Hello, before I get into today’s topic, I want to say thank you to the people who help everything it’s means the world to us less experienced.

So on to the problem, my car had had an issue with stalling in the past. It was due to a heavily worn ignition system. None and, I mean none, of the plugs, wires, etc had been changed. I changed everything except the coil. This helped quite a bit but it still has a problem.

The problem is, when I push in the accelerator lightly, in neutral and when the car is in drive, the car revs up till about 10-1200 rpm. When I hit this range the car drops rpm and struggles quite heavily, then it catches itself and continues climbing. It doesn’t not do this however when I push the throttle more. I just replaced the TPS and it’s still have this issue. This is a slight gas smell that notice only when this happens.

Note: I do have a vacuum leak in my interior and headlight which I am currently working on fixing.

Does anyone know if a possible solution to this problem? Could it be the coil or possibly and idle air control valve sticking? This is also a problem rpm when driving as well because at this rpm range in high gears(especially in overdrive durning city use), the car acts like it doesn’t even want to move and the car runs very rough and I feel a vibration.

 

Well...First off purchase a GM service manual which has everything in it to troubleshoot your motor and FIX your vacuum leaks to start. What is your current fuel pressure set to? If you do not know this, you DO need to find out since these motors are FP sensitive. Second...What did you set the TPS sensor to? If you just installed it without setting the voltage, it won't work right. Third...The CTS could be causing an issue with the fuel dump, but without doing the other things mentioned first, you are just shooting in the dark for sure. If you need help on this, call me. Send me a PM and I will send you my number. Fourth...The IACs are a controlled vacuum leak, if they do not work properly, your motor will not idle correctly. It sounds like you have multiple issues going on, so you have to check one thing at a time and then move forward to the next, this is where the GM service manual comes in. Hope this helps.

 

Thank you for the help. Just a question, what is a CTS? I’ve never heard of one before

 

CTS. Coolant temperature sensor (switch)

 

I also have another question. So I think I’ve fixed the vacuum leak at the air conditioning control panel. My blower motor wont not turn on when switched to the economy side of my controller. Is that normal? Also, how to I switch the vents between floor and upper and defrost?

 

Your panel looks like this...right?

 

Yes

 

Do the basics... check for diagnostic codes. Otherwise check fuel filter, correct fuel pressure maybe have a bad fuel pump? In 1982 the fuel pump is in the fuel tank but easy to replace. Finally, how old is the catalytic converter it might be contributing to your problems. Good luck!

 

Have you fixed any of the issues yet?

 

Check the vacuum line to the PCV. Mine was collapsed/torn. It was a pretty big vacuum leak (drivability/idle) and the PCV not engaging made the car stinky. Fuel pump/filter/fuel bellow quarter tank are also able to make car chuggle/surge. Don't trust your fuel gauge (reset trip counter at fill ups). Lastly the TBI gasket kit for $45 is easy (remove smog pump completely for clearance, don't just try to tighten screws to stop leaks instead press fuel lines perpendicular to mating surface to get good seal). You can test your TBI gaskets before you decide to replace by taking air cleaner off and seeing if they leak. To do this let the car sit overnight, then have a friend roll the key to power on (not ignition), the fuel rails should jump up to 13 PSI but the injectors should not squirt until you put ignition on (they don't prime, that squirt is a leak).

You appear to have worked on the AC controls but is possible your AC control unit is leaky/broken. Mine the vacuum source line that goes into the firewall grommet is snapped at the firewall. I bypassed the ac control system entirely, directly connected the snapped off vacuum source to heater control line(vacuum disables heater core). Prior to bypassing AC control my car would sometimes stall when idling. Basically the vacuum source line goes into the AC control piece (reed switch with other vacuum signal lines for hot/cold ect) and then provided the ac control isnt leaking the outlet feeds good solid vacuum to the heater core solenoid. Then you also have an AC compressor clutch electrical signal in the AC unit that tells the computer to expect the load of the compressor drive belt (bumps idle rpm up to compensate). So it is possible to get in a weird state of compressor on + heater on + a huge vacuum leak -> your engine idles/runs crazy.

**I also recommend getting a digital 84 shop manual in addition to 82. I also have the GMT 400 manuals from 88-95 (TBI motors) that I found shared widely online. Some of the later manuals have lessons learned and are more robust than the 82 manual. The engine diagnostic guides are better.

 

I totally agree with this in regards to the 84 GM service manual. They did a much better job at explaining things when it comes to troubleshooting. Like mentioned, lessons learned kind of thing that went into the 84 manual.

 

When you changed the TPS....did you calibrate the voltage?

Jebby