Can someone help me with this how to replace the TPS on my 1986 carb engine please.
TOny

 

You basically have to do a rebuild of the carb because you have to tear it apart to get to the TPS. At least replace the gaskets which only come in a rebuild kit.

 

You may have to buy the whole rebuild kit unless you can find an airhorn gasket that is sold seperately. IIRC, to replace the TPS, remove the air horn and the TPS should pull right out.

 

Gotcha, sounds easy enough. They have a rebuild picture diagram in my chiltons so I should be able to figure it out. What does IIRC stand for? Thanks
Tony

 

IIRC = If I remember correctly
IMHO = in my humble opinion

 

So how hard is it to set the throttle position sensor? Do you need a volt meter?

 

these may help:

https://www.thirdgen.org/techbb2/sho...ght=tps+adjust


https://www.thirdgen.org/techbb2/sho...ght=tps+adjust

 

I will check it out.
Thanks

 

Hi, I'm new here. I have a 1986 Camaro Berlinetta 4 bbl carb. I am getting code 21 and 15. 21 is the TPS and 15 is the CTS. My question is, when I test the wires coming off the TPS to the ECM is there Continuity on all three wires?

 

Sure, there should be continuity to ... something. Otherwise, wouldn't be much point in having a wire at all, eh???

The thing about "codes" that's hard for n00bs to grasp, especially about the really ancient Paleolithic stuff like the carb ECMs, is, the codes don't say "the {fill in the blank} is broken, replace it". Instead, the ECM, which doesn't have awholehelluvalotta brainpower, is simply telling you that it's confused; and is making its best guess at what's the likely culprit. Remember always, in these old Stone Age systems, the ECM only has a VERY SMALL set of "eyes" (aka [mr spock] "sen-sores" [/mr spock]) to look at the big wide wonderful world with, and whatever those few "eyes" tell it, is all it knows. So for example, if the ECM sees low RPMs, high vacuum (low load, engine not being demanded to produce power), and throttle at WOT (foot on the floor), what is it supposed to think? Those 3 conditions cannot possibly exist at the same time in the real world, but the ECM has no way of actually "knowing" which one doesn't agree with the others. They are TOTALLY incompatible. Now, any good Neanderthal would evaluate the likelihood of any given one being at odds with reality, and would figure out first (speaking strictly as a good Neanderthal) that the RPM signal isn't likely to break, so that signal is probably believable. But then, which of the other 2 might be broken? Well, the MAP sensor (for vacuum) just kinda sits there and senses MAP, but the TPS is a moving part, so it's more likely to wear out, right? So that's the "code" you'll get under those circumstances. Whenever you see a "code", you gotta understand how mentally challenged the ECM is, and try to get inside its tiny little mind and figure out what its 3.7 brain cells are trying to say on those rare occasions that they all fire at the same time. Go live in its cave for a fortnight in winter fighting off dire-wolves and short-faced bears and eating frozen-solid woolly mammoth meat so to speak.

But to answer your questions: on the TPS wires (there are 3) one should have 5V continuously when the key is on; one should be grounded; and one should vary smoothly from around 0.5V above ground at idle, to around 4.5V above ground at WOT. "Continuity" isn't the right question to ask.

Similarly, for code 15, the ECM has absolutely no frigging clue what the actual engine temp is, other than what the CTS tells it. BUTT.... and a very big BUTT at that.... engine temp behaves in predictable ways. It should start out cold (maybe), and if so, should reach some sorta "reasonable" running temp within some sorta "reasonable" time... let's say, it should at least reach 120°F within 10 minutes of running. ("Running" being indicated by continuous RPM pulses from the dist) If it doesn't reach some "reasonable" temp in some "reasonable" time, it figures the CTS is lying. Pretty good assumption actually as far as it goes. Problem is, it has NO WAY to know whether the CTS is even PLUGGED IN at all, whether the connector is fornicated, whether the wires are stripped bare right at the sen-sore and touching each other, or maybe it's just REALLY FORKING COLD OUT tonight, or what; so all it can do is scratch its beetled brow like any other australopithecus anthropus and gesture in wordless blinking confusion, "CTS ouch?". First thing to do for that one, is LOOK AT the coolant temp sen-sore with your advanced Cro-Magnon eyeballs and see if it's even plugged in at all, or if maybe the wires are farkled; and if neither, use your freshly-evolved bipedal locomotion to hike down to the corner and get a new one.

