BlackVette87

Hello All! Longtime car nut, off and on forum lurker since probably 2006...finally a corvette owner.

After much reading and researching this forum and browsing local dealers, craigslist, etc, I finally pulled the trigger and purchased a 2002 Corvette 6-Speed Coupe. 72,000 miles. Intake, Exhaust, Z06 replica wheels are the only mods I can tell. Good deal from local Toyota dealer on a recent trade in. Only issues I could see was a faulty oil pressure sending sensor (thanks to this forum) and a front left turn signal out. Happy I found an 01+ at a nice price point with mods I would already end up doing myself.

First day home was wonderful!

Second day... no crank no start.

I spent hours browsing the forum (finding several references to the wiring schematic for startup) and learned this is a pretty common problem. (This forum is a great knowledge resource.)

Nothing to worry about so I began trouble shooting as follows, in the order I have done them:

1. Clutch Position Sensor switch: Bypassed. Did not solve issue.
2. Check all relevant fuses. No issues found
3. TDR: Pulled out the unit. Jumped Red and Purple wires with key in on position, and car fired right up. Bought a new TDR at autozone. Plugged it in, no crank no start. Not the problem.
4. Notice the Key the car came with shows the resistor looks a little worn down. Measuring perfect 681 ohm's though.. It wiggles a little if I push on it as well, within the key shaft. Fiddle with it a little and car starts perfect. Next morning doesn't start. Go to local Chevy dealer and get a new key cut and programmed.
5. New Key starts the car perfect two times in a row. GREAT. Third start, nothing. No crank no start.
6. Intermittent starting or not starting for 2 days while I wait for new ignition cylinder to arrive based on the logic it must be poor contacts with resistor inside the ignition key cylinder.
7.Have local mechanic install new ignition key cylinder (along with new oil sensor and turn signals.) Says car started 15 times in a row with a mix of both my new and old keys.
8. I get the car back and starts great 2 times in a row. GREAT. Third time after a nice car wash. Nothing. No crank no start.
9. Car has no current codes on DIC and security light does not stay on during the no starts.
10. Writing this thread on corvetteforum hoping for good advice. I LOVE the car when I drive it, but bypassing the TDR with an 18GA wire in the driveway and parking lots is quickly wearing on me, and my wife (god bless her for signing off on this toy) is quickly starting to hint at "I told you we should've done...."

Current thoughts

1. Only thing left I can think of is that the car is losing the crank signal somehow. Is there a crankshaft position sensor that could be faulty?
2. I have made a 680 ohm resistor with two WAGO quick connects on either end to try and bypass VATS. I have searched, but can not determine where exactly this resistor should go to bypass VATS. Can anyone provide photos and/or directions for what wires I need to bypass and where exactly to find them? I know there are likely airbag and alarm wires in the same area, so I don't want to take guesses.

Also, some pictures attached just for the hell of it!

Any advice or help is greatly appreciated!

Tenshots1

May be a dumb question, but did you check with the dealership to see if they would make it right and offer any sort of help? Although I understand the car probably did not come with a warranty, an issue as bad as the car won’t start on day 2 is bad for business on their end. They may be willing to pay for a service or something. I don’t know how to fix your issue and wish you the best of luck. I just bought a 2002 M6 a couple months ago with a skeptical wife, so I understand the position you are in.

BlackVette87

The dealer I bought it from has agreed to cover up to $200 in receipts for work to get things sorted. Car was bought AS IS, but I don't think they tried to pull anything shady on me. Pretty pleasant experience with them actually. I think it is really just bad timing for something like this to happen. I must have started it 7 times while I was there throughout the process and never a hiccup.

I thought I had it all sorted with the new ignition but not quite there yet!

Evil-Twin

Not one mention of Starter solenoid wiring. Since all problems are intermittent its not a hard failure.. the most common lose connection in an intermittent start problem is the B+ to solenoid. it's close to the exhaust manifold and is susceptible to becoming lose. Some times simple things are overlooked.
Good Luck
Bill aka ET

BlackVette87

Ok. I’ll check that out, thanks. I didn’t think it would be anything wrong with starter since the car always works when manually bypass TDR.

twokbolt

The other thing I would check is the battery cable to terminal connection as well as the voltage of the battery itself.

run1fsr

Are you loosing all power when it will not crank? As noted above check battery terminals + cables and ground.

BlackVette87

Battery is perfect. Never measured below 11.5V. I’ve checked often. I do not loose other electrical devices (radio, lights, etc) when no crank condition.


Thanks for the tips though!

DaDuck

battery voltage at the battery terminals should be well above 11.5 V............you may have more than one problem.

Have the battery load tested at your local AutoZone, Pep Boys, or whatever is in your area.

