Explorer swap sensor confusion!!

I've been reading literally hundred of posts in forums and there seems to be (or I seem to be) confusion about using the stock explorer sensors when doing a swap.

I'll be swapping a 98 explorer 5.0 engine and want to use as many of the sensors as I can. I'll be using a A9* computer. Here's where I'm confused.

1. Some say the explorer TPS is different from the mustang and it has to be swapped.........some have used the explorer TPS though. Are they using the mustang TPS just because of the plug, or does it really send a different signal?

2. I'll be using the explorer TB, fuel rail, and injectors; I've read that I need to use the 94-95 mustang 70mm MAF. Will this work with my A9* computer, since it's from and earlier mustang?


Here are some other things I've found, most seem to agree, please let me know if any of it is wrong: I'll be using the RJM harness

-ECT sensor: move from the side of the coolant tube to the top.
-ACT sensor: tap the manifold; or place it between the MAF and TB (can also use the stock explorer tube. Explorer and mustang ACT sensors are the same, with the exception of the plug
- use monster mounts to retain the explorer oil filter cooler assembly.
- BC has headers for the "p" heads and also cables for the TB and cable for the AOD trans


Any other solutions to problems that you have seen or heard of would be appreciated. I just want to get well prepared to avoid any waste of time and most of all MONEY.

Hey charlien, welcome to CB. I know some of that (I think), but am going to wait for other, more experienced members to answer.
May be a cop-out on my part, but after all, you're asking so as to AVOID confusion, not add to it!

Good luck.

Paul

Thanks DD...I appreciate that.....most of the confusion comes from people saying "I've been running mine for 8 years without any problems". I doubt any of those guys have had their engines tuned by someone that knows better, so how do they know that their engines are running at 75% efficiency vs 100% efficiency (not that any engine could run perfect, but you get what I'm trying to say) I guess the computer is the crutch that makes these engines run when things aren't setup in the ideal fashion. And before anyone gets defensive.....you can run the engine without the IAT sensor, but it's not ideal; you can run the engine with 2 plug wires crossed, but that's not ideal; you can run a MAP sensor instead of a BP sensor, but that's not ideal (you get my drift) I want to build a rig that my wife and kids can take on a trip and not worry about reliability.

Are there any guys that live near Clarksville or Nashville, TN that have done the explorer swap....maybe we could meet up and you could tell me all of your build secrets!!!

1) The signal from the Explorer TPS will work with the mustang EEC. I did it on my V8 Ranger conversion. That was the final throttle body used. I did some wiring swapping around but I recall a lot of that was due to trying different throttle bodies. Was all tuned with a custom chip and the TPS was not part of the tune (nothing to tune there according to the dyno shop)

2) Which injectors do you have? Some were 19's and some were 17's. Wrong one and it won't run right. Also do you have the return style fuel rail? If not then add an MSD-2222 regulator for an external fuel pressure regulator and then you can use the non-return rail. And for the MAF, I will not promise anything. http://www.fordracingparts.com/2010-catalog/ page 203 they call out a difference between the older and newer old mustang MAFs. And from dyno runs I have seen a stock 55mm max out the output voltage and that was the limiting factor. If the '94 can handle more HP before the MAF voltage maxes out I read that as it is a different calibration.

ECT needs to see coolant temp at the front of the intake, before the thermostat. Beyond that it doesn't really matter. There are 2 holes in the intake from the factory. One for the temp gauge on the dash, the other to the heater. The EEC goes in the heater line but remember that the mustang is a full flow heater and the Bronco stops the flow of water through the core when the heater is off. So if you have no heater, just use the heater hose hole. With heater, get it down as close to the flowing water as possible. If you have the EGR cooler lines hooked up that will force water up the heater line to the point of the cooler fitting, so that will be good as well (ECT between manifold and EGR cooler)

ACT can go about anywhere it can see the temp of the air going to be burned. I have gone as simple as zip tieing it next to the open element air filter and it worked fine. This one only does a little fine tuning so it knows if you are dirving in -20 super frigid conditions or 120 desert heat. Being off a few degrees isn't going to really affect anything.

