getting rid of electric carb/dist.81 vet
12-09-2016, 05:18 PM
#4
there are several.
Manual switch in drivers compartment (manually activated each time needed)
Install a late model TPS sensor on the Throttle pedal inside compartment.
Do without lockup feature (trans guys say this could hurt life expectancy of trans)
I'm sure there are many more, but those are some off the top of my head.
Manual switch in drivers compartment (manually activated each time needed)
Install a late model TPS sensor on the Throttle pedal inside compartment.
Do without lockup feature (trans guys say this could hurt life expectancy of trans)
I'm sure there are many more, but those are some off the top of my head.
12-09-2016, 07:25 PM
#5
Race Director
DUB
12-09-2016, 11:17 PM
#6
Team Owner
Why do you want to remove the one-year-only components from your '81? If you think putting another carb on will make it faster, forget it. That carb is a 750 cfm Q-Jet which could easily support a stout 454 engine with no problem. If it needs rebuilding, send it to Cliff Ruggles.
That carb, the distributor, TPS, O2 sensor and computer all work together to regulate fuel flow for proper mix and correct ignition timing. If you remove ONE of those components, you need to remove (or defeat) ALL of them. As a minimum, both the carb and distributor need to be replaced with non-electronic units, and the ECU needs to be disconnected. As mentioned, the trans lockup feature is managed by the ECU. To retain its function, you would need to install a lockup controller (best choice); a circuit which will allow engaging it when needed and disengaging when the brakes have been applied (decent choice); or provide a switch for powering the lockup circuit when needed (worst choice, as lockup clutch can easily be damaged if left ON when it should drop OUT).
If your engine management system is still functional, leave it alone. If it needs to be repaired, repair it. If you just want more power, change cam/heads, headers, etc; you can still used the existing ECM to maintain fuel/air mix and manage timing and lockup.
That carb, the distributor, TPS, O2 sensor and computer all work together to regulate fuel flow for proper mix and correct ignition timing. If you remove ONE of those components, you need to remove (or defeat) ALL of them. As a minimum, both the carb and distributor need to be replaced with non-electronic units, and the ECU needs to be disconnected. As mentioned, the trans lockup feature is managed by the ECU. To retain its function, you would need to install a lockup controller (best choice); a circuit which will allow engaging it when needed and disengaging when the brakes have been applied (decent choice); or provide a switch for powering the lockup circuit when needed (worst choice, as lockup clutch can easily be damaged if left ON when it should drop OUT).
If your engine management system is still functional, leave it alone. If it needs to be repaired, repair it. If you just want more power, change cam/heads, headers, etc; you can still used the existing ECM to maintain fuel/air mix and manage timing and lockup.
Last edited by 7T1vette; 12-09-2016 at 11:19 PM.
12-09-2016, 11:35 PM
#7
Racer
You have to follow other posts. He has no check engine light, car dies when he hooks up mc solenoid wire to carb, But runs with it disconnected.
Pro, did you check the gauges fuse? With key on, that sends power to check engine light, m/c solenoid and egr solenoid. It is a pink wire with black tracer. With the key on, disconnect m/c solenoid or egr solenoid and check pink wire with test light to ground, it should light.
Pro, did you check the gauges fuse? With key on, that sends power to check engine light, m/c solenoid and egr solenoid. It is a pink wire with black tracer. With the key on, disconnect m/c solenoid or egr solenoid and check pink wire with test light to ground, it should light.
12-10-2016, 07:24 AM
#8
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12-10-2016, 07:28 AM
#9
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carb
You have to follow other posts. He has no check engine light, car dies when he hooks up mc solenoid wire to carb, But runs with it disconnected.
Pro, did you check the gauges fuse? With key on, that sends power to check engine light, m/c solenoid and egr solenoid. It is a pink wire with black tracer. With the key on, disconnect m/c solenoid or egr solenoid and check pink wire with test light to ground, it should light.
Pro, did you check the gauges fuse? With key on, that sends power to check engine light, m/c solenoid and egr solenoid. It is a pink wire with black tracer. With the key on, disconnect m/c solenoid or egr solenoid and check pink wire with test light to ground, it should light.
12-11-2016, 08:25 PM
#10
Race Director
Just watching this thread. I am not passing any judgment.
You know to get a hold of me if you need me specifically for anything.
DUB
You know to get a hold of me if you need me specifically for anything.
DUB
12-12-2016, 07:33 AM
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12-12-2016, 01:43 PM
#12
Team Owner
Have you replaced the bulb for the Check Engine light? They do burn out. (If it doesn't light with ignition key in ON position [before starting], the bulb is probably shot.)
12-12-2016, 02:24 PM
#13
12-12-2016, 02:27 PM
#14
I have had a stock 81 Ca. emissions car for 15 years. When they are operating accurately, they work well. You NEED the shop manual if you keep the system. It's a one year only system, and they even had an 81 ECM manual. I have it.
12-12-2016, 05:25 PM
#15
Race Director
To be totally honest. Throwing parts at this is NOT what you want to do. But do as you want.
You MUST be able to communicate with ECM and data. There is no way around this.
IF you can not pull up codes or get the ECM to communicate with a scanner....what I talked to you about has to be done. Which is why I mentioned where I get the ECM and chip from.
Everything I talked with you about would be EXACTLY what I would do of your Corvette came into my shop with this problem. No question about it. Which is why I mentioned that I would have to verify the wiring circuits to make sure they are good and not broken or grounded somewhere BEFORE I went to and bought the ECM and chip.
DUB
Last edited by DUB; 12-12-2016 at 05:28 PM.
