3FE to 5.3 in 1992 FJ80 Build thread (4 Viewers)

thatcabledude

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Nice! Yeah I am planning on using the stock pump if it proves up to the task. My 5.3 is set up with injectors that are in the 38psi range and my pump is pretty new. Figured I’d just send it.
Gauges, I am using a Dakota digital obd 2 for the tach signal and check engine light (admittedly I haven’t got the check engine circuit fully sorted yet). Oil sendor from the 3fe adapted to the LS, most other sensors are similar. Speedo is driven off the transfer output shaft. Other things like gear selector lights will be addressed using the original neutral safety switch in parallel to Gm one.
The check engine light couldn’t be easier. The wire for the CEL from the GM ECM just needed spliced to the single wire that goes to the bulb in the cluster.
 

masong

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The check engine light couldn’t be easier. The wire for the CEL from the GM ECM just needed spliced to the single wire that goes to the bulb in the cluster.
And that's it? No resistor or anything? I guess I was confused as that light is powered from two sources. One from the EFI main fuse and the other from the ecu, but I guess the EFI main is not in operation now anyway... Its been a minute since I was reading that schematic, I guess can get back to it soon now that mounts and stuff are in...
 

thatcabledude

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And that's it? No resistor or anything? I guess I was confused as that light is powered from two sources. One from the EFI main fuse and the other from the ecu, but I guess the EFI main is not in operation now anyway... Its been a minute since I was reading that schematic, I guess can get back to it soon now that mounts and stuff are in...
I just realized you removed a 3fe. I have ZERO knowledge of any 3fe specific factory harness, but I doubt the check engine light is any different.

With the 1fz, I interfaced everything that needed interfacing (cluster wise) at the connectors behind the glovebox. Including the CEL.
 

masong

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I just realized you removed a 3fe. I have ZERO knowledge of any 3fe specific factory harness, but I doubt the check engine light is any different.

With the 1fz, I interfaced everything that needed interfacing (cluster wise) at the connectors behind the glovebox. Including the CEL.
That’s where my connections are too and I have that CEL wire located, I’m excited to get to the point where I’m back to figuring out wiring.
 

masong

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Update. Wound up swapping out the muscle car oil pan for the Camaro oil pan.
Per recommendations here I sourced some firewall insulation. I chose some ceramic embedded paint that is supposed to reduce heat transfer, claims up to 30% reduction. Also got a transfer case attached to the transmission and it’s all in the truck. Which is pretty dang cool. Stoked.
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Stock check engine light is grounded, not powered, by the ecu. If the gm ecu is also designed to ground the cel then you're good to go, otherwise you simply add a relay to flip the signal
 
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Thatcabledude gave some good advice in using the Gen IV waterpump as the water neck is a short straight stub and won't interfere much with the intake piping. I just swapped mine out. Swapping from a 3fe as well, mine is a 91. If you do decide to run the Gen IV waterpump, get the thermostat housing and thermostat. I thought the Gen III housing would fit but it doesn't, as well as the thermostat... different size.
 
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Nice! Yeah I am planning on using the stock pump if it proves up to the task. My 5.3 is set up with injectors that are in the 38psi range and my pump is pretty new. Figured I’d just send it.
Gauges, I am using a Dakota digital obd 2 for the tach signal and check engine light (admittedly I haven’t got the check engine circuit fully sorted yet). Oil sendor from the 3fe adapted to the LS, most other sensors are similar. Speedo is driven off the transfer output shaft. Other things like gear selector lights will be addressed using the original neutral safety switch in parallel to Gm one.

I haven't seen anyone yet make the 91/92 tacho's work... they all had to find one from a 93-97. Some thing about it sends out a different signal than the 93-97.
 

masong

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Thatcabledude gave some good advice in using the Gen IV waterpump as the water neck is a short straight stub and won't interfere much with the intake piping. I just swapped mine out. Swapping from a 3fe as well, mine is a 91. If you do decide to run the Gen IV waterpump, get the thermostat housing and thermostat. I thought the Gen III housing would fit but it doesn't, as well as the thermostat... different size.
Good tip on the water pump.
 

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