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Discussion Starter #1
I recently bought a 87 4runner that is not getting a pulse to the injectors. I have checked the wires to the distributor and igniter and both are good although the wire to the igniter had a higher resistance I am getting 12v to the injectors and the wire to the ecu is good. the previous had replaced the ecu and he said he scanned the computer codes and it said short or fault in the injector wiring. does anyone here know what else I can check, and if there is a way to check if the ecu is sending the pulse?
 

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On my 86 I found that there was massive corrosion where the splices are to join the injector wiring for 1+3 and 2+4.
 

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Is the bundle of grounds hooked up on the intake manifold? Stupid question but not having them hooked up can cause all kinds of problems.
 

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get the battery ground to the block, battery ground to the fender, then the valve cover to firewall grounds all in good shape, then check the pickup coil in the distributor, get the specs and OHM it out, then wiggle the wires while you are doing the ohm test, that little guy is the cam and crank sensor for that rig, when it goes shithouse the ignitor and ecm dont know what to do. And the pickup coil can go kind of bad and kind of work, if the ohms fluctuate at all, get a new one.
 

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Discussion Starter #7
I checked the resistance of the pickup coil it check good 171 ohms, steady, and it is supposed to be between 140 and 180, I couldn't find the connectors that the 4x4 wire thread was talking about, but I checked the resistance between the injector and the computer and that checked good.
 

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Discussion Starter #9 (Edited)
I just recheked it with a better ground (e01 and e02 pins) and I get a better reading 10.1 volts but it's still not as high as the battery (12.4 volts) I also checked all of the other grounds and I don't get any voltage when I use pin e2 as my ground.
 

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I just recheked it with a better ground (e01 and e02 pins) and I get a better reading 10.1 volts but it's still not as high as the battery (12.4 volts) I also checked all of the other grounds and I don't get any voltage when I use pin e2 as my ground.

check with a manual to see what the values should be, we don't got them all memorized:p
 

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Between intake runners 2 and 3 is suppose to be the grounds for the injectors. It has three wires on a single lug 2 are the main injectors (they are wired in pairs) and one for the cold start.

People often leave that ground off if they take the upper intake plenum loose to get at the injectors.

You can see it on the bolt between the runners on the #3 side.
 

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Discussion Starter #15
after reading the fsm I checked the voltage going into the ecu with it pluged in, and I get 2.3 volts from the main relay and .4 from the battery... but I still get 10.2 volts with it unpluged. anyone have any idea why I would get these readings?
 

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generally if you show high volts with it un plugged and it gets pulled down when plugged in you have a short somewhere.

does the check engine light come on when you key on?
 

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Discussion Starter #17 (Edited)
Sorry I never replied to thisd thred but gnob was right about the short, I ended up finding one going into the fuse box... I'm still confused why the battery voltage would drop, I see why the voltage coming through the fuse would drop but not the battery voltage, anyway the injector problem is fixed now.
 
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