See? This stuff isn't too tough. Not even for a Denisovan relic like me.

 

Thanks Sofakingdom for the quick response, I will start troubleshooting ASAP

 

So Sofakingdom, where does the signal goes when it leaves the TPS?

 

ECM

 

Backprobe the top and middle leads to the tps with it connected and key in 'run'. Should get around 0.40 V with throttle shut and around 4.0V with throttle open wide.

The CTS doesn't usually fail, but the connector takes some abuse.

 

Thanks everyone, I'll get back and let you know what exactly going on

 

Ok everyone here's the latest;
I have a 1986 Camaro Berlinetta with 4BBl Rochester Carburetor, i just had it rebuilt Jan of this year. I have the idle set at 1000 rpm's. In the am after setting overnight, it starts between 1200 / 1300 rpm's, after i pump it a few times it idle back down to around 1000 / 1050 rpm's. When I place it in reverse it back down to around 720. after some miles street and highway, it's find. When pull in to park it is where the trouble starts. It idle at 700 sometimes 900 and fluctuate lower. Shut it off and start at 700 / 500 rpm's at the Service Engine Light comes on. My mechanic says it spits out a 15 and 21 code. 15 is Colant temp sensor and 21 is Throttle Position Sensor. I checked the TPS. 3.75 and .4 at WOT. Questions??? What's the idle rpm's suppose to be set at and the Big Question is what can be going on. The mechanic that rebuilt the carb says it tested find at the shot on a 305 engine. Help and Thanks

 

Idle should be around 700 - 750 out of gear, around 600 in gear.

1000 is too high.

If you're quoting numbers that come from that wavy-pointer thingy in your dash, they're probably wrong; specifically, higher than reality. Use actual test equipment of some sort to determine idle speed, not the trim package in the dash.

Those numbers you gave for the TPS make no sense. Should be somewhere around .5 at idle and around 4 - 4.5 at WOT. Measure between the blue wire and ground.

Look at your CTS wiring. Yellow and black wires going to a thing on the water outlet (where the upper rad hose meets the engine). If you still have the old kind with a circular connector, kind of coaxial looking, the connector is almost certainly destroyed, like they always are. Replace the sensor. It will come with a new pigtail with an entirely different style of connector, which is about a million times more reliable. Be sure to make good connections when you hook it up: solder the wires and use heat shrink tubing and tape over the joints.

 

Thanks Sofa. This is a fix I've been wondering about for a while now. Was having difficulty finding a replacement OVAL two-wire female connector.

 

Right: probably costs about the same to buy a sensor with a pigtail in the box, as a pigtail by itself... last sensor I bought that way was under $20.

The original style had a pin in the center that went to the yellow wire and a ring around it that went to the black one. They then spooged the whole thing with some kind of black tar stuff and wrapped it with tape. Or maybe the tar crap was the glue on the tape, I'm not sure. The pin was weenie, the ring was fragile, the tar or glue or whatever, was ... disgusting and got all over everything, and the wires had some kind of crappy insulation that crumbled to dust and let the wires short; and the tape kind of hid it all so you couldn't tell what was really going on inside the mess. All of it was totally unreliable. Or more accurately, it could be relied upon with absolute certainty, to FAIL. I found out about mine when I dunked the whole thing in a little bit of lacquer thinner to clean away all the goo, and saw what a total POS and FAIL it was, with the wires bare from the insulation falling off and them shorting together.

