"Glowing" ex manifold on a 2.5L S-10

"~^Johnny^~" > wrote in message
...
> On Tue, 4 Jul 2006 16:57:07 +0100, "Dave Baker"
> > wrote:
>
>>Advanced valve timing, not late valve timing, can cause fuel to burn in
>>the
>>manifold,
>
> Bull****.
>
> It would ping, and maybe pop back through the carburetor.

Valve timing not ignition timing you pillock. Learn to read.
--
Dave Baker
www.pumaracing.co.uk
Usenet - a collection of people who only open their mouth to change feet.

On Mon, 03 Jul 2006 21:29:07 -0700, ~^Johnny^~
> wrote:

>On 2 Jul 2006 18:11:10 -0700, wrote:
>
>>weeks] until it would hardly move. Any throttle movement would stall
>>the engine. And the exhaust manifold was red hot before I chose not to
>>drive it!
>>
>>Towed it home ... checked for a leaking TBI - NO CHANGE. Dropped the
>>exhaust pipe - NO CHAGE. EGR's OK .. MAP appears OK related tubing
>>and connectors OK ... where do I look next? Should I tear into the
>>distributor? .. what should I look for?
>
>Late ignition timing.

That's what I said, but some are not happy with the simple and obvious
-- they want to make it complicated.

Don
www.donsautomotive.com

On Mon, 03 Jul 2006 21:14:55 -0500, Don
> wrote:

>A very low idle is best for checking the timing. Put a timing light
>on it before you do anything else

For initial ignition timing,
it must be done at "curb idle".

That is, running, parked.
At the proper RPM.
No slower, no faster.
It must be at factory specs.
Idle speed should be as such.
If you rev it up to 2000 RPM,
it's still "idling",
but that doesn't count.

Adjust it to factory spec curb idle speed,
then check initial ignition timing.

Then, rev it up and check centrifugal advance.

--
-john
wide-open at throttle dot info

On Tue, 4 Jul 2006 23:09:46 +0100, "Dave Baker"
> wrote:

>
>"~^Johnny^~" > wrote in message
.. .
>> On Tue, 4 Jul 2006 16:57:07 +0100, "Dave Baker"
>> > wrote:
>>
>>>Advanced valve timing, not late valve timing, can cause fuel to burn in
>>>the
>>>manifold,
>>
>> Bull****.
>>
>> It would ping, and maybe pop back through the carburetor.
>
>Valve timing not ignition timing you pillock. Learn to read.

I'll give you a pass, this time.

A jumped tming belt/chain is a different issue altogether.

And I am not Polish. :-)

--
-john
wide-open at throttle dot info

On Tue, 4 Jul 2006 23:09:46 +0100, "Dave Baker"
> wrote:

>Dave Baker
>www.pumaracing.co.uk

Cute ... asshole.

Leave a valid email address next time.

=plonk!=

--
-john
wide-open at throttle dot info

On Tue, 04 Jul 2006 17:53:55 -0700, ~^Johnny^~
> wrote:

>On Mon, 03 Jul 2006 21:14:55 -0500, Don
> wrote:
>
>>A very low idle is best for checking the timing. Put a timing light
>>on it before you do anything else
>
>For initial ignition timing,
>it must be done at "curb idle".
>
>That is, running, parked.
>At the proper RPM.
>No slower,

If its slower than specified curb idle this will be only a small
difference -- if any. Close enough to verify the problem and get the
thing in the ballpark. Reved up is much worse -- could be off 20* or
more.

Don
www.donsautomotive.com

> no faster.
>It must be at factory specs.
>Idle speed should be as such.
>If you rev it up to 2000 RPM,
>it's still "idling",
>but that doesn't count.
>
>Adjust it to factory spec curb idle speed,
>then check initial ignition timing.
>
>Then, rev it up and check centrifugal advance.

Dave Baker wrote:
>
> "jim" > wrote in message
> ...
> >
> >
> > wrote:
> >>
> >> I dropped the exhaust pipe from the manifold and it didn't change
> >> anything. Regarding the lean vs. rich issue; you can definitely smell
> >> the slobbering. I suspect it's detonation/burn in the manifold. I'll
> >> look into the TPS too!
> >
> > It isn't the fuel mixture. If the fuel can't burn in the cylinders it is
> > going to burn in the exhaust manifold unless there is something causing
> > it to burn there like late ignition timing or late valve timing or both.
>
> Advanced valve timing, not late valve timing, can cause fuel to burn in the
> manifold, i.e. the exhaust valve opens early while the mixture is still well
> alight in the cylinder. Late valve timing would have the opposite effect.

Maybe, but advanced valve timing doesn't seem likely to happen due to
normal wear. Typically the symptoms described fit badly worn timing
chain/gears. That may well be due to the ignition timing more than the
valve timing. But any inefficient combustion that leaves fuel and air in
the correct mix in the exhaust manifold could cause the symptoms
described. Especially if the driver's response to loss of power is to
use more throttle. So driving 80 mph with a couple of bad spark plug
wires could produce the results the original poster described.

-jim


> --
> Dave Baker
> www.pumaracing.co.uk
> Usenet - a collection of people who only open their mouth to change feet.

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In article >,
~^Johnny^~ > wrote:

> Then, rev it up and check centrifugal advance.

Don't think so.

The entity posted thusly:

>I will try to check the timing, but I don't think I can get the engine
>to produce enough RPM ... it's idle is REALLY marginal.
>
>One thing I failed to mention was that the engine gradually began[over
>weeks] to sound like there was a hole or crack in the header pipe. I
>expected to see a hole or sever crack somewere BUT I DIDN'T. That
>STILL baffels me. Could severely retarted timing cause detonation in
>such a way to cause this.

Nobody has mentioned the possibility of some plugs not firing. I have
a 2000 F-150 that had this problem on two cylinders, and while driving
it to the dealership (about 30 miles away), i happened to look in the
rear view mirror and saw bright sparks dropping onto the pavement and
bouncing. It was chunks of something, superheated. Turns out that fuel
was being sent unburnt into the exhaust system, burning there, and
really messing things up.

In article .com>,
says...
>
>
>It's a 91 2.5L TBI ... the rig became progressively sluggish [over
>weeks] until it would hardly move. Any throttle movement would stall
>the engine. And the exhaust manifold was red hot before I chose not to
>drive it!
>
>Towed it home ... checked for a leaking TBI - NO CHANGE. Dropped the
>exhaust pipe - NO CHAGE. EGR's OK .. MAP appears OK related tubing
>and connectors OK ... where do I look next? Should I tear into the
>distributor? .. what should I look for?

I had something similar happen to me. Turned out to be a broken ignition
rotor. So I would start by looking at the ignition system.
-------------
Alex