Tuned my GT and having problem with MAF sensor


DXB.GT

GT Owner
Aug 17, 2017
17
Hi guys,
After owning my GT for a while, I decided to do some modification on it. So, I had done the following:
1-FFRP full exhaust
2-Accufab single blade throttle body
3- smaller S/C pully 2.7 inch
4- new K&N inbox filter
5-NGK TR7 ix spark plug
6- Accufab half halfshaft bolts
7- Lund racing custom tune

I have everything installed locally in Dubai, but the tune was done remotely by Lund racing. The thing is every thing was fine through the tuning but the tuner told me that my MAF sensor is not reading well at high RPMs and the car fuel is going rich. So, he told me to buy something called Mass Air Modifier, have a look the link is below.
http://www.jmschip.com/jms-mass-air...s-4002-f05-mustang-f150-and-most-other-fords/
I HAVE NO IDEA ABOUT TUNING, do anyone had the same problem??

Thanks guys

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NorthwoodGT

GT Owner
Jun 12, 2009
1,215
Michigan
My suggestion before you purchase that is to get with Rich at the GT GUY. he installed my Whipple supercharger and had to plug in what's called a "Mafia" sensor before the stock MAF due to similar issues you are having. it basically fools the OEM MAF and works like a champ. not sure where to purchase it but has to be a whole lot simpler and less expensive than the unit you are showing although it probably works good. mine is just a simple in-line plug in. hope that helps.
 

FikseGTS

GT Owner
Apr 15, 2007
461
South Florida
I got the Diablo Mafia as well, fixed the issue...
 

Xcentric

GT Owner
Mark II Lifetime
Jul 9, 2012
5,213
Myakka City, Florida
If the increased air flow is pegging the MAF, a MAFia (MAF interface adapter) can fix it. However, I've not heard of any pulley/tune that can exceed stock MAF range. Big Whipples or TTs, yeah.

Single blade TBs have been problematic. The double blade Accufab TBs work fine. 5 mm larger than stock and deliver all the air a pulley/tune (16 psi boost) needs.

Haven't heard of a Lund tune for the GT. Several rock solid plug and play tunes are available. Torrie's tune is widely used.

My mods are the same as yours, except for TB, K&N and tune.

You didn't mention any CELs. Maybe you haven't driven it enough for a CEL. You might check the codes. Sometimes you don't get a CEL until the same code is set three times. Could be one or two codes stored.
 
Last edited:

06fordgt

GT
Mark II Lifetime
Le Mans 2010 Supporter
Nov 8, 2006
1,908
Toronto Canada
I also used a Diablo MAF to deal with this issue.
 

DXB.GT

GT Owner
Aug 17, 2017
17
I will ask the tuner about MAFia
I think it will works well, just waiting for his response

If the increased air flow is pegging the MAF, a MAFia (MAF interface adapter) can fix it. However, I've not heard of any pulley/tune that can exceed stock MAF range. Big Whipples or TTs, yeah.

Single blade TBs have been problematic. The double blade Accufab TBs work fine. 3 mm larger than stock and deliver all the air a pulley/tune (16 psi boost) needs.

Haven't heard of a Lund tune for the GT. Several rock solid plug and play tunes are available. Torrie's tune is widely used.

My mods are the same as yours, except for TB, K&N and tune.

You didn't mention any CELs. Maybe you haven't driven it enough for a CEL. You might check the codes. Sometimes you don't get a CEL until the same code is set three times. Could be one or two codes stored.

Me neither, never thought that I will need some other modifications on my system. But, the tuner says that I need it in order to get a proper tune.
To be honest l spoke with Hennessey, heffner and Accufab. I got the 2.68 pulley from hennessy and wanted the plug and play tuner from accufab ( because I had the Accufab single blade t/b already and I know that it has some problem). I called Accufab and I told them I need a tune please do it for me ( called more than 30 times sent so many emails and waited for more than 2 months since 18th of jan) I don't know their reasons they may have some but i really got frustrated from them.
I called Lund and told them I need a custom tune, they respond within few hours yes we will do and finshed everything remotely on dyno close to my home in Dubai with in few days

Yesterday They finish the car, I drove it for short time. I can clearly say there is gain in power, the throttle not jerky as people says but there is difference. The car shoots flame some time (maybe because the MAF)
No CEL until now but I hope nothing comes out.

