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EFI Failed emissions test

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Pedestrian

Pedestrian

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Sep 10, 2008
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I don't wanna seem like I'm insulting your intelleligence, but are you running the H.O./5.8 firing order with your wires? That could be were your miss is coming from, rather than just timing? Again, just throwin possiblities out there. Hope you find the gremlin!

Not much chance of insulting my intelligence, if I was that sensitive I wouldn't post up asking for help. ;)
Firing order is correct for H.O.
 
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Pedestrian

Pedestrian

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From the numbers shown it is definately running very lean across the board.
No vacuum leaks, fuel pressure is spot on.
What could make it run lean? Bad MAF, Bad O2s.
 

70_Steve

Old Guy
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Dec 13, 2002
Messages
8,317
What could make it run lean? Bad MAF, Bad O2s.
I initially had lean issues with my EFI. Turned out to be the MAF housing that someone had ported to 59mm (damn Ebay stuff) instead of the stock 55mm. Plugs showed way lean, but exhaust smelled very rich. This was a new install so it could have been anything. Lucky for me during my parts gathering for the swap I picked up an extra MAF as part of a package deal with some other parts. Swapped sensors between them with no change. But as soon as I swapped housings the engine idled perfecty and my lean codes went away.
 
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Pedestrian

Pedestrian

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I initially had lean issues with my EFI. Turned out to be the MAF housing that someone had ported to 59mm (damn Ebay stuff) instead of the stock 55mm. Plugs showed way lean, but exhaust smelled very rich. This was a new install so it could have been anything. Lucky for me during my parts gathering for the swap I picked up an extra MAF as part of a package deal with some other parts. Swapped sensors between them with no change. But as soon as I swapped housings the engine idled perfecty and my lean codes went away.

Same MAF I passed the test with last year. I did submarine the engine so I suppose it is possible I damaged the MAF or the O2s. I will try pulling codes and see what I get.
 

needabronco

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Get a can of MAF cleaner and go to town on the sensor and the housing. Also clean out your intake plumbing. It makes a very big difference on my Bronco when the MAF is clean.
 
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Pedestrian

Pedestrian

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Get a can of MAF cleaner and go to town on the sensor and the housing. Also clean out your intake plumbing. It makes a very big difference on my Bronco when the MAF is clean.

That's the first thing I did Casey.
Pulled codes, but not sure if I am doing it correctly. I get two flashes to start with. Is this code 11 or is it a 2 for 28 the first code?
 

70_Steve

Old Guy
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That's the first thing I did Casey.
Pulled codes, but not sure if I am doing it correctly.
From OldFuelInjection.com

How To Count “Check Engine” Light Blinks

When the “Check Engine” light blinks during the test you will get several different blinks, the separation time between blinks is used to indicate what information is being displayed.

Turn key to RUN.
You will hear some relays engage and the fuel pumps prime the system. This is the EEC beginning the test.
The fuel pumps will stop and the EEC will now begin giving codes.
You may catch a brief flickering of the light. This is a rapid code read that is used by the code readers you can purchase. Do not worry all those rapid flashes you just say flicker buy will now be given at a slower pace of �, 2, & 4 second pauses.
First digit of first KOEO code (1/2 second between blinks)
2 second pause
Second digit of first KOEO code (1/2 second between blinks)
4 second pause
Next KOEO code
Once all KOEO codes are read the EEC will repeat them
6 second pause
Single Separator Blink (this indicates the change from KOEO codes to CM codes)
6 second pause
Codes from Continues Memory (uses same 1/2, 2, and 4 second timing as KOEO codes and also repeats them)
If nothing has been recorded by the EEC since last battery disconnect you will see:

Blink – 2 sec – blink – 4 sec – blink – 2 sec – blink – 6 sec – blink – 6 sec – blink – 2 sec – blink – 4 sec – blink – 2 sec � blink

This translates into 11-11 current condition (KOEO) and 11-11 in the continues memory (CM); or SYSTEMPASS
 
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Pedestrian

Pedestrian

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Retarded the timing back from 12 to 8. Installed a Mustang MAF sensor in the existing Explorer MAF housing.
Passed with flying colors:
CO .22 standard 5.0
HC 303ppm standard 450ppm

Looks like its even leaner with this setup so I put everything back to where I had it before. I now have another year to try and locate the 95 GT 70mm MAF assy I have misplaced.
See you all at the Stampede ;D
 

Viperwolf1

Contributor
electron whisperer
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Aug 23, 2007
Messages
24,448
Retarded the timing back from 12 to 8. Installed a Mustang MAF sensor in the existing Explorer MAF housing.
Passed with flying colors:
CO .22 standard 5.0
HC 303ppm standard 450ppm

Looks like its even leaner with this setup so I put everything back to where I had it before. I now have another year to try and locate the 95 GT 70mm MAF assy I have misplaced.
See you all at the Stampede ;D

What MAF were you using and which one is in it now?
 
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Pedestrian

Pedestrian

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What MAF were you using and which one is in it now?

I was hoping you would chime in on this VW.
I'm running the MAF and airbox from an Explorer 5.0 97 or 98
I know it's not perfect, but I'm still trying to find the 95 Mustang MAF I misplaced, I hate buying parts I know I have already.... Somewhere :(
 

AZ69EB

Sr. Member
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Jun 8, 2006
Messages
680
Congrats on passing the AZ emmisions! What day are you planning on heading north to the Stampede? I'm planning on being there Wednesday night.
 
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Pedestrian

Pedestrian

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Congrats on passing the AZ emmisions! What day are you planning on heading north to the Stampede? I'm planning on being there Wednesday night.

Shooting for Wed as well. I fouled up my reservation for the camper can't get it till Friday evening so I will be tenting it :(
 
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Pedestrian

Pedestrian

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Update, I located a 95 Mustang MAF that bolts up to my existing airbox. I don't have solid numbers but seat of the pants says it is much happier than the Explorer MAF I was using. We'll see how it does next year at the emissions station
 

Ranchtruck

Sr. Member
Joined
Feb 7, 2008
Messages
768
I know it wasn't your issue, but I figured I'd add to the initial O2 sensor location discussion. If you run an electrically heated O2 sensor, you can put it further back without issue. Think of the wideband probe a dyno uses, they put it in the tailpipe and it works fine. The 9-12" is for non heated O2 sensors which only read right when they are hot enough. Put them too far from the exhaust ports and the sensor will never heat up because the exhaust gasses have cooled too much by the time they reach the sensor. With a 3 wire or more sensor it has a heater so there's no restriction on placement.
 
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