1994 Trans Am A4

So as some of you may have read earlier I just did a header install. Hooker SuperComps with the Hooker 3" y-pipe. That deletes the cat and connects to my magnaflow catback.

I ordered o2 extensions for the sensors and that is all plugged in. The emissiosn stuff is not functional. No EGR, No AIR (but the pump is still there). The car is untuned for now. I ordered a cable to scan but they sent me the wrong one, so now I have to wait to get my OBD1 cable.

Here is where the fun begins. The computer is throwing a code. That doesn't surprise me, it's wondering where the EGR is at and it's MIA. I'm assuming this is effecting the car greatly.

Here is a breakdown on what the car is doing (I actually test drove it over the weekend a lot to see how it drives, what it does, etc).

- The fans stay on all the time - I found out here that it is a security feature when the SES light is on. A tune would fix this problem, thankfully (hopefully )

- When the car is idling or slowing down (I normally see this in 3rd, but it used to happen at a regular idle) it'll bounce from 1100-1500 like it doesn't know where to go. This is really weird.

- I throw it in gear and it pisses off my transmission the idle is too high so it slams going into Drive or Reverse especially if I had the brakes engaged. I've been doing it in my yard/stone driveway so it doesn't jerk the car as much. Why is it idling high? I'm assuming something SES-light related.

- When driving, the shift points are completely off from what it was before. Is the 4l60E electronically controlled? Like the fans being on, is this some kind of safety mode (part of closed loop) that only allows the shifts to be at 3000rpms? Basically, the car shifts 1-3 at about 3k. This is when I'm on it. I can hammer down pulling out and it'll still shift at 3k. What's up with that? And I don't think it goes into OD. Sometimes if I accelerate in 3rd it'll go into OD, but not on it's own. It also doesn't go from like 2nd to 1st.


I'm hoping a tune will solve all of my problems. I just need tome input and advice because I'm pretty new to cars but I'm picking up on things rather easily (thanks to lurking around here and the Search feature!). Thanks guys!

 

You need to see what the code it so have it scanned and get back to us.

 

Sounds like its in some sort of protection/limp mode. Yep, need to know what code you're seeing.

 

I figured. Alright I'm about to have a new cable shipped. I guess I'll be back when it comes in! Thanks.

 

Alright, I'll give you guys a heads up on my car situation. I don't know why, but the car threw a code every now and then when I'd be driving it. I didn't experience any power lags or anything. I also deleted the A/C quite some time ago and it never had the SES light come on (that I know of). This code doesn't appear right away. It usually takes a little while or I turn the fan on for this code to be thrown...

That being said, it only threw two codes.
Code 22: TPS Circuit (signal voltage low) - (See Code 21)
Code 66: Air conditioning refridgerant pressure circuit (low pressure) - Check the sensor electrical terminal connections and possible short to ground or open circuit in the sensor wiring. Replace the Air conditioning refridgerant pressure sensor*

I used FreeScan. Code 21 is "TPS Circuit (signal voltage high) - Check for sticking or misadjusted TPS. Check all wiring and connections at the TPS and at the ECM/PCM. Adjust or replace TPS*"

I don't understand how to actually adjust the TPS. It doesn't look like you can adjust it...Maybe I'm wrong? I had the car idling for like 10-15min. When I started getting asphixiated from the header pipe paint burning smell, I took it for a drive. Why aren't any emissions (AIR and EGR) codes being thrown?

It is definitely in closed loop mode. Any help would be great. Thank you.

 

What does freescan show for the TPS voltage at idle?

 

Your car is runing in limp mode.

 

Wow. Shouldn't the TPS be at like .67? It says...
Scaled-5, Volts-0.02, A/D-0x01

Freescan and Datamaster both say the same thing.

Since the old throttle body was replaced, the cables and tps shouldn't have moved. I found this site to adjust the TPS. Is it worth trying?
http://www.golenengineservice.com/html/tps.html

Would this cause the car to go into limp mode?

edit: if you want to see screenshots I can take some. It'll just be a PITA since I'm on dialup right now.

 

Screens:

Codes in FreeScan


Engine Data in FreeScan - Most of these fields constantly move as it idled. As you can see, it was idling high. Desired idle 662? Doesnt that seem a bit too low?


Sensor Diagnostics in FreeScan - Shows the TPS level.


Datamaster monitoring - help?

 

If I had that situation with my car, I would replace the TPS. An auto trans on a GM vehicle, from my experience, will NOT shift correctly if the TPS sensor is not reading correctly. It will shift erracticly, shift at way too low of an RPM, and cause performance issues. Have you made any changes to the TPS at all, or the throttle body in general? If not, definitely replace the TPS.

 

I replaced the tb with a Summit 58mm. It stuck open at 1500rpm. I had to push the thing (the metal part that springs back to the idle screw) back manually for it to go back to the correct idle. I took it off and sent it back and put the stock one back on. Ever since it won't idle right. The TPS probably just needs to be adjusted, but I'm not sure how to do it. I guess I can take it apart quick for another look. I hate to start drilling (following the instructions on the website link I posted up there) just to get it adjusted right.

 

sounds like your trans is in limp mode. itll slam into gears. and itll be stuck in 3rd gear.

TPS voltage should be around ~.5 at idle, and close to 5v at WOT

 

A new TPS did the trick. Thanks Jason. $30 from the auto parts store and it's kicking *** now.

 

Awesome! Its nice when a fairly cheap part fixes a list of problems. Glad to help. =)