Car's running extremely lean

MAC'n89Blckstng

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Jun 11, 2003

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Jul 20, 2004

#1

• Jul 20, 2004

• #1

I just got my Air/Fuel ratio gauges hooked up and after 5 minutes of driving the guages slowly shows a lean combustion to the point where none of the LED's are lit any more resulted by an extremely lean air/fuel mixture. Anybody know what could cause this? My oxygen sensors are about 6 months old so I'm pretty sure thats not it. Could a bad EGR valve cause my car to run extremely lean?
Thanks,
Jesse

 

shttygtstang

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#2

• Jul 21, 2004

• #2

what kind of gauges you use if there auto meter there junk and not right pull a plug that will tell u more than any gauge could clean your maf also that might help

 

Hawkeye_306

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#3

• Jul 21, 2004

• #3

I am trying to figure out a similar problem. My a/f gauges are always on the lean side. Has anyone had good luck running a/f gauges off the same O2 sensor the computer uses? I wonder if piggybacking a gauge on the EEC circuit causes the voltage to be split between the two—there must be some internal resistance in the gauge.

Granted, I could just be running lean (still tuning), but I think the question is still worth asking.

 

P

proxses

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#4

• Jul 21, 2004

• #4

Hawkeye_306 said:

I wonder if piggybacking a gauge on the EEC circuit causes the voltage to be split between the two—there must be some internal resistance in the gauge.

Click to expand...

Splitting the wire like that is like wiring the two in parallel. Both the computer and A/F gauge will see the same voltage. But the current required for the wire to transfer will increase. Not a big deal.
Many people run A/F gauges, so it might be one bad gauge.

 

HISSIN50

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#5

• Jul 21, 2004

• #5

unless you run a wideband o2 set up, dont infer much from the A/F gauges.
my two cents worth.

 

Hawkeye_306

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#6

• Jul 21, 2004

• #6

Good call, I`m an idiot. I suppose the ideal a/f gauge would have infinite resistance to have the least effect on the circuit.

 

BlackFox5.0

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#7

• Jul 21, 2004

• #7

Autometer a/f gauges are just a light show. They are totally innaccurate. I have a Tweecer and it is able to tell me O2 voltages, and an a/f based on that, and it's way way off.....The O2s are not made to be accurate, they just give the computer an idea of where it's calculations are off, and uses the feedback to correct.

 

MAC'n89Blckstng

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#8

• Jul 21, 2004

• #8

HISSIN50 said:

unless you run a wideband o2 set up, dont infer much from the A/F gauges.
my two cents worth.

Click to expand...

Autometer says that you cannot use an Air/Fuel guage if your car is equipped with a wideband 02 sensor. And if the guage is innacurate, then why would Autometer say that the gauge is extremely accurate, are you guys just saying this from personal opinion or are you an expert? Not trying to flame you or anything.

 

jrichker

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#9

• Jul 21, 2004

• #9

MAC'n89Blckstng said:

Autometer says that you cannot use an Air/Fuel guage if your car is equipped with a wideband 02 sensor. And if the guage is innacurate, then why would Autometer say that the gauge is extremely accurate, are you guys just saying this from personal opinion or are you an expert? Not trying to flame you or anything.

Click to expand...

How do you spell M.A.R.K.E.T.I.N.G? The Marketing department is where all good technical people go to become corrupted.
Say anything that remotely resembles the truth about a techincal product and that's called marketing.

The A/F gauges that use the O2 sensor signal will jump all over the place. The reason is that the O2 sensors "switch" between .2 volt lean and .6 volt rich with a curve that looks like the drop off a high cliff. The curve is almost straight up and down, so the voltage shoots from .2 to .6 and back down again 2 or more times a second at cruse.

 

Hawkeye_306

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#10

• Jul 21, 2004

• #10

Even if the gauges are inaccurate for determining actual a/f ration, they still tell you what the computer thinks the ratio is. It is beneficial to know both what is really going on, and what the computer thinks is going on. That’s worth the cost of the gauge to me. Just my opinion.

 

MAC'n89Blckstng

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#11

• Jul 21, 2004

• #11

Can anybody tell me what could be causing my car to run lean? I'd like to find out.
Thanks,
Jesse

 

K

kevsstang

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#12

• Jul 21, 2004

• #12

Did you pull the plugs on the car? Also if you have an open air K&N it could make it run a little lean. I was told that information because i am having the same issue. I have a thread going on this site called Please with a lean condition. check there some info has been posted by others and the links are for you to check out. Good Luck

 

MAC'n89Blckstng

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Jul 21, 2004

#13

• Jul 21, 2004

• #13

kevsstang said:

Did you pull the plugs on the car? Also if you have an open air K&N it could make it run a little lean. I was told that information because i am having the same issue. I have a thread going on this site called Please with a lean condition. check there some info has been posted by others and the links are for you to check out. Good Luck

Click to expand...

hmmm, good thought about the plugs, I may have them gapped to wide. The company that makes my coil says that I can have a .060 gap on my plugs, maybe I should close that up a little bit? I have the stock intake with the air silencer removed BTW. I'm still in for any feedback from anyone.
Thanks,
Jesse

 

BlackFox5.0

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#14

• Jul 21, 2004

• #14

Here is what I have datalogged. If you tell my the stock O2s are accurate, even after you see the numbers, then your beliving what you want....

Here is a datalog of my left (DS) O2, just look at the flucuation.

The numbers on the right are voltages from the O2's, the numbers on the left is the RPM

3688 0.617646992
3976 0.593232572
4080 0.507782042
4256 0.385709882
4272 0.112268202
4440 0.087853767
4800 0.114709646
4920 0.632295668
5176 0.707980454
5176 0.707980454
5504 0.46627751
5504 0.46627751
5808 0.070763662


FYI some wideband modules (not the sensor) can output to the autometer gauge so that it IS accurate. I forget which one though...