..... day 4 so far......open open open.
throttle position sensor code 21 help.
Le Mans Master
Joined: May 1999
Posts: 6,692
Likes: 29
From: Texas
It's a chain of settings. Everything in the shop manual is based on factory settings. When they say to set the TPS at .525 it's based on the factory idle off 550 ( I believe that's the right number). Picture it, rear and front TBI's are balanced, idle is 550 rpm, TPS is .527. That's your start point, if you adjust the idle screw you change the angle of the throttle plates on both TBI's. you are increasing the idle. The arm the TPS rests against changes with the opening of the throttle plates. So the TPS will show a higher voltage.
You can't set the idle first and the TPS last. At a higher RPM more air is passing through the TBI's but the TPS is telling the ECM the air passing is for 550 RPM because its set to .525( the 550 rpm value). So your air flow is for say 700 rpm but your fuel flow is for 550 rpm, no balance.
You can play with it. Get someone to sit in the car, started in gear, use a spark plug gapper and place it between the TPS arm and resting point on the TBI. See if it makes a difference, at some point it will surge and stall.
A big problem is small vacuum leaks over time your idle will creep up from 550 but the TPS is still set for .527. Your MAP is no longer reading 20 psi.We start playing with other settings rather then addressing the small vacuum leak. So your TPS tells the ECM idle is 550, MAP says its 450 because of manifold pressure loss, RPM are 750 or what ever, ECM thinks you are doing 18 mph and sends more fuel, IAC's are going squirrelly. Nothing works right any more.
So back to the beginning, everything must be set taking factory specs into account. Set everything at factory and increase from there. If the car doesn't like the factory RPM something else is wrong. No amount of adjusting will make it right.
You can't set the idle first and the TPS last. At a higher RPM more air is passing through the TBI's but the TPS is telling the ECM the air passing is for 550 RPM because its set to .525( the 550 rpm value). So your air flow is for say 700 rpm but your fuel flow is for 550 rpm, no balance.
You can play with it. Get someone to sit in the car, started in gear, use a spark plug gapper and place it between the TPS arm and resting point on the TBI. See if it makes a difference, at some point it will surge and stall.
A big problem is small vacuum leaks over time your idle will creep up from 550 but the TPS is still set for .527. Your MAP is no longer reading 20 psi.We start playing with other settings rather then addressing the small vacuum leak. So your TPS tells the ECM idle is 550, MAP says its 450 because of manifold pressure loss, RPM are 750 or what ever, ECM thinks you are doing 18 mph and sends more fuel, IAC's are going squirrelly. Nothing works right any more.
So back to the beginning, everything must be set taking factory specs into account. Set everything at factory and increase from there. If the car doesn't like the factory RPM something else is wrong. No amount of adjusting will make it right.
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 3,873
Likes: 25
ecm hasn't arrived yet. Dang...........You know how they say 3 or 4 days.......and then it's in your mail box the next day?..... Thats not it today......Guess I can go polish the cragers or something.......go giants!....
Burning Brakes
Joined: Feb 2000
Posts: 763
Likes: 281
From: Middleton, Id
I have my idle set to 750 rpm. Remember to set in drive - 550 in park will be to low in drive. I set my idle to where I want it, then set my tps to the factory setting of .56 volts. You have to remove a plug by the tps then use an odd shaped screwdriver to adjust the screw. I made a couple of permanent jumper cables tied into the harness. Makes adjustment easy. Is your dwell set correctly on your carb? I learned a lot on this system by getting the service manual and studying it. It takes some time but once set runs great.
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 3,873
Likes: 25
Does your mom know your up this late............. .....My quadrajet ran really good, even before the check engine light problem. In fact.......I'm thinking of removing the new tps, and putting the old one back in, just to save 35 bucks. I would mess with that tps adjustment if I could make a tool to get in the hole and turn the thing. So I guess Ill run it as long as it's running well..............Here comes mom............
.....My quadrajet ran really good, even before the check engine light problem. In fact.......I'm thinking of removing the new tps, and putting the old one back in, just to save 35 bucks. I would mess with that tps adjustment if I could make a tool to get in the hole and turn the thing. So I guess Ill run it as long as it's running well..............Here comes mom............
