booya93

Greetings from the wet portion of Northeast Florida,

I wanted to get some thoughts out about this newly experienced 'dream come true'. In October of last year I purchased a 93 Vette (LT1). She beautiful, has about 93k miles, etc. Mostly stock. The car ran great upon purchase.

Corvettes have been a childhood dream for me. My old man is a past vette owner and avid lover of vettes, so that's where I picked it up. I've been to Bowlingreen, been to Ecklers..every year, blah blah. I am not new to this engine. I have owned nothing but sports cars, all AMERICAN. My last three cars were two 93 Z28's, one auto, one 6-spd, and most recently I owned a 96 Transam, 6-spd. All of these cars were easy to work on and extremely reliable. Even diagnosis was easy (for the most part).

My gripe comes in as this. I have owned my 93 for about 9 months or so, adn of those this car has 'run' as it's supposed to for only one month. The car is in great looking shape, and certainly appears to have been taken care of.

Since purchased, I have had to replace the U-joints in the rear, both hub assemblies (a nightmare and all done with myself a friend or two and a couple of six packs), the waterpump, the plugs/wires, t-stat, coil pack, breaks, calipers, vacuum hoses/clamps..the list goes on with this stuff. And still as I type this, the car has a mis so bad that the car barely runs and is a problem as of late that has yet to be diagnosed.

I have spent much time reading through the posts on this site (fantastic site by the way) and have noticed just numerous issues with electric, engine, cooling, yadda yadda and the problems have descriptions and cure's that are difficult to even understand. I myself consider myself good with the ol wrench, but some of this stuff has me twisted.

Even some that I know, that I consider to be mechanics have trouble diagnosing this car for it has so many systems involved. The car has three times the fuses that my Transam had, and it's the same engine and transmission?!?!

On top of that, the car overheats in traffic, neither fan will come on and blows fuses within 10 minutes. So while I'm waiting to run hot wires to a switch for that, I have the t-stat out of the car. Both door panels seem to be falling off (though just spent part of the weekend fixing one), the engine light is on, the change oil light is on, even right after oil changes, I'm still hearing sounds from the rear wheels, it's just amazing.

My plight is to see if there are those that suffer the same amounts of work on their cars. I'm a proud owner, but a stressed one as well. I will continue to pour blood, sweat, tears and dinero's into this beast, but is there light at the end of this tunnel for what I have been brought up to know of this car being the greatest sports car made in the world today?

corvette1271

....very familiar feeling......i am on my third c4...the first one was an 87 that i i poured money into and really had it going good......and just because there was a prettier one at the dealer, i traded for a 90......i had it for 8 months, 14 visits to the shop, and $5k later i quit on it and turned it into a volvo....had a smile on my face ever since. about 4 months ago, i bought my third one....a 94 coupe....but i stared at that ad for weeks....and it was a private owner this time. i knew more about corvettes this time and so even though there is a long list of to-dos, i am much happier and am starting to slowly get everything done that should have been done by owners that have no clue as to how long a fuel pump has been in there or how old the filters are, or how long the optispark has been running....and the vehicle has become a daily driver. i was scared to even ask the wife if she would agree....the experience was that bad. well anyway....i really enjoy my car....be patient, keep fixing....your knowledge goes up every time...and by god, by the time you get finished and done...you will enjoy it even more.......i have anyway!

dbwade36

I feel your pain COMPLETELY. I have an 86 Vette that I bought two years ago. I have put so much time & money into it. It's not even funny. It runs fine now, except that the digital dash blinks on/off at times & the vette has a slow electrical drain, but it took about a year and a half to get it running right. I still don't use it to drive to work, because I am scared of getting stuck in traffic & having it die or overheat, or something, on me. But, I still love having a Vette.
Good luck bro.

Jet-Jock

Nice year...

I can't attest to whether there is light at the end of the tunnel, I'm in the tunnel too. But one has to remember as you work through replacing these items your going to eventually take care of most of them and you'll now have a vehicle with many years of service ahead of it.

I noticed in your list you didn't mention replacing the opti but did replace the water pump. I believe its a rule of thumb to replace the opti when doing the water pump.

About your engine miss, presuming the opti is in good shape here's what I ended up doing that solved my engine miss after nearly 15 month of replacing items. Pull and clean the throttle body. Install a new IAC and gaskets when you do this. I'll post some pictures. I had been cleaning it just from the throat on the engine and had no idea it was this dirty. For a few dollars for an IAC, gaskets and the t-body cleaner I was so happy it finally fixed it.

