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GM TBI low voltage at the injectors

87 4x4 suburban won't start has spark, fuel pressure, injectors have been cleaned, truck will start if fuel is poured down the TBI and then dies. Pulled injector plugs to check voltage both plugs pulse from 0 to .02 volts. Checked all fuses all seem to be good. What am I missing?

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  • Anonymous Nov 22, 2008

    I have read many places that this problem is related to a spark problem. The injectors rely on a signal from the distributor to tell them when to fire. Apperantly we are losing that signal somewhere and its not teilling the injectors to fire; however, if i spray carb cleaner, the engine will start and run fine.

  • Rod2Pieces Mar 16, 2009

    Bought an 88 GMC Sierra SLE 4x4 that needed repair. Replaced fuel line and it started but ran with a stumble. Replaced the fuel pump and the injectors won't spray. (Will start fine when gas/starting fluid is sprayed in but still won't spray fuel from injectors. Fuel filter is clean. Fuel pressure is good, swapped TBI units and it worked for about 10 seconds then went back to the same scenario. Tested both units for flow w/ air pressure through lines (both good) also put a jump wire to bared injector wires: Left wire to positive - opens injector, half the time just drips slowly. Other times it just makes the fuel pump run. Right wire to positive - makes fuel pump run only. I am at wits end with this truck seeing as my Buick's transmission blew to pieces so I need a set of wheels. I've been reading a lot of stuff online and it all seems to come back to the Distributor? I'm used to working with carb engines so I'm not too keen with TBI setups/problems.

  • snoopannie Apr 20, 2009

    my 1994 chevy 1500 pickup does the exact same thing.i installed a new fuel filter and fuel pressure oil switch with no help.started as stalling at idle to not idling at all.if it is on cold running circuit it is oktill idle drops below 1000 rpm.somtimes it will work fine intermittantly.i have checked wiring for continuity to ecm had ignition module tested checked distributor shaft for wear side to side also pickup coil for ohms reading all test ok.i believe i am losing the ground side of the injector harness witch suggests a ecm.anyone with ideas would really help.

  • Anonymous Apr 29, 2009

    85 3/4 ton chevy had a 6.2 diesal now has a 91 350 tbi ran good when swaped out but its sitting for awhile. all new gas in truck and lines but wont start. if i pour gas in the tbi it will run for a bit.


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Yesterday i posted my problem of no idle or start on a 1994 1500 chevy pickup.what i found was power and ground was good at the injectors.but no power at need to pull the four pin conector at the distributor .with a noid light conected to oneof the injector harness and a test light hooked to 12 volts prob the purple and white wire i believe ckt 436 when you probe it should light the noid light.if this is the case then the ignition module is module tested good 6 times at the local o"rilley auto parts house.also check power cranking at 5 amp fuse in fuse panel.

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Change fuel filter ?

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