Burning Brakes
Joined: Feb 2000
Posts: 763
Likes: 281
From: Middleton, Id
Does your mom know your up this late............. .....My quadrajet ran really good, even before the check engine light problem. In fact.......I'm thinking of removing the new tps, and putting the old one back in, just to save 35 bucks. I would mess with that tps adjustment if I could make a tool to get in the hole and turn the thing. So I guess Ill run it as long as it's running well..............Here comes mom............
.....My quadrajet ran really good, even before the check engine light problem. In fact.......I'm thinking of removing the new tps, and putting the old one back in, just to save 35 bucks. I would mess with that tps adjustment if I could make a tool to get in the hole and turn the thing. So I guess Ill run it as long as it's running well..............Here comes mom............Corvette Stories
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Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
Jim
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 3,873
Likes: 25
Sorry I came across that way..........
...........We try to keep it lite around here.....or it's like you say, people will just end up going to another forum. The good thing is......this is the best fourm in the world, your knowledge is appreciated on the tps setting. I looked around, and your the only one who knew. I have no idea how I'll get a tool down in that little bitty hole. They should have made a screw slot. But I guess they really don't want anyone to mess with emissions. So how do they expect us to keep there cars on the road if we can't fix them. I bet they never expected smog tests to be so tight..........ramair ......
...........We try to keep it lite around here.....or it's like you say, people will just end up going to another forum. The good thing is......this is the best fourm in the world, your knowledge is appreciated on the tps setting. I looked around, and your the only one who knew. I have no idea how I'll get a tool down in that little bitty hole. They should have made a screw slot. But I guess they really don't want anyone to mess with emissions. So how do they expect us to keep there cars on the road if we can't fix them. I bet they never expected smog tests to be so tight..........ramair ......
Burning Brakes
Joined: Feb 2000
Posts: 763
Likes: 281
From: Middleton, Id
Sorry I came across that way.....................We try to keep it lite around here.....or it's like you say, people will just end up going to another forum. The good thing is......this is the best fourm in the world, your knowledge is appreciated on the tps setting. I looked around, and your the only one who knew. I have no idea how I'll get a tool down in that little bitty hole. They should have made a screw slot. But I guess they really don't want anyone to mess with emissions. So how do they expect us to keep there cars on the road if we can't fix them. I bet they never expected smog tests to be so tight..........ramair ......
...........We try to keep it lite around here.....or it's like you say, people will just end up going to another forum. The good thing is......this is the best fourm in the world, your knowledge is appreciated on the tps setting. I looked around, and your the only one who knew. I have no idea how I'll get a tool down in that little bitty hole. They should have made a screw slot. But I guess they really don't want anyone to mess with emissions. So how do they expect us to keep there cars on the road if we can't fix them. I bet they never expected smog tests to be so tight..........ramair ......
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 3,873
Likes: 25
I never would have thought that tps needs adjusting when ever I adjust the idle stop. Wonder if that is alot of the problem. Well the ecm arrived.........I installed the old prom inside....and at least the check engine codes respond now. the bad news...........up comes code 51....bad prom chip signal. So I removed it.....installed it again, you really can't screw it up if your gentle.......nothing changed. Cleaned those connections at the ecm plugs.......followed then through the console, cleaned the weatherpack connectors as well. Still code 51.. Well crap..........I ordered a new prom from autozone weds morning.....should get here thurs. ya just never know if it's the comp, or the prom I guess. Just have to take a chance. Prom costs more than the computer. This dang smog check better work......
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
I never would have thought that tps needs adjusting when ever I adjust the idle stop. Wonder if that is alot of the problem. Well the ecm arrived.........I installed the old prom inside....and at least the check engine codes respond now. the bad news...........up comes code 51....bad prom chip signal. So I removed it.....installed it again, you really can't screw it up if your gentle.......nothing changed. Cleaned those connections at the ecm plugs.......followed then through the console, cleaned the weatherpack connectors as well. Still code 51.. Well crap..........I ordered a new prom from autozone weds morning.....should get here thurs. ya just never know if it's the comp, or the prom I guess. Just have to take a chance. Prom costs more than the computer. This dang smog check better work......
