Engine Correct MAF For 1993 Cobra X3Z ECU

ZephyrEFI

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Alright, so recently I bought a 70mm Cobra MAF that said it was "calibrated for 19# injectors". I noticed that it had a sensor on it with AFH55 on it, so I knew that was wrong. Mostly, I was just trying to make sure I had the right housing to use with my stock '90 GT cold air setup. Previously, I had bought a 70mm '94-5 MAF, so I was able to swap over the sensor from that one with the AFH70 number on it. ANYWAY, I've gone to an Explorer intake and throttle body, 24# injectors and an X3Z Cobra computer. Mostly Cobra spec stuff, right? I'm wanting the correct MAF to run with that computer, hence getting the 70mm one.

But, here's the thing. That sensor that came with my '94-5 housing is an F2VF. I've read elsewhere here on Stangnet that the F2VF and 70mm housing are a known, good combination with an A9L and 19# injectors.


My question is, does that make it the WRONG one to use with the X3Z and 24# injectors? I would have to guess yes!

Further complicating things, I was looking at the reman MAFs available out there for the '93 Cobra. Cardone claims the '93 Cobra, R, and GT/LX can all use the same 70mm MAF. You and I know that's not correct, so what the hell are they talking about?!

If I run the car as is, it will not idle. Like, at all. It rolls up and down like 1000 rpm. Not even close. Is a mismatched MAF the reason for that? I've looked for vacuum leaks, and haven't found any. I know about all the volumes that have been written about getting the SEFI 5.0L to idle, but I don't want to bother with any of that if I don't have the right MAF!

Thanks
 
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Mustang5L5

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Yes, it's wrong to use the electronics from the F2VF and the E3Z. The maf sensors themselves use a different transfer function and are not compatible.

If you compare the curves between the 93 cobra MAF and the 94 town car (uses F2VF MAF), you'll see they differ.


What heads are you running? Why not just stick with the 19# injectors. You can purchase a 91-93 cougar/tbird housing on Ebay and use the 70mm sensor from the 94-95 Mustang. I'm 99% sure the sensor is actually the same but cannot confirm this. Anyway, the cougar sensor housing is similar to the Mustang without the 4-bolt flange, so it will work in a Mustang stock intake tube.


I ran very similar mods as you with the 70mm SN95 MAF (with an adapter) and 19# injectors
 

ZephyrEFI

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Alright, now we're getting somewhere!

Sorry, I should've included that. I'm running GT40P heads. FTI GT40 cam. I AM planning on tuning it, but I'd like to start as close as I can get to correct for the combo beforehand. That's why I went to the 24s, so the X3Z would see what it expects to.
 

ZephyrEFI

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On your link I loaded the stock Fox and '93 Cobra curves, and they look pretty dang different as well. What are your thoughts on Cardone's assertion that GT/LX and Cobra MAFs are the same?!
 

Mustang5L5

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Well Cardone is wrong. There definitely is a unique MAF for the 93 Cobra. It needs to be used with the X3Z computer.

There are other ways to compensate for the 24# injectors, but if you set on using the X3Z ECU, you need a cobra MAF. Personally, I would prefer to use a A9L so i'd ebay off the X3Z and buy a quality aftermarket MAF for 24# injectors and run it with the A9x ECU and call it a day.
 

ZephyrEFI

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I emailed Cardone to see what they have to say.

Prices for ECUs being what they are, and the with the risk of getting a bad one from Joe Schmo ebay seller, I think I will stay with what I have
 

Mustang5L5

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Roger.

In that case really to answer the question as we need to know if the MAF transfer function of the f2vf sensor is the same as the original 1993 cobra MAF sensor? Hard to answer that without specialized equipment.

I have heard that even the f2vf sensor on a fox isn’t 100% right but is “close enough”
 

ZephyrEFI

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Oh, I meant that I'd like to probably get a reman MAF, but hopefully Cardone gets back to me with a good answer on whether the one they show for the Cobra is actually that, and not wrong, seeing as how they also list if for the GT/LX. I'd like to buy a MAF from someone who will be accountable if it's wrong. I notice Walker doesn't make the same claims. Maybe I'll just buy from them.
 

Noobz347

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I AM planning on tuning it

This portion makes the transfer curve irrelevant so long as the curve of the MAF is reliable. This assumes that you are tuning it from the first start. If not, any MAF that will get you close-ish will get the car onto a trailer.

If you're getting it tuned, I would bypass all of the Ford ECUs and put that money toward something easier to tune with an exponentially faster processor. If this portion becomes true then what meter your run becomes even less important.
 

vristang

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If a parts supplier says the GT/LX 5.0 used the same MAF housing and/or MAF Sensor as the 93 Cobra, then their database is WRONG.
Try checking on RockAuto, they usually have the correct part number/application, from my experience anyway...

The 'correct' sensor for a 70mm Ford housing, with an X3Z ecu, and 24Lb injectors... will start with an F1SF part number. I think I have seen this sensor available on other vehicles, but can't recall specifically...

The F2VF sensor and the F1SF sensor have significantly difference calibrations. Not interchangeable. Some folks have claimed mix-match setups work just fine, but I can't see how it would work properly.
If you do a search here for MAF Transfers, you should be able to find those transfer curves posted here. If not, maybe searching the Tuning section will find it?

Similar question from another poster... a while back...
There is a link in this thread that has the MAF Transfer posted for each of the factory sensor, and cobra sensor...
 