Thanks guys

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nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,176
OP - I assume that the tuning is being done via an SCT device and, as such, it should be very straightforward for you tuner to see MAF counts and to know if the increased air flow is exceeding the capacity of the Mass Air Flow sensor. With the modifications you have performed, this is a very real possibility. The device that the tuner is recommending scales the output voltage of the MAF so that the ECU sees a linear progression through the RPM range and, most importantly, the 0-5v range as expected by the ECU is not exceeded.

One of the historically most popular MAF scaling devices was the Dablo MAFia, but unfortunately it is no longer in production. You might check Ebay as this device is VERY simple and is literally plug & play (the OEM connector to your MAF plugs in to the MAFia, and the MAFia has a short connector that plugs into your OEM MAF.)
 

06fordgt

GT
Mark II Lifetime
Le Mans 2010 Supporter
Nov 8, 2006
1,908
Toronto Canada
Diablo stopped making them!?. Didn't know that.
 

texas mongrel

GT Owner
Mark II Lifetime
May 3, 2009
1,661
Houston Texas
Rich’s cold air intake flows so much more than stock that it needs a different MAF sensor. Don’t know where he sources it, though.
 

B.M.F.

GT Owner
Mark II Lifetime
Jan 29, 2009
1,782
Minnesota
I will ask the tuner about MAFia
I think it will works well, just waiting for his response



Me neither, never thought that I will need some other modifications on my system. But, the tuner says that I need it in order to get a proper tune.
To be honest l spoke with Hennessey, heffner and Accufab. I got the 2.68 pulley from hennessy and wanted the plug and play tuner from accufab ( because I had the Accufab single blade t/b already and I know that it has some problem). I called Accufab and I told them I need a tune please do it for me ( called more than 30 times sent so many emails and waited for more than 2 months since 18th of jan) I don't know their reasons they may have some but i really got frustrated from them.
I called Lund and told them I need a custom tune, they respond within few hours yes we will do and finshed everything remotely on dyno close to my home in Dubai with in few days

Yesterday They finish the car, I drove it for short time. I can clearly say there is gain in power, the throttle not jerky as people says but there is difference. The car shoots flame some time (maybe because the MAF)
No CEL until now but I hope nothing comes out.

Thanks guys

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accufab does not do tunes and probably why you did not get a response from them. They are a throttle body manufacture and a few other gt specific items.
 

B.M.F.

GT Owner
Mark II Lifetime
Jan 29, 2009
1,782
Minnesota
Rich’s cold air intake flows so much more than stock that it needs a different MAF sensor. Don’t know where he sources it, though.

I can not see this being true at all. The maf sensor is the same as all GT500's and they use huge inlets with no issues. I could be wrong buy highly doubt it. If anyone adds anything its a diablo mafia..
 

Xcentric

GT Owner
Mark II Lifetime
Jul 9, 2012
5,213
Myakka City, Florida
You can add the biggest air intake in the world and it's not going to flow any more air than the capacity of the supercharger.

Diablosport MAFias are available for Mustangs, including GT500. Was there one specifically for the GT?

https://www.americanmuscle.com/diablosport-mafia-0510.html
 

twobjshelbys

GT Owner
Jul 26, 2010
6,053
Las Vegas, NV
My pulley/tune/TB from Rich included a new MAF, it's a Ford part that I think cross referenced to an older Mercury but I don't have it handy to check. Check with Rich.
 

DXB.GT

GT Owner
Aug 17, 2017
17
accufab does not do tunes and probably why you did not get a response from them. They are a throttle body manufacture and a few other gt specific items.

https://accufabracing.com/ford-gt-sct-flash-tuner
It was in stock
I spoke with Mr. John and he said that he will do it

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DXB.GT

GT Owner
Aug 17, 2017
17
OP - I assume that the tuning is being done via an SCT device and, as such, it should be very straightforward for you tuner to see MAF counts and to know if the increased air flow is exceeding the capacity of the Mass Air Flow sensor. With the modifications you have performed, this is a very real possibility. The device that the tuner is recommending scales the output voltage of the MAF so that the ECU sees a linear progression through the RPM range and, most importantly, the 0-5v range as expected by the ECU is not exceeded.

