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Sudden large drop in mileage

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Old Jul 21, 2003 | 10:41 PM
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Sudden large drop in mileage

Hi,<br>My engine ran great for 9 months after the Banks kit was added (at Banks in Calif). Suddenly it dropped mileage from 21 down to 15. Dodge dealer stumped. I took it to a cummins truck shop, and they found a blown intake gasket. Replaced. Adjusted valves. Compression a-ok.<br>Now, more power, more low-end torque, but mileage still bad. Seems like more black smoke than when I came out of Banks shop. Power is not lacking, I can slip the clutch if I do a WOT.<br>I have 127,000 miles. Any ideas? ???<br>
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Old Jul 22, 2003 | 09:58 AM
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Re:Sudden large drop in mileage

Have you looked at the timing?
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Old Jul 22, 2003 | 10:19 AM
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Re:Sudden large drop in mileage

Check your timing. It was probably done already but also check your air filter. In fact I would remove everything from the air filter to the turbo and check for blockages. Also check for a crushed exhaust although that is unlikely if you have lots of power.<br>Let us know the fix.
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Old Jul 22, 2003 | 12:56 PM
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Re:Sudden large drop in mileage

When is the last time you changed your fuel filter?
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Old Jul 22, 2003 | 02:04 PM
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Re:Sudden large drop in mileage

Yes, the Air filter is a K&amp;N, we cleaned and oiled it as per spec, its not at all restrictive.<br>I had them change the fuel filter at Cummins.<br>It could be a timing issue, even though Cummins says its not likely. I don't believe they actually checked the timing even though I discussed it with them.<br>Back to the shop!<br>I get higher EGT than usual on the same hills, so there has been something change.<br><br>-Del
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Old Jul 22, 2003 | 11:04 PM
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Re:Sudden large drop in mileage

[quote author=dieseldel link=board=16;threadid=17382;start=0#162795 date=1058900653]<br>Yes, the Air filter is a K&amp;N, we cleaned and oiled it as per spec, its not at all restrictive.<br>I had them change the fuel filter at Cummins.<br>It could be a timing issue, even though Cummins says its not likely. I don't believe they actually checked the timing even though I discussed it with them.<br>Back to the shop!<br>I get higher EGT than usual on the same hills, so there has been something change.<br><br>-Del<br>[/quote]<br><br>Definately sounds like timing.
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Old Jul 22, 2003 | 11:32 PM
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Re:Sudden large drop in mileage

[quote author=Got Smoke? link=board=16;threadid=17382;start=0#162999 date=1058933069]<br>[quote author=dieseldel link=board=16;threadid=17382;start=0#162795 date=1058900653]<br>Yes, the Air filter is a K&amp;N, we cleaned and oiled it as per spec, its not at all restrictive.<br>I had them change the fuel filter at Cummins.<br>It could be a timing issue, even though Cummins says its not likely. I don't believe they actually checked the timing even though I discussed it with them.<br>Back to the shop!<br>I get higher EGT than usual on the same hills, so there has been something change.<br><br>-Del<br>[/quote]<br><br>Definately sounds like timing.<br>[/quote]<br>Is somebody typeing : J/K Yep timint sounds like the key to your problem. now how to fit that square peg into that round hole [undecided]<br>DM01
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Old Jul 22, 2003 | 11:46 PM
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Re:Sudden large drop in mileage

Whats the average mileage for a 12v 4x4?
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Old Jul 23, 2003 | 12:01 AM
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Re:Sudden large drop in mileage

stock I got 17-18 after the mods I get 20-23 on the road. around town suffers a little but the smoke is fun ;D<br>DM01
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Old Jul 23, 2003 | 12:53 AM
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From: North Central Arizona
Re:Sudden large drop in mileage

When my 3500 was new, I got 18-19 mpg consistently. When pulling my jeep on a trailer got 16, while really pushing it 75mph, no mercy thru Colorado mountains, etc.
After the Banks modifications, I got 19-21 consistently, that is why this 15mpg I'm now getting has me worried.
It used to smoke pretty bad before the Banks mods. Real clean after that until recently.

I could have gotten a new truck at 100k miles, but...I like this one too much to change. ;D

According to my engine plate, should be 13.5 degrees advanced timing (215hp engine stock). hmmm. Guess I'll have to find someone to time it, it must have slipped back some.
I didn't know that could happen! :

-Del
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Old Jul 23, 2003 | 11:33 AM
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Re:Sudden large drop in mileage

what kind of power ( hp torque) does the banks give on these?
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Old Jul 23, 2003 | 12:15 PM
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Re:Sudden large drop in mileage

kingofdodge, I don't know about the horsepower.
The torque is easily enough to slip the clutch, which holds to about 700 ft/lb. I think Banks specs 690 or something like that in their docs. But their spec is for a 180hp stock engine, and mine is 215 stock. So that makes a difference I'm sure.
And this is all with stock injectors. Their &quot;Powerpack&quot; changes the turbo &quot;enclosure&quot; (blanked out on the name), new torque plate of their design to match the increased air, low restriction exhaust system, K&amp;N low restriction air filter, and a high-rise split intake manifold. The manifold cools the front cylinders so all run more even temp, and really is noticable in the sound of the engine, it runs much smoother. Takes that loping sound away.

-Del
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Old Jul 23, 2003 | 12:39 PM
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Re:Sudden large drop in mileage

Have you check for riceburners trapped underneath?
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Old Jul 23, 2003 | 03:38 PM
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Re:Sudden large drop in mileage

What kind of power do you get with that banks kit? hp and torque wise
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Old Jul 23, 2003 | 04:36 PM
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Re:Sudden large drop in mileage

opps put it in twice haha thanks for the info
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