before I begin let me say I have read every thread on bogging hesitation on here.

ok my issuse is anything over half thottle my car boggs hard. i have an apexi neo as soon as I hit 100% any more on the pedal just boggs

car: 88s4 na

mods are:
tb mod, emission delete, no aux sleeves,slight ported intake manifolds. hot wired fuel pump, premix, no omp

things I have done: set tps, fixed a fuel leak, fuel filter, new plugs,tried 2 differant sets of plug wires, cas was stabbed correctly by rotary mechanic, fixed vac leaks, I have a fuel pressure gauge in line sits at 40 psi.

basicly I am running out of ideas, any other ideas are welcome.

this is the same setup I had on my other engine be fore it blew. and I never had this issuse .this engine is a rebuilt street port, I have about 220 miles on it and it hasnt been redline or abused. the way it drives is half thottle up to 3k to 4k.

 

I'd bet it is in your Neo settings.

 

I have no correction set I use it for monitor rpm ,thottle input and volts.

 

Do you have 40 psi fuel pressure at idle? If so, then it's too high.

 

yes its 40psi at idle I had to hot wire my fuel pump, because for some reason the wire that is used for the fuel cut off switch, when its connected my fc doesnt start. thats another issuse I need to figure out.

 

Is your fuel pump stock or not? If it is then disconnect the vacuum hose to the FPR after the car has been idling and warmed up some and see if there is vacuum coming from the hose or not. There should be vacuum and if there isn't then the FPR solenoid is not working properly. If there isn't vacuum then the fuel pressure gets bumped up from a normal 30 psi to about 40 psi which can be too much for the car. In a normal situation, the pressure should be close to 30 psi and removing vacuum from the FPR causes the pressure to rise to 40 psi.

 

all rats nest and soelinoids are gone, no etest here in fl. its a stock pump. I just have the fpr hooked to a vac nipple.

 

Pull the vacuum hose off of the FPR and see how it affects the fuel pressure. Also, make sure you have vacuum on that hose after taking it off.

 

ok so I warmed up the car pulled off the vac line and it made no change in fuel pressure stayed at 40psi. I have an adjustable fpr, should I try that and if so what psi should I set it at??

 

check your neo wiring, bet you chopped the wrong wire.

 

ill check it tomorro but I dont think I did. ive wired it up a few time in a fc already.

 

But was there vacuum on the line though?

 

probably not with the emissions delete. probably ran to the wrong port on the UIM pre-throttle body. that is about the only place where there won't be a vacuum signal. that or the fuel pressure regulator is bogus.

but yeah, if it's giving vacuum to your FPR port and the pressure isn't changing at all then your regulator is poop. still won't really explain the bogging issue though as that pressure is fine for a load, will be slightly rich out of load.

i'm still betting the AFM setting for the neo got defaulted somehow or the wiring was done improperly. in some cases you can drive the car without the AFM but it won't enrich the fuelling as needed when accelerating. so if the AFM wire patch was unsuccessful or the settings improper, yeah... no fuel no go.

 

ill check the settings and wiring on the neo. see what things are looking like. its just odd how taking off, cruising, decel its fine but as soon as my narrow band tps is maxed out it just boggs

 

check the pulsation damper. I had one go bad that did this exact same thing. drove fine till i went past half. do you have a wideband. whats it do when it bogs?

 

no wide band, I did the banjo bolt mod no p.d.

 

everything looked good with thesettings in the neo , i did notice at closed thottle it was sitting at .08 volts and fully open was 4.7 volts . i used the ohm method to set my tps, its worth trying to set 1 volt at idle but i dont think it would be that??

 

Have you tried setting your TPS via the test light method?

IMO it works better than the 1v method, or at least it worked better for me.

 

try taking the tps off the car,, then test it throughout the stroke
,, you are looking for a point that is open circuit or a short that is in the mid stroke of the tps

this bad spot on the reostat wiper will make the the stock ecu freak out and run with these issues
my guess is open circuit and when the signal restores
then the ecu interprets this as the initial off idle signal
and gives the engine a squirt of extra injection timing thinking the motor requires the accelerator pump shot

 

i had this same problem and all i needed was new battery terminals and to go through and clean my grounds up, i also threw in another ground just to make sure. but that was it. it might be somthing different for you but just thought id throw my experiances out there =)

 

a few other things, the bat terminal on the alternator may not be tight. your fuel pump hotwire may be iffy (rewiring it is cheap and easy), yes the battery terminals, or a bad battery may be the issue, knock off or broken fpr?, theres alot of those. and if you got it from ebay, have it checked to see if it funtions proper) faulty tps, a anolog meter works really well for checking for a bump. another common issue is the O2 sensor circut, try unplugging it and see if problem persists. bag plugs??? vaccume leak?

 

so for any one who said neo settings you were right, i knew i set the mode car type things like that. but i guess it didnt take so the other night i reset everything , woke up the next morning and bam it revs fine i can open my secondary thottles with no problems.