89 Suburban Help...no power..jerks on acceleration

On Sat, 1 Jan 2005 15:49:00 -0800, "John" > wrote:

>Hi LG..
>Ok..I'll do some crawling about and see if I can locate it..
>Thanks again for your help..John

Good luck with this. And a word of caution. Your fuel system is most
likely pressurized, at least mine is. at about 40 psi.

There is most likely a fuel *shut-off* button/valve in the trunk area
or there abouts. Do activate that, and expect some spray-out from the
pressure left in the fuel system. cover your eyes, use a throw-away
towel or something over the filter before you go about trying to
remove it.

Lg

On Sat, 1 Jan 2005, John wrote:

> Hi..
> Sorry, but I am not familar with FI engines.
> I know the fuel filter on my carburated vehicles is near the carburator but
> I cannot find the fuel filter on the FI 89 Suburban.

Probably means it is long overdue for replacement.

> If anyone can point me in the right area to locate it I would appreciate it.

Bolted to the floorboard or frame rail back by the fuel tank.

DO NOT attempt to service the fuel system without releasing system
pressure first.

> I am looking for a manual (Chilton's??)

Chilton's and Haynes books are an excellent tool for damaging your vehicle
and injuring yourself. Get a *factory* service manual, which can be had
from the dealer or much less expensively on eBay.

DS

Plug wires failing under heavy load would be the most common cause of
the jerking and loss of power sensation you are describing. Internal
cap arcing (spark scatter) comes to mind as another less common
possibility, and ignition module failure as a much lesser probability.
This is all based on the description of jerking under load or at high
RPM - pointing to hard ignition misfire. Have any of the secondary
ignition components ever been replaced? Its no huge deal to replace
them all on a high mileage 350. Try to get Borg Warner, Standard or GM
parts and regular AC Delco plugs- stay away from bargain brands. Cap,
rotor, wires and plugs would set you back around $100. The module is
$50+ but if it's original its not a bad idea to replace it when the cap
is off. Keep the old one as a spare if its good. The only thing left
in the secondary is the coil but I wouldn't suspect that yet. Not that
HEI coils don't fail, just that they usually wouldn't cause your
symptoms.

Its hard to diagnose without seeing the vehicle, but its possible that
a jerking and loss of power (to a lesser extent) could be caused by a
torque converter that's locking up inappropriately. There's about 4
electrical safeguards that keep it from engaging at the wrong time, but
a goofy TCC solenoid in the transmission or a fluttering TCC apply
valve in the valve body could theoretically cause those symptoms. This
is quite unlikely but just thrown out there for discussion.

Finally, I think the fuel filter is screwed to the inside frame rail in
the left or right rear wheel area. Not a bad idea to replace it for
maintenance.

Toyota MDT in MO

On Sat, 1 Jan 2005, Comboverfish wrote:

> Plug wires failing under heavy load would be the most common cause of
> the jerking and loss of power sensation you are describing.

Secondary ignition failure is one possible cause, but insufficient fuel
volume due to a clogged filter or weak pump is even more commonly the
cause of the symptoms described.

> ignition components ever been replaced? Its no huge deal to replace
> them all on a high mileage 350. Try to get Borg Warner, Standard or GM
> parts

Or Echlin...

> and regular AC Delco plugs

Or NGK, or Autolite...

> The module is $50+ but if it's original its not a bad idea to replace it
> when the cap is off.

Pfft. The ignition module is not a scheduled maintenance item. They don't
kinda-fail. And "while the cap is off" is silly. Removing the cap takes a
quarter-twist of exactly two screws.

> Its hard to diagnose without seeing the vehicle,

Exactly.

> but its possible that a jerking and loss of power (to a lesser extent)
> could be caused by a torque converter that's locking up inappropriately.

Re-read the poster's original question more carefully and then explain,
please, where the torque converter will be found relative to the poster's
manual transmission.