19lb injectors with return style rail...I think they went returnless in 99. Excellent info broncobowsher, thanks for the link...so exactly why do people want the larger 70mm MAF with the explorer components, why not just use the smaller mustang with the A9* computer, especially on a stock motor? Is it just a matter of want, not need. I'm wondering if this actually hurts the setup instead of improve it???? So you say no to the 94-95 MAF?

charlien said:

19lb injectors with return style rail...I think they went returnless in 99. Excellent info broncobowsher, thanks for the link...so exactly why do people want the larger 70mm MAF with the explorer components, why not just use the smaller mustang with the A9* computer, especially on a stock motor? Is it just a matter of want, not need. I'm wondering if this actually hurts the setup instead of improve it???? So you say no to the 94-95 MAF?

Click to expand...

All '88-'95 mustang MAFs are electrically the same and will work with the A9* ECMs. I have the early 55mm version but would like to try the larger 70mm if I ever find one.

charlien said:

19lb injectors with return style rail...I think they went returnless in 99. Excellent info broncobowsher, thanks for the link...so exactly why do people want the larger 70mm MAF with the explorer components, why not just use the smaller mustang with the A9* computer, especially on a stock motor? Is it just a matter of want, not need. I'm wondering if this actually hurts the setup instead of improve it???? So you say no to the 94-95 MAF?

Click to expand...

I think a lot of people want it more then they need it. As you stated, on a stock motor, you may gain some high RPM power. The Explorer intake is good flowing, the throttle body a little bigger, heads a little better, cam a little less. Under 4000 RPM (my guess) the 55 won't restrict.

Now are the 55 and 70 from the early 90's mustang the same? maybe.
What I see is a difference. If I could find the hidden goldmine on the tuner sites of MAF transfer functions for various stock MAFs it would be a lot easier to tell. I just can't find that info. I am sure it is there, somewhere...

The 70 MAF matches the Explorer throttle body and intake. It is what was in the factory Explorer and my reason for getting one.

According to the ford racing ...the 19lb injectors are good to 258 hp and the 55mm stock 88-93 mustang MAF is rated to 275 hp.

The stock 94-93 mustang 70mm MAF is rated to 350 hp, which is matched to the 24lb injectors, rated up to 326 hp.

Directly from FR:

"It is possible to have 2 MAF sensors that are equal in size, but capable of different maximum power levels. This is because the electronics in each
MAF are different and are capable of measuring different maximum airflow, despite the fact that the size of the MAF housing is the same. For example, you
can have 2 different 90 mm MAF sensors but one will be capable of measuring 60 lb/min of air, while the other can measure, say, 100 lb/min of air. They both
present the same airflow restriction (which is dictated primarily by their physical size) but they are definitely NOT interchangeable."

So while the stock explorer MAF is 70mm and the 94-95 mustang MAF is 70mm, they might not be interchangeable....since MAF are matched to injectors and the stock explorer injectors are 19lb (rated at 258hp), I would ASSUME that the 70mm explorer MAF is also rated to only around 250-275 hp. And since the 94-95 mustang MAF is 70mm (rated at 350hp), you would assume that the 94-95 mustang has 24lb injectors (rated at 326hp)......and it does. This would lead you to believe that while the stock explorer MAF is 70mm, it is not rated at 325-350hp like the 94-95 mustang.........which takes us back to the FR statement that "the electronics in each
MAF are different and are capable of measuring different maximum airflow, despite the fact that the size of the MAF housing is the same"

Is everyone on the same page??????

Seems simple right...now here's the kicker. The 94-95 mustang MAF has the OEM part # F2VF-12B579-AA, which just so happens to be the same part number as the 92-94 crown vic; 91-94 town car; and 92-94 grand marquis....which all used stock 19lb injectors..........

I'm beginning to believe I need a TweeCer and put an end to all of this!!!!!!

This information is wrong....please read down further for clarification!!!!!!!

