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Discussion Starter #1
i cannot find the box were to jump the wires to do a correct timing check on an 86 4runner with FI. It says to jump the T3 terminal on the hood, and in haynes reapir manual it says to jump from a connector. i have looked high and low and cannot find it any where please help.
 

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Trailer Trash Engineer
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It's a little box, should be attatched to the side of the fuse box in the engine bay. It's about 3/4" by 1 1/2" or so with a flip cover. At least that's where it is on my 87 truck.
 

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'20 gray crewcab 4x4; sold '09 access cab 4x4, '94 T100 4x4, '85 4x4, '82 2x4 pickup
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How about some education for a dummy? I don't understand why it should be necessary to do anything different for an ignition timing check on an EFI engine than on a carbureted one. I recall seeing instructions in a shop manual, but no explanation.
 

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reb said:
How about some education for a dummy? I don't understand why it should be necessary to do anything different for an ignition timing check on an EFI engine than on a carbureted one. I recall seeing instructions in a shop manual, but no explanation.
The reason for the need to disable the automatic ignition timing on EFI vehicles is that computer control has led to far better optimum performance. In other words, a modern EFI engine can vary things like ignition timing thousands of times per second.

I had the joy of setting the timing on my old ass Toyota Camry with a 3sfe engine. Without diabling the electronic spark control, the timing bounced all over the place! As much as 4 degrees or so. I set the timing to the "specs" by my eyes...and ended up with a slug of an engine!

Timing the engine with the proper terminals shorted with a paper clip made the crank-flash of the timing light ROCK SOLID!! NO bounce, NO guessing! The process of turning the distributor to set the ignition timing was awesomely easy.
 

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'20 gray crewcab 4x4; sold '09 access cab 4x4, '94 T100 4x4, '85 4x4, '82 2x4 pickup
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Thanx, Rycam. That makes sense.
 
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