Weird problems

JSGAuto

Registered User
Hi,
1990 SC Automatic
The car runs great at idle, in park or neutral. When the steering wheel is turned the RPMs drop and the car wants to stall. A tap on the gas smooths everything out. The same sythems occure when shifting from park into reverse or drive. The RPMs drop and the car wants to stall.

Any ideas?
Thanks
Jim
 
Believe it or not ,i had the same problem around the time that my power steering pump went bad. After replacing it those symptoms that you stated went away,however since I had to re seal my IC tubes when replacing the pump i may have sealed a small leak. Check for vaccumn leaks b-4 throwing any parts at it.
 
What is the process, and what materal do I use to reseal the IC tubes?

The motor mounts are on their last legs. The last time I had difficulty changing the oil because the filter is sitting very close to the frame.

Thanks,
Jim
 
IC tubes

If you need to seal these things up TBIRD88 has a teflon gasket set for them that will be reuseable...I got them on both my SC's and they work great...Get a set...

What is your idle set @? It may be too low for the IAC to compensate...I think the Autos should be idleing @ around 850-900 in Park...Does it even try to recover??

Brad
 
Bad motor mounts can definitely cause weird idle problems!

To test your motor mounts, do the following:

1) Open hood
2) Start car and put in gear (hold on to brakes)
3) While holding on to brakes, give it gas and look at the motor through your windshield and see if one side of the engine looks like it wants to jump out (couple inches or more of movement)
4) Put in reverse and do the same.

If one or both of the sides looks like it's going to jump out, that side is bad. (It's ok for them to move a little bit, but much more than an inch and they are shot.

Dale
 
I swaped IACs between my NA 3.8, and the SC. The IAC looked to be the same so I gave it a try. The NA one was replaced about 6months ago so I know it is good. There was no performace change between either car. So I think that can be ruled out for now.

Dale, I tried your motor mout test on both my cars also. This way I could use the NA car to get an idea what good motor mounts will look like with that test (they were also recently changed). In drive the SC engine wanted to jump out! The engine must have raised a good 3 inches. This happoned on the drivers side. The passenger side stayed still. It would suprise me if the engine hit the hood with the intercooler tubes!

Does anyone know a cheap place for motor mounts?

Thanks,
Jim
 
There ya' go. You'll be surprised how much better it runs after you get that mount changed.

For the record, the driver side is usually the most common one that blows. It is, after all, the one that has the most pressure exerted on it when you gas it in drive.

I don't know where to go "cheap." I got mine done at a local shop. Just get the quote and find out how many standard hours it should take and make sure that's the rate they go on. Cuz' it'll likely take them longer than the "standard hours." :D

Dale
 
I am probably going to tackle this project myself. I did mounts on a friends 3.8 NA, a buick 2.5, and a VW Cabriolet. So I figure I will save a few bucks.

I will be sure to post how the project turns out!

Thanks for all your help!
Jim
 
copper rtv

t-bird88's gaskets are very cool from what i hear........but you can re-seal your IC tubes with copper RTV !
 
Re: IC tubes

cudaz101 said:
What is your idle set @? It may be too low for the IAC to compensate...I think the Autos should be idleing @ around 850-900 in Park...Does it even try to recover??

Brad
Just FYI, the idle is not adjustable. The EEC controls the idle speed (senses it through the crank sensor) by fluttering the IAC valve back and forth. Idle speed for the auto is about 650-750 in and out of gear.

As far as JSGAutos engine mounts are concerned.. if you look from under the car, you will see that the limiter arm from the upper mount bracket will be sitting on the frame on the lower mount bracket. This is bad.. It will cause the knock sensor to pick up false readings and the EEC will retard the timing to adjust.. hence low stumbling idle. This is a very common problem, and I'd go so far as to say that if you have over 90,000 on the engine, the original mounts are shot.
 
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