That's great, opens up a new batch of MAF we can use. Bigger hole, same calibration as the A9's

But the comment about the 94-95 having 24's is incorrect. I have a '95 engine sitting on the floor of the garage. Untouched engine, standard GT. I just went and double checked, they are orange injectors. Those are 19's, not 24's. The 24's are light blue.

charlien said:

Thanks to Broncobowsher for steering me in the right direction.....and the answer to the MAF question is:

A9L Stock 55mm MAF Transfer is identical to the 94-95 70mm MAF Transfer
( 15.9998, 835.509 )
( 4.76807, 835.509 )
( 4.44312, 695.465 )
( 4.177, 595.977 )
( 3.88599, 499.658 )
( 3.54395, 399.219 )
( 3.35498, 347.574 )
( 3.14893, 295.612 )
( 2.90991, 243.334 )
( 2.69409, 201.828 )
( 2.58203, 182.5 )
( 2.44995, 161.272 )
( 2.31592, 142.261 )
( 2.15405, 120.083 )
( 1.98901, 100.122 )
( 1.88989, 90.2996 )
( 1.80298, 82.3786 )
( 1.69092, 72.8734 )
( 1.57397, 62.4176 )
( 1.46802, 54.1798 )
( 1.32104, 44.6745 )
( 1.18188, 36.7535 )
( 1.09106, 32.6346 )
( 0.884033, 23.7631 )
( 0.75, 18.6936 )
( 0.571045, 13.6242 )
( 0, 13.6242 )
( 0, 13.6242 )
( 0, 13.6242 )
( 0, 13.6242 )

I also discovered that while the 94-95 mustang has 24lb injectors which makes you think that the 70mm MAF is rated to around 350hp, the computer on these is actually calibrated to 19lb injectors, which makes all the sense as to why the 70mm MAFs transfer numbers match that of 55mm MAFs.

Click to expand...

You don't happen to have the transfer data for the explorer MAF do you (F57F)? I know a least a couple people have used them with an A9* ECM and claim to have no issues. I'm sure the curve is different but don't know how much different.

I did a web search on the stock injectors for a 94-95 cobra (not gt) and several sites came up with 24lb injectors....could be wrong though.

Here's a link:

http://allfordmustangs.com/forums/9...ctor-size-95-cobra-maf-sensor-calibrated.html

charlien said:

I did a web search on the stock injectors for a 94-95 cobra (not gt) and several sites came up with 24lb injectors....could be wrong though.

Here's a link:

http://allfordmustangs.com/forums/9...ctor-size-95-cobra-maf-sensor-calibrated.html

Click to expand...

Yeah the cobras used the 24 lb injectors with the same MAF but the ECM had a different program.

Fuel Injector and fuel pump information and sizes

Production vehicles with 24 lbs. Injectors
93-95 Mustang Cobra

93-98 Lincoln Mark VIII 4.6L DOHC
95-up Lincoln Continentals 4.6L DOHC
'03 Lincoln Aviator 4.6L DOHC
F-350 with the V10 engine
7.5L 460 V8 trucks
5.4L DOHC Navigator

Well after going through the transfer numbers again I realized that the A9* numbers are NOT the same as the 94-95 mustangs......THEY DO NOT INTERCHANGE!!!! Somehow when I was cross referencing tables, I must have copied and pasted the A9* numbers twice instead of the 94-95 numbers....here they are along with some flow data for the MAF sensors. I'm assuming that the computer is compensating for the differences and that's why some people are getting away with running the 94-95 70mm MAF with the A9* computer...

Flow Rates
Meter Flow Rate
Stock 5.0L 58MM (89-93 Mustangs) 606 CFM
Stock 5.0L 70MM (94-95 GT/Cobra Mustangs) 815 CFM

