Hey guys I'm new to the forums and I've got more of an inconvenience than a problem. I recently bought a 2000 f150 5.4l with 212,000 miles on it. The motor was perfectly fine but I had parts laying around and a short block built that I wanted to use. Long story short the short block had problems apparently and broke a rod so it came back out and ended up rebuilding original motor. Anyway I replaced the cams with these http://www.summitracing.com/parts/CCA-102200/
and installed obx stainless longtube headers. I'm also running maggy 94106 high flow cats and 2 1/2 true duals no mufflers. The truck seems to run fine other than when you try to start and take off with it cold. When I start the truck cold it revs up to about 1200 or so then dies sometimes and sometimes it will catch itself and not die. Every time I start it cold, though, it will usually die when put in drive or reverse if I don't give it gas immediately. As you can imagine that can be inconvenient of I'm in a tight space. When the truck is warm is starts fine and doesn't die when put in gear. Also it hasn't ever died at a stop sign or light and seems to run ok when warm. It idles at about 650rpms when in gear and kind of surges between 800 and 900 rpms when at idle in park. My question is do I need tunes to help the computer with the cams?

I've also posted this in the power hungry forums.
Sorry for the long post just wanted to give plenty of information.
Also it is throwing no codes right now.

Thanks,
Hill

 

To optimize the upgrades you have, especially with cams, LT's and high flows you should be running a tune. Someone else can chime in on whether you "have" to have a tune. If I were to guess, it would run without it, but not that great. You could also be having and IAC problem.

 

Ok thanks Toyz I'll check out that IAC next weekend and see if that is the problem (at school through the week). I plan on getting a tuner from power hungry, just don't have the cash right now for it.

Anyone else have any ideas?

 

Sounds like ur IAC is about done in. Cleaning the EGR system might help also. I would definitely run a custom tune with that much work. Any CELs? If you've kept up with the maintenance it should be pretty straight forward. Only motorcraft parts also .

 

Thanks for the reply ParnAZ, so far that seems to be the consensus. I do definitely plan on a custom tune but like I said just don't have the money right now for the tuner. I am debating on whether to just order a new one so it will be there when I get back home or clean the existing one to see if that is the problem. I don't know that I will go Motorcraft for this part, it is easily twice as much as others.

Thanks!

 

If you feel the motor hot idle is ok, it's not your cams causing the idle control issue.
The IAC does all the idle control.
It is proper to see high idle at cold start depending on how cold the ambient temp is then comes down to normal idle.
Clean your unit first with spray cleaner and the throttle body area as well after you remove the big air hose.
Cams depending on what their application is for, may benifit from some program alterations.
What does the seller say they are intended for?
Higher RPM or general RV application and low end torque?
Good luck.
.
I looked at these cams and see their profile timing is long enough to present somewhat less than smooth idle or some lope due to pump-back into the intake.
These are not the profiles I would have chosen for general street use in a truck unless I were going to lower the gear ratio and and do a transmission stall change to take advantage of the cams higher rpm power increases.
You likely will notice a drop in low rpm off idle torque.

 

The cams were said to be for trucks improving low end torque and were said to be pretty mild requiring no higher torque converter stall. The truck has plenty of power although I haven't had it over 2500 rpms yet due to break in. The cam also stated a noticeable idle and the idle is somewhat loped but sounds really good. I would like to put shorter gears in it sometime but again do not have the money right now. It has 355's right now and heavy 285/75/16's BF's on it and doesn't have any trouble pulling them. I believe it to be the IAC as I've looked around and the symptoms seem to match. It only has trouble with dieing when it is cold and the idle surges when in park. It does run much better and have no trouble dieing once warm. Hell its fine after like a minute of driving. Just kind of hickups at first.

Thanks for the reply Bluegrass, I appreciate it.

 

yes it needs to be tuned. Its dies when its cold because it is overfueling to compensate for the cams, because it is driving timing based fueling crazy.

