ping

[David Mulvey]

> At 06:58 PM 8/22/99 -0800, you wrote:
> >I have an 87 IROC-Z 5 Liter, I think I have the 12277165 but I am not 
> >sure.  


> WOT is Wide Open Throttle...
>  From the sound of it and the multiple weirdnesses you are seeing, I'd 
> suspect a ground gone bad for the computer or sensors...

I did check the signal wire from the MAF to the computer.  Also the signal wires to and from the MAF relays.  However, a thorough 
check of the ground wires I did not do. I did add two ground wires from block to the body on both sides of the engine.  But still a 
frayed ground wire to the computer or dirty contact might cause some trouble.

I suppose another "weird" cause could be noise from the ignition system.  The MAF signal wire goes right by the distributor and coil. 
Maybe a choke filter could be used on the MAF signal wire (if it's noisy) to allow only DC voltages to go down the wire.  I'll check 
it out this week sometime.  School starts this week, 2nd semester of calculus and homework will disable my free time as I know it.

I don't get any lean/rich errors.

The ping only happens after the car has warmed up for 7 minutes and WOT and semi-WOT. From talking to folks here on the list that 
means that maybe what circuit is giving bad readings is not being used, and/or when cold the car will get a richer mixture keeping the 
ping away and maybe also the timing is kept to a set algorithm rather than relying on sensor data for timing.  

The more I keep typing, the more I know I need a laptop/Diacom.  I have their brochure here.  Any used Diacoms out there that need a 
new home?



end
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David Mulvey KD6BZN
Lancaster, CA
(661) 723-0352