No Boost Low Boost

[vinnylightning]

Alright guys I am new to the site and a new owner of a 1999 Ford Lightning. I have a problem with my boost all of a sudden it stopped kicking in. My truck feels sluggish and the boost gauge struggles to get to 1lb of boost. I have heard many things about a bad boost solenoid or leak in a vacuum line. My supercharger is spinning engine is running fine. At WOT the supercharger isn't whining like it was when the boost was working. Im bummed out. Just wanted to know if anyone has had this problem or know a possible fix. Please Help!!! Im bringing it to a shop on tuesday to get it inspected and for the problem to get looked at just wanted to see if anyone had a solution. The truck has a pulley on it exhaust and other mods the truck only has 58k on it. Hope you guys can help me out.
-vinny

 

[WhiTriCobra]

Look at the boost actuator that's on the back side of the SC, driver side. With out it running, is the lever down almost touching the screw stop? When you start the truck, the lever should be raised. Make sure the vac lines running off are also connected and nothing cracked. That's what you might need to change.

Also look at your pulleys and look for belt dust. if you have a good amount of that, your belt might be slipping. Might need a slight smaller belt.

 

[vinnylightning]

When the truck isn't running the lever is at the stop on the supercharger. When the truck is running it is fully raised. I have not noticed belt slip and most of my vacuum hoses look fine. I'm bringing the truck to the shop to get NYS inspected and for this problem to be looked at. I have no check engine light on dash.

 

[JimIII@jdm]

If the truck has an aftermarket pulley and there is no tune installed it could be dumping boost if the bypass mod hasn't been performed. Give us a call at 732-78-0770 I would like to try and help.

JimIII@JDM

 

[vinnylightning]

So truck still is acting up a bit. I called Johnny Lightning where the performance parts are from and they said I need a tune. This makes sense but I am almost positive it was previously tuned. Is it possible for the truck to lose a tune or tune to get erased? The Johnny Lightning rep said it is dumping boost and that I am aware of.

 

[Dusten]

if the dealership flashed it back to stock, than your tune is gone.

 

[vinnylightning]

it was a private sale but i do have receipts it was tuned but years ago i don't have the programmer is it possible for the tune to get erased or lost like what the johnny lightning rep told me was i needed a tune maybe it needs a retune idk what are ways i can check the fuel pump and boost solenoid to see if they are bad i want to figure this out i have been doing a lot of reading and have heard many different things

 

[Dusten]

You can unplug the boost solenoid. Your fuel pump won't effect boost at all.

Do a google search for boost bypass, its a lame gimmick, but it'll show you where the solenoid is at.

 

[JimIII@jdm]

When you unplug the line from the accuator to the boost dump solenoid make sure to plug the dump solenoid line and to connect the Accuator line to a boost source. Like the fuel rail pressure sensor vaccum line. This can be done with a rubber t fitting just like used on or Boost Bypass kit We used this in the early days before the tuning software was advanced enough to shut it off through the computer. Now we just do that.

If your tune was written over by a Ford dealer the tune would be lost, or if the previous owner removed the tune before hand (in order to keep the tuner and possibly sell it....)

 

[Dusten]

If your tune was written over by a Ford dealer the tune would be lost, or if the previous owner removed the tune before hand (in order to keep the tuner and possibly sell it....)

Good call Jim, I didnt think of that.

 

[vinnylightning]

Thanks for suggestions guys got my boost up to 6lbs today chirped second gear feels a little better still not sure if i should get the truck re-tuned do you think that will be beneficial to the boost pressure?

 

[JimIII@jdm]

What did you do to make it work? You should see at least 8 a full throttle

 

[vinnylightning]

It's got a 6lb pulley on it it was pulling 12 before the problem I know or am almost positive my dump value is stuck open

 

[JimIII@jdm]

It's got a 6lb pulley on it it was pulling 12 before the problem I know or am almost positive my dump value is stuck open

Have someone rev the engine by cracking the throttle open a few times. Watch the lever on the bottom of the dump solenoid. If the arm swings back down to the stop its working. When you build boost that should close, if not it would probably create this problem.

With the 6lb pulley Id expect 13-14 psi total.