I had replaced plugs twice and wire twice, a new opti and just about anything I or the dealer could think of. Nothing worked. The throttle body cleaning did the trick. I did end up with Taylor Spiro Pro 8mm wires and NGK Iridium plugs, which I like both very much.


Hope this helps:





[Modified by 93JetJocky, 8:38 PM 6/21/2004]

rocco16

You say the car ran great when you purchased it.
Now, after lots of work by you and some beer-soaked buddies, it runs poorly.
Hmmmmmmmmmmmmm....
Get my drift?

Go back over everything you did to to car. Alone. Without the barley-pop.

There's a chance one of your well-meaning-but-challenged friends made a little "oops" that can be easily corrected. Maybe YOU made the mistake, even.

Not implying anything here except that, well, its happened before to some very good wrenches....
Good luck!

Larry
code5coupe

xlr8nflorida

Sounds like you got a ROACH of a car or you need a qualifed mechanic.

Your car should run to at least 150,000 miles without major problems.

Get that thing a throttle body cleaning, some new plugs and wires if needed and then check the opti, waterpump and serpentine belt.

Good Luck

jabez

Somethings like the flashing SYS and change oil light just need to be reset. No need to make things harder than they actually are.

AimHi

I feel your pain. This vette (I have a 95) is the most labor intensive vehicle I've ever owned. IMHO there is nothing that can replace it as far as the feeling you get when you drive it but it requires alot of work to keep up.

I won't get rid of mine, I haven't made her perfect yet. I still have door panels to fix, a clunk in the right rear, the manual fan switch to install and paint to clean up....but I love the car. I can't explain it. I'm currently in the process of having the LT1 completely rebuilt and can't wait to get her back.

This site can help with everything from picking the right tires to fine-tuning your chip. Hang in there and enjoy the comradarie.

Aim.

Sam Lam

Dude......the Vette is a "money pit", without a bottom. Some people spend money on golf, some on gambling, women, whiskey, etc. I like putting my spare folding money in my Vette. If you like the car, just pay your money and smile as the wind hits you in the face. I am too cheap to buy a new one and I like to fix my car almost as much as I like to drive her! Warning: driving a Vette is addictive!!
SAM

Jet-Jock

In your second to last paragraph you mentioned a number of issues. I'm not so sure there is a single answer to make each of them go away but some are pretty easy to deal with.

You mentioned that it overheats, can you be more specific about that. In the midst of this heat right now in traffic I'm seeing higher temps too (215-220) but was is important to note is what temp is it getting to and does it start back down and settle somewhere after you get moving and have air flow? I see upper 190's in the winter. Also looking at the radiator housing from the passenger side is an opening between the two radiator components. Shine a light in there and ensure it isn't clogged up with debris. If it is, you can fabricate a piece of 3/4 pvc cut one end on an angle and tape the other to the vacuum cleaner hose and very carefully slip it into the openeing there and you can suck most of that junk off the fins. Be very careful doing this though.

In the same sentence you mention all kinds of electrical related issues. Without re-quoting it all, none of the fans are coming on and it blows fuses? Is your AC system working? Is it basic air or electronic air?

If your AC is inop that second fan won't come on until the 220's so that would be normal. Why your blowing fuses is too difficult to diagnose here.

On the Oil Change lamp, just reset it - its a monitoring system. Key in and to On but not start. Press Eng/Met button and within 5 seconds press it again, then within 5 seconds again press and hold the Gauges button. The change oil light will flash about 12 times and go out. You have reset it.

On the Service Eng lamp, could have been a number of things even related to this blowing fuse issue that set a fault code. If you don't have access to an ODB-1, or ability to short the plug and read the codes from the display, you'll need to have the dealer or vette shop pull the codes and then clear the service lamp. You'll know more than when you can read them.

Door panels on this vehicle are a fairly good design. You have about 7-8 screws along the bottom the eighth would be towards the upper forward panel and is a very long screw. (Ecklers sells an interior screw kit with something like a thousand some odd screws in the kit. Its like $30. The kit is assembled with small zip lock bags each labeled as to what screw and what panel or item it goes in.) The door panel just slips in the window slot from the top and is held and screwed along the bottom. If it is having a difficult time fitting properly check to make sure no wire bundles or something else is not tucked out of the way keep it from fitting correctly.

