Item Posts    Sort Order

81 vett. engine light will not come on with key.

 
wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 12/10/13 06:31 PM

print this out.. go over it wire color verses connector pin first...


81Cccecmconnectorwiring Zpsd043b195

i clipped the image above so you can just check it one at a time from the image below..

81Upcccfeedbackcarb Zps1724d114

this seems to be the corrected version..

81 CCC Corrected Ecmconnectorv8 Zps5f7e6c55  

Post Reply
richard1061
I love my Chevy Chevette!
Posts: 19
Joined: 12/13
Posted: 12/18/13 06:35 PM

Hi wayne,  you will not believe this one.I ordered a new ECM, got it. did the ECM test #7, every thing tested good.  put in the prom turn the key on, smoked the prom and the ECM. To cut this short. The new ECM where the prom goes was in backwards. Factory defect.
What are the odds. Trying to get them to give me a new ECM and a prom free, will have to wait and see.  

Post Reply
wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 12/18/13 10:12 PM

contact cardone tech support

they offer some PROMs that were removed from the cores they bought..

you still have the old ECM...

please post all the numbers and letters or an image...



if the PROM socket was replaced and soldered in backwards///

what burned???? did the prom blow top blow off..

when you have a burn like that..

its really important.. look at the last 3 or 4 posts i made.. i found some slightly different info..

check each circuit with the ECM unplugged..

you can even check the system with the PROM removed..

so you don't take a chance with the hard to find proms..

if you call the local junk yards..   ask for a brain box with the 122 part number you have.. usually the last 3 or 4 digits.. some of them will also have them listed by prom letters..

i seem to recall you might be in the bay area..

check dorris auto wrecking in hayward..  

Post Reply
richard1061
I love my Chevy Chevette!
Posts: 19
Joined: 12/13
Posted: 12/19/13 12:19 PM

thanks wayne. It didn't blow off the top, but it did melt the center. looks like a finger print on top of the PROM. Cardone gave me a new ECM. waiting on a PROM. meanwhile I'll check out all the circuits.  

Post Reply
wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 12/22/13 07:28 AM

81Chevyv8ccc Zps0e2c36d0

1981Chevyv8cccpage2 Zps0b80ecf0  

Post Reply
wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 12/22/13 07:54 AM

hmm... seems there are aftermarket proms available for the 81's

hypertech and jet both seem to have 4 available for the 81 model 5.7s..

not a lot of description on just what they ***

delay the TCC engagement...  increase primary fuel flow at WOT..

or.. increase spark timing and fuel flow..

since the primaries are the only thing controlled..

still might get you up and running ...  

Post Reply
richard1061
I love my Chevy Chevette!
Posts: 19
Joined: 12/13
Posted: 02/04/14 05:09 PM

HI WAYNE.

got the hypertech street runner chip.  could not find a stock prom. for 81 corvette. I ran chart 7, every thing was good. started up vet.ran it around the block, cod 21 and 23 came up. reset ECM, still got cod 21 and 23. throttle position and m/c solenoid- mix control.
I have a rebuilt carb. what should I do next?  

Post Reply
wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 02/04/14 07:04 PM

i will get you so info later tonight..

is there any chance. that you might provide me with the original ECU and PROM number... so i can see if any of my junk yard friends around her have one. they have WALLS full of used ECMs..  

Post Reply
wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 02/05/14 01:33 AM

on the TPS sensor...  

A is 5 volts reference voltage
B is signal return to the ECM
C is reference ground.


TPS sensor adjustment and testing from wells

http://www.wellsve.com/custom_searches/pdf/instruction_sheets/990700569.pdf


thanks.. i have been looking for that chart.. i had one and it blew away one day..

oh... your TPS voltage setting.. choke wide open.. throttle closed after verifying its not on fast idle.    0.56 volts   measured between B and ***

the connector for the TPS is part Number 260 from wells or az.  

Post Reply
wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 02/05/14 11:16 AM

CCC Code 21 Zps345edfd4


CCC Dtc 23 Zpsa8bdb666  

Post Reply
richard1061
I love my Chevy Chevette!
Posts: 19
Joined: 12/13
Posted: 02/05/14 11:33 AM

thanks    I will give that a try.    the prom is still at cardone. this vet. is a stick.  

Post Reply
wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 02/05/14 01:30 PM

a friend needed to check his antilock brakes and bought a older scan tool that had the proper cartridge for it. cheeper than the cartridge by itself. it also included a PROM ID manual..



there are six proms shown.. does not show what options and which is for manual transmission cars.. these first part numbers are from an aftermarket info manual
these all use the 1224810 computer
81 5.7 vin L chevrolet

FO6079, 1224855, 6/80 release, updated yes. production use, OD8118  history

FP6088, 1224828, 5/80 release,   updated yes. production , OF8133 history.

HK5675, 1223829, 5/80 release,  not updated, production use, final release,

KT6428, 1224857  6/80 release, not updated, production use, final release.


OD8118, 1225480, 5/81 release, not updated,  running change, final release,

OF8133, 1225431, 5/81 release, NOT updated, running change, final release..

it sure looks like you will want either the OD8118 or the OF8133 for a factory prom..

those part numbers lead me to this page...