On 1 Jan 2005 17:07:15 -0800, "Comboverfish" >
wrote:

>Plug wires failing under heavy load would be the most common cause of
>the jerking and loss of power sensation you are describing. Internal
>cap arcing (spark scatter) comes to mind as another less common
>possibility, and ignition module failure as a much lesser probability.
>This is all based on the description of jerking under load or at high
>RPM - pointing to hard ignition misfire.

Crap. That would definitely throw a MIL code.

> Have any of the secondary
>ignition components ever been replaced? Its no huge deal to replace
>them all on a high mileage 350. Try to get Borg Warner, Standard or GM
>parts and regular AC Delco plugs- stay away from bargain brands. Cap,
>rotor, wires and plugs would set you back around $100. The module is
>$50+ but if it's original its not a bad idea to replace it when the cap
>is off. Keep the old one as a spare if its good. The only thing left
>in the secondary is the coil but I wouldn't suspect that yet. Not that
>HEI coils don't fail, just that they usually wouldn't cause your
>symptoms.

More ****ing into the wind

>Its hard to diagnose without seeing the vehicle, but its possible that
>a jerking and loss of power (to a lesser extent) could be caused by a
>torque converter that's locking up inappropriately.

It could also be caused by duck feathers caught up in the air intake,
you forgot to mention that.

> There's about 4
>electrical safeguards that keep it from engaging at the wrong time, but
>a goofy TCC solenoid in the transmission or a fluttering TCC apply
>valve in the valve body could theoretically cause those symptoms. This
>is quite unlikely but just thrown out there for discussion.
>
>Finally, I think the fuel filter is screwed to the inside frame rail in
>the left or right rear wheel area. Not a bad idea to replace it for
>maintenance.
>
>Toyota MDT in MO

In article >,
Lawrence Glickman > wrote:

> Crap. That would definitely throw a MIL code.

Nope. The GM systems of this era lack any ability to flag
ignition problems.

In article
ich.edu>,
"Daniel J. Stern" > wrote:

> On Sat, 1 Jan 2005, Comboverfish wrote:
>
> > Plug wires failing under heavy load would be the most common cause of
> > the jerking and loss of power sensation you are describing.
>
> Secondary ignition failure is one possible cause, but insufficient fuel
> volume due to a clogged filter or weak pump is even more commonly the
> cause of the symptoms described.

This thing sounds like it could benefit from a good thorough tune
up.

> > ignition components ever been replaced? Its no huge deal to replace
> > them all on a high mileage 350. Try to get Borg Warner, Standard or GM
> > parts
>
> Or Echlin...
>
> > and regular AC Delco plugs
>
> Or NGK, or Autolite...
>
> > The module is $50+ but if it's original its not a bad idea to replace it
> > when the cap is off.
>
> Pfft. The ignition module is not a scheduled maintenance item. They don't
> kinda-fail. And "while the cap is off" is silly. Removing the cap takes a
> quarter-twist of exactly two screws.

Agreed. If it will run at all, the module is probably okay.
Shotgunning one in is wasting money at this point and the cost of
a Delco ignition module (recommended) is closer to $130 if not
over. A NAPA Echlin module (second best choice) lists at $98.00,
the gypo Wells module (no way) is $50, but that is asking for
trouble and paying for the privilege.
On the other hand, the OP would want to closely examine the
distributor pole piece for a cracked magnet which -is- a very
common failure and will give the symptoms described.

> > Its hard to diagnose without seeing the vehicle,
>
> Exactly.
>
> > but its possible that a jerking and loss of power (to a lesser extent)
> > could be caused by a torque converter that's locking up inappropriately.
>
> Re-read the poster's original question more carefully and then explain,
> please, where the torque converter will be found relative to the poster's
> manual transmission.

Actually, the OP only mentioned that the truck in question has a
4 speed transmission. Could be either one, but a manual
transmission in a Suburban is quite rare.

