Jenny

Tom and I spent another ay bonding with eachother. I got there a littke late, as i overslept my alarm. When i got there we set up shop in his driveway. We opened my hood, and began tweaking the carb. Well, half of the vacuum hoses were on wrong, and it was idling rough. Taking off the distributor cap, we could see that it was used up. Mike went to the autostore and bought an accel cap+rotor replacement. We replaced it, and began working on the brakes [again] and the Fiberglass spring. The spring was pretty easy, been "bubba'ed" but worked out well.

That being said and done, we go back to the front with not-so-good news. It's a vacuum disaster. Random hoses, leaks. We did determine that my car did have a computer, also with random sensors laying around everywhere. After plugging up some vacuum leaks and replacing cap+rotor, it ran really rough... [still does :( ] Since everything is like it's supposed to be, the computer isn't compensating for the correctness of the components, including some backfire at WOT.. but only sometimes. It's still running pretty rough, the idle is poopie, and well, the underside of the hood is Fuked. Whoever put the new engine in didn't know what he was doing. Sigh... Could be worse. It's slowly getting better, i really don't know what i'd do w/o your help Tom, thanks for everything.

The next step, i think I have made up my mind, is to get a non-computer carb, new manifold and an MSD. Doing this, we can scrap ALL of the computer crap that i don't need, eliminate a lot of the vacuum hoses, and try to tune it all right. So thats the update. When i drop in the new engine i think we'll further be able to make progress.

Thanks again, I'd lose hope without you :). And have a very happy birthday! Talk to you soon!

If anyone has reccomendations as far as carbs, i was thinking Speed Demon 750. I don't know anything about intakes, but it will have to clear the hood, and work on my future 383. The Victor r. doesn't clear according to summit. Anny sugggestions are Greatly appreciated.

-Jen


PS- I did manage to lift the body up some more. Almost perfect. I'll re-adjust again in a day or so when it's done settling. :) ... And get those sparkplugs


[Modified by Jenny, 4:40 AM 1/21/2002]

73 LS-4

Hi Jenny, as far as carbs. I'd recommend trying to find a descent used quad at a yard and send it out to Lars for a rebuild and proper tuning to your engine. Would hate to put much more time and money into an engine that you are either going to replace or rebuild in the near future anyway. This way you could have a descent running carb so you can drive the car without fear, without bolting things on to your present engine which may be too much for it, and have further driveability issues. A 750 with a single plane intake (I believe the jr is a single plane) I doubt would run worth a darn on a stock 350 engine, so I'd wait till I had the 383 going before purchasing them. Just my oppinion :D

:cheers:
Pat Kunz

Stingy74

Jenny, I had an Offenhauser 360 under the hood of my 74. I absolutley had to have the Edelbrock Victor Jr. so I bought it without even caring to check if it would fit. It is about 1/8" shorter than the Offy, so I know it will fit. I use a drop base air cleaner and a 2" tall element. The wing nut just barley touches the hood. GKull has managed to fit a Victor Jr. with a 3" tall element with his custom made drop base. PS: The Offy is on the left and the Victor Jr. is on the right.

jimbr

Jenny,

I don't know what you have overall.... I can tell you that an Edelbrock Performer AirGap (new model) fits under the small block hood on a 70.
I just completed a top end re-do per all the stuff in my signature pic below.

So, I have the heads, stock manifold, ramhorn exhause manifolds, Q-Jet, etc. The car was running great with all this stuff - I just needed more SPEED. Let me know if you are interested in the Q-Jet.

Jim

Ganey

Jen

Sounds good. So you have an 80. Which engine, trans. & gears? You do not need a MSD.

:cool:

VolVette

Again, I am jealous that Jenny has a Tom to go to for help and questions! :D One day I am going to make the trip down to Raleigh and visit with Tom because I also have a crate engine that was installed improperly and with all sorts of quirks.

Lars is so helpful. I read his papers and try to work through my problems. I often call him and we talk through the problem. It's amazing how much he knows...

Stephen

Jenny

Yup! That is exactly the same problem. Hopefully it'll be sorted out before too long. If you're gonna do something, you might as well do it right.