I think it your more specific about the sound your hearing from the rear wheels someone here can help point you in the right direction. You mentioned replacing brakes, did you just do the pads or did you turn the rotors too? Pads are really all that are needed unless you have a cracked rotor then you'd need to replace it. Otherwise I would advise against turning rotors.

Have you obtained a set of Service Manuals yet? If not they are worth their weight in gold, I promise.

I don't think I would run it with the tstat out, but that is your choice. If there is any doubt the tstat is not working properly replace it with a new one. Actually since you have to open the coolant system up to remove the throttle body might as well have a new tstat to install at that time. Be sure to protect the opti at all cost when you open the coolant system. Stuff rags and such to keep coolant off of it. Draining it down is a lot easier than it seems. The drain valve is just below the lower hose on passenger side. You can actually reach it with one hand I forget which is easier but you figure that out. There is just enough room to grasp and turn it. Put an oil catch pan below and take out about 2 gallons (3/4 full oil pan). That should be enough to disconnect the hoses to the t-body and tstat without much mess. Its a plastic drain valve and has a lot of threads on it, but it only takes about ten turns I think to get good flow, I ended up coming out too far the first time and it popped out, no big deal you can start it back in while coolant is draining.

By all means make sure to fully bleed both bleed screws to purge the system of air after you replenish the fluid. It make take a couple of times and again protect the opti let the bleed fluid flow onto a rag. Coolant is deadly to an opti.

Keep the faith when all is done and its running good again you'll feel much better about things. Good luck let us know how things work out.



[Modified by 93JetJocky, 11:21 PM 6/21/2004]

65Z01

Shortly after I took delivery on my '88 in mid 2000 with 96k miles on the clock, it was in the Chevy dealership in Chandler, AZ for times and I even replaced a failed fuel pump myself. Since then I've put on brakes, a new exhaust system, water pump, had the A4 rebuilt (this was also for a mod) and two hald-shafts replaced. And you know what, I'm still glad that I own this Corvette.

There are two temp sensors, one in the right side of the block below #6 & #8 plugs for the gauges and one in front of the intake base for the ECM. Measure the resistance of the one in the intake base when cold and when hot; if resistance stays very high replace this sensor and your fans may may work ok again.

If that is not the problem, check out the fan control relays.

Insert the ends of a paper clip into the ALDL pins A&B (upper right), turn the ignition on and cound SES flashes to pull the codes. This will tell you why the SES light is on.

Stay with it, you will get the better of it.

booya93

Thanks to all that replied. I'm glad to know I'm not alone out there. And trust me, there will be no giving up. I already have too much sweat in this one to back out. I do catch a bit of a break though, the ol lady works for Discount Auto Parts, so at least I get parts to fix (well, most) for cost.

One thing you are also all right on, no matter how it's running, or how much I cussed the night before working on it. In the morning I get into a brite red corvette, it's my calling.

On the mechanics, thanks for all the advise. Much of the work on this vette has been learning the hard way, *especially* when it came to the opti. The engine had a wash shortly after purchase, and I learned quickly how little that opti enjoys water... Um,yeah. As far as the reply asking if the opti still works ok, I have no idea.. I have yet to pull the wires off to test if she's getting fire through all the plugs. It has just amazed me as well that there could be so many other possibilities that don't exist on other vehicles.

On the manuals, yeah, I had the chitlan manual (sp?) but someone wasted no time in stealing it. Ihave read about a 'shop' manual for this car, is this better?

Well, the weekend is around the corner and will be spent yet again on this beauty. The one fantastic thing, is that even if the car is not running, it's still nice to open the front door to see one of the sexiest cars on the road sitting there in the drive..

Thanks again and I hope to chatting with all again! Great site!

Mikez40

Sounds like you bought a junk, I would take the loss and sell it as fast as I could. You are throwing your money away IMO. There are to many nice ones out there for sale. It is a buyers market right now. I have owned 4 C4’s an, 86 coupe, (sold it with 120,000 miles on it) ’93 coupe, (sold it with 77,000 miles) 93 roadster (sold with it 68,000 miles) and now a ’93 ZR-1. (18,000 miles) Never had any of the problems you are having. I know the current owners of the ones I have sold, and they are still trouble free.
Good Luck, you are going to need it if you keep that car.

Aaron71771

The helms servicde manual is everything the Chilton wishes it was - every Corvette do-it-yourself-er should have the Helms manual. These are the GM service manuals.

OrthoAggie

This is probably your problem...if it ran right before the wash (when you bought it) and it stopped running right fairly fast, this is probably why you have a miss

booya93

Tis true, I have been trying to chase down what that water did ever since...

