NEOMASTERZ28

what will make a sudden loss of tq on a tpi, i plan to give it a full tune up and put an o2 sensor. anything to explain why a sudden loss of tq????????

NEOMASTERZ28

anyone ?

mystikkal_69

iTrader: (2)

try resetting the ecm. see if the power comes back.

SD or MAF?

NEOMASTERZ28

maf

ULTM8Z

My guess would be on the fuel side.

Fuel pressure?
Fuel filter?

Check these and let me know.

mystikkal_69

iTrader: (2)

o2 sensor would be a cheap start. once that is done replace the fuel filter as stated. if at all possible check the fuel pressure and report back with results. after replacing these things reset the ecm to clear it out and give it a fresh start. tune up wouldn't hurt if one hasn't been performed in a while.

bigals87z28

vaccum leak, blown rings, rockers losen up, crappy gas, timing's off,... could be serveral things.

sllt1776

you didn't mention if you were getting any codes. your cat could be clogged. when mine did...it was on a trip, just all of a sudden it started to bog and in a minute the top speed was maybe 20 mph. how old is your cat?

NEOMASTERZ28

ok well , i did a complete tune up. plugs,cap,rotor, all brass, new fuel filter,oil change o2 sensor. and it still bogs after wot about 3500 the tq will die and the car like jumps back, like backing off.

no codes just the egr one on the hwy.

timing is at 6 and there was a lil vac leak but still the car is still the same


sllt: the cat is the factory 1 chould be bad but i think i should plan to cut it off

sllt1776

well if there are no smog checks then do what ever you feel comfortable with. i would fix the vacuum leak. it may be causing the egr failure and maybe some other problem. i think just buy a hose need to replace all the vacuum lines at once, it's not too much and you can then rule that part out

ULTM8Z

Check your Throttle Position Sensor. It should be set at approx .6 V at idle. With a digital voltmeter on the blue (+) and black (-) wires, slowly open the throttle and observe the meter. It should smoothly go from the ~.6V to ~5V. If there are any spikes or sudden drop-offs along the way, you likely have a bad TPS.

The TPS triggers the "acclerator pump" for EFI. It tells the computer that you have suddenly increased the throttle and therefore need some more fuel. If the TPS loses the signal, it would be like taking the acclerator pump off a carb- the car would bog.

NEOMASTERZ28

how many volts should it have at wot ?

ULTM8Z

I believe it's 5V at WOT. The ECM sends out a 5V reference voltage for the TPS to work with. The TPS, being a potentiometer, simply regulates the voltage sent back to the ECM depending on what position the throttle shaft is in.

NEOMASTERZ28

At wot mine does not read 5v it reads 4.2 or 4.3 i rember reading it somewhere that it supposed to be 5 but im not sure so, its set at .54 and keeps the setting but not 5v at wot

plus there is a tq increace when the ac is on it even makes the tire chirp 2nd ? but not that much when its off

ULTM8Z

When was the last time the injectors were professionally cleaned or replaced?

NEOMASTERZ28

never stock 85 injectors, never had a professinal injection clean service i know some are a piece of crap but what shop do you recommed?


so what about read 4.3 volts a wot on the tps

mrr23

anything close to 4.5 to 5.0 is fine.

DANIELEK

Hook the car up to the laptop and take it for a ride and then watch your knock retard.

Before i started paying with the chip I had the same symptoms and my car was tuned up well. I hooked it up to the laptop and logged some data and i noticed that i was getting 10-14 d reterd at around 3500 RPM and it felt like the car wasn't pulling anymore but the RPM went up.

The spark advance on the original chip was way too much for my car. When i lowered the spark advance and took the car for a ride the knock retard was almost non existant and my car felt like a v8 should feel all the way up to 4500 RPM.

Just a thought.

D

NEOMASTERZ28

i just got the fp to 52psi and still no difference still boggs at wot or somtime in second at wot

on tpi when u go wot your giving it alot of air then air hits fuel so chould it be injectors?

or tranny casue some1 did mention that