Problems with B1501 set to 'Disable'

[jpgmtech]

Hi All!

Just spend the better part of a couple of weeks isolating a real hair-puller. This applies to trucks running OS 12628954, affects LMM's from 2007-2010 (verified)

Condition: Setting 1501 EGR Control to 'Disable' has the following effects which seem to manifest themselves after the engine is warmed up or after a prescribed run-time:
• Injection timing surge
• Turbo pressure and vane surge, both on cruise and acceleration
• Intermittent extremely black smoke on shifts (suspect this is the EGR valve physically opening even though my logs do not show it.)
• Intermittent lag on acceleration

What appears to happen is the turbo and injection timing modes seem to cycle back and forth with some kind of phantom EGR mode, causing the surging and intermittent black smoke.

I have several logs that capture the surging condition if anyone wishes to look at them. Originally I backdated a few trucks to one of my older tunes until I had the time to isolate this. I just finished A-B-A testing on two different trucks. I have only used B1501 recently, most of my LMM tunes disable the EGR with the original methods - setting B1502-1506.

Bottom line - leaving B1501 in stock position 'Enable' will solve a number of phantom problems with LMM tuning.

[duramaximizer]

Yep, you have to go through and set the EGR parameters to these:

I set all EGR flow data in tables 1526, 1527, 1528 to "0."

B1501 Enable
B1502 -100.000000
B1503 320.000000
B1504 -57.932176
B1505 -2.900000
B1506 -100.000000
B1520 300.951932
B1521 302.000000
B1522 300.951932
B1523 302.000000
B1524 -57.932176
B1525 302.000000
B1529 6000.000000
B1530 5999.000000
B1531 284.000000

[killerbee]

A big high 5 Joel!

[jpgmtech]

Hoping it saves some grief. I've noticed in other forums that a few guys have been setting B1501 to 'disable'. In one post, the guy noted that his tune had a couple of glitches much like the symptoms I described.

Had at least two guys up here wondering if I knew what I was doing when I had to take a few hours on their trucks instead of the usual 30 minutes. Not good for my customer base to see glitches like that, it hurts their confidence. Still, they are happy with the results!

[duramaximizer]

Hoping it saves some grief. I've noticed in other forums that a few guys have been setting B1501 to 'disable'. In one post, the guy noted that his tune had a couple of glitches much like the symptoms I described.

Had at least two guys up here wondering if I knew what I was doing when I had to take a few hours on their trucks instead of the usual 30 minutes. Not good for my customer base to see glitches like that, it hurts their confidence. Still, they are happy with the results!

Ya no shit.

[killerbee]

B1526-B1528 do not appear to function either, if I understand them. Are they suppose to stop egr opening when set to 0? I see no difference after entering all zeros.

[JoshH]

I've not experienced any of the problems you state by setting that table to disable with that OS. Were you doing that in addition to changing the other tables, or were you trying to disable the EGR with just that enable/disable button?

[jpgmtech]

I've not experienced any of the problems you state by setting that table to disable with that OS. Were you doing that in addition to changing the other tables, or were you trying to disable the EGR with just that enable/disable button?

I had set B1502-B1506 to disable EGR function originally, and the tunes I had problems with; I additionally set B1501 to Disable. I had in mind to shut down the EGR cleaning cycle that occurs after engine shut down, and that did fix that but introduced all of the above problems. I'm still cleaning up the odd truck that had B1501 set to Disable up here, including one today.

It could be that simply changing B1501 to Disable without changing any other parameters might be sufficient and may not demonstrate the problems listed above.

[jpgmtech]

B1526-B1528 do not appear to function either, if I understand them. Are they suppose to stop egr opening when set to 0? I see no difference after entering all zeros.

I can honestly say I never have touched those parameters to even know.

[JoshH]

I had set B1502-B1506 to disable EGR function originally, and the tunes I had problems with; I additionally set B1501 to Disable. I had in mind to shut down the EGR cleaning cycle that occurs after engine shut down, and that did fix that but introduced all of the above problems. I'm still cleaning up the odd truck that had B1501 set to Disable up here, including one today.

It could be that simply changing B1501 to Disable without changing any other parameters might be sufficient and may not demonstrate the problems listed above.

Hmmm, weird. I have done exactly what you said, and never experienced those problems. I have tried setting just the enable/disable to disable, but that doesn't disable the EGR (or at least it didn't for me).