1987 Corvette Questions

Hey there everyone It's been a while since my last post!

I recently got rear ended by a drunk driver in my 1991 Z28 Camaro Convertible and it's currently at the local junk yard being parted out.

However, I have purchased a 1987 Corvette C4+3 to replace my Camaro.

I LOVE this car!

For a 26 year old vehicle with 88,xxx miles it runs and drives like a brand new car!

I have been noticing a few weird issues with the car though and I was hoping someone could help me out :)

Well first off I'm curious as to know why my acceleration is like a slow obese cat at times. When I'm under 1700 RPM it'll kick in gear and the rear tires will let loose. But anything above that it, well, doesn't. I find it very odd. I'll put the petal to the floor at 2200 RPM and it'll slowly work it's way up to 4400 RPM. I have a feeling this is TPS but I could be wrong.

I also have a problem with the reverse/back-up lights. The C4 has 4 reverse lights (2 on rear fender/bumper and 2 on rear bumper). These lights only turn on randomly. I'll throw it into reverse and they will not turn on. But other times i'll throw it into reverse and they'll be as bright as day when it's night out. When they do turn on, if I wiggle the shifter they'll shut off. I honestly have no idea what this could be.

I put in a new alternator and battery just for maintenance but my battery levels are still fairly low. After 20 minutes of running time and the A/C on the voltage reads 11.8volts on the gauges. I'm not entirely sure if my A/C is draining a lot of voltage but I know those aren't normal running conditions.

Also, my A/C likes to work randomly as well. When I hit the switch I will hear the radiator fan turn on, the Idle shift, and I hear the internals of the compressor working but no air blows out. Could this be a bad blower motor? When It does work the air that comes out is fairly cold but the air flow is weak. It barely reaches my body even with all the air vents pointed towards me.

And last but not least, there is a slight "bump" or "rattle" sound coming from the rear end. I had it up on a lift the other day and I saw an exhaust bracket was snapped off but when I yank on the exhaust system it doesn't budge. Could the bumps on the road be strong enough to move the exhaust up and down to create the bump I hear? It's a very light knock but it's bothersome.

Any help is much appreciated! I know it's a list but the local Corvette specialists here in Florida are expensive so i'd rather do trial and error with a bit of help from you guys before I dish out some cash :iceslolan

If you are concerned about the TPS, and given the age of the vehicle (even with its low mileage) it would be good the check the TPS setting. This is usually done after cleaning the TB, cleaning the IAC, and checking/setting the throttle minimum air position. The symptom may also be indicative of low fuel pressure or injector flow or spray pattern issues.

For the back-up lighting, check the condition, function, and wiring of the neutral safety switch. I'm not sure if it is on the trans or in the console of an '87. On an '86 it is still in the console.

Does the interior fan work on heat, vent, or defrost settings? Does the air discharge from the correct outlet in all settings? If all air is discharging from the defrost outlets, that's an indication of a vacuum control problem.

No help on the rattle, but if an exhaust hanger is broken, repair it.

Thank you for the response, I appreciate it!

I have plans on cleaning out the TB hopefully on Monday and I will look up how to calibrate a TPS once I'm finished. I'll keep an update if it solved my issue. As for fuel pressure, I guess it could be a possibility, if I have a chance to get it up on a lift I'll do some snooping around for kinks. I'll also put some fuel injector cleaner through the pipes and see if anything clears up.

As for the reverse lights I did hear the neutral safety switch could cause this. I did run into this issue in my Camaro but it went away on it's own. I know what a bad switch can create and it's very bothersome. I'll do some research and figure out where this dang thing is located in the Vette.

I do try the other settings and they do not work when it acts up and becomes stubborn. Actually, the A/C worked today. It was as cold as ever but still the same average air flow strength. 20 bucks says tomorrow the fans won't kick on :lol: I did notice that when I have the A/C on "Auto" and at 60 degrees and level 10 power, the defrost vent blows as well. Could that be taking away from the other forward pointing vents? I'm not sure why it kicks on in the first place if i'm not hitting defrost. I have dealt with a vacuum control valve issue on the Camaro, i'll see if I have any new ones lying around :biggrin:

How should I go about cleaning the IAC? I've never attempted to clean one, don't want to ruin one by touching something I'm not supposed to :disappoin

Also, I've been noticing something fairly odd about my steering. I'm not sure how to describe it but the steering wheel won't turn unless I put quite a lot of pressure. I'll have the tires almost perfectly centered driving down the road, when I attempt to make a small left bend, I have to turn fairly hard to get the wheel to turn, then once it's turned it's easy-peasy to turn the wheel until I go back to the center. Is this normal or is my power steering acting up? It's with turing right as well. The power steering fluid is full to the marks when cold and hot.

EDIT: Sorry about all the questions but this one is probably the most bothersome and mind boggling to me: Before this Vette was sold to me the owner put new weather stripping on the ENTIRE car. Ever since then the windows have not been able to go all the way up without opening the door. The right side goes almost all the way up, maybe a 1/2 inch opening. The passenger side, however, I can fit my entire hand through. I have to lean over and open the passenger door, roll the window up, and close the door. Is the weather stripping not sitting right? Or am I missing something?

First, if there are no problems with idle speed, cleaning the IAC may not be necessary, but is normally part of the procedure. However, cleaning the TB and checking the minimum air position are necessary before setting the TPS voltage.

There should be no reason to lift the car to test fuel pressure. The Schrader fitting test port is on the RH fuel rail.

Does the car have manual HVAC controls or the digital control?

There are sometimes problems with idle speed after the car has been running for a while.

I'll have to purchase a new pressure gauge, I can't seem to find mine :confused: Fuel rail with pressure gauge at the plastic capped schrader valve, correct?

I believe it has the digital control. Displays a green number (sometimes). Shows exterior temp, current interior temp, increase temp or decrease by intervals of 5, I can adjust the power of the fans with a button instead of a sideways lever. All with buttons. Digital.. right? :lol: I noticed that sometimes the digital controls don't light up. No numbers, no bulbs lit up. Yet I can still turn on the A/C and control everything.

Sorry for the late response!