70mm TB and EGR issues

['88 5FOX]

I just had to wind up converting my car back to all stock (motor wise) because my mas air conversion wasn't working out like the instructions said. I can't figure out the signature thing so I will just tell what I have going on.

My car is a 88 lx 5.0, 3.73 gears, aod to 5-speed conversion, explorer upper and lower, 19lb injectors, BBK H-pipe, BBK headers, Flowmasters with dumps, and smog delete.

I have completely turned my car back to speed density. Need to be driving(missing the power). The only thing that is not completely stock at the moment is the TB and EGR spacer. I bought a 70mm TB and EGR spacer by professional products to put on the car. The TB came with an adjustable TPS plate. very annoying. haven't had the time to set that up correctly. But my question is do I have to have the car tuned with these new parts or will I have to have it tuned.

Plenty of power at wot w/ slight hesitation. Lot of hesitation at idle and take off. Any help appreciated.

Would also like some help on how to do the signature thingy.

 

[Mustang5L5]

No need fpr tune with those parts. Car should run fine.


When yup did the maf conversion, did you use a 5 spd mass air computer? If so, did you change the o2 harness to a 5spd o2 harness? If you tried to use a 5spd computer with the aod o2 harness, you would have issues.

 

[NIKwoaC]

No need fpr tune with those parts. Car should run fine.


When yup did the maf conversion, did you use a 5 spd mass air computer? If so, did you change the o2 harness to a 5spd o2 harness? If you tried to use a 5spd computer with the aod o2 harness, you would have issues.

+1. Those modifications aren't extreme enough to need a MAF conversion or a tune.

 

[cjrpony]

For the signature, go to User CP at the top of the page and then choose Edit Signature on the list on the left side of the following page.

 

['88 5FOX]

I ran the numbers to the computer and came up with a universal mass air computer according to google. I will put the computer number on here tonight and let yall try to decipher.

What sensor harness. the one that controls the o2 sensors? My o2 sensors haven't been hooked up for a year since I installed the h-pipe. car ran good so please don't ask how its running without them. Ran great for a year and when I installed the mass air it may have recognized that, not sure.

just for giggles what kind of issues would result from not having the right o2 harness.

Thanks again for the help and I will find that sig thing tonight.

 

[Mustang5L5]

just for giggles what kind of issues would result from not having the right o2 harness.

Anywhere from car running rich, idling like crap, poor fuel economy, and outright frying the computer.



technically, changing the O2 harness is not part of the Mass air conversion process. It's part of the 5-spd conversion process. There are two way to do the conversion...quick and easy, or factory correct. Quick and easy just uses the AOD computer and harnesses, while the right way changes the computer to a 5-spd EEC, changes the o2 harness to a 5-spd o2 harness, and changes the undercar transmission harness to a 5-spd harness including the provision for the NSS (what i was getting at in my other thread you had read)

Problem is most people do it the quick and easy way..myself included. That leads to problems when doing a mass air conversion because you really need to do it the factory correct way before swapping to mass air.

The o2 harness, believe it or not, has part of the nuetral safety circuit running through it, and depending on 5-spd or AOD, it's actually pinned out differently. The issue is that on one EEC, it's expecting a ground on pin 46, while on another, it's expecting voltage. The problem comes when you put voltage on what should be a ground. It causes issues and sometimes fries the computer. THIS is why the o2 harness matters a lot.

Now, not sure what instructions you followed for the MA conversion, but these are the basic instructions
Mustang Mass Air Conversion | StangNet

Now, those are right, but because you did a 5-spd swap, you gotta add in the o2 sensor part on your own since it technically should have been done during your 5spd swap.

Of course, before we go there, we need to identify what computer you used. Look for a 3-digit code on the box, like A9L, A9P, A9T, E3M, A9M, etc. That will help ID it.

The o2 harness can be repinned, and like i said in my other thread, you can jump Pin 30 temporarily to bypass not changing out the trans harness in order to read codes.

Also, not running o2's in general is hit or miss. The car can run fine, but fuel economy tends to suffer. Speed density is a little more forgiving in not having the O2's, which is why the car drove okay, but mass air isn't from what i've read. Might be another reason why the conversion didn't go so well.

 

[NIKwoaC]

No offense buddy, but I just don't understand why people think they can just remove/eliminate fundamental EFI sensors/components and expect the car to run right. And then get confused when they can't get the car to run right...? O2 sensors are a CRITICAL component in an EFI system, they are fundamental in achieving the correct A/F ratio and maximizing power and efficiency.

Just because the car ran "great" doesn't mean it was running "right". Start with getting the O2 sensors hooked up, following all the stuff Mike said above.

 

['88 5FOX]

The number on the computer is
f3zf 12a650 fb, which from my findings today is the "equivalent to the automatic computer"

thanks for the info. should be helpful if i can ever get the time to work on the car.

 

['88 5FOX]

I will hook up the sensors, but the problem was that i had them hooked up but one got broke off and somehow the harness got tangled up in my steering coupler and got broke and and only afterwards did I find out why the steering got hard then freed up. never adjusted timing since I have had the car and was still knocking 21-23 mpg's with the 5-speed. still doesn't mean it was running right but got me that much anyway.

next question is does the harness for the o2 sensors run in with the main harness or is it separate. Need to plan the time to find and pull one.

thanks

 

[Mustang5L5]

That is a 1993 aod computer....so it should have worked fine without swapping the o2 harness.


The o2 harness is separate from the main engine harness. The main disconnect is on the passenger side of the car underneath where the mass air sensor would be. Disconnect it there and you can remove the harness. I believe it also plugs into the low fuel sensor.

What problems did you have when you did the conversion? How did the car run?

 

['88 5FOX]

It would idle half decent but throttle response was horrible. Took it down the road and done an awesome job at WOT. even barked third. put my new throttle body on and didn't get any better. However i know the mass air was working because with the sensor unplugged it almost wouldn't run until the sensor was plugged in. I had to have been doing something right.

think that the o2 harness being all jacked up could have been a possible cause for that.
on that note the car doesn't run nowhere like it did before all this came about. even with everything back to speed density

 

[Mustang5L5]

Well, if the o2 harness is hacked to hell, it would be a very plausible cause for running like crap

 

['88 5FOX]

thanks for the info, gonna get a harness and see what turns up