12-13-2016, 07:53 AM
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carb
Bill,
To be totally honest. Throwing parts at this is NOT what you want to do. But do as you want.
You MUST be able to communicate with ECM and data. There is no way around this.
IF you can not pull up codes or get the ECM to communicate with a scanner....what I talked to you about has to be done. Which is why I mentioned where I get the ECM and chip from.
Everything I talked with you about would be EXACTLY what I would do of your Corvette came into my shop with this problem. No question about it. Which is why I mentioned that I would have to verify the wiring circuits to make sure they are good and not broken or grounded somewhere BEFORE I went to and bought the ECM and chip.
DUB
To be totally honest. Throwing parts at this is NOT what you want to do. But do as you want.
You MUST be able to communicate with ECM and data. There is no way around this.
IF you can not pull up codes or get the ECM to communicate with a scanner....what I talked to you about has to be done. Which is why I mentioned where I get the ECM and chip from.
Everything I talked with you about would be EXACTLY what I would do of your Corvette came into my shop with this problem. No question about it. Which is why I mentioned that I would have to verify the wiring circuits to make sure they are good and not broken or grounded somewhere BEFORE I went to and bought the ECM and chip.
DUB
12-13-2016, 08:07 AM
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carb
forgot to mention when i unplug m/c connecter it dosen.t change anything. bill
12-13-2016, 04:15 PM
#18
I ran my 81 with no/disconnected ECM and original auto trans for two years before I switched it to a 4 speed. The trans worked fine, not saying this is the best way. This is the way I got the car and I didn't know any of it at the time. But I never had any trouble. Trans worked when I pulled it.
12-13-2016, 05:11 PM
#19
Instructor
I had an 81' and was going to do what you are asking.
There's a lot to do if your going to get rid of the ECU.
Carb,HEI Dist, B&G lock up control, Electric fan needs to have a electric t-stat added.
Keep the exhaust manifolds and get plugs for the A.I.R. stuff.
After you do all of that you still haven't added any horse power yet.
Convert exhaust to true dual from a 74, but you'll need a new cross-member.
After you look at all of that, and realize it all has to be done at the same time, you realize there's no up side to this really.
If you decide not to make any changes as I did, you WILL need the manual and assembly manual. I have them both and there yours if you like, there on the pay it forward thread. PM me if you want them. I also have the cross member if you decide to make the mods.
Good luck in you decision. I ended up with an 80' instead.
There's a lot to do if your going to get rid of the ECU.
Carb,HEI Dist, B&G lock up control, Electric fan needs to have a electric t-stat added.
Keep the exhaust manifolds and get plugs for the A.I.R. stuff.
After you do all of that you still haven't added any horse power yet.
Convert exhaust to true dual from a 74, but you'll need a new cross-member.
After you look at all of that, and realize it all has to be done at the same time, you realize there's no up side to this really.
If you decide not to make any changes as I did, you WILL need the manual and assembly manual. I have them both and there yours if you like, there on the pay it forward thread. PM me if you want them. I also have the cross member if you decide to make the mods.
Good luck in you decision. I ended up with an 80' instead.
12-13-2016, 06:09 PM
#20
Race Director
Bill,
There is no way in knowing if it is in OPEN LOOP or CLOSED LOOP. The O2 sensors is the 'switch' so-to-speak in what makes the ECM go from OPEN LOOP to CLOSED LOOP when it gets hot enough. BUT it can kick out of OPEN LOOP and go back into OPEN LOOP if fuel is dumping into it.....thus cooling down the O2 sensor and make it switch back and forth. And not being able to watch this on a scanner....would be like siting beside glacier and waiting to see it move.
How it is running...better or worse is all a guessing game with you throwing parts at it and hoping for the best....because....IF you can not communicate with the ECM...that is all you are doing. Blindly guessing that something may work.
Do you remember in our conversation when I talked about that customer I had did work at home and replaced LITERALLY every sensor on the 89 Tuned-Port engine. AND it still did not fix his problem UNTIL he brought it to me and I replaced the BOGUS aftermarket ECM in it with A GM one. And the one I recently repaired that is just like yours...no communication.....and I replaced the ECM and chip and that fixed it.
This is not hard to do or fix and get right...because oddly enough I was just like many who may read this. I knew absolutely NOTHING....but now...it is no big deal and there is NOTHING to be afraid of.
And like in our discussion...if you are having someone do this work for you...it will be up to them to TAKE THE TIME and check the wire that I thoroughly explained to you about how I would do it if your Corvette were sitting in my shop. This is so you do not go and put a new ECM and chip in and find out that you had a broken wire like I mentioned CAN HAPPEN.
I do not know what more I can do for you but other than guess....and I really do not like doing that when I know what needs to be done. And this is only from my person experience when working on these Corvettes for my customers. I felt that in our phone conversation I tried to make it clear on what the next step was so you and your tech would not waste time. It is totally up to you on what you choose to do.. Until you decide to check the wire...and find that it is GOOD....then correctly get the ECM/chip installed with a GOOD ECM...I honestly do not know what more I can do. Because IF you can not read data...you know nothing at all to how the ECM is responding to sensor inputs.
Somethings in life are basically set in stone. Kinda like if a person wanted hard boiled eggs. If that person just puts the eggs in water...they will never get hard boiled eggs. They have to boil water. So trying to keep a computer controlled engine running correctly and NOT being able to see what the computer is doing...is as you can probably guess from what i have already stated.
YOU ARE NOT ALONE in this. I will not leave you 'hanging out to dry'. But I can not help you if the steps I advise on are not preformed. the choice is up to you.
DUB