So with that (original) setup, these cars were real bad about generating CTS codes; if the connection wasn't good, the ECM would think the engine was at like -40°F 100% of the time, and if the wires shorted, it would think the engine was at like 400°F 100% of the time. In neither case would it run right, and of course it would set a code either way because engines start out cold and get hot after running awhile, not stay the same temp - ANY temp - all the time.

The OP needs to get up off his/her keyboard, quit posting on the Internet, get down to the store, and get a CTS with pigtail. THEN if s/he still gets codes, come back and we can talk about what to do.

 

Ok everyone here's the latest;
I have a 1986 Camaro Berlinetta with 4BBl Rochester Carburetor, i just had it rebuilt Jan of this year. I have the idle set at 1000 rpm's. In the am after setting overnight, it starts between 1200 / 1300 rpm's, after i pump it a few times it idle back down to around 1000 / 1050 rpm's. When I place it in reverse it back down to around 720. after some miles street and highway, it's find. When pull in to park it is where the trouble starts. It idle at 700 sometimes 900 and fluctuate lower. Shut it off and start at 700 / 500 rpm's at the Service Engine Light comes on. My mechanic says it spits out a 15 and 21 code. 15 is Colant temp sensor and 21 is Throttle Position Sensor. I checked the TPS. 495 and 4.45 at WOT. Questions??? What's the idle rpm's suppose to be set at and the Big Question is what can be going on. The mechanic that rebuilt the carb says it tested find at the shot on a 305 engine. Help and Thanks

 

1000 RPM idle is still way too high. Should be 700-750 or so out of gear and 550 - 600ish in gear. Before twiddling the screw, verify your tach's accuracy; DO NOT use the thing in the dash.

Your TPS sounds like it's working roughly right. Time to move on and begin troubleshooting instead of hallucinating that the "code" means "the {fill in the blank} is broken, replace it".

When YOU checked the "codes" YOURSELF, what did YOU see?

Did replacing the coolant temp sensor take care of that code?

Are you listening/reading? Have you done ANYTHING to try to fix your car? You keep asking the same question over and over without actually DOING anything.

I suggest you quit with "mechanic" and learn how to work on this yourself. "Mechanic" is putting his kids through braces and soccer practice via your bank account. Your car is literally AN ANTIQUE; it is not realistic to pretend you can "take" to "mechanic" and not get bled dry. People with ANTIQUE cars must learn at least the least little bit about how to work on them themselves unless they own a printing press that spits out money. (which I realize you might... just sayin)

See post #10 in this thread for a discussion of "what can be going on". That's the mental discipline you have to adopt to deal with that sort of thing.

 

Here's the update;
Code 15, I replaced the Coolant Temp Sensor, code 21 TPS is inside the carburetor, after checking the codes myself, I found a code 44, Vacuum Leak. After changing the 02 sensor and all the vacuum lines, I was getting code 44. After taking sofakingdom advice, I replaced the carburetor with another and No More code 44. I didn't want to believe that my rebuild carburetor was causing the problem. I'm not a mechanic but now i'm a tinkerer. Thanks sofakingdom for the kick in the pants. I'll keep everyone posted when I get my rebuild carburetor back. The car idles at 730 and runs great.

 

Glad you got it sorted out, to bad it took so much $$$ but sometimes that's just the way it goes.

 

sofakingdom, can you tell me the original make and model of the alternator for a 1986 camaro berllinetta, 305 4 bbl carb, ac/

 

Delco 10si

Not very useful info though

What do you REALLY need to know? I.e. what are you trying to accomplish?

 

Just trying to replace the alternator, I'm trying to stay OEM

 

Just go to the parts store and ask for the one that fits your 1986 camaro berlinetta 305 4 bbl carb w/ac.

If you ask em for a 10si, they'll look at you like you have 3 heads growing out of your leftmost arm. Won't have the faintest vaguest dimmest remotest whiff of a glimpse of a hint of a clue what you're talking about.