FWIW, the motor is a late 350HO crate, the car appears to be an original California Emissions 305. :eek:

It is strong, but probably like your car, the vacuum was installed all wrong, and there are random sensors everywhere. We could try to piece it together, but when i drop the 383, i'd rip it all out, so it makes no sense.

I'll run some errands today, tty'all later!

Tom454

Obviously we a little help with this one...

The distributor is a computer controlled HEI with non-vacuum (electronic) advance.
The carb and manifold have been selected, now the tricky part...

Since the 383 is not too far around the corner, and since Jenny has no intentions of keeping the CE stuff, I believe the decision was made not to spend any more time trying to troubleshoot the existing can of worms.... which it is. The car does have cats on it.
There are a bunch of vacuum hoses & switches which are totally out of sync with each other... both ported & manifold vacuum. In order to work on this car, a factory shop manual and vacuum hose routing diagram are needed... it's a mess.

I have worked on a few of these systems, and I do know that if any one sensor is not functioning properly, the whole system hiccups.

RE: The distributor, since it is a good HEI unit, it seems prudent to keep it and find an aftermarket system that will work with it, rather than buying a whole new distributor. We will pull it out and make sure the endplay is within spec before we mess with the system.

Here are the issues-
1) Once the computer is disconnected from the engine, is there anything else it is connected to like, the transmission?
That is, will disabling the computer affect any other systems on the car?
2) Will an aftermarket unit work with the factory tachometer (which currently works well)?
3) Who makes an ignition system that will hook up to this dist with minimal hassle?

We have no tech info on the 80 CE system other than a write up from the "Small Block Chevy Interchange" manual. The write-up does not address the 80 Vette system direcly, so we are making a few guesses & assumptions.

If anyone has already gone through the pain of bypassing the electronics of a CE car, we could use some pointers. You know... those "gotcha's".

Tom

Guest

Jenny, nice write up. So did you get the spring already installed? If so, how is the new ride on the replacement, notice a difference?

Sorry I missed another "Day at Tom's"... :cry

Later,
Rob

CHEESERAL

Tom, I have an 81 shop manual if you want to use it also a Dr. Rebuild vacum diagram, again for an 81 but your welcome to use both if you think it would help.

Good luck.

Tom454

I'm clueless on the diff (if any) between 80 CE and 81... and I don't know what Jens total strategy is yet... so I'll leave that call up to her & mike. Thanks for the offer... maybe we'll need your expertise.

Tom

Ganey

Typically it differs between yrs., Fed.,Hi Alt., Calif, & Trans.
So far you have 80 Calif. which may be auto. only for Calif.

Many topics, latest: http://forums.corvetteforum.com/zerothread?id=221228

Non computer HEI & carb. & trans. converter lockup if auto.

CHEESERAL

Tom, I hear ya, I'm not sure either. The only thing I've done as far as the computer goes is follow the trouble shooting procesure in the manual until I got to the Replace computer leg of the guide on the 1st page and that fixed my problem. Check engine light steady after I put in a good bulb. Anyway the next time you guys get together I'd love to stop by and see what you're doing and I'll bring the book just in case. Don't know that I'd be any help but maybe I'll learn something.

Chuck

Stingy74

What transmission does the car have? 1981 seems to be the year that I remember th350 lockup's coming into play but a friend of mine, and fellow forum member Darcy Bast had an 80 with a lockup transmission. I'm not sure if lockup is controlled by the computer or not but it may be something you guys will have to think about before deciding to go non-computer controlled. That or make a switch.

