Timing retards briefly before advancing 95 3-VZE
09-24-2020, 10:53 AM
#1
Timing retards briefly before advancing 95 3-VZE
I just put my 3VZE back in my 95 4runner after a several-months-in-my-spare-time head gasket replacement. All back together but when I hit throttle, ignition timing retards (maybe 20 degrees or more) for a couple of sparks before reverting to its normally expected advanced state. There are no vacuum lines to distributor (all ECM). I am clueless. Any ideas?
09-27-2020, 06:29 AM
#4
I may have discovered the problem. There is a sensor (switch?) beside the temp sending unit that got snapped off. I don't even know what it is, but the only available candidate at the junkyard had the same sensor snapped off also.
Edit: Cold start injector time switch (Cold start module)... An expensive mofugger!
Edit: Cold start injector time switch (Cold start module)... An expensive mofugger!
Last edited by Simianalien; 09-27-2020 at 11:58 AM.
09-27-2020, 11:39 AM
#5
Registered User
A picture would help us identify it for you. It seems like most, if not all, of the sensors can be had online, from what I've seen.
It sounds to me, for whatever that's worth, like it might be the temperature sensor that sends the information to the ECU. If that's the case, the ECU is not getting any information about the engine's temp, so it's making an assumption as what the temp might be. I can't say, if that's the case, whether the ECU is assuming a warmed up, too hot, or completely cold, condition, But whatever it is using for the default temp is obviously wrong. That may be where the hesitation in advancing the timing is coming from. Maybe. I may be way off in left field, though. Can you find it in the FSM? It has to be in "The Book" someplace
Once you get it pulled, btw, make sure the threads it screws into are clean. They frequently develop a good layer of differential metal corrosion on them. Often, they provide the ground for that circuit, whatever it may be. The cleaner they are the better. Do NO use teflon tape to seal it, either. It has to have a good metal-to-metal contact to work properly.
I'm probably wrong, but I thought it was worth a shot...
Pat☺
It sounds to me, for whatever that's worth, like it might be the temperature sensor that sends the information to the ECU. If that's the case, the ECU is not getting any information about the engine's temp, so it's making an assumption as what the temp might be. I can't say, if that's the case, whether the ECU is assuming a warmed up, too hot, or completely cold, condition, But whatever it is using for the default temp is obviously wrong. That may be where the hesitation in advancing the timing is coming from. Maybe. I may be way off in left field, though. Can you find it in the FSM? It has to be in "The Book" someplace
Once you get it pulled, btw, make sure the threads it screws into are clean. They frequently develop a good layer of differential metal corrosion on them. Often, they provide the ground for that circuit, whatever it may be. The cleaner they are the better. Do NO use teflon tape to seal it, either. It has to have a good metal-to-metal contact to work properly.
I'm probably wrong, but I thought it was worth a shot...
Pat☺
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Simianalien (09-27-2020)
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