New Family Member
10-22-2014, 01:18 PM
#1
Le Mans Master
Thread Starter
New Family Member
Just picked up my first C4- 87. $3000 off a used car lot. This is the girl you don't bring home to meet mom. 
She's been around the block a few times.
Here's my first 3 questions- of many-
The rear brakes don't work- both calipers. What's the typical cure for simultaneous failure of BOTH calipers on a C4 ?
The engine fan is being run from a toggle switch. What's the typical cure for this? I assume a temp sensor & relay somewhere?
What interior colors did the maroon exterior come with?
(this one has a red interior) It appears maybe it was repainted maroon from red.
It looks relatively unmolested with 103,850 miles.
Floor is rotted on the passenger side only. The rest of the floor is solid no rust. I presume this is typical for a leaky T-Top. I can't see any of the other tell-tale signs of being in the rust/snow belt
Runs rough until warmed up... stalls. Probably TLC in the filter/intake etc and some fuel injector cleaner (maybe plugs/wires etc) will help- I hope.
She's been around the block a few times.Here's my first 3 questions- of many-
The rear brakes don't work- both calipers. What's the typical cure for simultaneous failure of BOTH calipers on a C4 ?
The engine fan is being run from a toggle switch. What's the typical cure for this? I assume a temp sensor & relay somewhere?
What interior colors did the maroon exterior come with?
(this one has a red interior) It appears maybe it was repainted maroon from red.
It looks relatively unmolested with 103,850 miles.
Floor is rotted on the passenger side only. The rest of the floor is solid no rust. I presume this is typical for a leaky T-Top. I can't see any of the other tell-tale signs of being in the rust/snow belt
Runs rough until warmed up... stalls. Probably TLC in the filter/intake etc and some fuel injector cleaner (maybe plugs/wires etc) will help- I hope.
10-22-2014, 04:03 PM
#2
That was a good deal for a running car. They sell C4's dirt cheap when they have problems because they are NOT like other GM cars of the same era and most mechanics do not understand them or how to work on one....
Good job ! Congrats !
well, the floor pan is not metal, the cabin section is fiber glass or compound. The pans are replaceable but most just repair them.
the toggle switch.....back track to find the bubba-rigged wire to the relay or the fan,. Take it out. probably on the green wire IIRC....remove. This is just a 2nd route ground path. Easy to un-do. ALL C4 electrical, everything is managed by the GROUNDS. To make something run, complete its ground. The ECM does this for most things. The 'hot' wire is already completed...
The fans SHOULD come on at 226 degrees. They run HOT. Not a problem. Just scares bubbas a LOT.
May need MAF relays. Read the flash codes and get back to us.
Get your FSM ASAP. That's a GOT TO ! !
They not expensive now, less than $50 on fleabay and there is a link here for new editions. I prefer the old 2 book paper copies because they had color schematics. new ones are B&W. That sucks for electrical....
Good job ! Congrats !
well, the floor pan is not metal, the cabin section is fiber glass or compound. The pans are replaceable but most just repair them.
the toggle switch.....back track to find the bubba-rigged wire to the relay or the fan,. Take it out. probably on the green wire IIRC....remove. This is just a 2nd route ground path. Easy to un-do. ALL C4 electrical, everything is managed by the GROUNDS. To make something run, complete its ground. The ECM does this for most things. The 'hot' wire is already completed...
The fans SHOULD come on at 226 degrees. They run HOT. Not a problem. Just scares bubbas a LOT.
May need MAF relays. Read the flash codes and get back to us.
Get your FSM ASAP. That's a GOT TO ! !
They not expensive now, less than $50 on fleabay and there is a link here for new editions. I prefer the old 2 book paper copies because they had color schematics. new ones are B&W. That sucks for electrical....
Last edited by leesvet; 10-22-2014 at 04:05 PM.
10-22-2014, 11:53 PM
#3
Le Mans Master
Thread Starter
That was a good deal for a running car. They sell C4's dirt cheap when they have problems because they are NOT like other GM cars of the same era and most mechanics do not understand them or how to work on one....
