree about too much being unecessary...

[lancaster,pa]

Have you guys checked the amount of diesel that is returning to the tank when extending your purge times, say, by removing the return from the tank and putting it in a bucket or using a sight glass,etc?

When messing with my purge time, I put a short section of hose from the purge solenoid directly into a bucket under the truck. In testing shutdowns, diesel started getting to that point in the return at just about 6 seconds. I assumed that adding a couple extra seconds to that time would get a little diesel back into the veg tank, but never tested it beyond that. I guess I need to test more...

Lamintdog,

Was wondering if you are using the manual purge or the automatic shutdown when doing your tests. Is there any difference in the two in terms of the amount of time it would take to see diesel exiting? - Patrick

[lamintdog]

I was testing the purge times when in automatic mode to set the amount of time the purge solenoid should stay open...

As for the difference in purge times comparing the two modes -

In theory, if you were running in manual mode and flipped the system switch to "off" to shutdown the VO pump and at the same time enabled the purge button manually and held it down while counting seconds and looking for diesel coming out of the purge solenoid, it should provide the same result (except it wouldn't shutdown by itself after 60second or whatever you have it set to).

My only problem doing it this way was that my arms weren't long enough to manually hold the purge button and watch the output of the purge tube... now if I was waytallwhitey on the other hand...

[lancaster,pa]

Lamintdog - Thanks for the info.
Clay - Is it correct that each second of purge pushes about an ounce of diesel back toward the V3 (a fifteen second purge pushing about eight more ounces than a seven second purge)? - Patrick

[Employee under the stairs]

it is about a ounce of oil/diesel per sec.

[sbaker]

Thanks for posting those numbers.

I haven't didn't spend much time trying to find the ideal setting, but I also increased my purge time to 15 seconds (from the 11 it was set to by DFA). I had some hard starts once in a while with 11 seconds and I could smell the WVO on start.

So far, I've left the run time at under 60 seconds though.

[lancaster,pa]

Thanks for posting those numbers.

I haven't didn't spend much time trying to find the ideal setting, but I also increased my purge time to 15 seconds (from the 11 it was set to by DFA). I had some hard starts once in a while with 11 seconds and I could smell the WVO on start.

So far, I've left the run time at under 60 seconds though.

Thanks for the post. Let us know how that works for you. - Patrick

[EX ON OIL]

I think for colder climates the run time needs to be at least 2min. I purge for 10 sec and run for 2min and start up is a non issue. Last winter I was running for only 50sec and the check engine light would come on. Once lengthened to 2 min that stoped.

[SwellMel]

I can change my purge time by moving the bottom wheel but the top wheel doesn't do anything, my run time from key out to engine shutoff is 50 seconds, how do I increase this?

[lancaster,pa]

I can change my purge time by moving the bottom wheel but the top wheel doesn't do anything, my run time from key out to engine shutoff is 50 seconds, how do I increase this?

It is necessary to change a setting on the run card. Do this by moving the #2 switch to the "off" position. You should end up with both #1 and #2 in the "off" position. This changes the adjustment from seconds to minutes. It will be necessary to move the wheel in extremely small increments to achieve the setting you want. The movement is so small that it can become tedious to get the setting you want, but it can be done. - Patrick

[lancaster,pa]

I can change my purge time by moving the bottom wheel but the top wheel doesn't do anything, my run time from key out to engine shutoff is 50 seconds, how do I increase this?

It is necessary to change a setting on the run card. Do this by moving the #2 switch to the "off" position. You should end up with both #1 and #2 in the "off" position. This changes the adjustment from seconds to minutes. It will be necessary to move the wheel in extremely small increments to achieve the setting you want. The movement is so small that it can become tedious to get the setting you want, but it can be done. - Patrick

SwellMel,
Should have mentioned that those switches (there are four of them) are located on the run card. They are red and white in color. - Patrick