80 81 CCC Chevy Prom Zps68d19f2c  

Post Reply
wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 02/05/14 01:52 PM

so.. the automatic cars came with

OH8114, 1225432, california cars automatic
OD8118, 1225430, federal automatic

CF5839, 1224869 Manual trans california 1st design
OJ8104, 1225433 manual trans california 2nd design

FN6084, 1225310 manual trans federal 1st design
OK8108, 1225434 manual trans federal 2nd design.

hmm.. slightly different that what the aftermarket posted..  

Post Reply
wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 02/06/14 01:44 AM

oh.. here is an old post of mine on adjusting the E4MC and E4ME carbs..


including a happy reply from someone it helped..




if you are using the E4ME feedback quadrajet carb and going from 305 to 350... you need to find a real 350 carb... they all look alike... only the part numbers and jets are differnt.

i have hurd that the last iron block cad with the 6.0 feedback carb jets and metering rods can be used on hotter 350s and still use the feedback carb......i think it was a 1981 deville california emission...

it has been a while since i took one of those carbs apart... i used to live and breath rebuilding q jets on normal cars..
i would imagine that if you had the proper ajusting tools and a scan tool or dwell meter you should be able to ream the primary jets out a tiny bit at a time until it is tuneable... be aware that it took a 7 million dollar flow bench almost 20 minutes a carb to let the computer to ajust those carbs to run good and pass emission...

tools needed... torx bit sets... 1 inch fuel nut wrench, idle mixture screw flexable tools(2), float height dipstick.(this goes down the bowl vent to measure the amount of float height on one side and amount of travel on the mixture solenoid plunger in another hole through the carb top...4/32 max travel... lean mixture setting tool, (this goes under the solenoid lever to ajust the stop height) a tool to ajust the rich stop from the top.... another for the throttle position sensor height...
and a tool with a j hook to set the air bleed in the top cover...thexton makes most of them.. and most autoparts stores have the idle mixture screw flex tools in stock... EDIT.. sorry.. they are ALMOST Impossible to get these carb tools now..


wait... this is complacated... it is hard... .... this is not... it only takes some practice and understanding of what is going on....

since the primarys needles are commanded to bounce up and down at 10 cycles per second... the computer can command them to stay up longer for a richer mixture or down longer for a lean mixture...

you can raise or lower the height of the needles travel to ajust the fuel mixture a bit to take up for worn motors...

there is a green connector near the carb usually on a green wire that is not connected to anything..

that can be hooked up to a old style dwell meter set to six cylinder scale to read the amount of dwell the computer is commanding the carb to ***

with the idle mix screws set at 4 or 4-1/4 turns out each... warm the motor till operating temp ... (192/195F thermostat please) read the idle dwell readings.. should be 28 to 35 degrees...


bring the motor up to 2500 rpms... and the dwell should be 35 to 40 degrees of dwell...

you can raise the lean limit screw through the top of the carb... a double d tool not the air bleed with a screwdriver... the air bleed is for fine tuning..

this is like balancing on a ball... a little here and a little there... and since you are changing the displacment it is going to be way harder... which is why i think the orignal 350 carb or the 368/6.0L cad jets...


if you need more info let me know... i will be watching... i would think that most of the better carb shops will have a proper jetted feedback carb that should bolt on without too much ajusting.. as long as you have installed all the necessory sensors...


and feedback carbs will not run well with any exhaust leaks before the oxygen sensor... fools the computer into thinking the mixture is beyond it aibility to control.....

oh ... and be sure that all the computer grounds are properly installed... clean and tight.... they all come out of the computer harness.....

and for others... the harness comes out with the motor... get under the passenger side of the dash... unhook the ecm... the connector to the dash side.. and the u shapped plastic lock on the plastic elbow...

the harness pushes straight out through the hole in the firewall.... lets you get all the ground wires on tight .. some are on the back of the heads.. and hard to get too...


the computer should work....

and .. when the 305's were properly tuned and the feedback carb ajusted they could pull down 22 to 23 mpg if you kept your foot out of it... i don't know what a properly built 350+ would *** just don't go crazy in the cam department... feedback carbs like a lot of vacuum…  




Ive changed my secondaries to CK rods . .When I did the other mods.
Just for the hell of it becuase I can never leave things be. LOL

I always had what felt to be a lean idle miss and it would only go away when I set the idle mixture screws to 4 turns .But I always thought that was to much. Even at 3 3/4 turns I would have a miss. Ive gone over all my vacuum hoses and no leaks . Even sprayed starter fluid by throttle shaft bushings and no leaks there.
So this morning I set mixture screw at 4 turns and adjusted dwell to 32 - 35 . I usually watch my gas guage move while driving around town ( it usually moves fast) . Now it has not moved at all around town today . Maybe just a needle with on the fuel guage .
I dont smell any gas and tail pipes arent black with soot.No more miss in the engine.
I Hope it stays this way .
 

Post Reply
wayne712222
My first time was in a Chevy
Posts: 140
Joined: 10/13
Posted: 02/06/14 02:31 AM

in case you don't have one.

Thexton 370 Zps39430fa5  

Post Reply
TO TOP