Seems like '82 issues are popular recently (or on-going). Here is my latest and most perplexing issue to date, but first off my question. Is there anything that could cause the TPS to read too high a voltage other than simply a bad TPS? The lowest voltage I can get is 1.7VDC with it rotated down and the highest is about 2.7VDC rotated up. 5.25 VDC at pin C and Ground on pin A.

My initial problem was a bad fuel pump that was causing the engine to surge. I also bought a vacuum line replacement kit and TBI overall kit. Replaced the pump, fuel hoses, filter, and was having some problems keeping it idling which I had never had before. If I kept the RPMs up it would run so I figured some adjustments were all I needed. Rather than do that I decided to replace vacuum hoses with a kit I had bought. The car started right up and the idle was better but when I tried to take it out for a drive the engine would die. Now it has digressed to the point that it is hard to start and even keep running. The fuel injector fuel delivery cone looks good but I believe engine is way too rich as there is a strong fuel smell and the plugs were all pretty wet when I looked at them.

Before I take the TBIs apart I want to get the damn thing back close to where it was before the fuel pump went bad. I know from reading the Sticky and all the other advice that there are a ton of things which can cause problems and I guess I'll be working through them.
Thanks,
Chris

 

It sounds more like a vacuum leak that has gotten worse more than a tps sensor. Have you replaced the plenum silicon yet with the felpro gasket?
Your manual should break down the tps settings but I recall .525 being one of the setting limits. The CFI system is very basic but all the settings need to be set and then left along. If you start adjusting 3 different things but you have a vac leak, you'll never get it running right.

 

No I have not broken any seals yet but planned on doing that when I rebuild the TBIs. Valve covers could also use replacing.

My hope after replacing the fuel pump was that it would be running like it had prior to that. Then I would move on to the next maintenance issue. I have experienced changing too many things at one time before and really screwed things up and I did not want to do that this time. If it is a vacuum problem I induced I can't find it (yet). Hopefully somebody will jump in with an answer to my TPS voltage issue too. Thanks for the reply and I'll keep digging, just wish my garage had A/C!
-Chris

 

you are reading the wrong scale.you need a scale 2vdc .525 is what your goal is .

 

I am using a Fluke digital multimeter so the scale does not matter.

 

if your meter will read that low ,,your good to go.fluke is the best .but some meters[cheap ones] do not like to read that low.

 

Your Fluke meter depending on model should be auto ranging when you are in DC. Anyway, if you can not get .525mv, the TPS sensor is bad. Set it like mentioned as close to that number as possible. The ECM needs to know where the blade position (idle) is with the key ON, engine OFF. Good luck.

 

Success! New TPS and the motor is running pretty good. Old TPS had a flat spot between 0 and 1.27 volts so I could not set it correctly. My guess is that the bad fuel pump I replaced was providing less fuel and that compensated for the higher voltage output to the ECU.

 

Two friggin' days the engine ran right. Today I get ready for a shake down cruise and the motor sputters but will not start. I did nothing to it since last evening. Looked around and can't find anything out of place so I rechecked the new Delco TPS I installed and it reads 1.6VDC instead of .525 V. Messed around with it for 15 minutes and it finally comes in. Try to start and no go. Recheck and it is back up over 1 volt. Removed it again and gave it a stern talking to. Reinstalled and wrangled it back to .530 V. to refire after I settle down a bit.

Questing for the experts: Do you ever adjust the tang on the end of the rotating arm of the TPS? Seems if I bend it a bit I will be able to get more adjustment since it looks like the correct voltage setting is right at the end of the physical positioning. Thanks,
-Chris

 

It is my understanding from the Service Manual that the TPS is simply a variable resister but I don't know if there is any other circuitry inside since it is sealed. My old TPS gives a resistance reading (very unstable) if I put my meter on pins A and B and move the TPS arm. Now when I look at my "new " TPS I have an open between pins A and B. Moving the arm makes no change on my meter. That could explain something, but I'm not sure what. Me >

Update: changed meter leads and now I have resistance, but it still comes and goes. Almost like there is a cap or diode in there. The reading I get is around 3 MOhm but goes down. Maybe I am over thinking this too. If anybody has the correct resistance values between pins A and B I would appreciate it.

 

I never adj a new one but I have bent the arm on a old one .it looked to me like the arm had gotten bent from maybe a heavy foot.I don't think you can get more adj but you can make sure that when your throttle is open all the way that the computer knows that.

