02 sensor affecting instant MPG readings?

[dirtybrd]

Does the 02 sensor have any effects on the instant MPG display or does that work strictly of the inj. pulses. When driving my car the instant MPG will vary some but will always end up reading 5 MPG, even if I'm cruising at 40MPH and in 5th gear. I think I might have a lazy 02 as I only get about 200 miles to a tank no matter how I drive it and my buddy said I had flames coming out the back so it's obviously rich.

[SlappyB6]

Sounds like a definite possibility. And yeah, it definitely sounds like you're running rich. I would pull out the O2 sensors and see if there's any build up on them. Try cleaning them first and see if that makes a difference.

And 200 milles to a tank? Wow, maybe I'll go for show instead of go. I have 340 on my current tank, and it's still at 1/4.

[CO AVANT]

200 miles is pretty bad. I'm even getting 300 with the 550's. I have an extra primary 02 sensor you can try and ship back to me.

[dougyfresh]

200 miles is pretty bad. I'm even getting 300 with the 550's.

Wow. I've pushed close to 400miles on a tank with 630s . Granted it was highway cruising but still..

[CO AVANT]

I have a little of what we call "a lead foot" I really need a 6spd out here for obvious high speed reasons. Too many open roads to haul ass on. If anyone finds a B6S4 tranny let me know ;)

[dougyfresh]

We should find you a 2.8L 5spd.

[CO AVANT]

6spd FTW. I want to be at 4000rpms in 6th gear at 100mph. I do not think the 2.8 gearing can get me there. What is clint seeing? I'm sucking gas down like crazy without better high end gearing in there.

Chris I can send this 02 sensor out to you today so you can try it out and send back. Just need to pay for shipping. No need buying one if that's not the problem. They are pricey.

[dougyfresh]

When I drove Clint's car: 70mph in 5th gear was 3,000rpm. I wanted to go faster but was hesitant due to Memorial Day weekend and being on a back road in NJ (if there is such a thing)

I think it'll be near, or slightly over, 4,000rpm at 100mph. I'll let you know (first hand) later this summer since my car will have the 2.8 trans in it.

[CO AVANT]

let me know what it is at 150mph too please.
Too bad you can't do that out there. I have never done that. I never speed.

[dougyfresh]

I have to make a few phone calls in order do to that around here.

Otherwise I'll have to wait until I come out there. Ever go to the Salt Flats? I think that would be a cool trip with the AVants.

[CO AVANT]

Roads, where we're going we don't need no stinking roads...

Salt flats would be fun....but I like to stay out of Utah as much as possible lol. No offense Sean There are a lot of paved roads with no one on them out here. And you can see for MILES

[sean1.8t]

damn you Jordan!

right when i click on the thread too

[GO-GOTEKNO]

Does the 02 sensor have any effects on the instant MPG display or does that work strictly of the inj. pulses. When driving my car the instant MPG will vary some but will always end up reading 5 MPG, even if I'm cruising at 40MPH and in 5th gear. I think I might have a lazy 02 as I only get about 200 miles to a tank no matter how I drive it and my buddy said I had flames coming out the back so it's obviously rich.

I have the exact same problem and it is killing me ...Is it the 1st one or the secondary?

[CO AVANT]

primary, 1st one

[CO AVANT]

damn you Jordan!

right when i click on the thread too

Sorry buddy.

[dirtybrd]

Jordan, you have PM.

[F16HTON]

Bad O2 sensor will cause it to run rich as fuck...almost to the point of misfires.

What are your A/F readings?

There is a test you can do to test the O2 sensor to see if it is performing properly. I do not have the specifics because I am in Texas right now and my Bentley is on my laptop at home. Basically you remove it from the testpipe/cat and measure the voltage going across it with a multimeter in free air.

Most likley the DTC that is associated with it has been disabled so you will have to revert back to good old American troubleshooting.

Pull your plugs and see if they are wet...only do it with the motor lukewarm or cold though...no need to ruin a head.

[F16HTON]

It would only be the primary...all the secondary does is report catalyst efficiency...

[dougyfresh]

Roads, where we're going we don't need no stinking roads...

In that case, I'm going to get myself a Mr. Fusion for the AVant.


Should hit 400awhp then!

[F16HTON]

Instead of doing the worthless 2.8 mod, would I can see about having few taller 5th (and 5th + 6th) gearsets brought over...

Same final result of lower cruising RPM without the shitty midrange gearing.

