1989 Buick Electra Injector Not firing


thesellars
05-25-2008, 05:06 PM
Hello Im Working On Wifes Grandads Car Its A 1989 Buick Electra Limited With A 3.8 Fuei Injected Engine And Has 83,124 Miles On It.The Car Started Being Very Hard To Start U Would Have To Turn It Over 10-15 Times Before It Would Crank and when it did crankk it would be missing it sounded like.So I Started Working On It,This Is What Ive Done So Far
1st I Had The Ignition Module Tested At Orielly Auto Parts And It Tested Bad So I Replaced It 100bucks,Then The intake was leaking coolant so i replaced intake gasketaround 80bucks for parts had to replace 4 bolts rusted and looked fragile.so with all that done its still hard to crank and when it does its still running rough.but sometims it would smooth out so i started looking at the injectors and i found one that wasnt popping but the it would just start popping and and smooth out then sometimes it get really rough at idle then i found another not popping but most of the time its just the one thats not popping.so i checked for power on the one wire and it has power on it,then i check it plugged up to the injector and i have power on both wires just like the other injectors i tested a working one and it has power on both wires when running so i have power.i hope u can understand what i talking about

thesellars
05-25-2008, 05:38 PM
ok tested the injectors with volt meter its injector 1 and then sometimes injector 6 will cut out so then im running on 4cylinders but with engine running and number 1 injector not popping the volts stay steady at like 13.70 on both wires on injector 3 the volts on one wire is pulsing around 13.40-13.70 that i can see so i got power on injector but not pulsing why??and why is 6 cutting out sometimes im thinking these are companion cylinders could it be a ground problem or is it the ecm

maxwedge
05-25-2008, 07:44 PM
The pcm grounds the injector based on pulse width, one bad injector can pull down others, you say you have voltage on both sides of the connector? When you say pulsing at 13.7 volts do mean on the ground or B plus side? A noid lite is the best way to monitor pulse activity as a quick check.

thesellars
05-25-2008, 07:54 PM
well on the number 1 injector both sides have power 13.7volts power not pulsing but the other ones that are pulsing on the b side

maxwedge
05-26-2008, 11:13 AM
Check the resistance on that inj. should be 11.0-12.5 ohms.

thesellars
05-26-2008, 11:19 AM
they are at 15oms

thesellars
05-26-2008, 11:46 AM
also should any of the pins on the ecu have resistance across them there is 3 plugs on the ecu 2 black and 1 orange.the orange plug doesnt have any resistance aross them the small black plug has 10 pins that have resistace between them.the big plug doesnt have any and this is the place where the wires plug into the back of the ecu

maxwedge
05-26-2008, 03:11 PM
That is a little high but inconclusive as the meter can be off a little. Not a commonly tested area at the the ecu. Check for good connections at the ecu , again with a noid lite if 1 injector does not pulse and 5 do, suspect the ecu, or the harness.

thesellars
05-26-2008, 03:18 PM
ok yea its a cheap volt meter so its a good guess its a little off i swaped number 1 injector with number 3 and cranked it up was still not firing about 20 mins later i recranked it everything running ok but when go back and crank it it will not be firing

maxwedge
05-26-2008, 03:25 PM
So the miss moved to #3 or not? If it moved the injector is bad, if it is still #1 then the harness has high resistance somewhere or the ecu is bad.

thesellars
05-26-2008, 04:00 PM
the number 1 is still missing so im thinking ecu cause harness looks good so is the ecu your thought to would the crank postion sensor have anything to do with it

maxwedge
05-26-2008, 07:08 PM
CPS would not cause one injector to not pulse. Check the resistance of the ground side wire from the injector connector to the pcm to be sure.

thesellars
05-27-2008, 03:15 PM
replaced ecm and it fired right up no spinning at all and no skipping thanks for your help:smooch:

maxwedge
05-27-2008, 07:19 PM
Great!!

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