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Discussion Starter #1
Hey all,

I recently did an engine swap on my '88 toyota 4runner v6, and I'm having an issue where the injectors won't fire.
They're getting power and the local ground is grounded. The EFI fuse isn't blown and when I grounded one connector directly (to the battery) all the injectors fired, so that was fine. The issue is that the injectors aren't being grounded at all, no cycles or anything, and I can't figure out why. Any thoughts?

Much appreciated.
 

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Discussion Starter #2
Also, the EFI relay is working and the only codes I'm getting are 41 and 51, both of which have to do with the TPS.
 

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rock crawler
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OK, what year V6 was the new engine and what vehicle did it come from ?
 

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Discussion Starter #4 (Edited)
The new engine is also from an 4runner 3vze from Japan, year unknown, but I'm running the old injectors and connectors on it.

A lot of people mention to check the wire splices, specifically the crimps for corrosion, but that wasn't the issue as mine were totally fine. I've gone through all the relays and grounds to make sure they're working, but I can't shake the feeling that I'm missing something. At this point though I'm at a loss. I'm resorting to trying a new ECU tomorrow. All thoughts are super appreciated!
 

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Discussion Starter #5
Hi all. So here's what I've looked at so far...

1) I pulled my harness apart and found the crimps to the ground side of each bank. They all look fantastic, doesn't appear to be an issue.
2) I removed and sanded down the ground connection to the rear of the lower intake, the upper intake, the ignitor and the driver side fender/exhaust manifold. All look good and check out with ohm meter.
3) I took the computer out and inspected the pc board to see if there were obvious signs of trauma (burned spots, smell of magic smoke, etc). It was clean and looked good (I know this isn't a great validation of the health of the ECU but it is all I can do for now).
4) I've swapped every sensor from my old engine to the new engine (including the distributor).
5) I've checked every fuse in the drivers side kick panel with an ohm meter - all good
6) I'm running the factory harness and injectors.
7) I ran a ground from the battery to the ECU case.

Here are my observations:
1) I get a quick pulse from the cold start injector when I first crank the engine.
2) I don't get any modulation on the injector harness while cranking. 12 volts to both sides only. When in the complete dark I can see a super faint pulse of the light, not sure what to make of that.
3) I'm not getting any relevant codes from the ECU.
4) I'm getting good spark from the distributor.

I'm going to buy a new ECU tomorrow and hope that it solves my problem. The engine ran before it blew (300k, bottom end died) and although it has been sitting for a good 9 months, I have a hard time believing it just died. So I don't expect that the new computer will solve my issues. If it does solve my issue I'm worried that I don't know what killed the computer in the first place and I'm doomed to kill the new one as well.

Questions:
1) Are there more fuses I should check other than the ones on the driver side kick panel?
2) What tells the computer to fire the injectors? Ignitor? The tests I've run say it is functioning but I'm not sure the tests have been effective.
3) What am I missing?

I feel like my issue is a) my computer thinks it is grounding out the connections to the injectors but it's ground source doesn't exist so nothing is grounding or b) my computer isn't even trying to ground my injectors (which makes me think there would be some codes explaining why or c) my computer is fried (hard to believe...).

Thanks all for your help - I really appreciate it. I need to get my truck back on the road, I start a new job next week and need this thing to be running!!
 
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