1992 S-10 ignition timing

#1

A few months ago a neighbor bought a 1992 S-10 with a 4.3L V6. It
cranked fine at first. Later it began hesitating as it was cranked. He
thought it needed a new starter, but it cranks fine if the spark cable
is removed from the distributor.

Once started it seems to run okay. Could the timing be off during
cranking? What could cause this?

#2

E Z Peaces wrote:

Quote:

A few months ago a neighbor bought a 1992 S-10 with a 4.3L V6. It
cranked fine at first. Later it began hesitating as it was cranked. He
thought it needed a new starter, but it cranks fine if the spark cable
is removed from the distributor.

Once started it seems to run okay. Could the timing be off during
cranking? What could cause this?

Could be a variety of things. Ignition timing being only one.
I would check the base timing per the manual and then see if the timing
chain is OK. Then run a compression check to see if there is a problem.

--
Steve W.

#3

Steve W. wrote:

Quote:

E Z Peaces wrote:
A few months ago a neighbor bought a 1992 S-10 with a 4.3L V6. It
cranked fine at first. Later it began hesitating as it was cranked. He
thought it needed a new starter, but it cranks fine if the spark cable
is removed from the distributor.

Once started it seems to run okay. Could the timing be off during
cranking? What could cause this?

Could be a variety of things. Ignition timing being only one.
I would check the base timing per the manual and then see if the timing
chain is OK. Then run a compression check to see if there is a problem.

If the starter cranks it with plenty of pep with the ignition unplugged
but has trouble when the the ignition is firing, what could it be but
advanced timing?

I think I see why he had no trouble at first. Depending on temperature
and battery condition, it may have cranked slightly faster before
winter, so that premature firing didn't slow it noticeably.

My theory is that in the past 17 years, somebody moved or replaced the
distributor, and they didn't time it properly. It was close enough for
the computer to time the spark once the engine was running.

To time it with a light, I understand I'd have to disconnect a wire that
I haven't found. For now, I've set the distributor back an estimated 5
degrees, which would be 10 degrees on the crankshaft. It sounds better.

#4

"E Z Peaces" <cash (AT) invalid (DOT) invalid> wrote

Quote:

Steve W. wrote:
E Z Peaces wrote:
A few months ago a neighbor bought a 1992 S-10 with a 4.3L V6.
It
cranked fine at first. Later it began hesitating as it was
cranked. He
thought it needed a new starter, but it cranks fine if the spark
cable
is removed from the distributor.

Once started it seems to run okay. Could the timing be off
during
cranking? What could cause this?

Could be a variety of things. Ignition timing being only one.
I would check the base timing per the manual and then see if the
timing
chain is OK. Then run a compression check to see if there is a
problem.

If the starter cranks it with plenty of pep with the ignition
unplugged
but has trouble when the the ignition is firing, what could it be
but
advanced timing?

I think I see why he had no trouble at first. Depending on
temperature
and battery condition, it may have cranked slightly faster before
winter, so that premature firing didn't slow it noticeably.

My theory is that in the past 17 years, somebody moved or replaced
the
distributor, and they didn't time it properly. It was close enough
for
the computer to time the spark once the engine was running.

To time it with a light, I understand I'd have to disconnect a wire
that
I haven't found. For now, I've set the distributor back an
estimated 5
degrees, which would be 10 degrees on the crankshaft. It sounds
better.

The pick up coil inside the distributor has two wires attached to it.
One is green, the other is white. When the distributor is advanced to
keep the spark BTDC, the plate that the pick up coil is attached to
rotates. Over time, this repetitive rotation causes the green wire to
break loose from the pick up coil.

Inspect the green wire and replace the pick up coil if you find any
signs of frayed wire or broken insulation where the green wire goes
into the pick up coil.

That should solve your problem. I've sold hundreds of those pick up
coils for exactly that reason.

There is NO substitute for experience!

--
Steve Spence
Independent AMSOIL Dealer
AMSOIL - The "Once A Year" Oil Change
Unemployed Car Guy - Trying To Earn A Living
35 Years of G.M. Parts Experience
URL: http://synthetic-oil-tech.com/1690163
Email: amsoil1 (AT) charter (DOT) net

#5

In article <%3Iml.5687$pX4.2094 (AT) newsfe08 (DOT) iad>,
"Steve" <amsoil1 (AT) charter (DOT) net> wrote:

Quote:

"E Z Peaces" <cash (AT) invalid (DOT) invalid> wrote in message
news:ePEml.5111$19.1561 (AT) bignews2 (DOT) bellsouth.net...
| Steve W. wrote:
| > E Z Peaces wrote:
| >> A few months ago a neighbor bought a 1992 S-10 with a 4.3L V6.
It
| >> cranked fine at first. Later it began hesitating as it was
cranked. He
| >> thought it needed a new starter, but it cranks fine if the spark
cable
| >> is removed from the distributor.
|
| >> Once started it seems to run okay. Could the timing be off
during
| >> cranking? What could cause this?
|
| > Could be a variety of things. Ignition timing being only one.
| > I would check the base timing per the manual and then see if the
timing
| > chain is OK. Then run a compression check to see if there is a
problem.
|
|
| If the starter cranks it with plenty of pep with the ignition
unplugged
| but has trouble when the the ignition is firing, what could it be
but
| advanced timing?
|
| I think I see why he had no trouble at first. Depending on
temperature
| and battery condition, it may have cranked slightly faster before
| winter, so that premature firing didn't slow it noticeably.
|
| My theory is that in the past 17 years, somebody moved or replaced
the
| distributor, and they didn't time it properly. It was close enough
for
| the computer to time the spark once the engine was running.
|
| To time it with a light, I understand I'd have to disconnect a wire
that
| I haven't found. For now, I've set the distributor back an
estimated 5
| degrees, which would be 10 degrees on the crankshaft. It sounds
better.

The pick up coil inside the distributor has two wires attached to it.

Yes it does.

Quote:

One is green, the other is white.

True but irrelevant.

Quote:

When the distributor is advanced to
keep the spark BTDC, the plate that the pick up coil is attached to
rotates.

Uh, no. The spark advance is 100% electronic. There is no plate that
rotates.

Quote:

Over time, this repetitive rotation causes the green wire to
break loose from the pick up coil.

True in 1976

Quote:

Inspect the green wire and replace the pick up coil if you find any
signs of frayed wire or broken insulation where the green wire goes
into the pick up coil.

He'd be much better off to concentrate on the magnet inside the pole
piece, specifically looking for -any- cracks in the magnet.

Quote:

That should solve your problem. I've sold hundreds of those pick up
coils for exactly that reason.

No you haven't. Those trucks weren't built in such a way as to make
your recollections true one bit.

Quote:

There is NO substitute for experience!

You certainly are proof of that!

I'm truly surprised that you skipped a golden opportunity to sell some
Amsoil magic monkey jizz to solve the OPs problem...

#6

Steve wrote:

Quote:

"E Z Peaces" <cash (AT) invalid (DOT) invalid> wrote in message
news:ePEml.5111$19.1561 (AT) bignews2 (DOT) bellsouth.net...
| Steve W. wrote:
| > E Z Peaces wrote:
| >> A few months ago a neighbor bought a 1992 S-10 with a 4.3L V6.
It
| >> cranked fine at first. Later it began hesitating as it was
cranked. He
| >> thought it needed a new starter, but it cranks fine if the spark
cable
| >> is removed from the distributor.
|
| >> Once started it seems to run okay. Could the timing be off
during
| >> cranking? What could cause this?
|
| > Could be a variety of things. Ignition timing being only one.
| > I would check the base timing per the manual and then see if the
timing
| > chain is OK. Then run a compression check to see if there is a
problem.
|
|
| If the starter cranks it with plenty of pep with the ignition
unplugged
| but has trouble when the the ignition is firing, what could it be
but
| advanced timing?
|
| I think I see why he had no trouble at first. Depending on
temperature
| and battery condition, it may have cranked slightly faster before
| winter, so that premature firing didn't slow it noticeably.
|
| My theory is that in the past 17 years, somebody moved or replaced
the
| distributor, and they didn't time it properly. It was close enough
for
| the computer to time the spark once the engine was running.
|
| To time it with a light, I understand I'd have to disconnect a wire
that
| I haven't found. For now, I've set the distributor back an
estimated 5
| degrees, which would be 10 degrees on the crankshaft. It sounds
better.

The pick up coil inside the distributor has two wires attached to it.
One is green, the other is white. When the distributor is advanced to
keep the spark BTDC, the plate that the pick up coil is attached to
rotates. Over time, this repetitive rotation causes the green wire to
break loose from the pick up coil.

Inspect the green wire and replace the pick up coil if you find any
signs of frayed wire or broken insulation where the green wire goes
into the pick up coil.

That should solve your problem. I've sold hundreds of those pick up
coils for exactly that reason.

There is NO substitute for experience!

Thanks a lot.

I was wrong in moving the distributor. Yesterday, when the block
temperature was probably below 40F, I had the same problem. The starter
would slow cyclically, as if there was high resistance at one point in
the engine's rotation. As the engine rotated easily with the ignition
disconnected, it seemed that one cylinder was still firing too soon.

I ran the engine a few seconds to back up ten feet. In the next half
hour I started several more times to move the truck a few feet. Each
time, the starter turned the engine normally. The plugs would have been
a little warmer than on my first startup.

I think cold temperatures, compression, and old plugs with big gaps and
rounded electrodes all require more firing voltage. My theory now is
that if the voltage required for a certain plug is high enough, the
spark will jump instead from the rotor to another terminal in the
distributor, causing that other plug to fire on the compression stroke.

The owner says he's heard that one of the plugs in this kind of S-10 is
very difficult to remove. If it's been in since 1992, that might be the
cause of the problem.

I'll check the pickup coil as you said. I'll also take a closer look at
the distributor cap.

#7

aarcuda69062 wrote:

Quote:

He'd be much better off to concentrate on the magnet inside the pole
piece, specifically looking for -any- cracks in the magnet.