Good job ! Congrats !
well, the floor pan is not metal, the cabin section is fiber glass or compound. The pans are replaceable but most just repair them.
the toggle switch.....back track to find the bubba-rigged wire to the relay or the fan,. Take it out. probably on the green wire IIRC....remove. This is just a 2nd route ground path. Easy to un-do. ALL C4 electrical, everything is managed by the GROUNDS. To make something run, complete its ground. The ECM does this for most things. The 'hot' wire is already completed...
The fans SHOULD come on at 226 degrees. They run HOT. Not a problem. Just scares bubbas a LOT.
May need MAF relays. Read the flash codes and get back to us.
Get your FSM ASAP. That's a GOT TO ! !
They not expensive now, less than $50 on fleabay and there is a link here for new editions. I prefer the old 2 book paper copies because they had color schematics. new ones are B&W. That sucks for electrical....
Good job ! Congrats !
well, the floor pan is not metal, the cabin section is fiber glass or compound. The pans are replaceable but most just repair them.
the toggle switch.....back track to find the bubba-rigged wire to the relay or the fan,. Take it out. probably on the green wire IIRC....remove. This is just a 2nd route ground path. Easy to un-do. ALL C4 electrical, everything is managed by the GROUNDS. To make something run, complete its ground. The ECM does this for most things. The 'hot' wire is already completed...
The fans SHOULD come on at 226 degrees. They run HOT. Not a problem. Just scares bubbas a LOT.
May need MAF relays. Read the flash codes and get back to us.
Get your FSM ASAP. That's a GOT TO ! !
They not expensive now, less than $50 on fleabay and there is a link here for new editions. I prefer the old 2 book paper copies because they had color schematics. new ones are B&W. That sucks for electrical....
I have a code reader just by chance. I'll see what it says.
I pick up the car on Friday. When it's solidly in my hands, I'll order the manuals. I have them already for my C2 & C3.
The front rotors are both shiny so the front brakes are working. The rear rotors are crusty rusty so I know the rear brakes are not functional. Should be an easy fix but I just thought I'd shorten the learning curve by asking here first. On C2's and C3's this can be caused by collapsed hoses.
So... you are saying that the floor pan just behind the firewall is fiberglass? Why are so many of the C4's that I look at busted out in that area (outboard front corner) ??
10-22-2014, 11:57 PM
#4
10-23-2014, 12:27 AM
#6
Race Director
The ECM controls the fan based on a CTS (Coolant Temperature Sensor) in the front of the intake manifold under the throttle body. Note that the water temperature you see on the dash comes from a different CTS, located in the passenger side head between spark plugs #6 and #8. If your car has the auxiliary fan in front of the radiator, that is controlled by a thermal switch in the driver's side head between spark plugs #1 and #3.
10-23-2014, 03:13 PM
#8
Yep, I was gonna say a bad master cyl for the rear brakes. The next guess would be pinched steel lines from MORE improper jacking.....bubba loves to slide the floor jack under the cabin and lift. I caught one idiot about to jack a car by placing the jack under the fuel tank...(spare carrier was removed)
If you pull the carpet and liners out, you can clean and repair the floor pans. Then grind the damage away from below and coat with a sealant or spray-on coating, rust proof or some other rubber in a can.
If you pull the carpet and liners out, you can clean and repair the floor pans. Then grind the damage away from below and coat with a sealant or spray-on coating, rust proof or some other rubber in a can.
10-24-2014, 07:53 AM
#9
Le Mans Master
Thread Starter
Thanks... easy fix on the floor. Needs new carpet anyways. I'm on my way now to pick 'er up. It's a 60 mile drive one way. Bringing brake fluid. antifreeze, oil, transmission fluid, power steering fluid and fuel injection cleaner. Hopefully I won't have any problems getting back.
10-25-2014, 09:55 AM
#10
Le Mans Master
Thread Starter
FYI Current cost on the FSM (Factory Service Manual). (ordered)
1 of 14102739: 1987 Corvette Owner Manual @ $25.00 each
1 of ST36487: 1987 Chevy Corvette Service Manual @ $100.00 each
1 of ST36487EDM: 1987 Chevy Corvette Electrical Diagnosis Service Manual Supplement @ $0.00 each
Subtotal: $125.00
Shipping: $9.77
Handling: $6.75
Tax: $0.00
Total: $141.52
1 of 14102739: 1987 Corvette Owner Manual @ $25.00 each
1 of ST36487: 1987 Chevy Corvette Service Manual @ $100.00 each
1 of ST36487EDM: 1987 Chevy Corvette Electrical Diagnosis Service Manual Supplement @ $0.00 each
Subtotal: $125.00
Shipping: $9.77
Handling: $6.75
Tax: $0.00
Total: $141.52
10-25-2014, 05:09 PM
#11
Melting Slicks
Damn, mine listed on A-zon for less are near perfect!
