Gen 3 Coyote Tuner said unplug MAF sensor

[walkerwde]

I posted on here a few weeks ago about how terrible my gen 3 coyote build is driving. I called a local reputable tuner and he told me to unplug the MAF and it should fix the issue and if it didn't I should fix whats wrong before tuning it. Do any of you have an understanding behind this and is he correct?

[edwardb]

I'm far from an expert. But have been through this exercise several times with Gen 2's and now the Gen 3. Doesn't sound right to me. Without a MAF signal, it may start but I'll bet it shuts right down again or at the very least goes into limp mode. Your Gen 3 is going to basically be undriveable without tuning. That's the bottom line. Many of us have experienced that. I'd be surprised if there's anything physically wrong with it. My tuner (Lund Racing) said that the Gen 3 MAF calibration is very sensitive, and once the stock air box isn't used (which it isn't in our case) the calibration is way off and the engine runs very poorly. It will start and run, and even go-kart. But actual driving it cuts out and is really bad. Likely will throw various DTC's as well. Mine did. I went through several iterations of tune with Lund. But it was a totally different engine right after installing the first version.

[BradCraig]

That sounds wrong, find a new tuner. My experience is the same as Edwards, once the tune is calibrated for the smaller MAF housing it runs MUCH better. Until then is will throw rich on both banks codes.

[Hoooper]

What hes saying is he assumes the tube your MAF is in is messing up the tune. ie: what the computer is set up to interpret for airflow based on your MAF reading is not matching up with reality. By unplugging it, that should put your computer into speed density (assuming Ford put a MAP sensor on the coyote) which calculates air volume based on volumetric efficiency tables and manifold pressure reading. MANY aftermarket engine tunes run solely on the MAP and ignore the MAF except to read the air temp (if the MAF is installed).

[edwardb]

What hes saying is he assumes the tube your MAF is in is messing up the tune. ie: what the computer is set up to interpret for airflow based on your MAF reading is not matching up with reality. By unplugging it, that should put your computer into speed density (assuming Ford put a MAP sensor on the coyote) which calculates air volume based on volumetric efficiency tables and manifold pressure reading. MANY aftermarket engine tunes run solely on the MAP and ignore the MAF except to read the air temp (if the MAF is installed).

If that's what the tuner is thinking, another reason to get a different tuner. The stock Coyote doesn't have a MAP sensor and anyone that tunes one would know that. For the Coyote, as mentioned, the MAF calibration is for the airflow through the stock airbox. Change it like we do on these builds and the calibration is wrong. For the Gen 1 and Gen 2 while it could be made to run better, it ran "OK" with the stock tune and the aftermarket intakes. For the Gen 3, it's more sensitive and just won't run acceptably without a custom tune. Because of the added direct injection? Or because the intake when from 3.5 to 4.0"? I don't know. Just know from experience and what Lund told me.

[Hoooper]

No MAP sensor really? Nearly everything has a MAP sensor to run with the MAF. If there is no MAP sensor unplugging the MAF will presumably put it into alpha-N mode which would run a lot better than a miscalibrated MAF but hardly the way a mostly stock coyote should be run

[GTBradley]

I can tell you from experience that the gen 2 will start and idle without the MAF in place. I didn’t tighten the band clamp sufficiently and the intake tube fell off while driving. It would not run under load though and acted as if it were running out of gas and died. Restarted and got about 25 feet before dying again.

[edwardb]

I can tell you from experience that the gen 2 will start and idle without the MAF in place. I didn’t tighten the band clamp sufficiently and the intake tube fell off while driving. It would not run under load though and acted as if it were running out of gas and died. Restarted and got about 25 feet before dying again.

Similar story, sadly. Mine started and ran a couple times. But wouldn't pull it's own weight and eventually wouldn't start at all. https://thefactoryfiveforum.com/showthread.php?29342-Welcome-to-the-Ride-of-Shame.

Also ask anyone who's put the MAF in backwards how well they run. :rolleyes: That one I don't know about personally but it's been talked about several times.

[Hoooper]

An MAF in backwards or still connected is way worse than disconnected. Disconnected the computer knows to ignore it because it isnt getting data, but installed wrong or the pipe fell off is data the computer thinks it can work with but is dead wrong. When the computer fails the sensor it moves on to other modes to keep running such as alpha n or speed density depending on the sensors the computer still has to work with, but a sensor that is still in and "working" is far worse. Quite a few high power computer tunes actually run originally MAF based engines on just the angle of the throttle plate and the RPM (alpha-N) which is a mode that a stock computer will fail into when the MAF is in failed state and there is not a MAP to reference.

[FFinisher]

I'm far from an expert. But have been through this exercise several times with Gen 2's and now the Gen 3. Doesn't sound right to me. Without a MAF signal, it may start but I'll bet it shuts right down again or at the very least goes into limp mode. Your Gen 3 is going to basically be undriveable without tuning. That's the bottom line. Many of us have experienced that. I'd be surprised if there's anything physically wrong with it. My tuner (Lund Racing) said that the Gen 3 MAF calibration is very sensitive, and once the stock air box isn't used (which it isn't in our case) the calibration is way off and the engine runs very poorly. It will start and run, and even go-kart. But actual driving it cuts out and is really bad. Likely will throw various DTC's as well. Mine did. I went through several iterations of tune with Lund. But it was a totally different engine right after installing the first version.

Ditto, find another tuner.

[Erik W. Treves]

Just a couple of additional thoughts - if that's the only thing told without explanation then I might grab another tuner. There isn't a MAP sensor. The engine is a "torque request" strategy... gets fun when when you do boosted cars. If you haven't had it tuned yet then there could be 10-20 things that are effecting the drivability - MAF in backwards is definitely one of them - but more likely the choice of MAF tube and positioning is the issue. The MAF table is based on a set amount of air needed to produce a set amount of power based on how open the throttle is and how much air the MAF sees. In these applications we completely change intake track and if the diameter of the tubes have been changed it probably will idle but it wont take the throttle well.

[GTBradley]

Similar story, sadly. Mine started and ran a couple times. But wouldn't pull it's own weight and eventually wouldn't start at all. https://thefactoryfiveforum.com/showthread.php?29342-Welcome-to-the-Ride-of-Shame.

Also ask anyone who's put the MAF in backwards how well they run. :rolleyes: That one I don't know about personally but it's been talked about several times.
Ha, glad to know I’m not alone in the overreation/overly-complicated-diagnosis department. I was low on gas and made the assumption that the gauge was the problem. Had I just opened the hood and looked around I would have saved us a walk home and the wasted time of getting a gas can and a ride to the gas station.

[Mike Garrett]

The Coyote Gen 3, as well as earlier ones, need to be tuned after they are in the car and running. I chose my local hot rod shop to tune mine on a chassis dyno and now it runs great. The reason I wanted to do it locally was to have the engine tuned to my local conditions. 443 HP at the rear wheels @ 7,000.

[edwardb]

The Coyote Gen 3, as well as earlier ones, need to be tuned after they are in the car and running. I chose my local hot rod shop to tune mine on a chassis dyno and now it runs great. The reason I wanted to do it locally was to have the engine tuned to my local conditions. 443 HP at the rear wheels @ 7,000.

Good to hear you found a local tuner and able to have a dyno result. For the record, a remote tune (like Lund Racing) would also reflect local conditions. The logs you provide to them, which they base the tune on, are completed by running and driving in your location.