Re: GTV6 Problem

[Formeister@domain.elided]

Dave,

Although I haven't experienced your exact problem, from the way you describe 
it it doesn't sound like an ignition problem, especially the way you  
describe it dying.  An ignition fault almost always cuts the car off like 
you've turned the switch.  Fuel related problems will cause 
stumbling/hesitation, etc.  What you've described sounds more like a vacuum 
leak, especially since it'll run o.k. once the revs are up.  At idle you may 
be getting too much air through a small vacuum leak that's not showing up on 
the AFM causing it to lean out and sputter or backfire.  When it's cold the 
computer automatically supplies a richer mixture so the effect of a small 
vacuum leak wouldn't be noticed.  If you're carefull,  you can put a hose on 
a small propane torch tip and with the engine running open the valve on the 
cylinder and direct the hose around vacuum hoses and injector seals, etc. to 
try and find it.  The engine will either smooth out or speed up if it finds 
one.  Also, make sure hoses from the air flow sensor to the throttle body are 
tight with no leaks.

Good luck,

Frank Formeister

>  From: DaveM <doc1590@domain.elided>
>  Subject: GTV6 Problem
>  
>  I've tried to help lots of people on the Digest with
>  their problems and now I have one that has me baffled.
>   1984 GTV6.  Runs great, starts fine!  BUT! When it
>  idles for any length of time it starts popping,
>  running rough and quits. It seems to run if I rev it
>  over 3000 or so, but as soon as you try to drive it,
>  and it falls below that, it loses power, runs very
>  rough and sputters to a stop.  It will restart and run
>  fine after sitting for a half hour or so. Drive in
>  lines at banks/fast food... traffic jams...  are
>  deadly!!!  No matter what the weather.  
>  It seems to be more related to either underhood
>  temperature or some other static situation than it
>  does engine temperature.  Although, it's never done it
>  unless the cooling fans were running.  They never come
>  on in normal driving, only when sitting.
>  I have spare everything and have changed:
>  
>  Coil
>  Ign. Module
>  ECU
>  Hall Sensor, then whole distributor
>  
>  I've removed all connectors and cleaned them including
>  all ground connections.  It does it with O2 sensor
>  connected or disconnected.
>  I connected a Bosch Autoforce tester (the expensive
>  one in the briefcase thing) and pretty much eliminated
>  any of the sensors or fuel system components except
>  pressure regulator and AFM (the Autoforce tester
>  checks the temp sensor in the AFM but not resistance
>  of the flapper).  I have not checked fuel pressure as
>  yet nor have I changed spark plugs or wires.
>  
>  The problem is thermal and I believe underhood.  I get
>  no black smoke indication of overly rich, but I
>  haven't actually checked Stoich.
>  
>  Any ideas would be appreciated.
>  
>  Dave Miller
>  Deltona, Florida
>  

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