A weak battery can and will cause many symptoms on a C5.

And new batteries can go bad in a couple months on a C5.

Good Luck on your quest to solve the problem....this forum will support you so heed the advise of those with experience.

Vetteman Jack

Moved to C5 Tech.

C5 Diag

First off congrats on your purchase !!...OK, NOT a bad crank sensor for a "no crank no start"...first I'd test the relay you purchased from "The Zone"...you must take that variable out of the equation... C2 and A1 (or pins 86 and 85) are your control side of the relay...you can connect C2 and A1 to your battery and use an ohmmeter to see if you have continuity across the other 2 contacts (C1 and A2)….if it tests out you'll know the relay is good...even relays I like to stay with OEM (sensors ESPECIALLY). So if you are jumping C1 and A2 (load side) and the car starts CONSISTENTLY you can take the "load side" as I call it out of the starting circuit equation...you should be good all the way down to the "S" post of the starter solenoid. Now in the crank position using a 12 volt test light connected to a good ground is pin C2 lighting BRIGHTLY with the test light ??….if it lights we know everything is good from battery positive down to the TDR...if it lights the only other thing is the BCM starter enable relay...with test light connected to battery POSITIVE when you crank does the test light illuminate A1 at the TDR ??...that will tell you that indeed the BCM is grounding that part of the circuit. At the BCM the pin is B7 (yellow/black) at connector C3 (connector at the bottom of the BCM)...I'd even check for continuity between A1 at the TDR and Pin B7 of the BCM !!

STRMLNE

I gotta tell ya, I would be PISSED at the dealer if I were you if the car had issues on day 2 of ownership and all they would cover is 200 bucks. I would definitely recommend going up the management chain with that dealer until they cover the whole repair. “As is” sure. But it’s starting to look like it was traded in for this very issue by the previous owner. It’s common practice that dealers will cover problems within 30 days of initial purchase.

Good news is that it’s most likely something easy. I had almost this exact issue recently. Intermittent no crank and intermittent lower than normal battery level readings. My usual dealer basically gave up on the car. Said they couldn’t find the problem. Took the car to another shop and they found it was a bad starter. Dealer put in a new starter and I have not had any problems since.

Good luck.

dleibman

Off topic question, why does c5’s eat up batteries ?

STRMLNE

Thy don’t eat them up. They are just really sensitive to low charges etc.

Bill Curlee

So, you say it will crank and run every time that you jump out the red & purple wires on the TDR. HMMMMMMM...…. That to ME, says the TDR isn't getting the low voltage low current signal (yellow wire) to actuate the relay.

The Yellow wire is your power signal to the relay when you have all the START sequence stuff completed. "Clutch depressed (manual) Park/Neutral (auto), key in crank". When you have all those condition met, there should be battery voltage on the YELLOW WIRE.

The Yellow/Black stripe wire is the GROUND circuit for the TDR relay coil. When the BCM see that all of the security conditions are met, it grounds that yellow / black wire. This allows the TDR coil to actuate and allows the red wire (12 VDC @ 60 amps) to connect to the purple wire which actuates the starter solenoid.

The next time it wont start, see if you get 12 VDC on the yellow wire. If you have 12 VDC on the yellow wire, ground the yellow /black wire and see if it starts.

You can also GROUND the yellow/black wire and take the BCM Security functions out of the equation. .

Bill

Bill Curlee

If you have a manual trans, turn the key to crank and hold it there. Then pump the clutch peddle on and off the clutch safety switch (on the fire wall). Each time that you open and close that clutch safety switch, you SHOULD hear that TDR actuate (CLICK)

BC

BlackVette87

Thanks for all the continued help! I will take another look at the TDR yellow wire and yellow/black as discussed in more detail here and do the voltage tests Will also run a disconnected battery test to make sure standby when off is no more the 20mA (as per search I did recently.)

clutch switch is currently still bypassed and TDR always clicks when key is cranked.

This is may be a silly question but what is the normal starting method supposed to be for the key. Today the car worked perfectly (and I enjoyed my morning and evening commute!) if I turned the key to ON, left the gauges all spike and reset as per sequence and then cranked the key, the car Worked like a charm 4 times in a row.

When I did a quick insert and crank, i got the no crank no start condition.


Evan

STRMLNE

That shouldn’t matter. In my opinion, it’s just a coincidence. Fuel pump primes between 1 and 2. But starter should always crank no matter what.

C5 Diag

Just turn the key and start !!...I never wait 2 seconds for the pump to prime before starting !!

C5 Diag

Wouldn’t worry about a parasitic drain if car consistently starts bypassing the load side of the TDR...concentrate on the “control side” !!