ZephyrEFI

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This portion makes the transfer curve irrelevant so long as the curve of the MAF is reliable. This assumes that you are tuning it from the first start. If not, any MAF that will get you close-ish will get the car onto a trailer.

If you're getting it tuned, I would bypass all of the Ford ECUs and put that money toward something easier to tune with an exponentially faster processor. If this portion becomes true then what meter your run becomes even less important.
I'm not that knowledgeable about tuning, but my goal has been to start with a "tune" that's as close to what the car will like as possible. That's why I collected the Cobra stuff that I did. I don't want to have to start from scratch, or be in the position to have to make big changes. From what I've seen so far about tuning, many plan on building a whole new tune, reading what the sensors are saying and how the car reacts. I really don't want to have to do that if I can avoid it.

That's why I didn't go to a Megasquirt, and that's why I'm wanting the correct MAF here. But maybe I'm dead wrong about what you can do with tuning software and that's not even possible, I don't know. I already own the Quarterhorse and chip, but they're not installed yet.
 

Noobz347

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I'm not that knowledgeable about tuning, but my goal has been to start with a "tune" that's as close to what the car will like as possible. That's why I collected the Cobra stuff that I did. I don't want to have to start from scratch, or be in the position to have to make big changes. From what I've seen so far about tuning, many plan on building a whole new tune, reading what the sensors are saying and how the car reacts. I really don't want to have to do that if I can avoid it.

That's why I didn't go to a Megasquirt, and that's why I'm wanting the correct MAF here. But maybe I'm dead wrong about what you can do with tuning software and that's not even possible, I don't know. I already own the Quarterhorse and chip, but they're not installed yet.

We'll send out a ping to @a91what

He's one of those 'Piled Higher and Deeper' (PHD) digital tuning dudes. He may be able to better see a good path forward using the majority of what you already have.
 

ZephyrEFI

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If a parts supplier says the GT/LX 5.0 used the same MAF housing and/or MAF Sensor as the 93 Cobra, then their database is WRONG.
Try checking on RockAuto, they usually have the correct part number/application, from my experience anyway...

The 'correct' sensor for a 70mm Ford housing, with an X3Z ecu, and 24Lb injectors... will start with an F1SF part number. I think I have seen this sensor available on other vehicles, but can't recall specifically...

The F2VF sensor and the F1SF sensor have significantly difference calibrations. Not interchangeable. Some folks have claimed mix-match setups work just fine, but I can't see how it would work properly.
If you do a search here for MAF Transfers, you should be able to find those transfer curves posted here. If not, maybe searching the Tuning section will find it?

Similar question from another poster... a while back...
There is a link in this thread that has the MAF Transfer posted for each of the factory sensor, and cobra sensor...
Thanks!

I found another complication. The stupid Walker one says it replaces factory part number F1SZ, not F1SF. Ugh. Could that be the difference between a part number and an engineering number?

And Rockauto is where I first encountered the confusing application info. BUT, it does list both F1SZ and F1SF there for this one...
 

ZephyrEFI

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Haha, look for yourself! It says 1991-1993 Mustang when you click on the number.

I went ahead and ordered the Walker one from Rock since it was cheaper anyway. I'm pretty sure they're both the right one. I just want to move this forward.
 

Mustang5L5

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Thanks!

I found another complication. The stupid Walker one says it replaces factory part number F1SZ, not F1SF. Ugh. Could that be the difference between a part number and an engineering number?

And Rockauto is where I first encountered the confusing application info. BUT, it does list both F1SZ and F1SF there for this one...
The part number on the electronics of the 93 Cobra MAF is F1SF-12B579-A. It's actually the same MAF used on the 92-95 T-bird Super Coupe, hence the "S" in the engineering part number which stands for the Thunderbird line. This is the only 70mm unit and the electronics will say AFH70 on them

Standard Mustang MAF for 91-93 is F1ZF-12B579-AA, where the Z = Mustang.
89-90 Mustangs use E9ZF-12B579-AA sensor
1988 CA Mustangs with MAF use a unique 5-wire (but only 4 pin) sensor E8ZF 12B579-AA,
The above three are 55mm housings and the electronics will say AFH55 on them.

A 90-93 2.3L sensor is F0VF-12B579-A2C and says AFH45.

I'm sure nobody cares about a 2.3L sensor or the standard 5.0 sensors but this thread will probably come up in a search one day (probably by someone who normally seeks help via Facebook) and might as well have all the complete info.
 
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ZephyrEFI

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Yeah, thanks! Great info.

I hadn't been able to prove the F2VF sensor was RIGHT, but I hadn't been able to prove it was WRONG either, haha.
 

vristang

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The part number on the electronics of the 93 Cobra MAF is F1SZ-12B579-A.
How confident are you in the F1SZ number? My notes are that the 93 Cobra used an F1SF sensor... but I've forgotten damn near everything I once knew...
I don't recall how to break down the Ford engineering numbers anymore either, so it could be that F1SZ is directly interchangeable with F1SF?
 

Mustang5L5

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How confident are you in the F1SZ number? My notes are that the 93 Cobra used an F1SF sensor... but I've forgotten damn near everything I once knew...
I don't recall how to break down the Ford engineering numbers anymore either, so it could be that F1SZ is directly interchangeable with F1SF?

I copied wrong. It is F1SF. However, in googling, it does appear F1SZ may exist. It may be a service replacement part

F = electrical and electronics
Z = Service part.
 
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