I just bougth my first tpi and I have some problem with my idle.
It is between 800-1000. And it's never stabil.
I've changed the wires, sparkplugs, rotor, distributorcap.
The fuel pump has been changed.
Plese help....

 

Is this a TPI retrofit or did it come stock on the vehicle? The Idle Air Controller (IAC) sometimes go bad and will cause an erratic idle. I am not saying that this is your problem, but it is the first thing I would check.
A GM manual or maybe someone else with more knowledge than me could tell you how to test it.

Cheers,
J

 

get some carb. cleaner spray and check for (find) the vacuum leaks you have. and get an ac delco factory pcv valve and leave enough carb spray to clean the throttle body and if you are willing, the iac motor's pintle and matching seat and passages in throttle body, well the casting that screws to the bottom of the t.b.-sometimes, mucho miles=restricted injectors=poor idle quality

 

From my personal experiences, I'd say check the resistance across the injectors. I think it should be about 15ohms. Also make sure the EGR is working. Another thing is check the connection at the tps. I've had all 3 of these things cause my GTA to idle lilke crap. Always run the codes first, and do a search on here for how to check the stuff I listed above. Good luck. Let us know what it was.

 

for a bad idle? when you say across the injector(s), are you talking a bank? restricted injectors usally dont show as an out of spec resistance. big ms at idle and blm and (for a while) integrator #'s skewed to the big end are an accurate determinator for low fuel flow.vacuum leaks are far more common. vacuum leaks cause typically the same scan tool readings-so not to go there first is to possibly replace good parts. remember-think simple first or k.i.s.s.

 

Pyrrano,

Welcome Aboard!

Idle speed on a fuel injected engine is controlled by the Idle Air Control and ECM.

The IAC is part of the throttle body, and these things don't stay clean forever.

There are a few easy things to do that may cure your problem, and should be done before you start diagnosing anything further.

IAC air passages and pintle need to be clean. The throttle plates and bores need to be clean as well. If this is not the case, you'll need to remove the air cleaner from TBI engines or the intake air bellows from TPI engines to gain access to the area to be cleaned. A spray-type carburetor cleaner works well for this. Cleaning the IAC passages on a TPI/MAF engine (1985-1989) will set a DTC, but you can clear that later. With the engine idling, direct the spray cleaner into the IAC air passages and around the throttle plates. Shut off the engine and continue cleaning the throttle plates by opening the throttle manually. Once everything is satisfactorily cleaned, replace the air bellows on TPI engines. Many times, this alone can solve IAC/idle speed problems.



If you set a DTC during the procedure, the SES light should be illuminated on the dash. This ECM retains DTC data for the previous 50 engine starts, so the codes will eventually be cleared. If you want more immediate results, after shutting down the engine disconnect the negative battery terminal for five minutes. This will clear the ECM of all diagnostic trouble codes. Clearing the ECM also clears any data learned about your engine, and clears the radio presets. If you have a Delco-Loc or Theft Loc II radio, make sure you follow the procedure to unlock the radio protection before disconnecting the battery. This five minutes is also just about long enough to clean both battery cables. Reconnect the battery. When you first start the engine after clearing the ECM, the engine will operate with base parameters programmed into the ECM PROM. These parameters may not be optimum for your engine, but the ECM will enter a Block Learn Mode soon after the engine is warm and enters Closed Loop Mode. The ECM will write new data tables specific to your engine and will eventually rely on those tables instead of the base tables of the factory program. You can expedite this process by driving the car for 20 minutes under varying conditions to allow the ECM to initialize. Or you can wait and drive the car normally at your convenience.

 

bellows, heh heh heh, he said bellows which reminds me, check for false air-unmetered air comin in at places it shouldnt be-anywhere AFTER the mass air sensor ducting that is torn or loose clamps at attaching points etc etc-base timing check at this point wouldnt be a wrong idea to try. HEYYYYY-cool man if you look in that throttle body you can see the groovy freebie power enhancement that can be performed by nearly all. byebye egr "bumps" and the smoothing and blending of all areas just behind the throttle body openings-also i would bet, were i a bettin man, that is, the openings leading to the runners have undergone a similar massaging. checkit-stock lookin ******