Rich B.

Haven't posted in a while because my 1986 L98 4+3 convertible has been down with a burned out overdrive. I have my own Eagle garage lift [4-poster] and hi-boy trans jack, so not a big problem getting it out. S-K Automotive on Long Island rebuilt my overdrive. Cost a bundle, and took some time. While the trans/OD was out, I replaced the clutch [pressure plate/friction plate/TO bearing]. Checked out the gearbox while it was on the bench; good enough...

When the OD came back, I bolted it up and put the trans back in. New U-joints & yoke on driveshaft, new pinion seal. All good to go.

Filled the trans with gear oil, the OD with ATF. New 700CCA battery. Switched the ignition on, pushed the clutch in, and it fired right up. Let it run for about a minute, shut it down, and opened the garage door...Tried to start it again and...nothing...No click, no rattle, nada...

That was a week ago. Since then I've -

(1) Pulled the starter out and had my garage bench test it. Worked fine.
(2) While it was out, I connected a trouble light to the "S" solenoid connector wire; turned ignition on; pushed clutch pedal in...no light...(no circuit?)...
(3) Disconnected my neutral safety switch [on clutch pedal] and jumpered purple wire to green/white wire...Tried solenoid jumper wire setup again; still no light...
(4) Tried my spare key - still nothing...both keys look OK; resistor intact...
(5) Checked all my fuses...especially the "Crank" fuse...all look OK...

The only part of my trans replacement that gave me a bit of trouble was the wire loom on top of the bellhousing...I had to push it back up repeatedly...I've checked it out from top & bottom; don't see any unplugged wires...All lights light up; dash display lights up; horn blows; etc...I have power...

So here's my problem...What could cause my car to not start??? Do I have a bad ignition switch??? Is there some other relay or switch that could be bad (or got knocked off)??? Keep in mind it fired and ran for at least a minute before this condition happened...

Any comments appreciated!

Thanks for your time/help!

Hooked on Vettes

When you turn the ignition key to On, the Security light in the Driver Information Center lights up for a second then goes out if the key pellet is read properly.

If the key pellet is not read properly, the Security light will stay On. The Starter will be disabled for a random time period, (Less than five minutes).

Disconnecting and reconnecting the battery will not disable the time out period.

If the Security light goes out, when you turn the ignition key to Start, 12 volts from a fusible link passes thru and out of the ignition switch via a Yellow wire that goes to the Starter Enable relay which is located behind the Driver Information Center.

The Starter Enable relay primary coil is grounded by the Pass Key Decoder Module which closes the relay.

12 volts from the Yellow wire passes thru the relay and turns into a Dark Green wire that goes to the Clutch Start Safety switch. When the Clutch pedal is engaged, the 12 volts passes thru the Clutch Start Safety switch and turns into a Purple wire that goes to the Starter Solenoid.

Verify you have reconnected all of the ground wires located at the driverside bell housing stud.

Rich B.

Hooked - Thanks for your reply!

I didn't know there were *any* ground wires on the driverside of the bell housing...there was one on the pass side...

I'll check all your points asap...

One thing I forgot to mention - I also replaced the clutch master & slave cylinders when the trans was out...It's possible that I may have knocked a connector off or loose under the dash when connecting the clutch cyl rod to the pedal...I didn't see anything hanging but I also didn't/don't know where to look...

I find it odd that it would start once then not again...

Hooked on Vettes

The 86 Helms service manual shows one ground wire attached to the
2nd bolt on the driverside bell housing.

There are two grounds attached on the back of the driver side head
just below the valve cover. You probably didn't mess with them.

Does the Security light going out when you turn the ignition to ON?

Make sure the trans. is in neutral if you jump the Clutch
Safety switch out and try to start the car.


If you were under the dash, it's possible you knocked loose one of the
harness plugs that goes to the ignition switch which is
bolted to the top middle of the steering column.

Rich B.

I did replace a metal plate or bracket there; I don't recall if there was a wire or cable *attached* to it, but there was a wire loom/clamp that held the wire loom going over the bellhousing to the starter...

Nope. Never even noticed them. Have to check tomorrow.

Yes it does.

I'll check that too.

Thanks again for the help! Electrical circuitry is my worst lack. Especially old greasy wires.

Hooked on Vettes

The fastest way to find the problem is to gain access to the
Starter Enable Relay and test the input and output voltages.

The Starter Enable Relay is located behind the Driver Info.
Center area. The Hazard Flasher and the Audio Alarm Module
and the Horn Relay are in the same area. If you turn the
Hazard lights on and listen for the tick tick noise you'll find
the Starter Enable Relay to the right of it.

The Starter Enable relay socket will have the following wires.

Dark Green/White wire. Wire goes to the Clutch Safety Switch. 12 volts when Starter Enable Relay closes.

2 Yellow wires will have 12 volts when ignition key is in Start

Dark Green wire is grounded to enable the relay. This wire is grounded by the Pass Key module.

Rich B.

