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Old September 29th 04, 03:55 PM
~^Johnny^~
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On Mon, 27 Sep 2004 14:07:34 -0400, Roger Ehrlich - Alumni-2004
> wrote:

>Thanks Philip & everyone
>
>Ok here's some more observations....
>
>Yesterday I did remove the EGR valve and there was much carbon in the
>valve and pipe. I used Carburator cleaner (sensor safe) to try & clean it.
>The valve seems to move/close more freely thereafter. I also
>replaced the PCV valve (FRAM PV295).
>
>However as I drove
>to work this morning and the car still felt like it was stumbling when
>accelerating. When gearing up from 1st to 2 & 3 my car hesitates, it feels
>jumpy, or stumbles with a lurching/bucking. My sense is that it
>seems like the clutch plate is slipping.


A severe, but positive test for clutch slippage:
Put it in 3rd gear, aply the parking brake, and try to "take off".
Let the clutch out while revving the engine. The engine should die, even
before the clutch pedal is all the way up.

An even more brutal (but still more positive test) is to rev the engine to
above 3000 RPM, in third gear with the clutch pedal down, parking brake
applied. Without modulating the throttle, slowly let out the clutch. It
should slow and stall the engine, evenly and eventually. Any upward blips in
the engine speed could mean a worn throwout bearing, or weak dampener springs
in the clutch disk. More severe slippage will, of course, be more obvious.

>However this symptom does not occur
>consistently. Sometimes it drives/feels very well. But when it happens it
>always does under lower rpm (1600-2500), typically as I am gearing up and
>accelerating with the gas pedal. I do not notice this under high rpm >3000
>rpm or when in gear 4 or 5 (maybe because of momentum). As I stated
>before, I tested the clutch, easing up on the pedal into 1st gear from a
>stationary position either on level ground or uphill, and the clutch does
>grab. Then if I press the gas pedal once in gear sometimes the jerking
>occurs. I cannot say that it appears to be a problem with the fuel pump.
>It primes fine when I turn the key to ACC, and the engine does not seem to
>sputter (like it's running out of gas). I'd suspect the clutch slipping if
>it was consistent. As Philip suggested I'll change the ignition wires to
>see if that does the trick (however when I changed the spark plugs last
>summer I did also measure the Resistance on the wires and they were
>fine). I would rather not spend money on changing the clutch plate or
>fuel pump if it is not necessary as these are very expensive.
>
>Thanks, Roger


Sounds more like weak spark on one or more cyls.
One or more coils are weak, or you have bad spark plug cables.

Take the car into a dark (I mean pitch-black) garage, run the engine at fast
idle, around 1800 RPM, and raise the hood. Look for any visible sparking,
corona discharge...

Ignition coils can also cause this symptom when they go bad.





>
>In article <Pine.LNX.4.44.0409241223250.7871-100000
>, says...
>> I have a 1995 Saturn SL1, SOHC, manual transaxle, with
>> 145,000 Km (much on the hwy). I do change the engine oil frequently
>> 5000Km, check fluids often, etc. In the past two
>> weeks, when accelerating, my car hesitates, it feels jumpy, or

>bucking/jerking.
>>
>> To resolve a recent stalling problem at deceleration and low rpm

><2000rpm,
>> I did the following:
>>
>> - changed fuel filter
>> - cleaned carbon out of throttle body with carb cleaner (was
>> O2 sensor safe), and there was alot of carbon...
>> - replaced vacuum hose between throttle body and crank case, old one was
>> weak & almost ready to collapse. (fuel/PCV line hose 11/32" ID, 50 PSI)
>> -used STP concentrated fuel injector cleaner in gas tank.
>> -spark plugs were gapped & changed last summer.
>> -replace air filter
>>
>> I don't think it is a slipping clutch, because the clutch feels fine and
>> grabs when I ease up on the clutch pedal when starting in 1st gear.
>> Although I feel this bucking in gears 1, 2, 3, not so much in
>> 4/5....typically at lower rpm < 2500 rpm 1500 - 2200 rpm.
>>
>> It could be the ...
>> -EGR valve
>> -ignition wires
>> -cap and rotor
>> -MAF/MAP sensor (where are these located?)
>>
>> any suggestions?
>>
>> Thanks, Roger

>
> Very good post. You covered a lot to eliminate a bunch of questions we
>here might of had to go through. I kinda suspect the EGR. It may not be
>closing off, at least not very well do to carbon. Btw Saturns never used
>cap and rotors.
>
>
>On Fri, 24 Sep 2004, Philip Nasadowski wrote:
>
>> In article
>> >,
>> Roger Ehrlich - Alumni-2004 > wrote:
>>
>> > - changed fuel filter

>>
>> Good.
>>
>> > - cleaned carbon out of throttle body with carb cleaner (was
>> > O2 sensor safe), and there was alot of carbon...

>>
>> Good. you might want to just remove and clean again to get EVERYTHING.
>> It's 2 10mm bolts and unplugging the cables. Really easy, at least on
>> the dual hamster models.
>>
>> > - replaced vacuum hose between throttle body and crank case, old one was
>> > weak & almost ready to collapse. (fuel/PCV line hose 11/32" ID, 50 PSI)

>>
>> Weird.
>>
>> > -used STP concentrated fuel injector cleaner in gas tank.

>>
>> Maybe it did something. I don't trust those things though.
>>
>> > -spark plugs were gapped & changed last summer.

>>
>> Ooooo.
>>
>> > -replace air filter

>>
>> Good too.
>>
>> > It could be the ...
>> > -EGR valve

>>
>> Maybe.
>>
>> > -ignition wires

>>
>> *ding!*
>>
>> Change those first. I bet the problem goes away. Mine was like this
>> too, i changed the wires - ran a LOT better. It just feels like it's
>> missing or hesitating every now and then, randomly? or, at low RPM, as
>> the RPM increases, it suddenly 'kicks in'?
>>
>> > -cap and rotor

>>
>> None - it's a DIS system. A coil per plug.
>>
>> > -MAF/MAP sensor (where are these located?)

>>
>> No MAF. MAP is on the intake manifold. I'm not sure about the single
>> hamster motors, but the two hamster ones have it to the left end of the
>> manifold.
>>
>> > any suggestions?

>>
>> Replace the plug wires. Do it first. I bet it fixes it.


--
-john
wide-open at throttle dot info
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