HAILERS

*******its not boost cut, unplugged the boost sensor and theres the cut, right smack dab at 3800. i read it forces the secondaries on at that rpm when the sensor isnt there or is capped off.********************************************** *****

Clear this up for me just a bit on the above. Was this with the vacuum hose off and plugged? Then in the driveway you raised the rpms til you reached 3800 rpm and it started acting carppy at that figure????????

IF and I say IF the above is the scenario, then that might be normal. The secondarys would have come on at 3800 rpm and made the mixture tooo rich which made the engine gurggle at 38000 in the driveway. That would be a good indicator the secondarys do come online.

IF the vac line was off and plugged and you were diriving moderatly, then the same would happen at 3800rpm unless you stomped on the pedal hard and kept going on up the rpms then it would clear up.

It's getting to be a long post. I forget. Does this car have a fuel cut defender?

LeeTheSlacker

car has a FCD

i unplugged the boost sensor alltogether from the harness when i tested that.
i figured, if it was boost cut, then if the ecu didnt get the boost signal then it wouldnt cut.

this is seriously stumping me.
everything checks out 100%, yet i still have the lean wall of death.

FC3S Murray

iTrader: (7)

Man, sorry to hear your prob. You could call HKS and ask for troubleshooting advice for your FCD.

I have experienced this annoying problem twice. Once with bad EGI ground and second with a fried f-con ROM.

Syonyk

Humor me.

Pull the passenger's floor panel up. Stick a voltmeter into one of the ground connections on the ECU (thicker black wires IIRC, but check the FSM for the pin locations) - you can stick a probe in from the back while it's still connected to the ECU and test things while it's running. Stick the other end to a clean point on the chassis as a ground.

Run the engine, rev it up past 3800 RPM with the boost sensor disconnected (so it'll try to bring the secondary injectors online).

See what the voltage between the ECU ground and the chassis ground does.

A bad ECU ground (for whatever reason) would explain this, including why the 2nd ECU did the exact same thing.

Another thing you can try (or may have tried) - what happens if you force the engine above 3800 RPM with a downshift? If you abuse your clutch to haul the engine up to 6000 RPM, will it stay there, or does it have no power until it drops below 3800?

The ECU ground is worth checking at this point. All the normal stuff checks out, so you're down to looking for weird problems.

-=Russ=-

LeeTheSlacker

grounded the **** out of everything. ran a ground from the battery - to one of the ecu bolts, then from there to the harness ground on the motor, then from there to the stock - battery cable. still cuts out.

im stumped.

boost sensor reads about 3.2v at 8psi

i guess ill switch the primaries and secondaries around, although i doubt there bad as ive tried two sets of secondaries.

if i downshift at 40 into second and put the car around 4k, and accelerate VERY lightly i can make it past the cut. but any more throttle then it takes to barely accelerate and the wideband goes way lean, like 15-16afr.

an ignition problem like bad plugs or a misfire or something wouldnt cause a lean condition? im stumped so i figure id ask about anything else that might be causing it.

car ran fine on the same harness when it was na, no problems at all. so the harness should be good..

egi ground? which ground is that? i ahve a million feet of 6gauge cable and a million ends, cant hurt trying some more grounds.

R_PROWESS

iTrader: (3)

I'm currently having the exact same problem as you man, EXACT only Diffrence is I have a tII harness that came with the turbo ECU, ALL electrical a direct swap over from the turbo parts car and it doesn't work! Makes sense of that. there aren't even any miss match electrical components as a plausible factor. Electrical it's all same as factory no fcd no apexi nothing.

Freshly cleaned injectors.. all 4 passed basically perfect. Swapped secondaries for primaries when this problem came up, still...

For the last 9 months I haven't had time to work on it I've been away from it at college, meanwhile doing research on how to fix it. Crack this bastard for me!