That's behind the radio??? Console + radio/AC fascia need to be removed to get at it??? <sigh...>

Let me ask a question about the starter first...How many wires should be going to the starter solenoid??? As it sits now (non-starting), I have three...one small wire going to the "S" stud on the solenoid; and two large battery-cable size wires going to the copper-colored 3/8" stud on the solenoid...

Is it possible that I've hooked a ground cable to the hot side of the solenoid??? Or is it supposed to have two large wires going to the hot terminal???

Hooked on Vettes

The Starter Enable Relay is behind the panel with the tell tale display
and switches that you flip for oil temp, voltage etc... so you
need to remove the center dash panel bezel then remove that display panel.

As for the starter wiring, the size of the ring lugs on the wires make it
idiot proof to hook them up wrong.

The purple wire energizes the starter solenoid. The Black one comes
from the battery and attaches to the large lug on the solenoid and
provides 12 volts for the starter motor.

If there is another large cable attached to the same point and has
a fusible link, I believe it provides 12 volts for the Blower
Control Module if you have the Auto Climate Control C68.

Rich B.

I don't have climate control, AFAIK...

The bellhousing bolts are 3/8", as is the hot terminal on the solenoid. None of my manuals show a pic of the starter w/attached & labeled connections. One of the guys at the local garage has a C4 Vette for his wife; I'll see if I can crawl under it & check out his starter.

If there was supposed to be a ground to the bellhousing on the pass side, then I may have mistakenly put it on the starter solenoid hot terminal...

I'm inclined to think that it's a wiring mistake on my part rather than a faulty module.

jhammons01

I hate to ask, where is that switch that the clutch pedal hits that indicates the clutch pedal is pushed in all the way.......

You changed a lot of things on your clutch and maybe that button got moved or misaligned.

I just went through this same thing....I messed up putting my clutch TO bearing back on......when I tried it....I messed things up worse (long story).....When it was messed up, the button was not getting depressed and it wouldn't do anything as far as trying to start.

Once I fixed my issues and that clutch pedal would reach the button....the car started fine again.

Sorry if you guys went through this option already....I just scanned the above post.

Rich B.

It's not a button; it's an aluminum box with a short rod that attaches to the pedal. If you take out the seat, lay on your back under the footwell and look up, it's directly over the clutch pedal, pretty much against the speedometer.

You can jumper it really easily (to eliminate the clutch safety start feature). Look at a black strut going from the floor to the side of the drivers footwell. Tucked behind it is a connector with two black wires going up to that switch. On the other side of the connector is the purple wire and the green/white wire. Connecting those two will cut the safety switch out of the circuit.

here's a scan from the Haynes manual -



**************************************** **********

talked to my local garage mechanic today; went over all the options mentioned above...He is also of the opinion that it is probably the Starter Enable Relay, behind the radio...

I'll check that out after I check the extra wire on my starter solenoid...

Rich B.

Between a new roof on my house, a Weimaraner with an ear infection, and working 10 hrs a day, I haven't had much time to do anything on the Vette until today...

Dropped the X-braces and the exhaust and pulled the starter out again...

Here's what I've got down at the starter...



No purple wire going to the "S" terminal; instead, a red wire...The lead with the tab is (I believe) my hot wire from the battery...The orange-ish lead shaped kinda like a stop sign is the one that I have no clue as to its function...

The other wire is for the knock sensor...

Here's the other side of the bellhousing, red circle shows the ground from the battery...there's also a small braided ground going somewhere under the heat shield; seems like it's fastened to something (I can't see)...



I can't feel or see any broken or loose wires...

I'll pull the distributor "lid" off and check the loom on top of the bellhousing, but I guess my next move after that is to check behind the radio...That Starter Enable Relay...

I notice there is a VATS Decoder Module back there, too...If I jump across the two Starter Enable Relay leads, will that cut out the VATS as well as the Starter Enable Relay???

Hooked on Vettes

You said there was a Purple wire at the clutch interlock switch.
That Purple wire goes to the S terminal of the starter. You say the
smaller wire at the starter is not Purple? In your picture, it looks like
the smaller wire and the Large Black wire which comes from the battery
are tapped together with electrical tape. Do you have an aftermarket
alarm? If so, could be some one cut the solenoid wire for the alarm and that's
why the color is incorrect.

Here's the schematic for the starter.

Item #1 is the ignition switch. When the ignition switch is in start,
12 volts passes thru the ignition switch and goes to the Starter
Enable relay. which is Item #2.

The Starter Enable primary relay coil is grounded by the Pass Key
decoder module if the key pellet matches the resistance the Pass
Key decoder module was programmed for.

12 volts goes thru the relay to the Clutch Safety switch show as
Item #3. You said you saw a Purple wire there and connected/shorted
the Green/White wire to the Purple wire.

12 volts passes thru the Clutch Safety switch if the pedal is depressed
and goes to the S terminal of the Starter Solenoid and also to the
Crank fuse used for the Cold Start Injector.

The other large Red Orange colored wire at the starter gets 12 volts
from the Black wire and is used for the Blower Motor for Hi speed mode.

