[Gmecm] Vortec L31 oscillating at idle

[Programmer]

Could be a couple things:

1. What did you end up using for spark plugs ?
2. Is the MAF clean ?
3. Fuel pressure is absolutely critical on this baby.

There is NO crank relearn on this one.

Lyndon.


----- Original Message ----- 
From: "Jake Tucker" <jktucker at usamedia.tv>
To: <gmecm at diy-efi.org>
Sent: Friday, March 16, 2007 7:55 AM
Subject: [Gmecm] Vortec L31 oscillating at idle


> Well, we're finally getting close to having a vortec injection
> transplant running in an '84 Suburban.  We started with a fresh 350 with
> vortec heads, and installed a vortec injection setup out of a '97 onto the
> motor to replace the TBI system that had been running the motor.  There 
> were
> a few setbacks along the way, but now the motor is running and appears to
> need just a little tuning.  The main problem now is that it is hunting at
> idle.  Engine speed oscillates from 300 to 1000 RPM's for several seconds
> before the engine dies.  This is especially a problem when it is cold, and
> the engine won't stay running at all without opening the throttle a 
> little.
> In general, the engine runs, but doesn't give the power we'd expect at 
> this
> point.  It is a '75 block that was rebuilt with Vortec heads.  To do the
> vortec conversion, all the sensors, intake, distributer, crank sensor,
> harmonic balancer, and accessories were transplanted from a '97 vortec 
> motor
> with a cracked block.
> Any ideas what would cause the oscillating problem?  I would like to
> watch the IAC motor counts, but I can't seem to find that data on the
> software I'm running.  Right now, I'm using car-code 2 which is sold at
> www.obd-2.com.  I also have the OBDII tuner by tunercat.  He has since 
> sold
> his design to Jet performance.
>
> Jake
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