4.6L V8 Technical Discussions Any questions about engine, transmission, or gearing can be asked here!

Engine breaking up, need some help

Thread Tools
 
Search this Thread
 
Old Sep 28, 2009 | 06:48 PM
  #1  
JDWalton's Avatar
JDWalton
Thread Starter
5th Gear Member
 
Joined: Apr 2007
Posts: 2,612
From: CT
Unhappy Engine breaking up, need some help

Hey all. so all of a sudden my engine starts doing some weired things, i noticed it when I was getting on the gas going onto the highway the other day, and now am able to generate it pretty much at will.

Most noticeably at anything over 3rd gear, if at 2800 to about 3800 rpm and at 1/2 to 3/4 throttle, I start getting violent popping and snapping from my exhaust and very horrible stutters in the power from the motor. Now say I just go for it full throttle from a launch, I can run all the way up over 100 with no issues what so ever, and every bit of power is there.

Now surprisingly, when I was at Ford today about the two bolts that hold the passenger side of my bumper to the fender being missing, I spoke with one of there service managers about this. Now he asked me about my intake, and noticed the supercharger.... and the long tube headers, but still made a appointment for me and said they would take a look (never mentioned anything about trying to charge or status of my warranty,) but with the questions he was asking me it felt like he was trying to feel me out to see if I knew what I was doing under the hood.

So anyway, it goes in Thursday. So far I have taken some electrical contact cleaner and sprayed down my mass air. I also ran it near out of gas and filled with some fresh 93. Neither helped. So far thinking I might be looking at a new mass air sensor, or maybe a TPS, but wanted to ask you guys your opinions also. If its one of those 2, I'm confident I can get Ford to cover it, but would start to run out of idea after that. Was thinking maybe O2 sensors, but those get expensive when I am throwing them at it just to see. Was also thinking injectors or plugs, but again, getting expensive for the injectors, and tedious for the plugs, and I would think either of those 2 options would cause problems in a much less isolated situation. Oh well, have at it guys, any ideas welcome at this point.
Old Sep 28, 2009 | 07:52 PM
  #2  
Stkjock's Avatar
Stkjock
Retired Mod
 
Joined: Jan 2007
Posts: 7,658
From: Long Island, NY
Default

never mind... missed the info in the post
Old Sep 28, 2009 | 08:01 PM
  #3  
Simon1's Avatar
Simon1
5th Gear Member
 
Joined: Dec 2006
Posts: 4,552
From: Redding, CA
Default

If you have a tuner I would suggest a data log be sent to your tuner.

I have had tuning issues with my car and it sometimes happens all of the sudden. When I was going through my issues I thought I had a bad TPS and MAF etc etc. The tuner stated the MAF either works or it doesn't, not half way. He also stated he had never seen a TPS go bad on our cars.


Instead of buying parts, have them salvage them from other cars to see if it makes a difference. A TPS or a MAF can be changed in a matter of minutes.

Did you try reloading the tune or disconnecting the battery?
Old Sep 28, 2009 | 09:38 PM
  #4  
GT Bob's Avatar
GT Bob
3rd Gear Member
 
Joined: Apr 2007
Posts: 763
From: Pa
Default

Without datalogging and diagnostic equipment, its hard to say for sure, but you do give some good info. The fact that it doesn't do it when the car is in a WOT state says that it's something to do with closed loop fueling during transitory conditions on the throttle... which is just a fancy way of saying that when your cruising and give a bit ore gas. At a guess, it may be something as simple as a loose vacuum hose, or a loose conection on a sensor. Wait and see what they find...
Old Sep 28, 2009 | 10:09 PM
  #5  
JDWalton's Avatar
JDWalton
Thread Starter
5th Gear Member
 
Joined: Apr 2007
Posts: 2,612
From: CT
Default

if it was vacuum releated, I shoudl also see the bouncing on my boost gauge right? cause it stays pretty smooth. but yeah, gonna wait and see, they said thell hook up there diagnostics tool and go for a drive to see what numbers there getting while they recreate the problem.
Old Sep 29, 2009 | 10:40 AM
  #6  
Starfire's Avatar
Starfire
3rd Gear Member
 
Joined: Jan 2008
Posts: 775
From: Chicago Burbs
Default

Not that it has any relation, but was wondering what power you are putting out?
Old Sep 29, 2009 | 03:34 PM
  #7  
GT Bob's Avatar
GT Bob
3rd Gear Member
 
Joined: Apr 2007
Posts: 763
From: Pa
Default

It's possible that you would see something, but not nessacarily. Depends on the relation of the leak to the boost guages pickup.
Old Sep 29, 2009 | 04:01 PM
  #8  
moosestang's Avatar
moosestang
6th Gear Member
 
Joined: Sep 2006
Posts: 11,278
From: Gainesville, FL
Default

Originally Posted by JDWalton
if it was vacuum releated, I shoudl also see the bouncing on my boost gauge right? cause it stays pretty smooth. but yeah, gonna wait and see, they said thell hook up there diagnostics tool and go for a drive to see what numbers there getting while they recreate the problem.
If it is a vacuum leak, then you should notice it at idle. I'd pull the plugs and have a look. The plugs are easy to check.

Last edited by moosestang; Sep 29, 2009 at 04:07 PM.
Old Sep 29, 2009 | 04:24 PM
  #9  
graygt07's Avatar
graygt07
2nd Gear Member
 
Joined: Mar 2008
Posts: 390
From: il
Default

when i floored or got deep in the throttle it felt like power was way down and the exhaust would pop. If i got on the gas but went slower into the power no problems. I changed the plugs and all was fixed. I was blowing out a plug when i floored it and the fuel was burning in the exhaust hince the poppong.
Old Sep 29, 2009 | 07:21 PM
  #10  
JDWalton's Avatar
JDWalton
Thread Starter
5th Gear Member
 
Joined: Apr 2007
Posts: 2,612
From: CT
Default

yeah, but i can still make WOT runs at full speed with no loss in power. It also idles and drives normal fine. It is just odd cause its at a specific RPM range and under a specific amount of throttle. Just gonna end up letting them run there diagnostics this Thursday, if they cant come up with something good, I'll pull plugs this weekend.



All times are GMT -5. The time now is 12:41 AM.