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

  • Tiny
  • bus933s
  • 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?

Sunday, July 29th, 2012 AT 8:51 PM

65 Answers

  • Tiny
  • saturntech9
  • Expert
  • 28,254 posts

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?

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Sunday, July 29th, 2012 AT 8:57 PM
  • Tiny
  • bus933s
  • Member

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.

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Sunday, July 29th, 2012 AT 10:11 PM
  • Tiny
  • saturntech9
  • Expert
  • 28,254 posts

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.

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Sunday, July 29th, 2012 AT 10:22 PM
  • Tiny
  • bus933s
  • Member

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.

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Sunday, July 29th, 2012 AT 10:31 PM
  • Tiny
  • saturntech9
  • Expert
  • 28,254 posts

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.

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Sunday, July 29th, 2012 AT 10:58 PM
  • Tiny
  • bus933s
  • Member

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?

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Wednesday, August 1st, 2012 AT 12:59 AM
  • Tiny
  • bus933s
  • Member

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

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Wednesday, August 1st, 2012 AT 1:09 AM
  • Tiny
  • saturntech9
  • Expert
  • 28,254 posts

Then your problem is at the fuse box then. Was that 5 volts at the fuse?

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Wednesday, August 1st, 2012 AT 3:09 AM
  • Tiny
  • bus933s
  • Member

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.

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Wednesday, August 1st, 2012 AT 11:59 AM
  • Tiny
  • mikederouin88
  • Member

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.

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Wednesday, August 1st, 2012 AT 12:37 PM

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