One of the historically most popular MAF scaling devices was the Dablo MAFia, but unfortunately it is no longer in production. You might check Ebay as this device is VERY simple and is literally plug & play (the OEM connector to your MAF plugs in to the MAFia, and the MAFia has a short connector that plugs into your OEM MAF.)

Yes everything have bean done by SCT the data log and the tune installation. Its weird to have voltage amplifier on my set up, but I will wait for the final dynograph and I will share it with you

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Art138

GT Owner
Mark II Lifetime
Jan 4, 2011
624
Weston,FL
What gap are you using on your NGK TR7s?
 

DXB.GT

GT Owner
Aug 17, 2017
17
What gap are you using on your NGK TR7s?

The gap is 0.029"



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nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,176
Yes everything have bean done by SCT the data log and the tune installation. Its weird to have voltage amplifier on my set up, but I will wait for the final dynograph and I will share it with you

OP - Let me explain further. Like many sensors throughout most modern cars, they are designed to give a a "signal" back to the ECU and most of these sensors are designed to provide a signal of 0v - 5v. In the case of the MAF, the sensor is designed for a particular position and air flow in a given car. The OEM attempts to maximize the full range of the sensor in order to have the most fidelity. So, let's say at idle, the MAF is at 0.5v. As the air volume to the engine increases (as detected by the MAF), the voltage starts to rise.... so, say at 1/2 load, the MAF may be around 2.5 volts and a full, maximum (OEM) air flow it is at 4.8v.

The problem arises when you make modifications to the GT and increase its airflow capacity. You have done this with more boost, and an improved exhaust system. As such, the airflow may be improved such that the MAF value goes to 5.1v!!! In the case when the ECU sees a value out of range (0-5v) from one of its sensors, it is usually programmed to go into limp mode. This is logical, if you think about it.... if the ECU has a sensor that it is dependent upon to safely operate the engine and that sensor has provided bad input, it can no longer be relied upon.

So, what this scaling devices do is that they plug into the MAF, and they scale down the MAF voltage readings back to the ECU. When these devices are in place, the tuner MUST re-program the vehicle to account for their presence. In our little scenario above, at 1/2 load, the OEM MAF value may be 2.5v but with the scaler in place, it may be 2.3v. The important part however, is that the MAF may yield a 5.1v at full load, but the scaler would report back a 4.9v to the ECU.... and everyone is happy.

Just a note about aftermarket intakes: The fact that a different intake may require a different MAF or the inclusion of a scaler on the OEM MAF DOES NOT (necessarily) mean that the intake is flowing more air. MAFs are calibrated to be in a particular position in the intake track where they can "see" a linear and reliable progression of air flow as demanded by the engine. Simply MOVING the OEM MAF in an otherwise stock intake track will require re-calibration and maybe even a scaler..... having nothing to do with genuinely increased airflow.

OP - if you want to post or PM me dyno pulls, that's great. The dyno file itself would be most telling - but minimally we need to see a plot with A/F ratios across the RPM range.
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,176
It appears that after a brief absence from the market, the Diablo MAFia scaler is once again available. I would highly recommend that this one be used as the installation is trivial. The OEM connector to the MAF goes to the MAFia and the MAFia has the EXACT connector to plug into the MAF sensor and you are done. In your case (with your mods), set the MAFia scaler to the "2" position and schedule a tuning session. If you are happy with LUND, great but otherwise I would highly recommend Torrie. We have done dozens of remote tuning sessions with him - many on GTs producing more than 1000HP at the rear wheels.
 

texas mongrel

GT Owner
Mark II Lifetime
May 3, 2009
1,661
Houston Texas
I can not see this being true at all. The maf sensor is the same as all GT500's and they use huge inlets with no issues. I could be wrong buy highly doubt it. If anyone adds anything its a diablo mafia..

Sorry, but when I accidentally loaded an old, pre cold-air tune into my car it wouldn’t start (or even try to). I borrowed Magic’s MAF a d fitted that and it ran, allbeit badly. Different MAFs.