Except I love the seats and interior, especially the Cinnabar. But other than that I agree, build it for what you want, its fun!

 

The interior is awesome. I really like mine. I have the original cloth seats which are immaculate and somewhat of an oddity.

 

Update.

New ECM is in, PROM switched over correctly, check engine light now works, but does not give me any codes / will not flash at all with diagnostic terminal grounded. Just stays on all the time. Going through the shop manual flow charts right now. Trying to understand the writing in it, the procedures are somewhat vague and require reading before and past your problem to understand the process of trouble shooting. We'll get it though.

81pilot, did you get those pictures of that tailpipe set up yet? Sure is a nice look, those straight pipes....

 

You may want to check out some of the older threads on this forum.

http://forums.corvetteforum.com/c3-t...he-1981-a.html

Your car will run just fine without the CCC. Computer Controlled Carburettor.

Your car does not have, or use, an ECM.

You can install a switch to run the trans kickdown, put rubber stoppers on all the vacuum lines to the rochester, wire the dist normally and your car will run just fine.

Take the bulb out of the "check engine light".

 

My check engine light has always been "dimley" lit.
After having valve cover gaskets replaced on the car, now the light comes on "bright", but only when I stop the car at a traffic light...accelerating puts the light back to dim.
Any analysis?

 

Grounded the ecm terminal 5, ecm goes into code flash mode! Gives me the proper code 12, then a code 51.....read as bad or incorrectly installed PROM. It's installed correctly, so now I need another one.

Anyone got one that is stock? I guess I'd settle for a "hot" chip if someone has one as well.......

 

Reading codes on an 81 Vette

Pull the ashtray out. You will see a connector, with the key on – engine not running, ground the two plugs on the connector closest to the driver (a screw driver works well). You will hear a clicking in the engine compartment (This is the Fuel Mixture solenoid and it is normal). The check engine light will begin to blink. It will blink the code 12 three times (Code 12 = Blink, pause, Blink, Blink, long pause then it will do this two more times). After it blinks 12 three times, it will blink any other codes saved in memory. When all stored codes are complete, code 12 will blink three more times. If there is nothing in between the 12’s, there are no codes. The definition of the codes is shown below. The service manual has good troubleshooting for each code and there is lots of good help in the forum.

12=No Reference Pulses to the ECM
13= Oxygen sensor circuit
14 shorted coolant sensor
15= open coolant sensor
21=throttle position sensor circuit
23 =M/C solenoid circuit
24 =Vehicle Speed Sensor
34 =Vacuum sensor
42 =Electronic spark timing
44 =Lean oxygen sensor
44&45 = Faulty Oxygen sensor
45=Rich system indication
51= Faulty PROM
52= Faulty ECM
54 = Shorted M/C solenoid
55 =Ground 8V

 

Great news that you are getting codes. At least you know that the computer is working.

Look at the PROM again closely. It is very easy to bend a pin under or out and will look like it is seated in the plug correctly. If the pin is bent, be VERY careful when straightening it. They break easily. Sometimes they can be fixed and sometimes they are toast.

The only place I know to get a prom is Hypertech. http://hypertech.com. If I remember correctly, they cost as much as the computer. You can check ebay, but I usually see ECM without PROM's I don't know where all the PROM's go?

 

Well, I pulled the PROM back out, and a pin was indeed out of the socket. The clear plastic PROM "holder" is a pain to use, more designed for removal not installation, so I pulled the chip out of that, took the metal case off the ecm, and carefully installed the PROM in the socket, watching every little pin go where it belonged.

Put it all back together, energized it, check engine light came on, stayed on; fired it up, light went out. Stayed out. Ran it for 20 minutes, in place, rpm's up, down, all over. Idles up until warmed, I tapped it and it fell to perfect idle. No check engine light.

Turned it off, put it into diagnostic, and code "12" over and over. Nothing else.

I want to take it out and run it on the highway, then through town and see how it goes, and if it will trip a light/code.

I can't believe it has not tripped a code!!! Stay tuned....

 

WOW!! that is great.

 

Just got back from a 50 mile cruise. Light comes on at key up, goes out when started.

Never blinked the whole ride, talk about lucky!!

Next issue to fix now is the wheel / tire vibration.....and the exhaust....and the parking brake.........and...........

Gotta love old cars!!!

 

Great that you finally got this issue fixed. And yes, there is no end to next issues.

 

Hey everybody. This is my first post and Im new here because well i just bought a 1981 corvette. The car is in pretty good condition but it sat for a long time with poor weather stripping. I have replaced the tires, weatherstripping, radiator, fuel pump, plugs, distributer, all the bushings on suspension, belts, gaskets on oil pan and headers, oil change and fixed a broken gas sender unit. ugh. so last thing I thought I was going to have to do was have the Carb rebuilt, which I did. it drove amazing for like 45 minutes. It started doing the rough idle, stall out, wouldnt shift out of the highest gear. So I did a ton of research and it looks like I also have a bad ECM. I just bought one today and was lucky enough to find one available. I am not ready to get rid of the computer system as I want to do a full LS swap in the future instead. I will make sure to keep the original prom chip and install it correctly. This car is pretty stock, ac doesn't work, and neither do the high beam, right turn signal dash indicator lights, but they function outside the vehicle. Oh and the coolest thing was there was an original 1981 corvette shop manual in the car in a plastic bag! I wish I could scan it for yall!. Im also tackling the headlight vacuum relays. I didnt realize it needed this much work but I got a really good deal on it, it belongs to my best friends dad who sadly passed and they offered it to me. After doing the bushing I have a negative camber on my rear drivers tire I need to address.

Im glad I found this site, I would never have guessed it to be the ECM.

 

Welcome to the forum.

As an FYI, it's not a good idea to open old threads, especially ones that are 11 years old. It's always better to open a new thread with your info, and if needed, add a link to an old thread

Have fun here!