Boy....I can't count the number of times I have heard that. Usually its a defective ECM.
Jim
Racer
Joined: Sep 2011
Posts: 408
Likes: 1
From: Ormond Beach Florida
I never would have thought that tps needs adjusting when ever I adjust the idle stop. Wonder if that is alot of the problem. Well the ecm arrived.........I installed the old prom inside....and at least the check engine codes respond now. the bad news...........up comes code 51....bad prom chip signal. So I removed it.....installed it again, you really can't screw it up if your gentle.......nothing changed. Cleaned those connections at the ecm plugs.......followed then through the console, cleaned the weatherpack connectors as well. Still code 51.. Well crap..........I ordered a new prom from autozone weds morning.....should get here thurs. ya just never know if it's the comp, or the prom I guess. Just have to take a chance. Prom costs more than the computer. This dang smog check better work......
https://docs.google.com/document/d/1...nOYdwY5jQ/edit
Advanced
Joined: Mar 2005
Posts: 58
Likes: 0
Bad ecm
I have owned 2 1982's over the years and one of the biggest problems I have had was bad reconditioned ecm's.Many years ago,maybe 20 I got so many bad ecm's in a row that I sent mine out to a place (don't remember)that rebuilt and tested and mailed back to me.Very frustrating when you get a computer in the mail,then you start looking elsewhere for a problem only to end up having to pull the ecm again.Hope u have better results.
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 3,873
Likes: 25
Okay...........The prom arrived from autozone a day early. Very cool.
So I plug it in, and run another test. good so far. I run up the engine hopefully to get a closed loop. Then decide to take it for a spin and see if i get a code.
Yep.........#21..tps. And really thats good. cause now I can continue where I left off.
You guys are really going to laugh when I tell you what I did putting the carb top back on. The little hook that moves the tps during adjustment sticks down where you can't put the top of the carb back on.............Yea that one.......
........I removed the hook, and installed the top. I didn't know the function of the thing.....so off it went. It's the american way.
So no wonder I get a tps code. So heres the good news......I have several quadrajets of that variety. I'll use the top from one..... and make the adjustment accessible.
Then I'll make a tool to test the tps as in all your postings. Back in a min..............
So I plug it in, and run another test. good so far. I run up the engine hopefully to get a closed loop. Then decide to take it for a spin and see if i get a code.
Yep.........#21..tps. And really thats good. cause now I can continue where I left off.
You guys are really going to laugh when I tell you what I did putting the carb top back on. The little hook that moves the tps during adjustment sticks down where you can't put the top of the carb back on.............Yea that one.......
........I removed the hook, and installed the top. I didn't know the function of the thing.....so off it went. It's the american way.So no wonder I get a tps code. So heres the good news......I have several quadrajets of that variety. I'll use the top from one..... and make the adjustment accessible.
Then I'll make a tool to test the tps as in all your postings. Back in a min..............
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 3,873
Likes: 25
Good news. I'm on a roll.............I didn't have to change carb tops after all. I just installed the little hook I removed from the tps adjustment. Alls good. No codes after 5-miles of around the block......burnout.....around the block...... So now I need to change 1 vacuum line from the tvs to exhaust flapper thing, and it's smog check time.................
..........P rayer starts now.
So now I need to change 1 vacuum line from the tvs to exhaust flapper thing, and it's smog check time...........................P rayer starts now.
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 3,873
Likes: 25
Monday morning, I running up in the hills to the neighboring countys dmv, to change where the car resides. It's not a bi annual test county. So once I pass this test..........that'll be it till they change the law or something. God I dont ever want to go through this again. remember to vote tues...................
Thread Starter
Safety Car
Joined: Jan 2009
Posts: 3,873
Likes: 25
Well i did it. Went to the other county and changed the location of where the car resides. And get this............I just paid the reg, and she handed me the tags! I almost asked about the smog test........But I zipped it for once and ran. So for 3 months, getting this ready for it's retest.......I could of just did this instead and be driving it. So I wonder..........could a guy just move the cars location from county to county and never test again? The catch on no biannual testing is that you must pass once.......then your good till they change the law in that county. Run forest run...........