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Discussion Starter · #1 ·
Hey everyone! I know I made a post a while back about my Camry (91 4cyl 3SFE Automatic 128k miles) shaking at idle but I have some more information that may help diagnose. It seemed like a lot to post in a reply so I figured a new thread might be better.

the problem: When car is in gear at idle there is a pretty violent shaking. When I put the car into park or Neutral the shaking goes away. When driving the shake disappears. Here are some things I have noticed.
  • car shakes when under load at idle
  • shaking becomes worse when electronics are used such as rolling windows up and moving the steering wheel (power steering pump).
  • when idling in gear at a cold start there is hardly any shake. When the car reaches operating temp, the shaking becomes more violent.
  • when driving, there is no noticeable shaking and the car runs great and smooth.

what I have tried so far:
  • cleaned throttle body and IAC
  • replaced spark plugs
  • replaced distributor cap
  • replaced all transmission and motor mounts (one transmission mount was in half but still shakes after being replaced)
  • replaced alternator
  • had timing belt kit installed
  • checked for vacuum leaks
  • replaced air filter
  • Ran fuel system cleaner through the gas tank x2

Was thinking about replacing the coil pack next but I’m unsure if it would make a difference as the car drives great otherwise.

I know these engines aren’t supposed to be the smoothest and it is an older car so I don’t expect it to be completely still but the vibrations are so bad that I’m having to put the car in neutral at stops to save my hands from tingling from shaking so much. Any help or info is greatly appreciated! Thanks in advance.
 

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Toyota Collector
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Check all engine mounts for cracks and general damage/wear. There will always be some vibration at idle car in gear that's why Toyota went with balance shafts 1992+.
 

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92 Corolla, 90 Camry
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When you jumper the diagnostic connector to put car into test mode, what does the car do at idle in park/neutral, vs in drive (but not moving)?

When in test, what is the idle speed and the timing?
Does the 3SFE have the electronic idle air control or something different?
When engine is under load at idle and in gear, the engine idle up should increase idle speed to compensate. An example of this is when the AC is on constantly (when at max cool), or going back and forth as the compressor turns on/off (less than max cool) so that the idle speed doesn't drop down causing rough idle.
 

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3s-gte in a Camry?!?
'89 Camry Alltrac
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Sounds like the idle is just a bit too low. Does the car have a tach? If so, what's the RPM while stopped in gear?

If not, maybe you can get a diagnostic tach for testing purposes. There is an unused connector at the distributor for a tach signal (1/4" spade fits in it)

-Charlie
 

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Discussion Starter · #5 ·
Thanks for the replies! Unfortunately mine doesn’t have a tach. I noticed that connector but wasn’t sure where I could find a diagnostic tach. And when I try to look it up it just brings up multimeters. Do you have a link to one? I saw a diagnostic tach that looked like it plugged right in to the port in an old repair manual but I’m sure those are hard to find now.

I’ll have to check the idle when the TE and TE1 are jumped when I get home! And I’ll update.
 

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92 Corolla, 90 Camry
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Jumping the test port without a device that gives you rpms will only give you the engine codes blinking on the clusters engine light.
After jumping test port you can connect the actron below between the diag connector IG- and ground and see the rpm reading which should be pretty stable vs not in test mode since computer is constantly changing the rpms and other parameters.
I have this that is a voltmeter, ohmmeter, rpm etc
 

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3s-gte in a Camry?!?
'89 Camry Alltrac
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Discussion Starter · #8 ·
Awesome! Thanks for the links. I got one on order. How would I adjust the idle if it’s too low? I noticed if I put my foot on the brake and then very slightly tap the gas pedal the vibrations completely go away while idling in gear.
 

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3s-gte in a Camry?!?
'89 Camry Alltrac
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9,089 Posts
How would I adjust the idle if it’s too low?
It is officially not adjustable... but it will be good to know what we are starting with.

This reminds me of the Accord my high school girlfriend drove (and '88-ish, during the mid-90's). It had >300k miles on it (manual transmission!) - and would shake badly at idle. The fix? Keep the AC on all the time so it would idle-up. 😆

-Charlie
 

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Discussion Starter · #12 ·
I’ve read elsewhere there is an adjustment screw in the throttle body. It said it was a flathead screw located in a tube like hole that is supposed to have a black rubber cap on it although mine does not have the black cap. Is that screw for something else?

I noticed the screw was only backed out 1 full rotation from being completely seated. I backed it out another full rotation and a half (2.5 turns total) and it greatly lowered the vibrations while in gear. But then I also noticed though that while in park the idle rpm’s seem higher also. I’ll update with the exact rpm’s once I receive the tool.
 

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3s-gte in a Camry?!?
'89 Camry Alltrac
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9,089 Posts
I’ve read elsewhere there is an adjustment screw in the throttle body. It said it was a flathead screw located in a tube like hole that is supposed to have a black rubber cap on it although mine does not have the black cap. Is that screw for something else?
That's why I said officially. The ECU will seek the programmed idle via the ISC valve assuming it is working well. There is the bypass screw, as you found, which is officially not supposed to be used.
But then I also noticed though that while in park the idle rpm’s seem higher also.
You'll need a real tach to know what you are doing with the idle screw. And as I said, the ISC may just push it back 'too low' after it adjusts to the change.

-Charlie
 

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Discussion Starter · #14 ·
Gotcha, thanks for the info! It seems like someone else may have adjusted the idle screw prior to me because the black rubber cap was not there. What is that screw typically supposed to be set to?

Is the ISC the same as the IAC and is there a way I
could go about testing if it’s working properly or not? I had an issue prior where the car would rev very high in park or neutral but after cleaning the IAC that problem was resolved. Wondering if maybe it would need more cleaning or replacement.
 

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3s-gte in a Camry?!?
'89 Camry Alltrac
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9,089 Posts
Is the ISC the same as the IAC and is there a way I
could go about testing if it’s working properly or not?
Oh yes, IAC = ISC. I may have been confused, as both terms are used for the device that controls idle speed.

Similar how MAF (mass air flow sensor) is the modern term/device for the AFM (vane air flow meter) on the gen2 Camry. They do the same job in a different way.

-Charlie
 

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Discussion Starter · #18 ·
Ok I Got t
Plant Sky Gauge Cloud Bicycle accessory

Sky Plant Cloud Gauge Measuring instrument

he tach reader and here are the results I got. I’m assuming the 019 represents 1900rpm (in drive) and the 029 represents 2900 (in park/neutral) both of which seem way too high. Should I just try adjusting the idle speed screw (on top of the intake manifold) or adjust the ignition timing? I noticed the shaking is much better after I backed out the idle screw a few turns (it was almost all the way closed). But the shaking is definitely still stronger than normal after it warms up.
 

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Toyota Collector
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Is the throttle cable binding/not returning or too tight? That is way way too high you're not going to fix that by turning the idle screw.
 
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