Could that cause just one cylinder to fire too soon, and only during

cranking with the engine cold?

I'll look and try to figure out what the pole piece is. Before, I found
that the rotor didn't budge when I pulled up on it.

#8

On Feb 18, 11:31*am, E Z Peaces <c... (AT) invalid (DOT) invalid> wrote:

Quote:

Thanks a lot.

I was wrong in moving the distributor. *Yesterday, when the block
temperature was probably below 40F, I had the same problem. *The starter
would slow cyclically, as if there was high resistance at one point in
the engine's rotation. *As the engine rotated easily with the ignition
disconnected, it seemed that one cylinder was still firing too soon.

I ran the engine a few seconds to back up ten feet. *In the next half
hour I started several more times to move the truck a few feet. *Each
time, the starter turned the engine normally. *The plugs would have been
a little warmer than on my first startup.

I think cold temperatures, compression, and old plugs with big gaps and
rounded electrodes all require more firing voltage. *My theory now is
that if the voltage required for a certain plug is high enough, the
spark will jump instead from the rotor to another terminal in the
distributor, causing that other plug to fire on the compression stroke.

The owner says he's heard that one of the plugs in this kind of S-10 is
very difficult to remove. *If it's been in since 1992, that might be the
cause of the problem.

I'll check the pickup coil as you said. *I'll also take a closer look at
the distributor cap.- Hide quoted text -

- Show quoted text -

To check the base timing, you need to disconnect a single wire
connector ( I think it's brown but don't quote me) underneath the
carpet around where the passenger's toes would rest.
That's where it is on my 91 S-10..
All the plugs are hard to git to IMHO.
Try pulling off the tires to have better access...K

#9

Ken wrote:

Quote:

On Feb 18, 11:31 am, E Z Peaces <c... (AT) invalid (DOT) invalid> wrote:

Thanks a lot.

I was wrong in moving the distributor. Yesterday, when the block
temperature was probably below 40F, I had the same problem. The starter
would slow cyclically, as if there was high resistance at one point in
the engine's rotation. As the engine rotated easily with the ignition
disconnected, it seemed that one cylinder was still firing too soon.

I ran the engine a few seconds to back up ten feet. In the next half
hour I started several more times to move the truck a few feet. Each
time, the starter turned the engine normally. The plugs would have been
a little warmer than on my first startup.

I think cold temperatures, compression, and old plugs with big gaps and
rounded electrodes all require more firing voltage. My theory now is
that if the voltage required for a certain plug is high enough, the
spark will jump instead from the rotor to another terminal in the
distributor, causing that other plug to fire on the compression stroke.

Not very likely unless the cap is shot. I have pulled plugs that had the
electrodes burnt off that still fired.

Quote:

The owner says he's heard that one of the plugs in this kind of S-10 is
very difficult to remove. If it's been in since 1992, that might be the
cause of the problem.

That would be the plug in cylinder 4, sits behind the steering shaft on
the drivers side. The easy way to remove it would be to buy a swivel
plug socket. (Sears sells one that fits very well, it is shorter than a
common 5/8" plug socket)

Quote:

I'll check the pickup coil as you said. I'll also take a closer look at
the distributor cap.- Hide quoted text -

I would start with a simple tune up, new plugs, wires, GOOD cap and
rotor. Pay close attention to plug wire routing. Then go from there.

--
Steve W.

#10

Steve W. wrote:

Quote:

Ken wrote:
On Feb 18, 11:31 am, E Z Peaces <c... (AT) invalid (DOT) invalid> wrote:

Thanks a lot.

I was wrong in moving the distributor. Yesterday, when the block
temperature was probably below 40F, I had the same problem. The starter
would slow cyclically, as if there was high resistance at one point in
the engine's rotation. As the engine rotated easily with the ignition
disconnected, it seemed that one cylinder was still firing too soon.

I ran the engine a few seconds to back up ten feet. In the next half
hour I started several more times to move the truck a few feet. Each
time, the starter turned the engine normally. The plugs would have been
a little warmer than on my first startup.

I think cold temperatures, compression, and old plugs with big gaps and
rounded electrodes all require more firing voltage. My theory now is
that if the voltage required for a certain plug is high enough, the
spark will jump instead from the rotor to another terminal in the
distributor, causing that other plug to fire on the compression stroke.

Not very likely unless the cap is shot. I have pulled plugs that had the
electrodes burnt off that still fired.

The owner says he's heard that one of the plugs in this kind of S-10 is
very difficult to remove. If it's been in since 1992, that might be the
cause of the problem.

That would be the plug in cylinder 4, sits behind the steering shaft on
the drivers side. The easy way to remove it would be to buy a swivel
plug socket. (Sears sells one that fits very well, it is shorter than a
common 5/8" plug socket)

I'll check the pickup coil as you said. I'll also take a closer look at
the distributor cap.- Hide quoted text -

I would start with a simple tune up, new plugs, wires, GOOD cap and
rotor. Pay close attention to plug wire routing. Then go from there.

Thanks.