HAILERS

((((((((((((((I'm currently having the exact same problem as you man, EXACT only Diffrence is I have a tII harness that came with the turbo ECU, ALL electrical a direct swap over from the turbo parts car and it doesn't work! (((((((((((((((((((((((((((((9

I'm not a bit surprised yours didn't work if it's a series four and you used the Turbo EM harness.

If curious do a serarch with my name. I'm tired of repeating myself even though I now it's different people asking. Or search rotary ressurections site and he explains how to do it.

Bottom line is: REMOVE THE DAMN TURBO EM harness an reinstall the non turbo harness and make the ONE wire change that is needed. THat's for the twin scroll actualtor. The one wire change I mean.

I've a knee jerk reaction to WE THE PEOPLE. It usually signifys a group of dead beats figuring out how to take my money (my labor) to pay for something they should be doing for themselves. Blood suckers is another word that comes to mind or Democrat.

R_PROWESS

iTrader: (3)

we the people in my case is a bmx company

LeeTheSlacker

i have a non turbo harnesss!

so waht in the world is causing this.

im totally and completely stumped.

you seem to know your stuff hailers, any ideas? i got you all the boost sensor voltages and such.

R_PROWESS

iTrader: (3)

I'm lost at what to do too..

According to HAILERS it's my s4 turbo wiring harness may be causing the problems and that I should get an s4 n/a harness, which I'm not about to go buy one when that is exactly what you have and it isn't working for you, (Assuming our problems have identical causes) why would it magically make my car work?.. basicly to go buy the "right" harness to replace the "wrong" factory harness that came with the car specifically for that ecu and engine? In my eyes, if the harness was my problem than your car should be running right now. but i'm not saying HAILERS that you are wrong by any means, don't get me wrong. im just trying to justify all this.

have you installed a fuel cut off switch to de-flood? Maybe mis wired it somehow and interfered with the secondaries signal?

The only things i have done to the electronics.. emissions removal, install cd player, and fuel cut off switch. any of these apply to you LeeTheSlacker? process of elimination here.

LeeTheSlacker

emissions removal, cd player was in the car before i turboed it.

i dont have a switch, but i need one. likes to flood.

im so stumped

R_PROWESS

iTrader: (3)

Hey man fixed my problem it was this, the one i had in there was bad, i don't know which model it was from or if they differ from turbo model or n/a of the same series but i swapped it with the other one i had and everything operates very smoothly and they come online now. hope this helps you out bro

blmcquig

iTrader: (15)

^ the injector resistor.

um, i had the exact same problem on my car for the longest time. ended up being the ecu. if you can find someone who will let you borrow theirs for a couple minutes, you can plug it in and try it. who knows, i think its worth a shot.

Sandman FC

I too am also having the same problem, cept mine is an S5 na. Im stumped as well. Do S5's have a resistor box as well?

Icemark

multiple bumps deleted.

LeeTheSlacker bumps are forbidden in the 2nd gen technical section. Why did you think your questions are more important than anyone elses?

TehMonkay

iTrader: (-1)

Jacob Cartmill once had the exact same problem, was the injector pack *** well. Buuuuuut.

Are the injectors out of the 88.

Because if you use the injectors from the 88 or aftermarket injectors, if your car has an 87 or older harness it shouldnt work anyway.

So before you post the same thing again, get back to us after you do this.

-Test the resistance from the ecu wire for the injector ground to the ground on the injector plugs

-Try switching out your resistor pack with one from a donor

-Test the resistance of the main ecu ground.

If it's an old crusty s4na harness you could have damaged the ground by moving it around anyway.

LeeTheSlacker

because my car was broke and i was pissed and my thread was on like the 5th page? why does it matter, really?

anyways cars fixed. tii fprs on the back of the rail, on the na its at the front.

i overlooked this and hooked the lines up how the na goes. switched the lines to the secondary rail and it runs great.

R_PROWESS

iTrader: (3)

I have the 87 tII harness along with the cleaned/rebuilt 87 550cc injectors, I don't have anything 88' or aftermarket. but at least this lets people know what to look out for.