Jenny

Here's another twist to the story. According to the VIN # on the car, it's an L-48. The fifth position is a "8". Were it a cali car, it should bee an "H" according to the chart i'm looking at. I'm getting really frustrated with all this. And to think that the tranny is involved with all this computer stuff just makes it all worse. :sad: I guess next step: how do i figure out if the tranny is computer lockup. I'll do some more reading and detective work :( Definitely not- cool :(

Cheeseral- I don't think i have a check engine light. :confused:


[Modified by Jenny, 6:28 PM 1/22/2002]

CHEESERAL

Hi Jenny, check engine light on mine is the lower left light in the gauge cluster, mine didn't have a bulb in it when I got the car, I'm not sure if you're 80 should have one or not. As far as the tranny goes I think the lockup tranny has a place to plug in a 4 prong elec connection on the drivers side, but I can't remember now. Mine is just a 3 speed th350 as my car was originally a 4 speed and now is an auto. I do have the lockup wiring harness if ya need it.

Chuck

DaveL82

Sorry but I'm a little confused. The car is an 80 right? I have a 1980 L82.

Heres what I understand about the cars. The L82 and L48 were both offered that year. Both of these do not have computers! The only car with a computer from what I recall, is the California version and it came with a 305 instead of a 350.

Not sure why you would have a computer if you do have the L48 car. Even the lock-up torque converter is controlled by engine vacuum, 3rd gear selection and car speed, but none of these uses the computer. 1981 was the first year for a 50 states vette with a computer.

A back fire can be cause by not having the air pump hooked up to the correct (timed vacuum port) if the car has an air pump for emissions. If not hooked up right it will allow air to be injected into the exhaust when you let off the gas which will cause a back fire.

Dont forget to replace the HEI control module in the distributor. These show up failed as running OK when cold but them idle rough, hesitation and backfires when warming up. When rotor goes bad, it allows stray sparks to go through rotor and hit center shaft advance weights or HEI module. Look under rotor to see if these is orange/rust looking stuff on advance weights. If so, rotor was shorting out.

FYI - if the car is an 80 and is an L48, you can remove the computer because the car isn't supposed to have one. Did someone but an later engine/trans in it?

Jenny

Oh hey- I didn't notice you were in garner. I used to work at the Staples a loooong time ago. I will check again to make sure i do/don't have it. I did manage to find this:
http://iotech.no/corvette/technical/...tics/index.htm

ALthough i can't see any of it because i'm on a mac. But it does look like the transmission has comp. lockup. Sigh. I should just get rid of the stupid thing. Each day my hopes get shattered. :nonod:

Jenny

Dave, thanks for your reply. It really helps a lot to get as much information as possible. Based on this site, http://www.vettesite.com/vin.asp , my car is an L48. But, since it had a computer, Tom and i were convinced it was a CE model. But when you look at the VIN #, it does not have the "H", but rather a "8" where the engine designation is. The car has a 350HO Crate Engine, casting numbers confirm this. This engine was discontinued mid-late 90's and put out 300hp/370ft lbs. The prior owner of 12 years had it installed in 1994. That is that. It is obvious that the computer is there, In the battery box. Looks original so i really dunno. Its a mess.

DaveL82

If the car is an 80 305 car with computer make it easy on your self.

Get the parts for an L48 or L82 non computer car. If it is an L48 this may not have come with the air pump in 80.

For the distributor you need to change it, even if just to a rebulit unit for a non computer 76 to 80 car or truck with HEI. You must have an HEI unit with a vacumm advance.

I would also recommend going with a rochester from an 80 (or 79). This way if you ever have to hook up emissions everything is there. 80 carb had a electric choke element that can be added to any rochester carb with integral choke (choke housing is on carb, not intake manifold). I run the rochester on my ZZ4 with no problems.


The real issue is what is used to control the transmission. If it's just the turbo 350C this will be easy. I even disconnected the lockup on my 80.

I have changed out my L82 motor with the ZZ4. I also have all the emissions hooked up (egr is mounted but does not work because L89 aluminum heads don't have exhaust passages). I like to make it look stock, but have the extra hp.

Start with the basics. Find the vacuum advance type distributor and hook it to the carb port with vacumm at idle so it will run smoother at idle (edelbrock sells new rochester carbs that will work on the 80 if you want to go new). Hook the light assy and dash vacuum hoses to the manifold but you must have a one way vacuum valve in the system. Hook the power brakes to the carb or manifold. With just these items hooked up, you should be able to get the tuning done and go out for test drives.