Why is my LS1 getting horrible gas mileage?
08-01-2005, 02:15 PM
#1
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Why is my LS1 getting horrible gas mileage? I drive a 1998 Trans Am WS6 Automatic, and the gas mileage is horrendous. I usually get 8-10 miles a gallon. Usually 130-140 miles a TANK. I don't drive it hard at all, im very easy on the gas. What usually causes a car like that to be getting horrible gas mileage? LS1's should be getting 15-20, not freaking 8mpg. Its getting really annoying and expensive having to refill the car every 3-4 days.
08-01-2005, 02:19 PM
#3
Yea, I was getting about 10mpg before the tranny swap. Now that I only have 4 gears, it's gonna be interesting to see what I get now.
Do you have a big cam? That's when I lost mine.
Do you have a big cam? That's when I lost mine.
08-01-2005, 02:20 PM
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Originally Posted by King James
What mods? What maintenance have you done? More info is needed.
1.Hypertech programming
2. FIPK
3. Corsa Exhaust
4. Subframes/LCA's
5. Descreened MAF
6. 3.73's
Just oil changes basiaclly.
08-01-2005, 02:30 PM
#5
Descreened MAF and HPP3 tuning are not great combos for WOT performance, but I don't think they're contributing for your poor fuel economy. Biggest contributors to bad gas mileage are usually cheap to replace:
Spark plugs
O2 sensors (bad ones will screw you).
MAP sensor
Dirty MAF hot wire elements (clean them).
Check and replace these items and check out your fuel economy again.
Spark plugs
O2 sensors (bad ones will screw you).
MAP sensor
Dirty MAF hot wire elements (clean them).
Check and replace these items and check out your fuel economy again.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
08-01-2005, 06:51 PM
#7
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Originally Posted by Patrick G
Descreened MAF and HPP3 tuning are not great combos for WOT performance, but I don't think they're contributing for your poor fuel economy. Biggest contributors to bad gas mileage are usually cheap to replace:
Spark plugs
O2 sensors (bad ones will screw you).
MAP sensor
Dirty MAF hot wire elements (clean them).
Check and replace these items and check out your fuel economy again.
Spark plugs
O2 sensors (bad ones will screw you).
MAP sensor
Dirty MAF hot wire elements (clean them).
Check and replace these items and check out your fuel economy again.
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08-01-2005, 07:13 PM
#9
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Do you have a scan tool? Would be good to see a log of your commanded AFR, LTFT's, and S1 O2 voltages.
it's not hurting much either. I'm getting ~20mpg with mine.
Originally Posted by 4mula
the 3.73 rear gear isnt helping much on milage
08-01-2005, 07:14 PM
#10
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I'm running 4.10's with a 12 bolt and I average close to 19 mpg. Lots of quick runs through 1 and 2. I can't help it. I always hit 150 miles at the mid tank readings. Something is very wrong.
08-01-2005, 07:17 PM
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somethings gotta be wrong. even with those gears it shouldn't be that bad. im near stock, but my car is running rich and i still get no worse than 17 ever
08-01-2005, 07:19 PM
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also check your fuel filter. if that is clogged then that could be the culprit.
its recommended to change it out every 15k miles or so.
check the air filter, make sure your not misfiring, possibly from bad plugs, wires, etc...
its recommended to change it out every 15k miles or so.
check the air filter, make sure your not misfiring, possibly from bad plugs, wires, etc...
08-01-2005, 07:35 PM
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Originally Posted by Grave
Ha... yeah, same here. I get about 160 some-odd miles out of 3/4 of a tank.
If it helps any... my A/F ratio is around 13.0:1 in low/mid RPMs until 4000, and around 12.5:1 around higher RPMs.
I'm willing to bet my it's because I have a few small leaks around on my headers where the collector and cat meet. Maybe the outside air is making the O2 sensor think it's running lean and dumps more fuel?
Other than that... I don't know why it does what it does. It runs like a champ. I just have the standard issue entry level bolt-on mods, nothing internal (yet).
08-01-2005, 10:38 PM
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I was getting 15MPG then I hooked up HP tuners and realized that I had a problem with an O2 sensor and they were running in the high 800's constantly. I ended up changing out a bad O2 extension and I am back up to 20.5 MPG.
08-01-2005, 11:48 PM
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Originally Posted by Patrick G
Descreened MAF and HPP3 tuning are not great combos for WOT performance, but I don't think they're contributing for your poor fuel economy. Biggest contributors to bad gas mileage are usually cheap to replace:
Spark plugs
O2 sensors (bad ones will screw you).
MAP sensor
Dirty MAF hot wire elements (clean them).
Check and replace these items and check out your fuel economy again.
Spark plugs
O2 sensors (bad ones will screw you).
MAP sensor
Dirty MAF hot wire elements (clean them).
Check and replace these items and check out your fuel economy again.
08-02-2005, 05:42 AM
#18
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All the HPP3 does is copy the high octane tables to the lower octane tables. Usually makes you run too lean, a descreaned MAF on an auto will just accentuate that.
