supercharged 5.0 true fire 98 explorer sport

gmanpaint · May 4, 2015

Another silly comment to add.

The one way booster vac check valve, is it working correctly?

Is the vac tree intact? I can see it being damaged by accident while installing stuff. :dunno:

vroomzoomboom · May 4, 2015

you mean the bypass valve on the supercharger? if so, yes its working. there really isnt any vacuum trees. i had to screw in a few brass fittings to the back of the supercharger for my vacuum lines.
fast rundown so far of what i have tried. blocked off egr, pulled vac line and blocked it off going to the brake booster. checked compression, cam has been installed straight up. checked lines, they are all new, or less then a year old, same with pcv valve. wanted to try and block that off, but couldnt reach it to unplug it.
the dumb thing is when you pull the line going to the brake booster it feels like theres lots of vacuum, but when you put your foot on the brake peddle its like you have manual brakes, and the gauge backs that up as well.

Turdle · May 4, 2015

Plug the brake booster line and recheck engine vacuum. The booster could be leaking, is my thought.

gmanpaint · May 4, 2015

The valve on the "brake" booster vac line is what I am meaning. It's a one way valve. If it is cracked/bad, you could have a leak, and the brakes wont have power as you say.

I keep forgetting the 5.0 vac set up is a bit diff then the 4.0, and the vac lines are ran diff. Whoops...

vroomzoomboom · May 4, 2015

jon, i put a pair of vise grips on the vacuum line, and pulled it off the booster and didnt see a change. i will try it again, but use something to block it with.
greg, i never did swap the booster when i put the v8 in. its a 4L SOHC booster in it still.

Dono · May 4, 2015

There is nothing left of 'stock' vacuum routing on Tims motor. I would really think that you would hear such a big vacuum leak. You don't.
My first guess was EGR, but that's capped and sealed tight. The vac bypass on the supercharger shouldn't stop the manifold from showing vacuum even if its not working.
Something between the throttle body and the top of the block is letting air in

I really think the leak is something internal. We should be able to hear the leak if its external. Tim, why didn't we think to go to my truck and pull the brake booster vacuum line and feel the vacuum? duh. Hindsight is 20/20.

Tim has his larger injectors in there now, but can't really start the tuning process until the leak is found.

On a side note, I can't believe how loud Tims truck is with that new motor. I see a different style muffler , or an addition of some kind in the future.

Now, what else is there that can cause an internal vacuum leak?

vroomzoomboom · May 4, 2015

Dono said:
On a side note, I can't believe how loud Tims truck is with that new motor. I see a different style muffler , or an addition of some kind in the future.

strait pipes! yea, it differently got loud. as for yours....yeeep. double duho! i bumped into my son and asked him to come over tomorrow and watch the gauge for me. i am going to pinch the pcv valve with pliers and do the same again with the booster. i am also hoping 4pointslow has seen the datalog. that to might show where it is

Turdle · May 5, 2015

If internal vacuum leak is suspect a compression check would help find it by eliminating the valves and rings.

vroomzoomboom · May 5, 2015

been there, done that to! lol lowest was 170 highest was 180. i have been on the phone with 4pointslow. tomorrow i am going to take a close look at the pcv valve to start by pinching the line going into it. if vacuum goes up then the valve is bad. if thats not it, i am going to somehow have to pull it out and see if its sucking air into the gourmet. if it is, then the intake gaskets are leaking for some reason.

vroomzoomboom · May 5, 2015

tried again today. pinched the line going to the pcv valve. no change. pinched the line to the booster. no change. i was lucky and was able to get to the pcv valve and pull it out while the truck was running. no vacuum going into the hole where the pcv goes.

ahodges · May 5, 2015

Do you only have 1 PCV valve? Do you have a breather hose from one of the valve covers to your intake piping after the MAF?

vroomzoomboom · May 5, 2015

its kinda like yours. i have a pcv valve on the passengers side valve cover that vents into the intake tube between the throttle body and maf

Turdle · May 5, 2015

There should be very strong vacuum at that hose. The hole is where the vacuum goes to.

Unless the supercharger is causing positive pressure in the intake.

Frankly, it sounds like something is clogging the intake, like tape over the lower intake ports to keep stuff from falling in there.

ahodges · May 5, 2015

Is it still missing on #6 ?

vroomzoomboom · May 5, 2015

jon, i had only used tape on the inside of the mount after i put it on (and did forget to take it off so the supercharger came off for that before i even finished bolting it down). other then that, i never needed to use any. i covered things up with bags if it sat overnight. as for the supercharger causing positive pressure, i dont know how it would do that unless it was spinning backwards. donno, just asking. it this point i am not going to rule out too much as of yet.
andy the miss was because i did the valve wrong on that cylinder. we found that out using a temperature gun pointed at the header (it was about 100 degrees colder then the rest), and doing a compression test. i have readjusted it, and it is firing on all 8 now.
for giggles, i even just put a new pcv in it, and it didnt change anything

delexploder · May 5, 2015

Do your heater controls work? Also im not sure how your vaccum line is setup for the evap but when mine split open I had a hell of a time figuring out what was wrong and it gave no codes

vroomzoomboom · May 5, 2015

if i knew how to draw out how i have my lines, i would post a pic of it to show how i have them. i will check on the evap tomorrow and see. havent tried the heater controls yet. my one buddy is starting to think i keyed the cam wrong. god i hope thats not it. i did also talk to james henson today, and he is going to send me a updated tune in the morning so i get get it to run with the injectors i have in it now.

corkey · May 5, 2015

if it has compression it's getting air from somewhere,,
you also said it runs,, so it gets enough for that too,, have you tried taking off the intake pipe to the air filter and putting your hand over it while it's idling to see how much vacuum pull there actually is ?
has to be something simple, could be one of the reasons it wouldn't run before,,

You don't miss much when it comes to this stuff, so it has to be something small,

ahodges · May 6, 2015

You have the PCV valve hole plugged with something on the back of the GT40 intake right?

List of places the vacuum line run:
PCV valve in valve cover
PCV valve at rear of intake manifold
Brake booster
EGR valve
Vacuum reservoir for heater controls
Fuel pressure regulator

I think that's it... If all of those are sealed then it has to be internal. Is it running lumpier than it did the first time around?

4pointslow · May 6, 2015

Injectors

After you get the tune corrected for the new injectors send me another datalog at Idle and 2000. They can be on the same datalog. About 10 seconds of each. Engine at operating temperature.

Do you have the brake booster attached to a vacuum port that is pre blower or post blower. also the boost gauge and fuel pressure regulator should be only things post(after) blower. If it is set up that way then at least you know they are in the right places.

Is the supercharger bypass being held fully open at Idle and does it close when the throttle is blipped.

Edit; I had open and closed backwards.

supercharged 5.0 true fire 98 explorer sport

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