Stock 94/95 Cobra MAF Transfer (J4J1)
Volts kg/hr
16.00 882.07
5.00 882.07
4.60 717.31
4.20 568.72
3.80 443.57
3.50 362.46
3.30 313.98
3.10 270.26
2.90 230.66
2.70 195.49
2.50 163.17
2.40 148.28
2.30 134.97
2.20 122.30
2.10 110.89
2.00 100.12
1.90 89.98
1.80 80.79
1.70 72.24
1.60 64.32
1.50 57.03
1.40 50.38
1.30 44.36
1.20 38.97
1.00 29.15
0.90 25.03
0.80 21.23
0.60 14.57
0.50 11.72
0.00 11.72
Stock 94/95 GT MAF Transfer (U4P0 & W4H0)
Volts kg/hr
16.00 932.13
5.00 932.13
4.75 808.56
4.50 697.67
4.25 598.50
4.00 510.10
3.80 446.74
3.60 389.39
3.40 337.11
3.20 290.85
3.00 249.03
2.80 211.65
2.60 178.38
2.40 149.23
2.20 123.57
2.10 112.16
2.00 101.39
1.90 91.25
1.80 82.06
1.60 65.27
1.50 57.98
1.30 44.99
1.20 39.29
1.00 29.47
0.75 19.96
0.60 15.21
0.40 10.46
0.00 8.87
0.00 8.87
0.00 8.87


Sorry again for the bad info...Something I did figure out when trying to clarify all of this is that FMO put MAF and injectors together and then programmed the computer to use them...the OEM MAF are not "calibrated" to an injector size...the computer is.

I hope all of this is right..please correct me if anything is wrong.

I just took all those numbers and overlayed them in an Excel sheer and charted them. Too bad I can't post an Excel sheet here.

Quick look, anything under 2.5V or 150 Kg/hr of airflow and all the MAFs read real close to each other. So they should all start, idle, and gently drive all about the same. But when you start getting into the higher regions of the airflow the lines start to spread a bit

If you have an engine flowing 500 Kg/hr with an A9 computer it should expect to see 3.88V,
But with a '95 MAF that 500 Kg will be a hair under 4V
4V to an A9 computer is about 540 Kg, the computer will try and feed the 500Kg of air as if it were 540 Kg. Or you are going to be about 8% too fat under load. But idle should be right on.

The Cobra and GT lines overlay up to about 4V then they seperate noticably.

I would love to find a 5.0 Explorer MAF transfer function and stick that in there. In the mean time here is the graphed transfer functions of the 3 listed MAFs. OK, having trouble uploading pictures today. Will try again later.

-Stock 5.0L 55MM MAF (89-93 Mustangs) flows 606 CFM.
-Stock 5.0L 60 MM TB flows 526 CFM.
-A 300 cubic inch engine (302 c.i.) flows 521 CFM at 6,000 rpm.
-I can't find any flow ratings on the explorer 70mm TB, but bases off other TBs, it's probably around 700 CFM.

These are numbers I found on some mustang websites...you can see that the 55mm MAF is more than adequate to supply the engine.

With Closed Loop (CL) control, the ECU has feedback to tell it whether it hit the desired A/F ratio target or not (well, sort of, as we'll find out). At part throttle, when the engine runs at the stoichiometric (chemically correct) 14.6 A/F ratio (required for minimum emissions, and maximum catalytic converter efficiency), the combustion products should ideally be only water vapor and carbon dioxide. If the A/F ratio was a little lean (too much air and/or not enough fuel), the excess (unburned) oxygen will show up in the exhaust gases. Using an O2 sensor, the ECU can now detect when the engine is running lean. Problem is, the factory O2 sensors have a narrow band for sensing oxygen. In other words, they can really only tell the ECU if there is some oxygen in the exhaust, but not precisely how much. So the ECU doesn't really know how lean the engine is running, only that it's running lean.

So what happens when the engine is running rich and there is no oxygen in the exhaust? The ECU will assume that if there's no oxygen present in the exhaust, then the A/F ratio must be rich. At that point, the ECU makes a conscious decision to lean the A/F ratio, that is, until it reads oxygen in the exhaust again. At that point, the ECU knows it went too far (it's now lean), so it will richen things up again until the oxygen disappears, but now it's rich again, so the ECU will again lean things out, and so on. In CL mode, the ECU will continually cycle the A/F ratio lean, then rich, over and over, hovering the A/F ratio closely around the stoichiometric point.

