TPS VOLTAGE

bi19tri said:
Does lower tps voltage lean it out or fatten it up?
Neither one.

The TPS tells the computer how far the throttle is opened. The computer uses this information along with input from the MAF (mass air cars only), Baro or MAP (speed density cars only), ECT, ACT, RPM and O2 sensors to determine the air to fuel ratio. It ignores the input from the O2 sensors at WOT (wide open throttle).

Here's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by Charles Probst :ISBN 0-8376-0301-3.

It's about $20 from Borders.com see http://www.amazon.com/ . Select boo...feeler gauge and give it about one more turn.
 
Right now it runs real rich at idle and 20mph in second it bucks real bad of couse its a 347 with an anderson n91 cam so im not dealing with a stock motor at all.
 
Get a custom chip. It should run you around $300 - $900. If you weren't willing to spend $1K on a custom chip, or spend 200+ hrs learning the Tweecer, then you shouldn't have gone to a big engine with EFI. Sorry, someone should have been honest with you about those points.

Do you want to take that time and spend the money to learn the Stang EEC? If so, that's great! Or, do you want to spend your time on other mods and other things? Most people choose the latter.

If someone told you that you didn't need a custom chip with your setup, then they are full of it! If you have a custom chip, get the problem fixed.

The Tweecer and EEC is *not* something you learn over night. Also, very few really take the time and effort to understand the EEC well enough to tune well with a tweecer. Unless you're willing to put in ~100-200 hours of time learning and understanding the Tweecer and the Ford EEC-IV, don't bother. IMHO, it's *not* worth it for most people.

FYI: My TPS FAQ:
http://www.veryuseful.com/mustang/tech/engine/Mustang-TPS-FAQ.html

Consider this, if you don't want to take the time to read and understand my TPS FAQ, don't even think about wasting your money getting a Tweecer. You'll do more harm than good. I'm NOT saying that you "couldn't" learn how to use the Tweecer, I'm saying that "most" people do NOT have the time or want to spend the time to learn on how to properly use a Tweecer.


If you are interested in learning the EEC, that's great!
Here's a place to start:
A Quick Overview of the Inner Workings of the EEC (Mustang Fuel Injection Computer), by TMoss:
HTML/web version: http://www.veryuseful.com/mustang/tech/engine/EECIVInnerWorkings/
PDF version: http://www.veryuseful.com/mustang/tech/engine/EECIVInnerWorkings.pdf

A GREAT, IN DEPTH, Very Technical, Referance for the EEC IV. A MUST READ!: http://www.veryuseful.com/mustang/tech/engine/eec-IV-Tech98.zip

More at:
http://www.veryuseful.com/mustang/tech/engine/
 
I was planing to do a dyno tune and have a chip burned or a tweecer or even a pms just wanted to get it to run better to brake it in before running it on a dyno
 
The above posts have very good info.

The problems you are having are NOT going to be caused by the TPS.

I agree that self tuning is not for the faint of heart, you have to be willing to learn what Ford did and why. I am using a tweecer and have enjoyed it. However there are many people who have bought one thinking it was plug and play, only to get frustrated in the first weekend of tuning. They usually sell the tweecer pretty quick and get a dyno tune.

The bucking problem does sound like a tune issue.

The only other question left to ask is if you are getting any trouble codes. If so, you will want to fix them before going to a dyno.

Good Luck,
jason
 
bi19tri said:
I was planing to do a dyno tune and have a chip burned or a tweecer or even a pms just wanted to get it to run better to brake it in before running it on a dyno
What MAF and injectors are you running? Chances are that you're not going to be able to do much without a tune. For $300, you used to be able to get a mail-order chip. If you had a ProM-77, did NOT have an air filter in the engine bay, and sent the company the MAF curve and all of your engine info, you had a "chance" of getting a decent tune. It was often good enough to get you to a real dyno session.

If you can afford it, the PMS is a better way to go. The Tweecer requires a lot more effort. For most tunes, the PMS is more than good enough. However, even with a PMS, plan on 20-40 hours of learning. In the end, IMHO, it will be *well worth it*!
 
There is a place in concord nh that will do it for like 399.00 but I would like to be able to do it for myself and make changes if I needed to. I have 42lb fms injectors and an 80mm C&l maf you cant live very far from me?
Dave