ra42mario

Hello everybody I'm a new member. I bought a 1977 Corvette that had a blown engine. I never ran the engine, but the car did have electrical power.

I removed the stock engine and installed a Chevy 400. When I was removing the old engine I forgot to remove the neg. cable and I touched the alternator with a wrench which sparked. I didn't think much of it at the time and disconnected the battery.

Now my 400 is in the car (for the most part). My alternator is not hooked up, but I need to rotate the engine so I plugged the battery in to bump the motor with the starter and to my suprise I had no electrical power when I put the key in the ignition. I was able to bump the starter with a screw driver, but nothing when I put the keys in the ignition.

Any tips? I looked at the fuses behind the dash (hard to see those things!) and all the fuses looked to be intact. Maybe the fusible links? I tried looking for them but can't find spot the links and a google & forum search didn't turn up anything.

Thanks in advance,

Mario.

71coupe454

I have a wiring diagram for 71 if you would like me to email. I think the file may cover other years but should help with fusible links locations.

aussiejohn

Mario,
Welcome to the Forum. You will never ask a stupid question here, as we all knew nothing about Corvettes at some stage in our lives. A few of us have not progressed much, though!

When you turn your key on, does anything work? The wipers, radio, indicators etc.? If not, then you need to look at the fuse box and starter motor terminal where the thick battery lead goes. A thick red wire should come from the same terminal and go to the fuse box.

Inside your steering column is a small rack and pinion that has the pinion at the end of the ignition key, and this drives a toothed rack that activates the actual ignition switch further down in the column. Perhaps the rack is not moving, or not moving enough to activate the switch.

Find the thick purple wire and check that this is getting power from your column. Then find the other end that should attach to the starter solenoid and see if that is getting current. Keep at it and you will find the culprit.

Regards from Down Under

aussiejohn

ra42mario

yes i would appreciate a copy of that diagram. my email is ra42mario@gmail.com

When I bought the car the owner showed me the lights and everything worked, I believe I just blew a fuse/fusiable link when I made the bonehead mistake of not disconnecting the battery then I arc'd the alternator.

I will check the suggested locations for fusiable links tomorrow. Appreciate the suggestions I will keep you updated.

Mario.

Bo5co

Hey Mario,

I'm mailing you a wiring diag for '77. It does sound like you've 'let the smoke out' of the fuse link.

Concerning fuses - a visual inspection is not reliable. I've seen quite a few that looked fine and were blown toward the ends where one cannot see. I always hit both side with a test light when tracking down electrical issues, never trust what I see until that light lights up.

71coupe454

Its sent, hope G-mail will take a 10meg email.

Brass Pass

Mario,

Before you start hunting down fusible links, make sure you put the battery cable on the right lug of your starter.

I just put a new engine in my car also and everything electrical was working before. When I went to fire it up... Nothing. I started doing what you are about to do and then realized I had put the positive battery cable on the wrong starter lug. A quick check may save you some time and grief. Just a thought...

** I just realized there might be a difference since yours is a 1977.

ra42mario

Well I got it working.

It ended up being the thick red wire that goes to the same terminal as the thick Black positive wire.

Thanks for all the help guys, now let me get back to finally getting this motor installed!

Thanks,

- Mario.

ra42mario

Well I thought I had it fixed, but guess not.

Here is what happened:

I went to try and fire up the newly installed SBC 400. When I put the key in and turned the ignition on I had radio, dash lights, wipers etc... then we (me and my neighbor) tried starting the car. The starter spun a little bit. Car didn't start so we tried it two more times then aboslutely no power at all.

The battery is from my boat, its brand new marine battery. I have it on the charger now but the gauge on my charger says its got a good charge on it.

I think the issue might be my starter. I have the THICK black wire and the red wire on the same terminal. Then I have the other wire on the Post that is nearest the engine block. The post that rests near the fender has nothing on it. Is this the proper configuration? When I got the car most of it was taken apart so I'm not sure how it went.

