APEX TURBO MISSES AT FULL THROTTLE fuel problem?

[DooAssassin]

I dont know tho if its that. Reason being, people have issues with too much pressure and runs rich at idle. That should mean its getting all the fuel it needs to perform. Does anyone know if this is true? It could be the problem, but its defiantly only one cylinder at a time, the other 3 seem to run good...... or it could be just the first cylinder to lose its fuel pressure.

 

[TBird]

It is possible to run rich (have high fuelpressure) @ idle and starv for fuel @ boost, if it's a restriction in fuelflow pressure will drop!

 

[YamerHammer]

The external pump is the pump to provide fuel pressure, but under a load (Boost) if the internal pump can't supply the external you will loose fuel pressure for the fact that it can't supply the external pump with it's needs at full boost. The fuel pressure regulator no matter how much supply you give it should control the fuel pressure but if you can't supply it then it drops off.

 

[DooAssassin]

internal pump is coming out, is there a way to run it with out the pick up for now? Like using the original pick up but with out the pump installed? Just to eliminate the issue. I will let you know how that goes.

 

[mulot30th]

Powdeerlites sells a pumpe eliminator kit... this is what you need, it works.

 

[rxrider]

MCX has a new pickup to install in the tank, it replaces the internal in-tank pump, it reuses the filter element. We do not run with the stock pump, we always remove them on the MCX kits. The internal pump is known to degrade in terms of pumping capasity over time. Thus it will restrict fuel flow causing starvation and cavitation in the in-line pump.

Tell us your clutch setup, like many others I'm pretty sure you're at the limiter a lot. Not good as running on the limiter will kill your exhaust headers causing them to leak.

Tell us you clutch setup, we need to know the following details:
- primary spring
- clutch weights and how it's weighted
- secondary spring
- helix angles
- helix spring twist in degrees or #'s
- drive belt condition
- drive belt ride height

 

[DooAssassin]

Im on it tonight...Thanks

 

[DooAssassin]

here is what I have for now:
Dalton Spring 53/133
stock apex seciondary tight.
Belt is just to say sitting out of the seciondary
Belt has one day on it and has a small burn mark but not on the top just the lower sides and very small.
I will get you the rest shortly. Thanks for your help

 

[DooAssassin]

oh and I have the revs low right now to try and eliminate the miss issue 10-105

 

[mbarryracing]

Very well could be electrical and not fueling at all... Something rather simple but have you tried new spark plugs? Could be one or more is actually loosing the spark (blowing out) when the cylinder pressure and turbulance really comes up at WOT loads, I had this very issue on the dyno... drove me nuts trying to find it.

What plugs are you currently running? Don't ever use the dual electrode plugs because they are definitely more susceptible to misfire under boost, run the stock plugs and try gapping them at 0.018"

 

[DooAssassin]

I just put the dual plugs in to try to fix the issue with no results. But the gap is alittle over .20. I will gap it again. But I dont think its the issue. Who know maybe it is. Thanks. I ordered a pump eliminator. Does anyone know what is the best way to check fuel pressure and were to get a guage?

 

[mulot30th]

12-15 psi is not enough pressure to have ignition problems.... even with stock apex coils... unless the coils are defective?

 

[mbarryracing]

I don't think eliminating the in-tank pump is the fix because I run all the way to over 20 psi with the stock pump setup with an inline external walbro pump without issue. Doesn't mean your stock pump isn't crapping out, though.

I've seen weak spark plugs cause misfire at 6 psi...

 

[TT]

A few possibilities if you have ruled out rev limiter, spark plugs and TORS.

Could your boots lifting under boost? Do a pressure test of the comp.side of the turbo system to eliminate boost leak between the plenum and throtle bodies.

Are the mcx injetors working under boost? Unhook the vacum line to the mcx box and plug it off. Add a new vacumline to the mcx box, fire up the sled and let it idle, then add 2-4psi to the mcx box. If injectors are working sled should start to die running rich on your O2 meter.

 

[DooAssassin]

how do you do a pressure test on the compressor side? Thanks