Superkop

Ok gang, I have seen some indepth troublshooting on this board for all sorts of problems, and am very impressed with the wide range of experience and knowledge here...that being said - figure this one out: TPS set at .540, goes in a nice sweep all the way up to 3.214volts then goes O.L. I replace switch and set it all up, checking throttle linkage and everything else for binding or other improper working, adjust it and bam, same chit again, AT THE SAME VOLTAGE POINT, right around 3.2volts. Now is the O.L. a full on/open throttle condition? I notice if I bring the throttle up to about 3/4 which is where it hits that point, adn then whack it a quick blast, it doesn't react, but if I ramp the throttle all the way to WOT, the motor goes right up to 6grand. I am wondering if the point of open lead is the switch applying full signal/i.e. maxing all the parameters to the ecm, or is is a fault in the ecm or the HYPERTECH chip that is in there(not my choice..). I am doing a set of injectors and an adjustable regulator this weekend, along with a new temp sender switch and T-stat, so Id like to be sure when I am finished that I don't have other issues as well. This pig sat for over 8 years in a garage and just went to pot, so thats why I've done all the work; new fuel pump sender.piping assembly, new lines, new brake lines (complete) new icm, FULL tune-up, FP relay, brakes, injection, etc. etc.

vetteoz

iTrader: (13)

Not that I am aware off
Testing spec for TPS are
.54 Volts Idle, ~ 5 Volts Full Throttle.

(although I have never had one go 5V ; just over 4V in most cases)

AlkyIROC

Although all transducers including a TPS operate from 0-5v, they generally only go from 0.5 - 4.5v. That leaves a margin for error if they go beyond the normal upper and lower limits.

The O.L. means Out of Limit. Since it's happening at WOT, I'd say the WOT setting is going above 4.5v just as you go past 3.2v or slightly above 3.2v, voltage drops to zero. Either way, it's an O.L. error. If nothing worn is found, replace the TPS and try again. I've found TPS with worn or broken internal springs. The spring forces the internal rheostat to close when you let off the throttle. If the spring is broken, it sort of floats with the linkage and can cause weird problems.

EagleMark

Actually we don't even know what vehicle your working on? Your TPS voltages are what my sons Toyota does... and what are you measuring with? Multimeter could be going OL because of the way it is set...

Superkop

Its an 87 IROC, factory 5.7 car, and I am using a good SnapOn meter. The original TPS did this, going OL after 3.24volts and 3/4throttle, so I put a new one on, adjusted it to .565 at idle, and it does the exact same thing, at the exact same spot and reading. The car and TPI have been tuned, and it runs awesome, and the injectors and regulator work are just for my own good feelings. I am really thinking its got to do with an ecm or chip function. Although I am going to check the range limits on the meter and maybe try a different range. I personally was reading the OL as open lead...too much circuit/wire checking I guess. Hey Alky...I run a pair of 540's opened and stroked to 598" in my boat, but at 540" those motors were bulls! I went to bigger displacement, lower comp because EVENTUALLY a pair of Moonyhams and injection are coming their way. Was looking into some Jacobs Performance 706" motors, but to dress them was a nightmare!

AlkyIROC

Tall deck engines are nice but they're difficult to squeeze into a production car.

Superkop

Those 706" motors needed a custom base manifold that would cost me about 1,200 each...and they wouldn't fit inthe boat because mine are side by side motors, and the clearance between them is thin. A kid in the area runs a 722" Sunny's motor with some big turbos in his Nova. I hear its dam fast

Superkop

UPDATE: New BBK fuel reg, Accel injeectors, injection, idle, timing all tuned,......TPS checked with meter up one range - PRICELESS. .600 idle clean sweep to 4.65 votls WOT. She runs perfect, although having sat for 8years made everything stiff, and shifting was hard at first, but a few miles of running around and its mint. Fix a few bugs and some tires without flat spots and walla...a mint IROC. Funny how I forgot how torqy these setups are, the rear end brakes loose wiht a tap of the peddle, and if I mash it, she goes right to redline, even with BF Comp TA's fairly warm. NOT good if you don't expect it though

jeremymsl

I know this is an old thread but im hoping someone will help me cause i cant find anything, i have my tps set at .64 iv read that the factory is from .54-.75 now i used to have it at .54 and i just did my milage (with 90% of the tank with the car running .54 volts) and i like it so will putting it to .64 volts make my milage worse or better or even noticable?