UPDATE - I haven't gone a full tank yet to get exact figures, but just swapped the plugs/plug wires/front 02's. Did the swap at just over half a tank, and after driving another 30-40 miles, it already looks like I'm on pace to do about 50 miles over what I was doing during the first post. From what I've read recently about people having here on LS1tech having the same issues, I feel strongly those front O2's were the issue. I will post once I run through another full tank of gas to show the actually mileage difference. Thanks again for the help, everyone!
UPDATE - I haven't gone a full tank yet to get exact figures, but just swapped the plugs/plug wires/front 02's. Did the swap at just over half a tank, and after driving another 30-40 miles, it already looks like I'm on pace to do about 50 miles over what I was doing during the first post. From what I've read recently about people having here on LS1tech having the same issues, I feel strongly those front O2's were the issue. I will post once I run through another full tank of gas to show the actually mileage difference. Thanks again for the help, everyone!
I get about 230 miles out of a full tank with my 427ci......thats driving aggressively half the time. I get well over 300 on the highway, like 350.
You have 02 sensor issues most likely. You can spend money on parts trying to make it better.......but a simple 2 minute scan with the engine running will tell all.......
Your 02 sensors are probably trashed and not switching properly. NO...you won't get a SES light or code until they are very bad or failed. You'll run real rich till you change them.
+1 on putting in a fresh set of front 02 sensors. I strongly recommend using AC delco as I've seen Bosch ones set 02 sensor heater resistance codes. Also make sure you have no brake drag (check service brakes and parking brake) and all of your maintenance is up to date.
177 miles per tank is pretty bad (and also a poor way to judge fuel economy but thats a whole other story). My 87 Camaro beater with a 4 barrel LG4 running on the rich side gets about 12.5-13.5 mpg around town (running the needle down I can go around 200 miles a tank).
__________________ ~Ryan~
'02 Z28 - Stock for now
'99 T/A - full exhaust, tune
'87 Sport Coupe - Winter beater
+1 on putting in a fresh set of front 02 sensors. I strongly recommend using AC delco
No such thing as AC Delco 02 sensors anymore, its been about 4 years now. If you go to any GM dealership.....you will get an AC Delco box...with Denso 02 sensors in them. Or any auto parts stores that sell AC Delco 02 sensors....they will be the same, Denoso sensors. The same ones sitting next to them on the shelf in Denso boxes.
And those thieves at the dealerships are charging as much as $180 each....
Some auto parts stores are as low as $60-$100 each.......
So make sure you all buy Densos at Amazon.com or rockauto.com
I get about 230 miles out of a full tank with my 427ci......thats driving aggressively half the time. I get well over 300 on the highway, like 350.
You have 02 sensor issues most likely. You can spend money on parts trying to make it better.......but a simple 2 minute scan with the engine running will tell all.......
Your 02 sensors are probably trashed and not switching properly. NO...you won't get a SES light or code until they are very bad or failed. You'll run real rich till you change them.
Check it.....
.
Quote:
Originally Posted by FiredUpZ28
+1 on putting in a fresh set of front 02 sensors. I strongly recommend using AC delco as I've seen Bosch ones set 02 sensor heater resistance codes. Also make sure you have no brake drag (check service brakes and parking brake) and all of your maintenance is up to date.
177 miles per tank is pretty bad (and also a poor way to judge fuel economy but thats a whole other story). My 87 Camaro beater with a 4 barrel LG4 running on the rich side gets about 12.5-13.5 mpg around town (running the needle down I can go around 200 miles a tank).
Hey guys, it looks like you may have missed it on my previous post that one of you quoted - but I just swapped the O2 sensors along with a few other things. It looks like it has fixed the problem. I agree that measuring "miles per tank" is a relatively inaccurate way to measure fuel economy. However, my day to day schedule, and by result, my driving, is very habitual - meaning I go almost the exact same places at the same frequency throughout the month. The point where my "check gauges" light comes on has typically been +/- 10 miles of the same number each tank (usually 165-175). However, since I swapped the O2 sensors recently, that number increased by 25-35 miles to about 200 miles - and this is after swapping them with less than half a tank of gas remaining. I just filled back up tonight, so I'll report how far I am able to go on the next tank as soon as my "check gauges" light comes back on!
Thank you all very much for your help - I really appreciate it.
No such thing as AC Delco 02 sensors anymore, its been about 4 years now. If you go to any GM dealership.....you will get an AC Delco box...with Denso 02 sensors in them. Or any auto parts stores that sell AC Delco 02 sensors....they will be the same, Denoso sensors. The same ones sitting next to them on the shelf in Denso boxes.
And those thieves at the dealerships are charging as much as $180 each....
Some auto parts stores are as low as $60-$100 each.......
So make sure you all buy Densos at Amazon.com or rockauto.com
Approx. $40-$45 each. Sometimes cheaper.
.
For what it's worth, I purchased the Densos on Amazon - they were $33.xx a piece. FAR cheaper than any retailer I received quotes from!
you can have the O2 sensors tested ,replace if needed.and clean the MAF correctly.get new plugs ,and clean the injectors.clean out the IAC,(ideal air curcite).
FWIW, i too was a victim of the amusing gas milage, had o2's replaced cleaned TB, MAF and had injectors ultrasonic cleaned.
Apart from resolving my poor gas milage (260kms to a full tank on my 98) it feels like a new car, accelerates better not popping back in exhaust, doesnt smell pig rich anymore, it amazes me just how much of an effect these little buggers can have!!
Great to see you are also getting improvements, i would also suggest you have a go at the plugs and wires just because this will " pop" your cherry as it were.. Number 8 plug is going on my tomb stone!! Its a great exeperience!
