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4.0 Swap: Runs dies and VSS Wiring


ottoparts

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For the folks that have performed a 4.0 swap into their B2. Did you hook the VSS wires to the wiring from the transmission/transfercase or to the wiring coming out of the firewall?
I got my swap done, however it only runs for 30 seconds and then shuts off. Starts right back up, then dies again after 30 seconds. Any ideas?
Swap info: 94 Explorer 4.0, 91 Explorer wire harness, 88 B2.


Thank you
 


ottoparts

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The fix did not have to do with anything for the VSS. However in case you'd like to know what I did there, I wired it to the transmission/transfer case.
The problem was a self induced one. When I installed the Explorer in-tank fuel pump I had to replace the plastic plug on the electrical connection. I had inadvertently switched two wires and had the pump running backwards and not pushing the fuel out. Switched the two wires back around and all is well.
 

Uncle Gump

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So... if that were the case... how in the world did it even run for 30 seconds then die?
 

ottoparts

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So... if that were the case... how in the world did it even run for 30 seconds then die?
HA! I didn't catch that I didn't address that.
The reason it had the ability to run for 20 - 30 seconds is that I still had the in-frame fuel pump in play. I believe that it had enough suction to pull through the in-tank pump enough to fill the lines but couldn't fight the reverse flow of the in-tank pump to keep running. Knowing that I could remove the in-frame pump due to installing the Explorer in-tank pump, I did. Second filter now in place.
This is where I figured out what my issue was. When I removed the in-frame pump and it no longer ran at all. However I could still hear the in-tank pump priming.
Test light, tissue, and in-tank pump out, I was able to figure out the flow was backward son the in-tank pump.
 

Uncle Gump

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That is the common thing to do... replace high pressure frame pump with a filter.

I just transformed my fuel system also. It all went in the trash. High pressure in tank pump... single in line filter... new nylon lines and connectors. Simple... done.

I wasn't sure how to answer your original post when I first looked at it. Then neglected to revisit it. Happy you got it figured out and come back to post about the fix.

Be sure to let us know how you like the 4.0L.
 

jmcfates

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That is the common thing to do... replace high pressure frame pump with a filter.

I just transformed my fuel system also. It all went in the trash. High pressure in tank pump... single in line filter... new nylon lines and connectors. Simple... done.

I wasn't sure how to answer your original post when I first looked at it. Then neglected to revisit it. Happy you got it figured out and come back to post about the fix.

Be sure to let us know how you like the 4.0L.
Hey, I know this is an old post, but I am doing a 4.0 swap into my '85 Bronco II from a '95 explorer. Can I just swap the fuel pump over or am I better off buying a new one?

If buying is better, what recommendations would you have on a good reliable fuel pump?
 
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Uncle Gump

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All auto parts are a crap shoot these days.

As far as using the explorer pump... I'm not sure. I doubt you could swap the entire fuel sender.

I just chose an aftermarket pump... I bought two to have a spare.
 

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All auto parts are a crap shoot these days.

As far as using the explorer pump... I'm not sure. I doubt you could swap the entire fuel sender.

I just chose an aftermarket pump... I bought two to have a spare.
So the stock fuel sender will work with a brand new pump?
 

Uncle Gump

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Yes it will...

20220705_081817.jpg


20220706_090416.jpg


This is just an aftermarket pump... inhad to modify the sender a little.
 

ottoparts

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Thank you Gump for answering him.
I too do not know if a 95 Explorer intank pump would work or not. I used a 93 Explorer intake pump. After wiring correctly, it's been good so far.
 

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