Some help with a MAF conversion

[dreamison]

Hello,
I am finishing up a MAF conversion on my 91 f150 5.0 4x4 With E4OD. I am using a computer from a 95 bronco its a WAY1. My problem has to do with the O2 sensor. According to ford fuel injection website I have a 3 wire O2 sensor but mine is actually a 4 wire. Also according to them the 95 has dual 4 wire O2 sensors. I was planning to split the signal from my single sensor into the two pins #43 and 44 in my eec connector. the problem I am running into is that on the wire diagram for the 95 truck they show two sensors running to pin#43 and 44 but on the pin out sheet they only show the O2 signal going into pin #44. Its simple enough to split it into the two pins however pin #43 on my 91 connector already has a solid purple wire in it. I cant seem to figure out what this wire is as there is no reference to it on the wire diagram and the pin out sheet for 91 shows it empty. Does anybody know what this wire is? I tried to trace it back and it runs into the harness towards the radiator. Any help sorting this out would be appreciated.

 

[dreamison]

Here's a thought. For the guys out there with 95 f150's do you have one or two O2 sensors? They swore to me at oreilly that I had two on my 91 according to their computer.

 

[dragogt]

Sorry man I can't help ya..

 

[conanski]

According to some info I have and the diagrams on fordfuelinjection.com pin 43 on the trucks is a WOT AC clutch disconnect.

 

[dreamison]

If it is the a/c disconnect would it move to a different pin on the 95 computer? From what I have been able to find on maf conversions it seems like the 95 trucks only have one o2 sensor. Is this correct. The write ups say they move the o2 from pin 29 to pin 44. It appears that the mustang computers are the ones that need dual o2 inputs. I just dont want to end up running one 02 signal to the computer if I need two. I dont know how that would affect the engine but I imagine that it cant be good for the left and right mixtures.

 

[dreamison]

Sorry guys I have one other question as well. Is pin 49 the the o2 ground on the 95 truck computers as well. The pin out sheet on ford fuel injection shows that pin empty for 94 and 95 but o2 ground for all other years. Where do I groung the o2 sensor?

Thanks

 

[flareside_thunder]

I can't help you either but my 95 Mass air truck only has ONE O2 sensor.....Perhaps you've got a Mustang EEC? If you can e-mail me the wiring sheets I may be able to help you decipher what you've got going on by looking at my harness. Just a thought. Sorry I couldn't be of any more help and welcome to the site. I'm part of the latenight crowd so I'm usually on until 3 or 4 am EST. Also, reference this page for your pins...looks like the 95 mass air computer is empty on pin 43. http://www.fordfuelinjection.com/truckpinouts.html

 

[conanski]

According to my Chiltons manual on the '92-94 SD trucks the HEGO is on pin 29 with sig-rtn on pin49. On the '95 MA trucks the sensors occupy pins 43 & 44 with sig-rtn tied to pin46 and pin49 is empty.

 

[dreamison]

Thanks for the response, my confusion was coming from the diagrams on ford fuel injection. They show a dual O2 sensor setup on the engine harness for 95 trucks but I found out today at the dealer that trucks up to 95 only ran one o2 sensor and then three in 96. The only other question I have is where to ground the o2 sensor. My 91 computer has a specific ground pin for it at pin 49. Should I ground it to pin 60 which is the ground on the eec or just use a chassis ground.
After that I can fire it up and see what happens.

 

[flareside_thunder]

The way I see it a ground is a ground right? Unless of course the O2 Sensor ground is imperative to it's function, I don't see an issue with grounding it to the frame or chassis.

 

[Alvin in AZ]

Did you go to AutoZone.com?

What is your WAY1?
5.0 or 5.8 Fed or 5.8 Cal?
I saw where it claims a WAY1 was 5.0 computer, but is it really?

-------------------------

The Federal diagram shows one 4 wire heated sensor.
1) V/O = 12v
2) Gy/LtBu = 29(5.8 auto) 44(5.0 auto)
3) Bk = shows chassis ground
4) O = 49

{edit}
http://fordfuelinjection.com/files/bronco_1995_25-04.gif
That shows the 12v wire is Pink/Orange instead of Violet/Orange.
Also agree with AutoZone in that it's a 5.8 and Gy/LtBu goes to 29.