Hey guys, it looks like you may have missed it on my previous post that one of you quoted - but I just swapped the O2 sensors along with a few other things. It looks like it has fixed the problem. I agree that measuring "miles per tank" is a relatively inaccurate way to measure fuel economy. However, my day to day schedule, and by result, my driving, is very habitual - meaning I go almost the exact same places at the same frequency throughout the month. The point where my "check gauges" light comes on has typically been +/- 10 miles of the same number each tank (usually 165-175). However, since I swapped the O2 sensors recently, that number increased by 25-35 miles to about 200 miles - and this is after swapping them with less than half a tank of gas remaining. I just filled back up tonight, so I'll report how far I am able to go on the next tank as soon as my "check gauges" light comes back on!
Thank you all very much for your help - I really appreciate it.
Good to hear your car is running better. Nothing sucks more than having your car run like a giant floppy...
Good to hear your car is running better. Nothing sucks more than having your car run like a giant floppy...
LOL I was wondering when I might find you in here, Marc!!!!
So no luck so far guys - I jumped the gun on reporting my results. Gets about 120-140 miles on the first half of the tank and then by 165-185 the fuel light is on again. Crazy how much that needle starts speeding up the closer it gets to empty. If anybody else has any feedback - I'd appreciate it!
Just to recap, things I have tried so far: Plugs (NGK), Wires (MSD), Air filter, fuel filter, front O2's and ran a can of sea foam through it. Only mods are SLP lid and SLP Loudmouth II exhaust (LM went on last night).
Oh and for those of you who don't like the miles per tank method, I have actually calculated the miles driven/gallons spent - comes out to 13-15 MPG, depending on how much highway driving I've done on the tank.
My 2000 Z28 A4 ran poorly a year after installing a SLP lid and a oiled air filter. It took a while to figure out but I cleaned the MAF with a can of CRC MAF cleaner, and all ok. Worth a quick shot of cleaner at 7 bucks and 15 minutes work. My car never got bad mileage, usually around 21 mpg. I get about 300 miles to a tank, best of 335 miles.
My 2000 Z28 A4 ran poorly a year after installing a SLP lid and a oiled air filter. It took a while to figure out but I cleaned the MAF with a can of CRC MAF cleaner, and all ok. Worth a quick shot of cleaner at 7 bucks and 15 minutes work. My car never got bad mileage, usually around 21 mpg. I get about 300 miles to a tank, best of 335 miles.
I've actually spent the past 30 minutes reading about the MAF. This will likely be my next thing to check. I've seen a suggestion to unplug the MAF and see how it runs without it. Can someone confirm that it is actually safe to unplug the MAF and run speed density temporarily? Using the search function yields a ton of conflicting information. Thanks everyone for the feedback.
LOL I was wondering when I might find you in here, Marc!!!!
So no luck so far guys - I jumped the gun on reporting my results. Gets about 120-140 miles on the first half of the tank and then by 165-185 the fuel light is on again. Crazy how much that needle starts speeding up the closer it gets to empty. If anybody else has any feedback - I'd appreciate it!
Just to recap, things I have tried so far: Plugs (NGK), Wires (MSD), Air filter, fuel filter, front O2's and ran a can of sea foam through it. Only mods are SLP lid and SLP Loudmouth II exhaust (LM went on last night).
Hey man its worth a shot trying to scan it with the hptuners. that may give us more insight to your problems
That would be fantastic, sir! Does that mean I need to shell out $250 before we can do that? I appreciate the help.
Almost all speed shops will scan you for free....if you have any in your area. My dealership does, believe it or not. Call a couple GM dealers, maybe they will.
Can someone confirm that it is actually safe to unplug the MAF and run speed density temporarily? Using the search function yields a ton of conflicting information. Thanks everyone for the feedback.
Yes, it is safe. I had a friend who complained constantly about poor driveability. He had me borrow the car for a day; I unplugged the MAF and it ran fine. He's been driving it that way ever since - too cheap to replace it.
But as someone suggested above, first clean the thing. Then, if that doesn't help, unplug it.
Another thought is that your factory cats may have become clogged. Although that should throw a code, you can't always count on that.
__________________ 00 Formula Bright Silver A4 Bolt-ons, SS3600 stall, 3.42s; PB:12.37/109.62/1.69 02 Formula SOM M6 lid/catback 09 G8 GT Black/Onyx 19's, sport pkg - stock - wife's car 69 GTO Judge 400 4 spd.
69 GTO 428 TH400
Almost all speed shops will scan you for free....if you have any in your area. My dealership does, believe it or not. Call a couple GM dealers, maybe they will.
.
Thank you for the info! I appreciate it!
Quote:
Originally Posted by RevGTO
Yes, it is safe. I had a friend who complained constantly about poor driveability. He had me borrow the car for a day; I unplugged the MAF and it ran fine. He's been driving it that way ever since - too cheap to replace it.
But as someone suggested above, first clean the thing. Then, if that doesn't help, unplug it.
Another thought is that your factory cats may have become clogged. Although that should throw a code, you can't always count on that.
Thanks for the confirmation, RevGTO. The cats was the other option I was looking into. If it's not throwing a code, is there anything that can be done to check these other than removing/replacing them?
So unplugged MAF this morning - car seems to run the exact same without it plugged in. It threw an SES about the third time I started it today, but still no change in the way the car drives. For those of you with knowledge in the matter (lemons12??), does this tell me anything? Does this mean it was fine all along or does this mean that since there is no change that it has been bad all along and just not throwing a code? Any input is appreciated.
Hey man its worth a shot trying to scan it with the hptuners. that may give us more insight to your problems