[sean1.8t]

how about a dogbox 6 speed w/ 1-4 gears strait cut. and 5th and 6th oem and taller?

i'd be willing to pay, oh, i dunno.... $800 for that..

sound good?

[F16HTON]

I can do that but it would cost $15K to rent for one season, $60K to buy outright (Kraftwerk Transmission)

Of course it would have sequential shifting too. :)

[sean1.8t]

alright, you're good at this...

$900! and not a penny higher

[dirtybrd]

Bad O2 sensor will cause it to run rich as fuck...almost to the point of misfires.

Remember we were talking over AIM about misfires I was having, I tried plugs, coils, CTS and harness. It went away about 90% after I put the cams in, thus leaning it out.

[dirtybrd]

I tried another 02 sensor ,not yours Jordan, but I did receive it and will try it also. Nothing changed. Still reading 5 MPG, still getting small misfires when transitioning from off to on boost, and first start up in the morning. It still stalls (5 times on the way to lunch) and won't start when the engine is hot without giving it some throttle. I need help. I've been thinking of switching back to NGK 7s instead of the FR5DTC I'm running. Or drilling a hole in the throttle plate to lean it out @ idle.

[SlappyB6]

Have you checked to make sure none of your vacuum lines or intake/lines are clogged, leaking or cracked? And did you check for correct gapping on the plugs? (I'm sure you did). Just throwing out ideas. Clogged injectors?

[dirtybrd]

Everything appears to be fine, FR5DTC can't be gapped.

[SlappyB6]

I'm gonna guess something electrical then. Bad ground or sensor?

[dirtybrd]

Anyone else?

[absolutegtr]

how about a dogbox 6 speed w/ 1-4 gears strait cut. and 5th and 6th oem and taller?

i'd be willing to pay, oh, i dunno.... $800 for that..

sound good?

The sound of straight cut gears......

[CO AVANT]

What about trying to plug a random maf back in? What about testing the voltage of the 02 sensor plug with a voltometer?

[dirtybrd]

I removed my MAF connector. I never had any issues until the turbo blew and I sent my ECU out for the 8500 file. I really think there is an issue with my flash. I just changed my plugs back to NGK 7s to see if they help.

[jessefrank]

Heh, CO Avant or Greg
Do you know the procedure for checking the front O2 sensor or what readings to check for with the Voltometer?

I'd like to see if mine is working before i bite the bullet and replace it (I've had some issues that I think my be related to the O2. Just looking for a waty to test it since I don't have acess to VAG COM)>

Thanks,
Jesse

[CO AVANT]

you could always have Dirtybrd (Chris) send you the one I sent him and try it out. Then send it back to me. I forgot the specs on the 02 sensor plug voltage. I'll try to find it. PM diagnosticator, he might know off the top of his head...

[dirtybrd]

I did a little Vagging today.
@ idle channel 001 -28.1 and in boost 20
@ idle channel 031 .930 and in boost 1.991
What do you guys think? I only have 3 sensors that regulate fuel, 02, CTS, and MAP. I tried another 02, no change. My CTS and the connector are new and soldered in. So I thought my MAP sensor might be reading boost all the time but it was 1000 mbar and 1010 mbar at idle. I'm lost. I guess I need to do some old fashion diag. I have two small pre-turbo exh. leaks but I don't think it would affect it that much plus it's been like this before the leak started. Today I filled up 15.5 gallons and got 188 miles to the last tank. That's just under 12 MPG.

[F16HTON]

Call me Chris, you are running rich as fuck...surprised the plugs are not fouled. I ran into this situation with a GTRS on a 337 that I installed, it was seeing the same O2 readings and was the primary O2 sensor that was bad.

[dirtybrd]

I got a primary 02 out of used car from work, it had about 60k on it but it might be bad also. Jordan did send me a spare 02 he had and told me that he got the same values from it as a new one. I guess I'll try that one to see if it helps, if not I'll call you, I still have your number.

[F16HTON]

Don't even waste you time taking readings...put the new sensor in and replace the plugs. Everything should be A-OK. May take a bit for the ECM to adapt.

[dirtybrd]

I'll do it tomorrow. I just didn't want to spend $130 on a new 02 without being sure. I just hope it works, in the morning it sounds like a bridge ported rotary, rut, rut, rut and the stalling is rediculous. It always happens with people in the car, and they ask how I can have almost 10k in a motor and it stalls. Very sucky!

[A4TL]

yah i replaced my old o2 sensor and guess what no trim changes.

waste of $160 (too much i know).