Jet-Jock

I'm sorry but I have to disagree with the one response you got that you bought a piece of junk. Many of the items you mentioned are normal wear and tear, and at that mileage its normal to have replaced many of them. I would not let that response get to you. Some of these maintenance items such as water hoses, brakes, shocks, belts and stuff are normal to replace them as preventative maintenance. You didn't mention whether or not you had the coolant flushed, I would recommend that. The dealer if you have a good one in your area can do a good effective job for a reasonable cost.

Definitely go with the 'red' GM Service Manuals. If you can't find them reasonably on ebay you can get them directly from Helms or Ecklers carry's them too. They will run you just over $120. or so. But very well worth every penny.

Water so much isn't deadly to the opti, its the coolant that is more deadly to the opti. It really depends on this engine cleaning you did. Unfortunately, you didn't seem aware that it should have been protected. Most times when people have done this, it just required it to dry out. But you may and I stress may have a related issue there. Obviously you can test to ensure it is working properly and I would do that to rule anything out there. But I would again refer back to the throttle body if you haven't done that yet. I can say with some assurance that several people who have reported the same type symptoms and did a full cleaning on the t-body found it did take care of that problem.

If you can please be more specific about the miss you see symptoms of. Did it occur after you washed the engine or was it there before? Is it a slight miss from idle rpm up to about 1200 rpm? Is the miss there while it is idling? Does it go away when you get more than the 1200 rpms? If you have a fouled up IAC it won't idle correctly. I mentioned getting a new one, however you can clean the old one but there are precautions when doing that and should be aware of them, plus you can't buy the gasket for it alone. The only way to get the gasket is with a new IAC. Some people have made there own, that would be up to you, but the new part is not that expensive. If you look at the picture I provided the lower triangle opening on the back side of the t-body that in the picture is all black in side that is the air outlet from the IAC, so if that is filthy then you can imagine and see from the pictures what 90K miles does to an IAC.

I think your fine you just need to work out this issue with some logic. Good luck.

booya93

Thanks for the great info. Ah, the miss. Well, it has been missing on/off since the origional wash 8 months ago. It was fixed briefly, presumably after the opti dried out. But for last last few months it was been steady. For a while at idel, it was missing so bad it would almost stall, sometimes it would stall. under hard acceleration you could almost feel it trying to break free of the miss, lurching forward (feeling all cylinders firing). A mechanic told me to replace the coil pack because it had a small chip missing out of it, so I did. Once I replaced that, the miss went from stalling the car out at idle, to a 'smooth' miss, if there is suck a thing. Before replacing that, you could be sitting at a light and watch the tach jump all over the place. After changing the coil pack, now, the miss is bad, but the tach holds as smooth as ever, not flinching in the slightest! But the miss is hard from idle all the way up to readline, no matter what gear, how fast, etc. If the rpms are low, and you push the gas slightly, it feels like the car is going to fall apart. So I have to drive with it in overdrive most of the time, just to keep it from shaking so bad. It's really been upsetting me because the wallet is getting thin and I have yet to isolate the issue. Now on a note, I was recently checking the vacumes (as I think I was saying above) and I unplugged the hose on the passenger side of the intake, and it seems to run slightly better with it off! Strange.. But the miss is still terrible, just now it doesn't stall out as much. When I hook the vaccume back up, it drops the idle very low, about 400-500.
Thoughts?

azzkikr

I didn't follow all the threads... but I can hear ya crying all the way in south florida as I have gone through the same thing with my '87 which had 91,000 carefull miles on her... (200,000+ now!) It simply amazes me how much people will replace - rather than just going to a "corvette mechanic" and having it done right the first time rather than replacing everything - and still having the same problem. One thing I have learned is that if you have your battery disconnected... it takes the computer some time to "re-learn" the fuel curves. My car will stall and then run rough for a little while (maybe a day or two) but then she's just like new. This probably insn"t your problem, but remember it for future reference. Hope you figure it out before your wallet runs dry. Good luck withthe car!

Jet-Jock

I don't want to jump to a conclusion on this so we can try to take it step by step. First, defining the condition: "Cuts out, Misses" A steady pulsation or jerking that follows engine speed, usually more pronouced as engine load increase, not normally felt above 1500 RPM or 30MPH. The exhaust has a steady spitting sound at idle or low speed.

Does that describe it? (The following are some test that isolates the above operating condition so they may or may not apply but I wanted you to see them.)

