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Discussion Starter #1
What the heck with my 1995 TBird.
Bank 1 too lean and too rich and Bank 2 too lean and too rich.
500 miles on DOHC engine.
1998 Cobra Intake/ Kooks headers
True dual exhaust with H pipe.
Smoke checked engine, no vac leaks.
Installed new front NKG O2 sensors - no help.
New Walker MAF put on the car when engine installed.
Actually, the rich codes appear first, then the lean codes pop up a little while later.
But all codes will appear on the same drive.
Engine of course has been tuned and idles and runs very very well.
My tuner says the idle data log shows sometimes 14% rich and sometimes 14% lean.
So we don't know which way to adjust until we find out why the lean/rich happens.
Wide band Lambda indicates 1.0 +/- .04 at idle after full warm up to 195 F.
If I just easy drive to car, the codes usually don't show up.
If I max accelerate to highway speed from idle or city speed several times, that is when
the CEL comes on.
I hope this isn't a glitch with the LiveLink software like before.
Any ideas as to what may be wrong?
 

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7,619 Posts
I would suspect either the tune, or the MAF.
 

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Discussion Starter #3 (Edited by Moderator)
I would suspect either the tune, or the MAF.
Thank you MadMikeyL,
I'm ordering a new MAF now.
We're pretty confident about the tune being good.
 

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You need to datalog and see where and when it's doing these things.

Even looking at the stock O2 sensors would give you an idea, just when they stop switching and go rich or lean will tell you what is wrong, combined with the MAF data.

A wideband would help a lot.
 

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Discussion Starter #5
You need to datalog and see where and when it's doing these things.

Even looking at the stock O2 sensors would give you an idea, just when they stop switching and go rich or lean will tell you what is wrong, combined with the MAF data.

A wideband would help a lot.
Thank you Grog6.

New MAF arrives next tuesday.
I pulled my MAF to use as a core for the new one I ordered today.
Will do another data log then.
 

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Post it up; there's several of us who do tuning, and have tuned our own cars.
If you are using an xcal2 to tune with, there's a tutorial on datalogging in the EEC thread.

We're not going to bash on anyone, we're amateurs as far as that goes.

And we don't want to be responsible for some idiot thinking he can run pump gas, 15:1, and 19lb injectors. With a stock maf on his 5.4l swap...


We can read a datalog, tho, because we've done a lot of it. :)

It could be as simple as some perimeter invoking a table that isn't set, or an adder that isn't set.

It could even be in the EEC itself, as 95 eecs are known for hanging open injectors.
A noid light set is the way to check that problem.

I'm assuming 95 EEC because you didn't specify. :)

BTW: If the lean part is at high rpm, DO NOT go WOT or you are likely to break something.

The normal operating mode for a bad tune is rich as fsck at idle transition, good thru the midrange, and leaning out the higher you go.

That breaks pistons by making them holy. :)
 

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Discussion Starter #7
Thank you Grog6 for the generous offer to read my data log.
When I get the new MAF installed . I will take you up on that.
My EEC is a 95 (my manual calls my computer a PCM, so I hope we are talking about the same thing)
I have the Noid light test kit and my wiring passed.
I have brand new 24lb. Ford/Bosh blue top injectors and they passed the injector pulse test and all measured 14.7 ohms.
The last two data logs I have did not catch the switch from rich to lean.
The first log data log was Idle and free rev. Done as one continuous log, idle log was 14% rich.
The second log later that day was WOT. Before going WOT, it was idling 14% lean.
According to my tuner, WOT numbers are good.
So between the first log and the second log the lean/rich idle thing happened
 

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Super Moderator
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12,423 Posts
I'm almost out of MAF on my Lightning 90mm. Any suggestions? :p

In regards to "And we don't want to be responsible for some idiot thinking he can run pump gas, 15:1, and 19lb injectors. With a stock maf on his 5.4l swap... "

I’ve got a friend who thinks he can run E85 gas, 11.5:1, and 60lb injectors with a 90mm Lightning MAF on his 5.3L swap. I know it’s not a 5.4L but is it close enough? ... asking for a friend. ;)
 

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Yeah, I know what Friend Tuned you car, TM. :)

And I guarantee you he didn't do it at idle, and open rev. That's basically useless.



OP, You need to drive the car, gently, to do the actual tuning. Or use a Dyno.


Here's a website that can help:



I'd bet his mail tune wouldn't be 14% off.
 

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Premium Member
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Discussion Starter #10
I would suspect either the tune, or the MAF.
Right you are MadMikeyL, removed the new MAF that had 500 miles on it
and installed a NAPA remanufactured MAF.
No check engine light - or error codes- for almost 60 miles over the last three days.
Good call and thank you.
BTW, my MAF is a stock Lincoln Mark Vlll MAF not a 90mm Lightning that I think others may have
misunderstood since I wasn't clear on that. My bad.
 

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Right you are MadMikeyL, removed the new MAF that had 500 miles on it
and installed a NAPA remanufactured MAF.
No check engine light - or error codes- for almost 60 miles over the last three days.
Good call and thank you.
BTW, my MAF is a stock Lincoln Mark Vlll MAF not a 90mm Lightning that I think others may have
misunderstood since I wasn't clear on that. My bad.
Glad you got it figured / worked out.

My apologies, I kind of hijacked your thread. I was joking about my own engine. I have the 90mm Lightening MAF. I was joking about it nearly not being enough for my engine. (Which is true ... I am almost out of MAF capacity under WOT.) 😲
 

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Discussion Starter #12
Glad you got it figured / worked out.

My apologies, I kind of hijacked your thread. I was joking about my own engine. I have the 90mm Lightening MAF. I was joking about it nearly not being enough for my engine. (Which is true ... I am almost out of MAF capacity under WOT.) 😲
No apology needed TM.
This site has helped me out so much.
I could not have built my Bird without you and all of TCCoA's help through all these years.
Ya'll make me proud to be a member.
 
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