 

Since I could not seem to get what I believe is a logical resistance reading on the TPS I decided to make a test rig and check it with voltage outside the vehicle. Using a computer power supply and ground I had my 5 volts and ground. I was able to move the arm of the TPS and see a pretty linear voltage change on pin B. The arm had to move farther than I thought to hit the .525 Volts but it was pretty steady.

Back in the car the process of adjusting seems to be something else though. I can get the voltage close but when I tighten the TBS is changes. Like from .525 to .691V. Something else it does is change to a higher voltage after I open and close the butterflies. Watching my meter it looks like a capacitor discharging. So I set it low and after tightening I got it closer as in about .550 V.

Something is going on but I'm not sure what it is. Tomorrow I am going to chase ground back to the ECU and verify it is good. If anybody has suggestions I'll follow up on them too. I just hope this TBS is not bad. Thanks,
-Chris

 

when you tighten and your voltage changes that I have found is normal.what I do is tighten one where it does not move much ,,,,get it close then tighten the other one slowly.when your voltage changes when you open and close the throttle can be because you have movement on the butterfly shaft..550 should be close enough. try it and see how it runs.some tps seem to to be harder to set then others. but they are very sensitive.with this you can set the tps live.http://www.winaldl.joby.se/ http://www.aldlcable.com/

 

So, like mentioned the voltage will move around a bit as you tighten the screws down...that is normal and can be somewhat of a PITA at times to set. Best way is to get it close and then tighten it down a little more so that it is a bit harder to move and gently tap the sensor to dial it in and then lock it down.

Is your TBs balanced and no play in the shafts? If they are worn, they may be cause the blade angle to change a small amount to cause an off setting at times. The only reason I say that is because you replaced the TPS and I wouldn't think the new one would move that much by itself, but I guess it could happen.

Good luck with the adjustment.

 

Tried to start the car again this morning and it bucked and chugged and was only able to run if I played with the throttle. The Check Engine light came on and I read a code 22 (low TPS Voltage). I rechecked the TPS setting and it was at .671V.

Disconnected the black connector on the ECU and read continuity beween the TPS connector and the ECU pins 5 and 11 which is good. Reconnected the ECU.

Tried again to read resistance on the TPS between pins B and C but came up with 0 ohms. This is different than my old TPS so either that is another fault indication of the old TPS, or AC Delco has designed some circuitry into the new TPS that requires a voltage input on pin A for an output.

After I put everything back together and reset the TPS (again) to .530V the engine fired right up and idled perfectly smooth at 1000 RPM.
Now I thought I was back to where I was last week. I let the car run and at about 5 minutes it died and would not start. Reconnected my TPS wiring adapter and the voltage was at 1.7V and decreasing (looked like a capacitor discharging slowly). I watched the voltage come down to .53V and the car started back up but died pretty quickly. I left the meter attached and when it died the TPS voltage shot up to about 2.7V and started decreasing. My guess is that was the result of a instantaneous flutter of the butterflies as it died.

So it will run, but I need (any help appreciated) to figure out why it is doing this.
-Chris

 

dis connect battery .then try again

 

Will be back with some info for you that may help....gotta check on something about this first.

With it cranking up and immediately dies....is something else....especially it if the TPS is set correctly.

DUB

 

Did that, no difference. I put the original TPS back in and tried to adjust it. Best I could get was .298 V, then it jumps to 1.4V. But the car did start and tried to run. I also Googled "checking a TPS for resistance" and although it is not the recommended on-car way to test I did find several sites and a YouTube video discussing it. From what I saw I believe I should be able to get a varying resistance reading and I am just not seeing it. I have 4.6K Ohm between pins A and C, and 0 Ohms between A and B or B and C. At this point I am going to try and return it for and exchange (wish me luck).

 

OK, not to be a (jerk) about this in any way, but do you have a GM Shop Manual? It clearly spells out how to troubleshoot this issue and a lot more. The manual is a MUST for ANY CFI car.

 

No problem, yes I do and I am using the manual. Unfortunately for me the test results I am interpreting are not consistent. For example, the code 22 I get is telling me the TPS voltage is low, where it is in fact reading hi. The voltage with the TPS at rest should be a constant but when measured it is reading high at times but steadily decreases on it's own even though the input voltage of 5 volts is not changing. I believe the new TPS I bought it bad and that I should be able to bench check it with an ohm meter. That checks bad too. Thanks for reading through this mess and I really appreciate any and all advice provided.
-Chris