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TurboBaron · **Is A/F ratio supposed to stay static at Idle?**

This is pretty much the only wierd problem with my car.

'87 Lebaron, '88 T2 engine, '87 T2 computer.

At Idle, my a/f meter swings back and forth erratically from dead lean to the high side of stoich. Rarely goes to rich unless it's cold outside and the car has been sitting for a night.

My 3-wire O2 sensor is brand new when the engine went in (about 6 months ago).

With the mixture all over the place, I don't have a steady idle, and yet in gear, I get a (for the most part) steady idle. It only goes wonkey in neutral or park.

Where would I start with this??

puppet · 06-25-2006, 11:03 PM

The swing is normal.

**speedyshelby16** · 06-25-2006, 11:56 PM

+1 ^^ I got 2 td with af gauges both do it.

johnturbotron · 06-26-2006, 07:02 AM

Mine moves around also with my wideband hooked up it moves around.

TurboBaron · 06-26-2006, 08:33 PM

Is the idle speed supposed to rise and fall with the lean/rich cycles?

22turbo · 06-27-2006, 03:53 PM

Quote:

Originally Posted by TurboBaron

Is the idle speed supposed to rise and fall with the lean/rich cycles?

Mine does, so I think that's normal also.

Dan

Edit: It does not move up and down a lot, just about 25-50 rpm or so.

TurboBaron · 06-27-2006, 04:07 PM

Mine swings approximately 500 rpm. I have a digital dash so I can't say for sure exactly but each "bar" on the tach equates to 250 rpm.

My engine will sway from 750 rpm to 1,250 rpm when in neutral or park.

daytonajesse · 06-27-2006, 05:57 PM

you need to clean out your TB and AIS real good with some carb cleaner. Fixed me up nice!

Juggy · 06-27-2006, 05:58 PM

check your sensors on the throttle body, it might even be time for a good cleaning!!

TurboBaron · 06-28-2006, 12:08 AM

TPS and AIS are both new, throttle body completely soaked and cleaned out about 6 months ago when the new engine was put together.

Today, It was only really cycling by about 250 rpm..... between 750-1000.

I may double check it with a proper tach to see what the acutal variation is. But if other people have the same deal going on I guess I have to live with it. I have a friend with a TBI Laser and he says his idle is all over the place and that the computer actually tries to change the timing at idle. We verified this with a timing light and his timing (and mine) does indeed jump around at idle.

*sigh*

Whoever said new cars are better needs his/her head examined. I don't have ANY issues like this with my '70 Inline-Six Gremlin.

daytonajesse · 06-28-2006, 10:51 AM

Jumping timing at idle with the CTS still connected is completely normal. This could be a hep issue.
Your other car doesnt have gremlins cuz it IS a gremlin, it's probably the reason your "new" car is having probs!
p.s. dont get it wet!

TurboBaron · 06-28-2006, 03:42 PM

LOL!

tkelly27 · 07-01-2006, 08:05 PM

My van does exactly the same thing you are describing, and the timing jumps around when I pull the CTS. I have no idea what's causing it, I will try the TB cleanout though.

william · 07-07-2006, 02:12 PM

Idle fluctuating 250 rpm is not normal, especially on a relatively stock setup like you have. The AF "swinging" is normal at idle, but there shouldn't be fluctuations of the idle that go with it. What is your ignition timing set to? How is your idle vacuum?
I guess you could "live with it", but I wouldn't.

Una · 07-07-2006, 02:19 PM

Quote:

Originally Posted by tkelly27

My van does exactly the same thing you are describing, and the timing jumps around when I pull the CTS. I have no idea what's causing it, I will try the TB cleanout though.

Loose shutter assembly inside the distributor. Pop the cap, rotor and HEP out.. See if you can wiggle the metal shutter wheel independently of the center hub.. Pretty common for those to come loose a bit.