Mechanics

FUEL, SPARK, GOOD INJECTORS... WONT START (RUNS WITH CARB CLEANER)

1992 Oldsmobile Cutlass • 330,000 miles

GM 3.1. Was running, shut off went shopping come back out cranks no start. Has good spark, full tank and 42 lbs fuel at schrader valve, can hear pump at key on. Noid light in 1 plug showed no light key on, no light when cranking. Pulled plenum ohm'd all injectors are between 1.5-2 ohms. What else to check and how?
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Bus933s
July 29, 2012.



So do you have power to the injector wire that is supposed to have power at the injectors with the key in the run position?


Saturntech9
Jul 29, 2012.
With all injectors disconnected and key on, there is 2-3v on one side of each connector. As soon as I connect ANY 1 injector back to its connector, there is no power at any remaining open connector.


Tiny
Bus933s
Jul 29, 2012.
Alright theres the problem the pink wire with a black stripe should have battery voltage with the key in the run position. Its power from the inj fuse.


Saturntech9
Jul 29, 2012.
I am amazed how quickly I received a response - this forum is great! Thank you.

So do you mean there is a short between the fuse and the injectors? Would this include possibly the injector control module? I am somewhat confused - I thought the injector connection should read battery voltage only when the pulse signal is sent.


Tiny
Bus933s
Jul 29, 2012.
No here is how it works you get battery voltage from the inj fuse on the pink wires with a black stripe. That power comes straight from fuse. The injector is plused and control by the ground side of the injector circuit. That would be the light blue wires going to the injectors. Then those wires change to a dark blue color and go back to the ecm/electronic control module. That is what controls the injector pluse. Lets start by seeing what the voltage is at the inj fuse in the fuse box with the key in the run position?Also make sure the battery is fully charged. Check both sides of the fuse. It could be a crossion in the fuse box causing a bad connection even.


Saturntech9
Jul 29, 2012.
12v at battery, no reading at injector fuse. Fuse block in general is getting power (i.E. Fuel pump fuse reads 12v). I do have all the injector connectors and connectors that attach to anything related to the plenum detached, as I pulled the plenum. Do these need reconnected to get a reading?


Tiny
Bus933s
Aug 1, 2012.
Take that back. About.5v at the fuse (I didn't have a good ground on the tester 1st time).


Tiny
Bus933s
Aug 1, 2012.
Then your problem is at the fuse box then. Was that 5 volts at the fuse?


Saturntech9
Aug 1, 2012.
In the group of the small 2 prong fuses, where 2 are labeled something to do with injectors, there is only 0.5v on both sides of each fuse. In the other half of the fuse box, where there are larger 5 prong fuses, such as for the fuel pump, there is 12v.


Tiny
Bus933s
Aug 1, 2012.
Also check your crank shaft sensor conecter. That crank shaft sensor controls the pulse to your injecters. And it is common on the 3.1, 3.4, & 3.8 for the conecter to be bad. You can but it at any local part store. Part # PT5666.


Tiny
Mikederouin88
Aug 1, 2012.
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