When making the jumper between the switch to read the voltage do you need to jump all three connects or just the A and B terminals? I am just using the a b and getting no reading.

 

You have to have all 3 hooked up between the wiring harness and the TPS (to make sure all circuit paths are complete between the ECM and the TPS), but you only tap into 2 of them to check voltage with your DVOM. I forget which two wires, specifically. It's been too long since I have done this. Try different wires, see what you get. I hooked it up wrong the first time, too. Didn't get a reading, obviously, but didn't hurt anything, either.

 

Yeah, i got it now, didnt have the "c" jumped, got the volts reading corectly, do I need to set my aic? It is idling good, right at 650 in D. I am still getting my rpms jumping on me when I go from like 45 to 25, gets to about 1000 and jumps up to 1400, doesnt do it all the time, I do a have a code 33 though, maybe I will try to disc. the negative bat. cable and re set...any ideas?

 

If you set a 33 error code, the ECM will go into limp home mode.

So, disconnect the negative terminal for 2 minute and reconnect, in order to reset the ECM (clear all codes).

Complete the minimum air routine (found somewhere on the 3rd gen board) to set the IAC correctly.

Next set the TPS voltage at .60 V,,, AND check the TPS for correct function. As you slowly and continously open the TB plates, the TPS voltage should increase accordingly.

If the engine does not run and idle good then come back to this board.

 

OK Doc, have done it with mixed results. The rpm jumping is much better, smooth going from high speed (45-50) to 20 it goes right sdown and doesnt jump rpm's. But setting the idle was not easy, the car wouldnt idle at the 400 rpm, it would die when it gets to about 500, so I know that is not set real good. But at the .60 volts the throttle seems more esponsive than it did. The other problem is I still have the code 33. I did the negative cable disc. and it is stillthere, ran the codes and 33 is all I get. Also when I have my paper clip hooked up to get the codes and turn the key to on, my rad. fan comes on? It does seem to run better but the 33 code and the fan thing dont seem normal. One other thing the tech ast. doesnt to remove the paper clip when starting the engine to set the idle? the chiltons book says to start the engine and then remove the clip........ Anyway I hope you can help me on this, I appreciate it.

 

When you put the paper clip between holes A & B on the ALDL diagnostic connector, and turn the key to ON, the fan will run, thats is normal.

If you disconnected the negative terminal for 2 minutes, all error codes are reset. Did you drive the car after resetting the ECM? which could have brought back the 33 error code.

In the tech articles on third gen, follow the IAC procedure. However, I do set the idle RPM to 600 to 650, not the 450 as the tech article calls out. This will result in the IAC being at about 10 to 20 steps during warm closed loop idle. I like it better this way.

After all of this stuff:
1) resetting ECM to elimenate error codes,
2) completing the IAC procedure,
3) setting the TPS to 0.6 Volts, (yep, this makes the throotle more responsive). You could even try 0.64V.

Do the static timing, set it to 8*(spec is 6*, I think), and do not forget to disconnect the EST wire,,, VERY IMPORTANT.

One more thing (if the above is not enough), Hunting for idle RPM is almost always caused by a vacuum leak, even a very small one. So, if you have taken any of the TPI stuff apart, this could be the root cause of your engine hunting for idle.

The 33 error code can be set by a faulty MAF, but mostly due to:
At the same time, the ECM "sees":
1) engine under 2000 RPM,
2) MAF reading over 45 gms/sec, and
3) less than 25% throotle.

Note: A higher setting for the TPS may contribute to the third item above. I do not know how the ECM figures out the throotle is at any specific %. ???????

Hope this helps.

 

I assume then you take the paper clip out before starting the engine? says in one placecan damage the ecm.....

 

Yes, take the paper clip out after disconnecting the 2x2 IAC connector and after turning the key off. Then start engine and set the idle to 600 RPM.

When you have turned the TB idle screw so that the engine is idling at 600 RPM, turn engine off and reconnect the IAC connector.

You now have the closed TB idle air (getting no air thru IAC) set for 600 RPM. With the IAC in action, the ECM will now control the steps of the IAC so the the commanded ECM idle RPM is maintained, that is 750 RPM at warmed up temperature.

 

I think it might be time to bring it in to a garage. I can't for the life of me set the idle at 600, whe n I unplugg the iac and start the engine, it will die if Idont keep pressure on the throttle. Is there any secret to it? It just doesnt want to sit at any point to idle.....

 

Make sure the engine is warmed up at operating temperature.

 

yeah, the engine is warmed up. It just won't idle with iac unhooked. I can turn the screw all the way out and still doesnt want to idle, just dies out. Also my ingintion cylnder is messed up, it has a push button switch for starting, although the key turns to the start position and I ca nstart it with the key it doesnt go to the true off, at least the off on the column. It will go to the run, start but that is it, it wont click back to the acc pos. The key does come out, how many pos. are there? Could this cause my codes tonot clear properly? I can't get the ses light to come off, whenever I disc. batt. and then try to set the idle, the light comes right back on (I am taking the paper clip out after putting key to on and unhooking the iac plug. But when I go to set the idle the light comes right back on, and it just dont want to settle down to idle.

 

While we are on the subject what should the minimum wide open throttle voltage be? 4.??Volts. Allen

 

First things first. If you're setting minimum air, DO NOT rely on the in-dash tachometer for an RPM indication. USe a separate diagnostic tach to set the minimum air position RPM.

TPS voltage at WOT only needs to be at or above 4.2VDC in most stock programming to signal WOT to the ECM.

 

Thanks Vader. In all my searches I never really found a definitive answer. Allen