84 fieor-- 94 N* swap (Page 13/24)
Will FEB 11, 09:35 PM

quote
Originally posted by mcfrandon:

okay all I have left is the wiring and coolant lines. How are you guys running the temperature gauge? Do you use the fiero sensor and wiring and just install it into the water crossover?



I use the 3 pin CTS that includes a gauge sender in the same housing as the ECM sensor.
Will FEB 11, 09:42 PM

quote
Originally posted by mcfrandon:
there is a little cannister valve on what looks to be like vacuum hose coming out from below where the shift linkage cables come out, that looks like its for the brake booster right so just connect to engine vacuum aka that large metal hose coming out by the fuel lines? correct?



There is a vacuum hard line on the firewall near where the shift and throttle cables come through. This does go to the brake booster. I don't know about any "canister valve" there.


quote
Originally posted by mcfrandon:
I can't seem to find a good wiring diagram for the 84 engine harness. Can i connect the N* coil pack tach signal to the fiero tach input, if so any info on what that wire looks like would be great.



The 3 pin connector for the coil pack is power, ground and tach. You can hook that wire up to the tach, but the 4 cylinder tach will read twice the RPM the engine's actually turning. I don't remember if the OBDI ECM has its own tach output or not.


quote
Originally posted by mcfrandon:
Any Info on the coolant routing would be helpful. I have the left side coolant tube going to the thermostat. right side to the larger connection right above that. I need to find out which coolant ports on the water crossover and water pump housing go to the surge tank and heater core inlets. Im not sure which ones are feed and return.



You have the coolant plumbing backwards.

The thermostat is on the waterpump, retained by a 1.5" steel nipple that bolts on. Connect this to the RIGHT coolant tube.

The engine coolant outlet is the upper coolant connection on the engine. It is 1.25". Use an inline filler neck and connect it to the LEFT coolant pipe.

I can look at my heater hose routing tomorrow.

[This message has been edited by Will (edited 02-11-2015).]

IXSLR8 FEB 12, 02:34 AM
I'm using a 1998 pontiac grand prix water temp sensor (with the three pins). One wire goes to the fiero temp gauge in the gauge pod and the other two wires go to the stock caddy coolant wires. It is mounted in the cadillac water temp hole in the side of the head.

I'm also running an aftermarket mechanical coolant gauge. I threaded the coolant part of the water log by the water pump belt.
IXSLR8 FEB 12, 02:37 AM
The canister thing may be a check valve or a filter for the vacuum line going to the brake booster.
Bloozberry FEB 12, 06:44 AM
It is a check valve to protect the brake booster from over-pressure in the event of a backfire through the intake.
fieroguru FEB 12, 09:15 AM

quote
Originally posted by Bloozberry:

It is a check valve to protect the brake booster from over-pressure in the event of a backfire through the intake.



Or is it so the brake booster retains vacuum while the engine is at WOT or once the engine stalls? The same check valve orientation could do both (maintain vacuum and protect from a backfire), but I think its more important to keep power brakes at WOT and during an engine stall.

Also the cylindrical canister at the firewall isn't on the 88's.
mcfrandon FEB 12, 12:34 PM
thanks for all the speedy info guys

going to pick up the coolant sensor and pigtail today. Looks like autozone has them both in stock: TU178 and 417.

also going to pick up some hoses for coolant and vacuum.

Some questions on the N* wiring... Do I need to have the extended brake switch jumped to B+ or leave disconnected

Do I need to have the oil level switch, fuel pump feedback or power steering switch jumped to B+

Are you guys using the stock fuel pump wiring or going the hotwire route
IXSLR8 FEB 12, 03:09 PM
I didn't use the oil level switch, fuel pump feedback or power steering switch.

I used stock fuel pump wiring with Holley racing fuel pumps in both of my N*'s. It would be better to use 12v direct for more power to the pump under load if you plan to have spirited driving/racing.
mcfrandon FEB 12, 08:50 PM
ok so I got it fired up again so i can start tucking the wires and getting the last few things in there.

On the middle connector there a connection that says fused to battery connection so I would assume that is for power, some idle and fuel trim memory, but if i have that hooked up directly to the battery (fused) then it won't shut off till i disconnect that one.

On the fuel pump can i just use a fused 12v ignition power to it? Or do i need to add a relay for some reason like the "hotwire" shows, because right now its 12v ignition fused
Will FEB 13, 10:16 PM
There is a wire in the Fiero harness that goes from the battery junction block directly to the ECM. swap the fusible link out for a fuse and connect that wire to the hot at all times pin of the Caddy computer.

Connect the wires that powered the Fiero ECM in run, bulb test and start to the corresponding inputs of the Caddy computer.
It's that simple.

There's no reason to run the fuel pump any way other than the way GM did it. The only change you should have to make to that circuit is to connect it to the Caddy PCM instead of the Fiero ECM.