Rough running 98 4.0 after tech library intake mod

[13kidd]

So I decided to go ahead and try the intake mod in the tech library so you can fit a conical filter on your intake and I noticed that when I was driving my truck it was running rough after the mod but only when I would stay at a constant speed. When accelerating it felt normal and also when slowing but when coasting it would be very jerky and would slow down and speed up very quickly. Now I'm not sure if it was screwing with the computer in the truck or what but it was definitely the new filter screwing up the engine because I put the old intake back on and it runs just like before, anyone have any idea how the mod could be causing this?

 

[13kidd]

Bump

 

[adsm08]

Sounds like you didn't get something sealed right either at or behind the MAF.

 

[Bob Ayers]

Put the OEM intake back on. There is absolutely no benefit to the mod you did.

Did you read this disclaimer in the Technical section:

Any and all modifications will likely cause a vehicle to behave differently than stock.

 

[13kidd]

Put the OEM intake back on. There is absolutely no benefit to the mod you did.

Did you read this disclaimer in the Technical section:

Any and all modifications will likely cause a vehicle to behave differently than stock.

If you would have read my post I said I had put the old intake back on, and yes I did read the disclaimer. I wasn't complaining that this mod screwed my truck up I was simply just trying to figure out if anyone had any idea on why this was happening is I could get it working correctly. And how can you be ABSOLUTELY positive that there is no benefit at all? I'm not saying there is but I would love if you proved your point.

 

[13kidd]

Sounds like you didn't get something sealed right either at or behind the MAF.

That's what I was thinking but I'm pretty sure that it would have to be a seal leak where the MAF connects to the new part since I didn't mess with any of the intake after the MAF. Thanks for the tip!

 

[adsm08]

By "intake" I mean anything that air passes through. So it could be the seal at the sensor, the seal around the TB, anything. Put a little RTV around the inside of the tubing where it meets another piece.

 

[shane96ranger]

What filter did you install? Did it start doing it immediately? If you installed an oiled filter, I wonder if your MAF sensor got some on it. That will cause the symptoms you are experiencing.



Sent from my Quad Core Acer A210

 

[adsm08]

What filter did you install? Did it start doing it immediately? If you installed an oiled filter, I wonder if your MAF sensor got some on it. That will cause the symptoms you are experiencing.



Sent from my Quad Core Acer A210

Which would not go away again when he put the original stuff back on. This mod uses the original MAF.

 

[Bob Ayers]

By "intake" I mean anything that air passes through. So it could be the seal at the sensor, the seal around the TB, anything. Put a little RTV around the inside of the tubing where it meets another piece.

Be careful telling him to use RTV. If he doesn't use "SENSOR SAFE" RTV, then he will be buying O2 sensors........

 

[Bob Ayers]

If you would have read my post I said I had put the old intake back on, and yes I did read the disclaimer. I wasn't complaining that this mod screwed my truck up I was simply just trying to figure out if anyone had any idea on why this was happening is I could get it working correctly. And how can you be ABSOLUTELY positive that there is no benefit at all? I'm not saying there is but I would love if you proved your point.

A couple things for you to consider:

1) All auto manufacturers design intake systems to be as efficient as possible due to CAFE standards.

2) The OEM intake / air filter are not the limiting factor for air flow, you could put a sewer pipe on for an intake and you won't get any more air.
Take a look at the diameter of your throttle body, and intake runners.

All you will get with the aftermarket intakes is more noise.

 

[James86]

A couple things for you to consider:

1) All auto manufacturers design intake systems to be as efficient as possible due to CAFE standards.

Fuel efficent or power efficient? Air intake mufflers don't help fuel economy, they decrease engine noise.

2) The OEM intake / air filter are not the limiting factor for air flow, you could put a sewer pipe on for an intake and you won't get any more air.
Take a look at the diameter of your throttle body, and intake runners.

All you will get with the aftermarket intakes is more noise.

To a degree, yes. Just like exhaust systems, there is a REASONABLE limit to how much more flow you can get, but unless you do headwork, there's only so much more to be scavenged.

So back to solving his question and sidestepping the criticisms....


How much did you "modify" for this cone adapter? did you replace the whole hose, or just stick a billet adapter on the MAF and slap a cone in place of the airbox? There are multiple "mods" listed in the tech library. It'd be a little easier to figure out what was wrong if we know what you did.

 

[Bob Ayers]

So back to solving his question and sidestepping the criticisms....


How much did you "modify" for this cone adapter? did you replace the whole hose, or just stick a billet adapter on the MAF and slap a cone in place of the airbox? There are multiple "mods" listed in the tech library. It'd be a little easier to figure out what was wrong if we know what you did.

Fuel efficent or power efficient? Air intake mufflers don't help fuel economy, they decrease engine noise.



Both! Noise is caused by air turbulence which decreases MPG, and power.

 

[Bob Ayers]

Here is some bench flow test data for different intake configurations on a F-150 5.4L. If you compare the displacement ratios to air filter area ratios of the 5.4L and 4.0L, they are essentially the same. So, as you can see from the data, the OEM intake setup will out flow what the 5.4L can pull:

 

[James86]

We aren't any closer to seeing if he goobered a sensor.... hope the OP is still around