Forget the test light and go to Radio Shack and purchase a decent
Digital Multimeter for less than $50.00.

Rich B.

That is correct. Not at the switch itself (both switch wires are black), but at the connector down by the strut.

No alarm system. The smaller wire is actually taped to the knock sensor wire; the battery hot lead is not taped and is also not in the loom.

I'll try to find where that purple wire turns into the red wire...It's possible that someone cobbled it together and I accidentally pulled it off...or it may have had an alarm that a previous owner removed...

OK; good...my memory isn't as bad as I thought, then...and that wire belongs on the solenoid...

I assume the digital multimeter is for finding where the 12v gap in the circuit is???

I'm getting further along every time I work on it...After 24 years, I suppose my luck had to run out sometime...

Thanks for the help! I appreciate it hugely!!!

Hooked on Vettes

At the Clutch Safety switch connector is also a Light Blue wire
and a Gray/Black wire. They are used to disable or enable the
cruise control circuit.

As for purchasing a Digital multimeter, a light bulb can't tell you
what the voltage is.

A basic multimeter can be used to test for voltage, current and resistance.

In this case you could use the meter to check for continuity of the wire from
the Red wire at the starter to the Purple wire at the Clutch Safety switch.

And yes using a voltmeter you can easily follow the 12 volts from
the ignition switch to the different parts of the starter circuit.

Could be Bubba Jr. has messed with the starter circuit wiring.

Rich B.

I don't have anything like that *at* the neutral start switch connector...Nothing nearby, but I'll have to wait until I'm done underneath to check that stuff up top out...

Quite possible...I dropped the X-braces/exhaust/starter and undid all that tape at the starter...The red wire goes up into the loom (unbroken) over the top of the bellhousing...inaccessible...

The purple wire at the neutral start switch connector goes through the bulkhead into the wire loom somewhere under the brake booster...again, inaccessible...

Somewhere between that connector and the starter the purple wire connects to the red one...or did...and I can't get to that loom from on top...

Previous owner may have had an alarm, or an anti-theft device, or even a remote starter installed...The only way I can get to that loom on top of the bellhousing is to pull the gearbox & bellhousing out again...Take all the wires out of that corrugated plastic tubing and check them out for breaks/grounds...PITA, but that's the only way I can get to that part of the wire loom feeding the starter...

Not terribly hard, or time consuming (two days work maybe), but it'll have to wait for cooler weather...No ventilation in my garage and I can't open the door with the car up on the lift...

I'll bookmark this thread and post back when I get something to report...

Hooked-On-Vettes = Thanks for all your help!!! Hopefully, I'll get it sorted out before too long!!!

Hooked on Vettes

People troubleshoot problems in different ways.

In your case I'd recommend you gain access to the Starter Enable relay
and perform some voltage or light bulb checks at the relay. That will point you
in the direction of where the problem is.

You have no voltage on the Dark Green/White wire at the Clutch
Safety switch. That voltage comes from the Starter Enable Relay
when it closes.

Why the color of the solenoid wire changes doesn't matter until
you determine why you have no 12 volts at the Clutch Safety switch
which provides the 12 volts to the Starter Solenoid.

Are you sure the Purple wire for the S terminal hasn't changed color due to
the heat from the exhaust and it now appears to be Red?

No need to bolt the Starter back up until you find out why the 12 volts
is missing.

Just make sure you tape/tie the loose wires up at the Starter so they can't short out.
The large Black wire at the Starter is Hot at all times and not fused.

Rich B.

It's possible...

Good advice.

I had a couple hours free today, and checked a bunch of things...but first...

This connector was not attached to anything...It is in the area by the neutral safety switch connector, in the drivers foorwell, near the black strut...It has two wires; one is pink w/white stripe; the other is all white...The plug says "PED" over "A" and "B", with the letters in line with the wires...Leads are "stacked" horizontally...



Does anyone recognize it??? Does anyone know where it would connect to???

**************************************** ************

The other things i checked -

A - With battery connected, starter out of car, ign on, clutch in, ign in Start position

= No power to red wire at starter

- same as A above but a jumper on the neutral safety switch connector = no power to red wire at starter

- Same as A above but neutral safety switch disconnected = no power to grn/wht lead (or purple lead)

B - Checked all fuses w/multimeter = all fuses show continuity

C - pic of my fuse panel does not match pic in Haynes manual for 86 Vette - I don't have a "Crank" fuse...



Before dismantling console, radio fascia, etc, I'll wait for any advice on that connector...

Hooked on Vettes

The Green/White wire should have 12 volts on it when the ignition key
is in Start. Guess where the 12 volts comes from

The Starter Enable Relay.

Trash the Haynes manual and get the Helms manual. Contact
Agent 86. He has it in PDF format. May have a hard time contacting
him since it's golf season



The Crank fuse is not your problem but guess where the Crank fuse is
located?

It's in the Auxiliary Fuse Block.
Same area where the Starter Enable Relay is.

Rich B.

... ...

... ...

OK...I'll start tearing the radio out...

Thanks again for your help! Any idea what that pink/wht & wht wire connector is for???