On Sun, 02 Jan 2005 03:42:33 GMT, aarcuda69062
> wrote:

>In article >,
> Lawrence Glickman > wrote:
>
>> Crap. That would definitely throw a MIL code.
>
>Nope. The GM systems of this era lack any ability to flag
>ignition problems.

wow that sucks

In the old days, I would put an inductive Timing Light on the wires to
see if juice was getting to my plugs. I knew my plugs were good, I
had a distributor, rotor, vacuum advance diaphragm, centrifugal
weights. That's about it. I just clipped on to a wire and watched
the light. No OBD **** required.

Lg

On Sun, 2 Jan 2005, aarcuda69062 wrote:

> > Secondary ignition failure is one possible cause, but insufficient
> > fuel volume due to a clogged filter or weak pump is even more commonly
> > the cause of the symptoms described.

> This thing sounds like it could benefit from a good thorough tune up.

Agreed. The OP didn't know where the fuel filter was, which makes me think
it's highly probable it's not the only thing that's been neglected. Air
filter, entire PCV system, secondary ignition, the throttle body and IAC
probably need cleaning...

> > Pfft. The ignition module is not a scheduled maintenance item. They
> > don't kinda-fail. And "while the cap is off" is silly. Removing the
> > cap takes a quarter-twist of exactly two screws.

> Agreed. If it will run at all, the module is probably okay.

Yep (until someone who doesn't know the difference installs a black/yellow
coil instead of a black/white coil or vice versa!)

> Shotgunning one in is wasting money

Yup.

> On the other hand, the OP would want to closely examine the distributor
> pole piece for a cracked magnet which -is- a very common failure and
> will give the symptoms described.

Another good suggestion.

DS

DJStern, in my short time here you seem to come off as a bit of a
jackass to just about everyone; legitimate posters, helpers, and the
occasional dumb-ass who probably deserves it. So since you feed on
negativity instead of the help others are offering in this otherwise
good forum, this will be the only time I respond to your asinine
comments.

The torque converter will most likely be found in his 700R4 automatic.
Since I actually know quite a lot about car repair -and- don't waste my
time attacking every poster who I've deemed to have usurped my
knowledge, I read John's '4 speed' comment to mean 700R4, the clearly
most likely 4 speed available for the Suburban. Then I capped it off
by saying it was just fodder for discussion. Even though a randomly
engaging TC would cause his symptoms...... Huh.

Some people wouldn't mind spending money on a component that's likely
to fail soon like a GM ignition module, when its buried in the back of
a full sized truck engine compartment in a possibly HIGH mileage
engine. You need to climb on the engine or over the fender to get to
it. Oh and $50+ means 50 or more dollars, not that the exact brand he
must get costs exactly $50. Infact there are cheaper crappier ones for
around $25. Huh.

Oh, and they do kinda fail. GM ignition modules across the entire line
have acted up in so many different ways its unbelievable. You may want
to note I said "much less probability" than anything else in regards to
module failure though. Huh.

I agree that a decrease in fuel volume will cause power loss, but the
way that fuel delivery gets strangled over time by a dirty filter
wouldn't cause the same pronounced jerking that I got the feeling the
OP was experiencing. I would classify the symptom caused by a
momentary insufficient supply of gas due to partial restriction as a
hesitation or soft dropout. He said the engine sounds as if its
bogging down which seems to conflict with jerking, so I thought torque
converter for a brief moment which could cause both. None-the-less,
jerking symptom usually = secondary ignition. Huh. Usually = in
general = most of the time. Huh.

Done with you.

aarcuda69062, I know about the distributor shaft / reluctor problem,
its just that a cracked or 'weak' (as some guys call it) reluctor has a
reduced field effect and can't trigger the pickup coil at low rpms.
The usual symptom is stalling near idle speed. They seem to work OK at
higher rpms where John is having his problems.

Toyota MDT in MO