 

To Carcrazy, your correct if it were a Speed Density motor but it's a MASS AIR motor.
They have no MAP sensor as you knew it, controlling fuel via intake vacuum.
The last MAP motor for trucks was in about 1995+/- on the 5L and 5.7L push rod engines..

 

typo. It needs tuning. the timing profile is now completely different.

 

Thanks guys, yes I'm going to get it tuned when I get the money but if replacing the IAC valve helps it when starting cold then I'll be able to stand to wait for a tune. I don't really have the 500 bucks laying around right now for it ya know?

 

Hey guys thanks for all of your help. I got the new IAC valve put on and the idle is much better and doesn't die when started cold.

It's still running a little finicky though, it died a few times today right in a row when taking and then letting of the gas again like to take off then shortly stop at a stop sign again. Sometimes it will drop to about 400rpms when pulling up to a stop sign but catches itself.

Much better than it was but I guess I just really need to get the tunes done for it to run 100% again.

Thanks for all your help though, I appreciate it

 

Technically, the cam has reduced the intake vacuum due to the longer intake profile (delay in intake valve closing).
Off idle, the loss in cylinder pressure further causes a loss in torque until higher rpm is reached where the motor 'comes on the cam' as they say.
In that area before the cams comes on, you can/may see soft driveability issues
This is one reason for raising the converter stall speed. Off idle you get to that stall point with less load a lot quicker so the motor hooks up faster.
When you begin to go away from an engineered design, you get into mutiple changes that should be made to take better advantage of the total.
Then computer tuning needs to be optimized to take full advantge of all the changes.
Good luck.

 

If you would check out the Comp Cam website, you would see that the cams you bought are designed to work with the stock configuration, no tune is required for it to run right. You also don't need lower gears as that cam is designed for the f150 and 3.23 to 3.55 gears. That's a good camset for a nice sounding idle and a little more pop but it's a long way from any kind of high performance cam set. If you're having running issues, it's not the cams and a tune is not going to help but may make it worse.

 

Lab, I respect you professional positions.
Don't take everthing they say at face value. The vendor has been saying what they say for a long time. It's part of a sales incentive pitch on the reader.
Think; if they did not say what they say, how many decisions 'not to buy' would result in lost sales if a number of specific requirements were to be given and the buyer was not willing to meet them.
They made a sale in this case and it's up to the owner what he does with/about it after the sale.
A call to their cam helpline and specific questions were asked, would have uncovered much of the following, if that person were honest with knowledgeable answers.
.
The cams are not race grade in profile but they do get to the edge of it in this size motor or there would be no 'lope' as they say, to the profile and as the owner experiences.
The exhaust sound as you note, is the earlier opening of the exhaust valves when cylinder pressures are higher.
As the profile duration increases, the peak torque moves higher as does the peak HP.
Net result is some loss of low rpm torque [as compaired] to stock.
The cams were designed for a lighter car/Mustang and not just for an F150.
Do take note that in a 4.6 displacement, the profile will act as a longer duration cam than it would in the bigger displacement 5.4 where it would be smoother running at low rpm where Torque /HP peaks would not move up as far. This is well known in performance circles.
This owner may well have other issues but no one here can lay a cause 'as yet'.
I suspect there could be a decell issue with speed sensing that may be causing the motor to die on decell/low rpm.
Explained;
Upon decell the PCM is supposed to close down fuel injection, close down to a min the IAC to a point the motor won't stall, all sensed by the TPS position and speed sensing method per the model year and transmission.
This is the same general method used on Ford FI since 1985.
If something is amiss, then he still has an issue.
Unless some one knows and checks it out, he won't get any improvement by himself.
I'm sorry to have a difference of opinion but I have also given supporting comment as to why, based on many years of modified and race motor experience and a student thereof of racing.
When it comes to lubericants, you have my ear as the one to go to, here.
Best reguards.