'90 Cutlass Supreme 3100 PFI

[Scott Shotton]

Fuel injectors are basically solenoids with a specific resistance. 
Temperatrature effects resistance.  If the injector resistance drops to
far when hot, it could shot down the injector driver.  If it is a banked
system, you loose three cyls.  When the driver cools, it works again.  A
condition that requires an increased injector pulse width can magnify
this problem.

For example:  GM 2.8 and 3.1 L.  The injectors are under the plennum and
are exposed to a lot of heat.  If the injectors are just starting to
fail, you can:  warm the car up, go for a ride, mash the accelerator to
the floor and the car will instantly die.  Reason:  the demand for fuel
maxes the pulse width, and because of lower resistance, the circuit
flows more current which over heats the driver.  I can't count the
number of 2.8/3.1 injectors I have replaced for this problem.

I think injector resistance specs for your car are about 12 ohms each. 
Just check them all and if one or two vary by a decent ammount, you
found the problem.  It is not very likely that all of the injectors went
bad.  You can save a chunk of change if only one is bad, but some say it
is a good idea to replace the set.

Scott




mccabet at mediaone.net wrote:
> 
> I need some help diagnosing a problem with a '90 Cutlass Supreme with
> the 3100 PFi engine.  The scenerio goes like this:
> 
> Engine starts and runs when cold.  It will re-start as long as you don't
> let it sit for a few minutes.
> 
> Once it has sat, the engine will start and then promptly die.
> Depressing Gas pedal makes it worse (Dies quicker).
> 
> Checked fuel pressure - 42PSI Key On Engine Running, 44 Key On Engine
> Off.
> 
> Scantool shows no error codes in system.
> 
> TPS checks good with no fluctuations noted.
> 
> I know chrysler systems better than any other so I am lost on this one.
> A shop claimed the injectors was bad a quoted $1200 to fix.  I don't
> think it is injector related since the engine will start and run when
> cold.  By The Way, the engine will keep running and will even restart as
> long as you don't let it sit.
> 
> Any help appreciated.
> 
> Thank You!
> --
> Thomas McCabe
> -mccabet at mediaone.net
> '80 Cordoba, 340, Auto (904) w/ shift kit & 6500 Rpm shift points, 3.23
> SG
> '83 Cordoba, 318, Auto
> '85 D250, 340, Auto
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