Remember, these cars are still that, meaning the basics apply, like vacuum leaks, fuel delivery, etc. The electro-gadgets fine tune what the 'old stuff' did, but will never find a cracked hose. Codes help,but can also mislead.
I seem to remember that there was some wood sandwiched inside our floors.
Use a quality DVOM as these are rather low-voltage electrically controlled machines. Dirty/corroded or, weak contacts/wires can be a bitch to find but may also be the only problem.
As a multi-GEN Corvette guy, your mechanical skills will be essential, but also need a slight enhancement for these newer cars.
Remember, these cars are still that, meaning the basics apply, like vacuum leaks, fuel delivery, etc. The electro-gadgets fine tune what the 'old stuff' did, but will never find a cracked hose. Codes help,but can also mislead.
I seem to remember that there was some wood sandwiched inside our floors.
Use a quality DVOM as these are rather low-voltage electrically controlled machines. Dirty/corroded or, weak contacts/wires can be a bitch to find but may also be the only problem.
As a multi-GEN Corvette guy, your mechanical skills will be essential, but also need a slight enhancement for these newer cars.
10-25-2014, 08:32 PM
#12
Le Mans Master
Thread Starter
Damn, mine listed on A-zon for less are near perfect!
Remember, these cars are still that, meaning the basics apply, like vacuum leaks, fuel delivery, etc. The electro-gadgets fine tune what the 'old stuff' did, but will never find a cracked hose. Codes help,but can also mislead.
I seem to remember that there was some wood sandwiched inside our floors.
Use a quality DVOM as these are rather low-voltage electrically controlled machines. Dirty/corroded or, weak contacts/wires can be a bitch to find but may also be the only problem.
As a multi-GEN Corvette guy, your mechanical skills will be essential, but also need a slight enhancement for these newer cars.
Remember, these cars are still that, meaning the basics apply, like vacuum leaks, fuel delivery, etc. The electro-gadgets fine tune what the 'old stuff' did, but will never find a cracked hose. Codes help,but can also mislead.
I seem to remember that there was some wood sandwiched inside our floors.
Use a quality DVOM as these are rather low-voltage electrically controlled machines. Dirty/corroded or, weak contacts/wires can be a bitch to find but may also be the only problem.
As a multi-GEN Corvette guy, your mechanical skills will be essential, but also need a slight enhancement for these newer cars.
Yes... I can definitely see a learning curve here. I do have 4 Fox Mustangs and a Lincoln with EFI & EEC-IV so I'm already in digital mode but the C4 is a lot different than the Fords.
I already have several DVOM's so I'm good there. I have a scope too, but don't anticipate a need for it.
This car has enough rattles to supply all the Gerber babies. I have my work cut out for me.
11-04-2014, 12:28 PM
#15
Le Mans Master
Thread Starter
On a hunch... erratic backfire through intake... rough idle... stumble on acceleration...
Pulled distributor cap to see rotor and turned crankshaft. Rotor didn't move. Timing chain & gears are obviously shot. My first project. No big deal. I'll git er done. Do I assume a factory roller cam?
Pulled distributor cap to see rotor and turned crankshaft. Rotor didn't move. Timing chain & gears are obviously shot. My first project. No big deal. I'll git er done. Do I assume a factory roller cam?
11-04-2014, 03:49 PM
#17
Le Mans Master
Thread Starter
11-04-2014, 03:52 PM
#18
Le Mans Master
Thread Starter
11-04-2014, 04:11 PM
#19
Burning Brakes
I just happen to have a new rear set of pads and rotors for an 87 I got along time ago when I had my 87.I would let go for $40.00 plus shipping if you were interested.
11-05-2014, 07:07 AM
#20
Le Mans Master
Thread Starter
Don't know why only the rear calipers/pads are ineffective. We'll see when I get there.