Under hood MPI relay?

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jeffball610
Too Much Time on His Hands
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Joined: Wed Feb 22, 2006 5:29 am
Location: Las Vegas, NV

Under hood MPI relay?

Post by jeffball610 »

I'm just about done with my wiring and I'm trying to decide where to put the MPI relay at. There is no real reason for me to run it under the dash like the stock unit. However, I'm sure it's there for a reason.

Is this unit heat sensitive enough to keep it out of the engine bay? There's no real reason for me wanting to put this in the engine bay other than to keep things clean. Running it in the cabin would require me to run a couple wires away from the main harness to the MPI relay and then to the ECU. Putting it in the cabin will only require me to run one wire back to the engine bay for the starter relay.

Any thoughts on this?

I'll post pics of my wiring harness when I'm satisfied with it. I've eliminated a ton of the wire lengths and about 30% of the wires from the ECU for non-essential stuff. I've also hidden most of it under the intake manifold and along the firewall to keep it clean. We'll see if it works.
Do it in a Datsun!
1972 Datsun 510
7-bolt 4G63T, EVO 9 pistons and rods, Garrett GT3076R, "flipped" stock intake, Toyota R154, Z31 R200 w/ CVs
Bill Hincher
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Post by Bill Hincher »

no reason at all to put it under the dash, 300zx are under the hood
just pay close attention to wire sizing, because the pump will draw a lot of amps
screemin eagle
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Post by screemin eagle »

no electronics like heat. on top of that its mitsu so i would try to keep it as dry and cool as possible. why not just mount it right by the ecu?
88 conquest 4g63 now sporting a crankwalked boat anchor
jeffball610
Too Much Time on His Hands
Posts: 619
Joined: Wed Feb 22, 2006 5:29 am
Location: Las Vegas, NV

Post by jeffball610 »

I figured the heat and possible water might be an issue. I think I will try to make a small bracket and mount it on the ECU itself to keep the wires short and clean. Also, since I have my ECU mounted on the driver's side, I can run my fuel pump wires etc. along that side to keep it nice and neat.

Hopefully I'll have the majority of the wiring done by the weekend to show everyone my progress. I'll still have all of the chassis wiring to do and I'm still trying to figure out a better fuse box situation. The stock 510 uses glass fuses and the Mitsu stuff is difficult to remove the wires from the block. I'll see what I come up with.

Anyone know of an easy fuse block to convert over?
Do it in a Datsun!
1972 Datsun 510
7-bolt 4G63T, EVO 9 pistons and rods, Garrett GT3076R, "flipped" stock intake, Toyota R154, Z31 R200 w/ CVs
Bill Hincher
Donating Member
Posts: 1625
Joined: Thu Jun 22, 2006 8:57 pm
Location: Toledo,Ohio
Contact:

Post by Bill Hincher »

I like to use a 1974-79 Honda Civic fuse block, I hope they are still out there, they have ten fuses and are in a self contained box and make a very clean install

If you cant find that, fuse boxes are available at radio shack
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