{edit2}
http://fordfuelinjection.com/files/bronco_1995_25-01.gif
That's does a pretty good job of showing the grounds.
They refer you to another page.
20 is the ECU's "case ground".
40 and 60 are "power ground".

---------------------------

Californicated vehicles show two sensors for '95 and are 5.8's...
1) V/O = 12v split
2) Gy/LtBu = 44
3) Bk = shows chassis ground, both.
4) R/Bk = 43
5) Gy/R = 46

---------------------------

Alvin in AZ
ps- In the Code Room we used S = Slate instead of Gy. So... Green = G

 

[dreamison]

Hey Alvin,
Thanks for the info.
I have reliable information that way1 computer is for 94-95 f-series 5.0 with federal emissions, MAF and E4OD. The 5.8 computer equivalent is a lay1. But they are wired differently. As far as the o2 sensor is wired, pin# 44 is o2 in, black is ground and red goes to rely+ but there is no reference to the to the orange wire which is labeled as o2 ground. As far as pin #49, on the 95 way1 computer that pin is occupied by the TOT(transmission oil temp) sender. I have the pinout locations specific to my way1 that I got from the dealer I will try and get it posted soon.

Here is my theory feel free to chime in... anyone...

The power in for the o2 sensor powers the sensor, the black ground wire grounds the heating part/element directly to the chassis and is kept separate from the ground for the sensor itself, I assume because it has a much higher draw to heat the sensor. The orange sensor ground grounds the more delicate sensor part of the system directly to the eec, I assume so it has a reliable common ground with the other sensors that may result in more accurate output. I know were the signal wire goes...

If this is true then I can splice the orange o2 ground into pin 40 or 60 which are both eec grounds.

What do you think?!?

 

[Alvin in AZ]

OK, doggonit I just lost a couple hours of research.
Poof, it was gone.
Took too long to save it or what?
So I'm going to have to boil it down this time.

This is from your pinout list?...
>the o2 sensor is wired, pin# 44 is o2 in,
>black is ground and red goes to rely+
>no reference to the to the orange wire which is labeled as o2 ground.
>pin #49, on the 95 way1 computer that pin is occupied by the
>TOT(transmission oil temp) sender.

>have the pinout locations specific to my way1 that I got from the dealer...
>What do you think?!?

I've never trust lists like "pinout" lists, found too many mistakes. :/

I say... go to the dealer and ask for a look at their...
"Engine/Emissions-Diagnosis 1995 Shop Manual Car/Truck"
...or buy one for yourself or something. :/

It's just a huge "folder".

The schematic you want is on the other side of the pinout list they
gave you or only one page way from it.

I have one of those folders for '91.

Mine's got a list a whole-page-long of updated pages added to it.
I see most of those "updates" as -mistake fixes- and was involved
in that sort of thing "back when" and see nothing unusual about it.

But this folder is like the "final official word" on all this stuff.

Their "update" may not have "fixed" the pinout list?
Or who knows what?

Easier to get it right the first time than to buy new parts to replace
the burned-up ones, IMO.

This one at least mentions changes in 5.0, 5.8 and Cal...
http://fordfuelinjection.com/files/bronco_1995_30-2.gif
...others in this same file make like there wasn't. :/

Others have suggested Mustang computers for exactly this reason.
If you had the parts truck instead of only the computer you'd be
$%^in' in tall cotton.

Alvin in AZ
ps- Have you posted this to FSB?
I've read about wiring problems with a WAY1 before.
Was that you?

 

[dreamison]

No have not posted in FSB yet, but have found some good info on there about this issue. Apparently there were alot more e4ods in the later broncos than the trucks. More common to have 4r70w in the truck. The last diagram helped alot, it shows the wiring configuration for the 12pin e4od connector. I verified all the wire going to my eec connector and they match.

I guess what it boils down to is that the 91 computer used an independent ground for the o2 sensor at pin 49 and the 95 way1 computer did not use an independent ground for the o2. so I am trying to figure out were to ground the o2 sensor...

 

[Lost]

Here's a thought. For the guys out there with 95 f150's do you have one or two O2 sensors? They swore to me at oreilly that I had two on my 91 according to their computer.

ALL MAf equipped trucks I had have 1 o2. My current 94 with the same combo as yours has 1 also . LIke the auto parts store computers r reliable.

But some do have 2 . Good luck on swap .