ECM fault?

[Akselrud, Boris]

1. My brother owns an auto repair shop with all the tools including
scanners. No trouble codes has ever come up, unless you disconnect something
on purporse.

2. I don't know if such thing as fuel conditioner would make any difference.
Basically whatever my brother did in his shop with the engine did not have
any slightest effect on idle behaviour. I could feel more power after new
spark plugs, wires, distributor, timing set, fuel injector cleaner etc.
However Idle behaviour remains the same: 2 sec or smooth running followed by
2 seconds of rough idle.

3. I even was to a dealership with the intention to fix this problem. They
responded that this is normal for that engine and even newer cars exibit
stronger rougness (as well as charged me for the job they done and wich had
no effect what so ever). However this is not the first V8 engine I drive and
I believe that this idle behaviour is certanly not normal.

4. O2 sensor is new.

5. Car has 110,000 miles.

6. Could you explain what do you mean by was it "exposed to any silicone" ?

Do these 5.7 TBI engines run rough at idle?

Thank you for the responce.

-----Original Message-----
From: nacelp at jvlnet.com [mailto:nacelp at jvlnet.com]
Sent: Monday, November 08, 1999 3:30 PM
To: gmecm at efi332.eng.ohio-state.edu; gmecm at efi332.eng.ohio-state.edu
Subject: Re: ECM fault?


Try some good fuel system conditioner (ie Quaker State/Slick 50, only stuff 
that comes inna metal can).
Has a complete tuneup been done?. All the electrical/wearable parts, at
once?.
Has it been on a scope, do you own a scan tool?.
Personally I can't diagnose your car over the net,
These are just a cople thing to look at.
What shape is the O2 in, miles, was it exposed to any silicone?.
Grumpy


>Unfortunately no one answered my first post regarding what I think is ECM
>related problem in 5.7 TBI in my 1993 Cadillac Fleetwood.
>The problem is erratic or I would say unstable idle. Looks like ECM is
>leaning the mixture (don't know for sure) causing idle to go below
>comfortable level for 2..3 seconds followed by 2..3 seconds of smooth
>operation
>