nitropowered

hey i got a 89 GTU i have a k&n intake kit and cats removed, and when i hit 6k rpm the car seems to loose power, it will go all the way to redline but it jerks and runs like **** other then that it runs great starts no problem, no smoke, any suggestions?

PureSephiroth

search for 5/6 ports. they are probably stuck shut.

edit: by removing the cats you probably lost too much backpressure. they function on exhaust backpressure. You should wire them open if this is the case.

ddub

No he has an s5, his run off the airpump not backpressure.

If it were the aux ports he would have a loss of power before 6k, if this is just happening from 6k and up it sounds like a fuel problem maybe (like a clogged fuel filter?). You can try doing grounds too and seeing if that smooths it out at all.

nitropowered

i havnt tried a fuel filter, and it did it with the cats on as well, i just baught the car for 200 bux and i dont know what kind of maintinece was dont to it.

Tofuball

Make absalutely sure your VDI is opening properly, and your front throttle plates arent 'hanging' stuck shut. I know thats a problem I've seen on turbo models.

nitropowered

yea all the throttle plates are opening, its odd, when you hit 6500rpm the starts to jerk and buck, but it will go to redline.. i dono never ran into this on my S4

Falcoms

I'm actually having the same problem on my '90 GXL. I just had the injectors cleaned and replaced the tranny with a TII trans. I know I have a vac leak somewhere off of the hose on the passenger side of the engine bay with a hose that has a "T" fitting below a (I assume) 1-way valve that's green and white. IDK where the hose that plugs into that goes, but I do know that I don't have the cruise control hooked up to vac or to the throttle plates. I actually get a momentary loss of power at 6300 RPM and I run out of steam at 68-7200 RPM (temp. depending). I would suggest looking into this as well. I too have gutted the cats (I had bonez high flow duals and they fell apart from age, which I found out during the trans swap), but IDK where that would fit in on an S5 with the problems.

Falcoms

hey, look!

z4csl428

not necessarily, my VDI quit working bc a hose blew off but i didnt notice it, my 6 port kept working fine, so i didnt notice the loss of power until the 5500-6K range and it would jump and sputter to redline. i checked everything but then noticed the hidden hose had blown off, hooked it back up with the support of some zip ties and it was fine...

nitropowered

what hose what this? the car has 148k miles on it, should i tear it down and get all new vac lines? and intake gaskets?

nitropowered

what hose what this? the car has 148k miles on it, should i tear it down and get all new vac lines? and intake gaskets? and my dad owns an auto repair shop so i have acces to tools and parts.

RETed

TPS


-Ted

z4csl428

i made that post just to tell you not to rule out the VDI, but it could be anything. the hose i was refering to was behind my UIM (by the way this is on an electronic setup so i dont think this would apply to you). dirty injectors, clogged cat, bad fuel pump, non-working VDI...anything could cause this problem. theres no need to tear down an engine just for this problem.

Falcoms

Any possibility of getting a pic of this hose in question for reference, being that IDK where I oopsied exactly?

z4csl428

the best things to do would be adjsut your TPS to 1 volt, and check to see if your VDI works by putting grease on it and driving it for a while under load (above 5500 RPMs most of the time) then check to see if the grease was smeared...

ajsuper7

my tps was failing on my vert and the car would usually run pretty awful if i tried to sustain high rpms above 5500 to 7000 (automatic cars have 7k redline) ive replaced the tps and what do you know it pulls great all the way to redline.

nitropowered

my friend adjusted my TPS but there was no difference

slpin

iTrader: (9)

winner of the day!

RETed

This is not about TPS adjustment.
This is about the TPS out-of-spec at WOT.
Check resistance of the TPS green and black wires.
I'd bet it's over 5.0k ohms when you open the throttle to WOT.
If it is, it's the TPS causing the high RPM hesitations...
TPS can go back when resistance starts to creep over 5.0k ohms at full extension.


-Ted

rx7lover0147

new clutch?

RETed

Uh, no.
Bad clutch doesn't prevent the engine from revving higher.


-Ted

Falcoms

I already had pretty much settled on this being my main problem being that its been getting worse since the trans job, and right after the job, I was running up to ~82-8400RPM (temp. depending), so I had already figured this, being that I already had a bad one with blow opens when I bought the car, and this is a used replacement (you know, temporary ). My question to Ted is: is the green and black wires the ones to check on an s5, s4, or both? I only ask becuase I remember that I had to guestimate which two they were because the teamfc3s website didn't say the right colors for my (s5) TPS.

RETed

The wires colors are identical for all FC's - dual TPS or not.
The wires are not solid color - there is a stripe on them, but I don't recall the stripe colors right now.
I do know that the main colors are black and green.


-Ted

Falcoms

^ Okay, we gots it figured out. It's kind of dark out now, so I'll check it out tomorrow after my multi-meter defrosts. I looked and it appears that the TPS is at ~2250 ohms cold, so I'm pretty sure that it's outta wack. We'll just have to wait and see wether or not theres a short or blow-open.