If so, lets do a cylinder balance check. First do a visual inspection to make sure nothing obvious is apparent. ECM grounds are clean and tight. Vacuum hoses for splits kinks and tight, air leaks at the throttle body, ignition wires for cracking hardness, routing and carbon tracking, and wiring connections in good condition.

- Start the engine and let it stabilize.
- Disconnect the IAC connector.
- Disconnect each injector harness one at a time.
If there is an RPM drop on all cylinders (equal to within 50 RPM) then we need to look at another condition (rough, unstable or incorrect idle), reconnect the IAC.
If there is NO RPM drop on one or more cylinders or excessive variation in drop, check for spark on the suspected cylinder using a scope or spark tester.

- Check the distributor for cracks. With the engine running spray the cap and plug wires with a fine water mist to check for shorts. (Yes I know folks will freak about spraying the opti with water, but water shouldn't hurt it coolant does. And this is the decribed procedure
by GM.) Also make sure those opti connections are secure. When you seat the wire it makes a click, also the inside of the boot should be well coated with silicone grease to keep it water tight. The drivers side will be difficult to get to, you may have to remove the drive belt and possibly the belt tensioner to get to them. Those two are not too big of a deal to remove, a little difficult to get at them. The belt tensioner has a key to align it back up during reinstallation.

- Check the spark plug wires by connecting an ohmmeter to the ends of each wire. Stock wires should be about 30,000 ohms. Replace the wire if you have a bad one.

- Check your spark plugs for insulator cracks, wear, improper gap, burned electrodes and heavy deposits. If your using the stock AC platinum plugs, make sure the puck is there under the ground strap of each. A missing puck will cause a huge gap. Remember to do this with a cool engine and use anti-seize.

- The next item in this test is to check the injector drive circuits. It requires an injector test light.

- The last two are check fuel system for plugged fuel filter and low pressure. Finally contaiminated fuel but after this long of time I doubt this one.

___

Your describing several conditions that don't pigeon hole into one category.

Hesitation, Sag, Stumble = momentary lack of response as the accelerator is pushed down. Can occur at all vehicle speeds. Usually more severe when first trying to make the vehicle move as from a stop sign. May cause engine to stall if severe enough.

Rough, Unstable or incorrect Idle, stalling = engine runs unevenly at idle. If severe, the engine or vehicle may shake. Engine idle speed may vary in RPM. Either condition may be severe enough to stall the engine.

Is it hard staring or does it fire right away with the slightest touch of the ignition?

Your's seems to fall into several categories so if you can narrow it down it helps.

The rolling idle could be isolated to a couple items TP sensor, IAC and/or dirty throttle body.

I understand about the wallet issue, but your looking at a couple things here. I think most shops that service vettes would charge you $75. to get those codes you spoke of earlier with the SES lamp. If you need to do it youself and need better instructions let me know and I'll try to replicate them for you.

For under $70. including shipping give Chris at Superior a call and get a new IAC (pn 17112193 your cost should be 58.00) and a throttle body gasket (pn 10105379 about 3.70). Pickup some throttle body cleaner (not carb cleaner) and follow the steps I stated earlier clean that throttle body off the engine and replace the IAC when you reinstall. You'll also be bleeding the coolant so that may help some with the over heating (may). This is not too much money and definitely isolates the throttle body. When its dirty it doesn't seal up correctly and causes the idle to be all over the map. If the IAC is filthy its having a hard time trying to adjust. (Remember too that once the O2's come up to temp the computer is controlling the idle rather than the SFI mode. This one can be fairly easy to determine if you have a cold engine and start it, the start mode will probably be minus the miss, as it reaches about 190 engine or 315 C at the O2s it switches over and the O2s are feeding valid voltage data then to the ECM. You can see it cycle over and the miss becomes obvious.)

I'm real interested in the plugs and wires you have. Refer to my mention before about the AC Platinum missing pucks.

See if you can answer some of these questions, and we can go from there to continue to isolate the problem. There was a mention of resetting the computer parameters by disconnecting the battery. It will relearn new operating parameters and that alone can change the way it behaves. I'm not 100% convinced this will help you right now but something to consider.

I was going to be suspect of the opti but then you mentioned some other things and that indicated to me the opti seems to be working and the problem is elsewhere. That's just an eval based on what you said.

Lets isolate these items, and see where you are.



[Modified by 93JetJocky, 7:28 PM 6/22/2004]