apex popping and wont hold rpm

[hiherthanu]

o6 turbo apex 66 aero side mount aem 02 sensor, turbo connection manager

Ran fine the first half of season, then all the sudden....when I gas it the sled runs to 10600 starts popping then falls off and the fuel ratio guage shows lean. RPMS fall off to 8500 or so and keeps popping

I put in a new 02 sensor the beginning of the season and just had the mangar reprogrammed adding 12% from 8500 to 11000......STILL THE SAME PROBLEM

IDEAS?????

 

[julio]

sounds like you are hitting the rev limiter. your belt may be slipping.

 

[Veedy]

There's a definite difference between lean pop and rev limiter. Sounds like fuel management problems. Can you get your box tested or re-flashed ?

 

[Boostfreak]

How old are your plugs?

 

[hiherthanu]

Im pretty sure its not the rev limiter......it never builds the rpms back up when it starts popping.

the fuel manager is no longert available....the shop that I got it from no longer uses them...it was hard to get it reflashed this last time.

plugs have 1500 miles on them. Maybe and issue there?

If the problem is the fuel manager, what is the best manager to use?

 

[hiherthanu]

has anyone had trouble with the fuel pump? is there a fuel filter Im missing that may be plugged?

 

[Veedy]

Thats another thing, what is your fuel pressure running at ? do you have a guage on your sled ? Guys are having good luck with the Pure Logic boxes now and have a new program that rocks. Call Dean at Alpine motor sport in Salmon Arm BC. 250-804-4334, he will get you going in the right direction.

 

[lakercr]

If I was to describe what a sled does when the intercooler comes off the boots it would read a lot like this...

 

[Pastor]

Bad plugs

Innercooler coming off or developing leak under boost

Entire throttle body coming off at the motor under boost


Check very very carefully to make sure the throttle body is still on correctly at the motor. I broke an innercooler mount and it was not very noticeable but at about 9 lbs boost it was lifting the throttle bodies right off the motor.

I have seen this with several guys now.

 

[hiherthanu]

THANK YOU ALL. Im gonna start checking things out. start by removing the intercooler and checking all connections, then the plugs and finally fuel pressure.....fuel should be 40 lb @ idle and 45+ revved up??

 

[julio]

fuel

the other thing you should do with the fuel presure is make sure it goes up with boost.
I just did this to make sure Ididnt have a prob. I took the line off the presure regulator hooked it to my air compressor set at 10 lbs started the pump (turned on the key) and applied presure. pump runs at 45 with the extra presure it jumps to 55. a pound of fuel pres. for a pound of air.
you can also presureize the entire boost system, makes it easy to find a leak.. julio

 

[tntm7]

if your regulator is working right it should go down 2-3 psi from key on motor off to engine running at idle, another words turn the key on you see 42psi, with engine idling its common to see 38-39psi,
If you have been running stock or std plug gaps you may have ground tracked your coils out. The cdi coils cant take the stock gap for very long before they go south, need .018-.022 plug gaps on boost cdi ignitions.
It will also rave havock on your ECU from the electrical noise generated with stock plug gaps.

 

[hiherthanu]

Ok heres what I found today.......fuel pressure @ 42lbs at idle whne I run the engine up the pressure gains 1lb @ 6500....im assuming the fuel pump is fine. I ohmed out the coil sticks...they check out fine. check all the hose clamps on the intercooler.

I did however find the positive battery loose on the battery, Im hoping this is the problem....

 

[Pastor]

What you are decribing sounds exactly like your throttle bodies are lifting off your engine at boost.

I am not talking about throttle bodies to inner cooler.

I am talking about motor to throttle bodies.

You have to get down with a flash light, if there is any gap between the black throttle body boot and the engine it has lifted.

It will look pretty good and even hold a little boost but at about 8lbs or so they will lift and you will pop.

Starting from the top looking down you have 1. inner cooler 2. hose clamp 3. rubber hose 4. hose clamp to throttle body 4. Throttle body 5. factory black boot to throttle body 6. black boot conecting throtte body to engine.

In most cases it happens because of a fracture in the support mount on the inner cooler that keeps everything from lifting.

#6 is your problem.

It may look OK at first glance but you are describing exactly what happens when the the black factory rubber boot lifts off the engine.

I hope this helps.

 

[hiherthanu]

I went back out the the shop and check the connection between the throttle bodies and the block. looks o.k. I pulled up on the intercooler while shining a light on the rubber boot, i didnt see anything moving or lifting.......is there another way to check this?

 

[Pastor]

Is the black boot up against the motor as far as the boot can possibly go?

There is a grove inside the boot that fits over a ridge on each of the intakes into the motor.

If it is not pressed completey on it will look right but under boost lift.

We are talking about something like a quarter inch difference from being on right and looking like they are.

 

[hiherthanu]

your right sir, mine is about 1/4" from the motor. whats the fix? I was wrong i have a innovate a/f guage.....ive heard these arent the best.

 

[Pastor]

I have a boondocker kit, so I can tell you what I had to do, it will be close to the same.

Remove the innercooler, when I remove mine I have discovered that If I loosen the clamps closest to the throttle bodies I have better angles for the screw driver.

Once the innercooler is off. You have to take an allen wrench and really really loosen the factory boot against the motor. Make sure the boot is not loose on the throttle body but so far I have never seen that happen.

Push the throttle body and boot back onto the motor, it is not as easy as you might think. I have learned to take the time to really loosen the clamp. There is a ridge on the intake of the motor and if the clamp on the boot is not really loose you push it on and think you have nit but you don't, the boot has to seat over that ridge.

When it is on correctly it touches the motor, the boot hits the motor, top and bottom.

Once it is on correctly, tighten it back up good and tight.

Then put the innercooler back on etc.

My Concern is why did it come off? I have had this happen and seen it on several others but I have always been able to figure out why. Usually the mounts on the innercooler had a break in them, sometimes a hair line and you could hardly see the break.

It would be nice for you to know what allowed it to lift so it does not happen again.

 

[Pastor]

Did you get it fixed?

 

[hiherthanu]

I been pouring all day, weather finally good enough to work. gonna get on it tonite