In CL mode, the ECU will still go through its normal PW calculation, then adjust the PW if necessary, based on what the feedback loop (O2 sensors) is saying. Any adjustment to the calculated PW is handled by the ECU as a Short Term Fuel Trim (STFT). With modern (second generation) On Board Diagnostics (OBD II), many ECU parameters can now easily be logged in real time, including the STFT. Depending on the ECU and data-logging system being used, STFT can be reported differently, sometimes as a plus or negative percent (minus STFT meaning the engine is running lean, so the ECU is reducing its calculated A/F ratio in order to get the actual desired A/F ratio), or as a number around 1.00 (STFT numbers less than one, meaning the ECU is correcting a lean condition).

Adaptive StrategyIf the ECU constantly needs to shorten calculated PW to achieve the desired 14.6 A/F ratio in CL mode, it knows its programming is calculating a PW too long (possibly from erroneous sensor inputs), and it will remember that correction for next time it makes a PW calculation for the same operating conditions of load and rpm. In other words, the ECU actually learns. The remembered corrections are known as Long Term Fuel Trims (LTFT). The LTFT work oppositely to the STFT, i.e., a plus LTFT (or LTFT greater than one) indicates the ECU is adding some to the calculated PW, in order to get the A/F it wants, based on what it's learned in the past.

Even though the ECU only knows it's hitting the desired A/F ratio when the A/F ratio is stoichiometric (in CL mode), the ECU can also apply the learned corrections (LTFT) any time the ECU is operating in OL mode, and commanding an A/F ratio other than stoichiometric. This Adaptive Strategy allows sensors to age and drift in their readings, but the ECU can now correct for the errors, and still hit the desired A/F ratio in the end.


Typical EFI systems use low-cost,... read full captionTypical EFI systems use low-cost, "narrow band" Heated Exhaust Gas Oxygen sensors, like this Ford unit.In the real world, adaptive strategy can be a problem. For some ECUs, corrections learned at one set of operating conditions (e.g., idle) are also applied under other operating conditions (like high-rpm WOT). In that case, if you have a MAF sensor that reads too rich at idle (typical of many aftermarket MAF sensors), a leaned idle correction is learned, which if also applied at WOT, can spell disaster. For these applications, it's necessary to either rework the adaptive learning table in the programming to prevent learned corrections from being applied under other operating conditions, or make certain the MAF sensor calibration is corrected. The least desirable, last-ditch technique is to disable adaptive learning in the tune. Whichever way, a custom tune is required.

Closed Loop mode (and Adaptive Strategy learning) is usually only active during part throttle modes, when the engine and O2 sensors are up to stabilized temperatures, and the goal is an A/F ratio right at stoichiometric. During the first few minutes after the engine is first started, and during high-load periods (like WOT) when a richer A/F ratio is intentionally desired, OL fueling strategy is typically used. Thus for maximum power, we need to ensure the ECU calculates the correct OL injector PW, so we get the WOT A/F ratio right. This is where a proper tune comes in.

Broncobowsher said:

I just took all those numbers and overlayed them in an Excel sheer and charted them. Too bad I can't post an Excel sheet here.

Quick look, anything under 2.5V or 150 Kg/hr of airflow and all the MAFs read real close to each other. So they should all start, idle, and gently drive all about the same. But when you start getting into the higher regions of the airflow the lines start to spread a bit

If you have an engine flowing 500 Kg/hr with an A9 computer it should expect to see 3.88V,
But with a '95 MAF that 500 Kg will be a hair under 4V
4V to an A9 computer is about 540 Kg, the computer will try and feed the 500Kg of air as if it were 540 Kg. Or you are going to be about 8% too fat under load. But idle should be right on.

The Cobra and GT lines overlay up to about 4V then they seperate noticably.

I would love to find a 5.0 Explorer MAF transfer function and stick that in there. In the mean time here is the graphed transfer functions of the 3 listed MAFs. OK, having trouble uploading pictures today. Will try again later.

Click to expand...

I charted it too.

Do you think that running with a mismatched MAF/PCM combo causes the computer to run closed loop (off O2 sensors), that's why people are having surge problems?

"In CL mode, the ECU will continually cycle the A/F ratio lean, then rich, over and over, hovering the A/F ratio closely around the stoichiometric point."