4wd help!!
01-17-2018, 08:27 PM
#21
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Thank you for the input. I will def disconnect and see what happens. It def seems like shifting transfer case lever to 4hi sends message to ecu which in turn drops rpm and then does something to cut fuel delivery upon throttle or erratic throttle. I noticed my dash pot is pretty suspect not sure if any of this operates differently in 4wd, like tps sensor or the like??
01-18-2018, 07:27 AM
#23
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No, it's not normal. With a manual transmission vehicle, there is no connection between the engine computer and the 4wd system - the ECU does not (or should not) know whether you are in 2wd or 4wd. If you are getting idle speed changes when you shift to 4wd, there is an illegitimate cross-connection; either messed up wiring or vacuum lines gone astray.
I may have posted this before in this thread, but if not, attached is the entire 4wd management wiring diagram. As you can see, it's pretty simple.
I may have posted this before in this thread, but if not, attached is the entire 4wd management wiring diagram. As you can see, it's pretty simple.
01-18-2018, 05:23 PM
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Awesome! I think I’m slowly getting somewhere. I disconnected the switch at the transfer case and all is good. I switch to 4hi and no change in idle and acceleration is normal. I am starting to rule out vacuum lines because I replaced the ADD lines all of them and triple checked the connections. It def engages 4wd with light on dash and all but the crazy surging is present. I am tempted to just do the ADD delete and leave transfer case switch disconnected so I have proper 4wd without issue but I would really like to try and diagnose this issue. Thank you for your help!!
01-19-2018, 08:05 PM
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No, it's not normal. With a manual transmission vehicle, there is no connection between the engine computer and the 4wd system - the ECU does not (or should not) know whether you are in 2wd or 4wd. If you are getting idle speed changes when you shift to 4wd, there is an illegitimate cross-connection; either messed up wiring or vacuum lines gone astray.
I may have posted this before in this thread, but if not, attached is the entire 4wd management wiring diagram. As you can see, it's pretty simple.
I may have posted this before in this thread, but if not, attached is the entire 4wd management wiring diagram. As you can see, it's pretty simple.
So I am thinking that it could be my relay? Even though I here it clicking and the 4wd engages could it still be faulty creating electrical issues?
01-19-2018, 08:06 PM
#26
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No, it's not normal. With a manual transmission vehicle, there is no connection between the engine computer and the 4wd system - the ECU does not (or should not) know whether you are in 2wd or 4wd. If you are getting idle speed changes when you shift to 4wd, there is an illegitimate cross-connection; either messed up wiring or vacuum lines gone astray.
I may have posted this before in this thread, but if not, attached is the entire 4wd management wiring diagram. As you can see, it's pretty simple.
I may have posted this before in this thread, but if not, attached is the entire 4wd management wiring diagram. As you can see, it's pretty simple.
So I am thinking that it could be my relay? Even though I here it clicking and the 4wd engages could it still be faulty creating electrical issues?
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