RIO68

The post nearest the fender is empty--you should have another black wire that is ground and most will put it on the bell housing bolt closeast to the frt of the starter. Get you a test light and check the circuits according to the wiring diagram and you should find any problems.
Patience is a virture!! Good luck you can do it!

ra42mario

So here is an update:

I bought a test light, one that turns GREEN when its on negative and RED when its on positive.

First thing I did was put the ground clip on a ground (bolt that holds the seat down) and touched the battery terminals. When touching the Negative I got a Green light, when I touched the positive I got nothing. If I touched directly to the Neg & Positive on the battery I did get light.

I then went under the car to where the starter is. I ground the test light on the Frame - Motor Mount. I got nothing.

So I figured maybe the battery is weak/bad? I changed out my battery (which is a new marine battery from my boat) to one I had in the garage that I know couldn't start a car, but figured maybe it could hold enough juice to atleast turn the lights on. I charged this battery for about 5 hours on the charger then I put it in the car.

I reground the testing clip to the seat hold down bolt, then touched the terminals. Now this time the test light lit up when I touched both positive and negative terminals. So I then tried to turn on the inside lights, nothing.

I went back under the car and put the grounding clip back on the frame motor - mount then I touched the big thick black cable on the starter. The light lit up Red which means I was getting positive juice.

So now I'm GUESSING (or maybe wishing?) that the battery is just so weak that it won't give me lights since it did atleast light up the test light this time.

I'm taking my Marine Battery back to Walmart (yeah i know, this is what I get for buying batteries at walmart) to exchange it for a known good one. So keeping my fingers crossed that everything works out.

Let me know your opinions on my diagnosing this problem, I feel very comfortable with mechanical side of cars, but not yet with electrical so I'm nothing but open years to your suggestions!

- Thanks, Mario.

ra42mario

Update:

Went around with the test light following the Red wire that runs from the starter, to the alternator, back into the "bulkhead" connector which leads to the fusebox. I have power all throughout it.

I checked the fuse box, I have power on all the fuses on the LEFT hand side of the fuse box (if you are facing it from inside the car) except for the Hazard/LPS (small short fuse) on the very bottom, and I have NO power to any of the ones on the right hand side. The ones on the right handside seem to be all accessories that the ignition needs to be on for.

Any suggestions? I do not see any fusible links that are broke anywhere, and I've verified the Positive/Hot that runs from the alternator back into the car is good.

What can I do to take the alarm out of this equation, which fuse do I pull to eliminate it from the system?

Could this be possibly a bad ignition switch since I have NO power inside the car but I do in the engine bay?

ripforrey

Mario;
This is a great site. I never would have got my 76 rolling without much help from the other members. FYI you can send a private message to a poster by clicking on poster's name.
Sounds like a fuse link. I got one of the liminated 2'X3' wire diagrams for my 76. It's like $10 easy to follow; not to mention clean the grease off.
Good luck

70ZZ3 96LT4

Did you connect the ground cable that connects to the engine block and connects to the frame near the passenger side motor mount? My 68 and 70 have this ground connection cable, don't know about your 77.

If your alternator does not work when you get your car running there is a fusablel link between the alternator and the relay on the drivers side inner fender. This fusable link runs from one of the wires that is on the connector that is pushed into the top of the alternator.

noonie

77's have a feed connector hidden under the brake booster which commonly heats up, corrodes and looses it's connection and will give your symptoms. Test for power on the side that enters the outside of the fuse block.
Tough to get at and clean.
Here is a pic.

ra42mario

Fixed it!

I took my Voltmeter to check voltage. My test light was working on everything, but my voltmeter returned better results. At my battery I had a healthy 12.45volts. But at my starter and alternator I had 4-7volts. My cables looked very good at the battery, but I jacked the rear of the car up and went to inspect the negative cable. At the frame I found a very BLUE corroded wire that was swollen. I replaced it with another ground cable (2g) and I had power. I went bought another ground strap (4g) to replace the one on the motor mount/frame but I haven't got around to doing it quite yet.

Now to move forward with this project. I appreciate all the help guys, sorry I dragged this out instead of inspecting the BOTTOM of the ground cable and not just doing a quick visual on the pristine condition top of the cables.