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.

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.

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

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.

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

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.

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

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.

Sounds simple enough.. Can i just run that fused power wire off the stud on the alternator or will I run into an issue? I guess i could use the starter too but i'd rather not. Im using the 2 heavy gauge wire positive battery terminal wire off the cadillac

It looks that I have it wired up correctly except for the fact that the ICM clicks a bunch when I turn the key on and off

The wire that supplied hot at all times battery power to the Fiero ECM already runs from the junction block by the right strut tower to the stock ECM location. Don't dork with it, just connect it to the hot at all times input on the Caddy PCM.

i dont have that wire or the junction block. 84s didnt have them as far as i can find

The '85 and later cars had the C500 in front of the right strut tower right next to the junction block. '84's had the C500 in the middle of the firewall... not sure where their junction blocks were.

A two speed fan was optional on the '88 four cylinder cars. Every other Fiero had a single speed fan. I think I hooked mine up to the low speed fan output on the Caddy.

hmm yeah im stuck on getting the fan to turn on. As far as I have read the 84s have a 2speed fan if they have AC which mine does. just not sure how they wire up or if mine even works. hunting for a diagram right now

I suspect that you have two fan relays: one for the low side and one for the high side of your 84 coolant fan. You can probably run your ECU high and low fan wires to each appropriate relay. Both need to be hooked up or you will throw a code.

Say you only use the high side like I did (one speed fan). You will have to plumb in an extra relay for the low side wire so your computer won't throw a code.

got the cooling fan deal figured out. After decoding the fan wiring diagram here:https://images.fiero.nl/pffimages2/84fanground.JPG I finally understood the relay was bad. luckily I had snagged one off my other 84 a while back and just had it sitting in this car. I guess they are hard to find. Set it up to use the caddy low and high speed fan controls. now i just have to wrap it up, try to make it look nice, and add coolant

quote Originally posted by mcfrandon: what are you guys doing for the park/neutral ecu pin

I addressed that by not running the Caddy computer.

what are you using? the shelby computer you mentioned?

I have been driving this thing for a few days now. pretty sure i forgot to mention that. Having tons of fun and just working on the little things.

Got the ebrake to work again, headlights, hvac, but im still working on the wipers. they seem to blow a fuse every time i try them. None of these things were working when i got it so it's came a long way.

I need to get an exhaust on it, just waiting till i get back from vacation. doesn't seem to be a lot of room with the factory northstar manifold/crossover

That must be loud without the exhaust. I'd get pulled over here in Oregon for that. Oregon is getting a lot tougher in the Portland metro area.

What clutch and flywheel did you end up using?

yeah I had a cop behind me for a block or 2 at 10pm and he didn't seem to mind. then again it just looks like a pos right now. Sounds good tho anyways. Nice low rumble at idle and smoothes out real nice after a couple thousand rpms.

That reminds me last time i was in portland I passed a pretty cool fiero, it was 2 colors i think like an orange and green or something. 2 bright colors.

I went with the spec flywheel and stage 2 plus clutch or maybe stage 3 plus. can't remember right now. Either way looking at those clutches it seems the "plus" versions are the way to go.

By the way, could you summarize how you finalized your OBD1 Computer regarding: VATS, VSS, ABS and what you did for the automatic tranny outputs?

Well thats still in progress kinda. I think its running in full power mode, im sure i would notice if it wasnt.

VATS: used ebay 50hz circuit
VSS: I just t'd into it, works find and don't have to mess with the speedo
ABS: nothing done... yet? not sure thats an issue or not
Auto tranny: no wires hooked up except the park/neutral wire which doesn't seem to effect anything if its unplugged or not.. revs 6k either way.
Tach: used potentiometer and did not cut any wires or traces.

Im having trouble with the ISCV motor clicking. I have taken it apart and lubricated it and tried to set the gap and such but it doesn't set properly or atleast the way I want. If I set it up so it will stop clicking (adjusted out, throttle plate more open), it won't drop rpm right away on clutch in or when shifting. If i screw the adjustment bolt all the way in so it is as short as possible, it will run exactly the way it should, but will click when the key is turned on or off. So this could be one of the auto tranny issues, but i really dont think so. I think I might have a bad throttle position sensor and it just isn't reading correctly, but i dont know if the ISC motor and the TP sensor communicate but it almost seems like they would have to. Or i guess i could have a bad ISCM. I have one of each lying around so I will try both when I get back from cali and check the wiring.

Thanks for your kind reply, eh.

Im probably going to send the PCM to Wester's Garage unless I can figure something out. Howell won't get back to me. Westers said they could delete all the CEL codes except the engine related ones and basically make it run as a standalone. I just wish there was some way I could read the CEL without having the caddy information center. Or build a CEL reader by using one from pick n pull or something.

What I read is that this pcm has 2 separate processors, one for engine and one for transmission. Unlike the obd2 which is built together as one. They probably check each other but it doesn't seem like they rely on each other to run properly.

I have a Howell chip in my OBD1 computer for my next N* swap. I just sent my chip assembly in and they sent it back with a new reprogrammed one. They were fast. Did you talk to them on the phone or send an e-mail? E-mails were slow. Phone is fast. Tell them you are sending them your chip. Then mail it with instructions regarding what your configuration is.

Wester's can do it but its $45 a crack everytime you ship a computer over the border.

I was emailing them. He was saying the one I have would be very difficult to modify, and never got back to me..

I picked up a 94 seville instrument cluster the other day. hoping I can wire it to display codes. maybe its far fetched maybe not. I need to find a wiring diagram first, kinda excited

quote Originally posted by mcfrandon: I picked up a 94 seville instrument cluster the other day. hoping I can wire it to display codes. maybe its far fetched maybe not. I need to find a wiring diagram first, kinda excited

It is no problem to do I wired mine up to do the same, I'm sure many other have done same thing to retrieve codes..

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87GTseries 1 3800sc (7.597 @88.53 1.579 60ft)
(series II swap in progress)
85GT Northstar/ 4t80e
86GT 3800 n/a---sold
Northstar Rebuild

quote Originally posted by mcfrandon: what are you using? the shelby computer you mentioned?

Correct. I ran the OBDI computer with a special chip for several years. The Shelby just runs better, and is tunable so that it can grow with the engine as I add mods.

is the shelby obd2? do you have to change the manifold to the newer one?

LS1/Shelby is OBD2. It requires 1995 to 1999 throttle body assembly with the newer style IAC stuff.

1994 has a unique intake manifold.

bad and good news guys... bad news is that i found out yesterday when i was installing my new hood that the Left front of the car had been in an accident and the frame was bent. Good news is i picked up an 87GT fastback today. So i will be transferring the power plant

ok i picked up a 1998 seville intake with sensors and ECU for the OBD2 conversion. now will i actually need a ls1 computer or can i write the same software or edit the parameters on this brain box? getting ready to pull the engine out of the 84 and put it in the 87. thinking about doing cams and springs while its out if im going to run the custom tune

update ordered an LS1 computer tuned for high octane and setup for the northstar conversion. very excited. Taking time to rebuild the 2 motor mounts i made seeing that the one i used for the front completely tore allowing the engine to punch a huge dent into the trunk wall of the old car LOL. also had to rebuild some of the rear motor mount because it was in the way of the exhaust which i hadn't really thought about. Also having quite the fun time trying to find a muffler that will fit that area and have the right size piping to flow well. The local exhaust shop is recommending an old style camaro muffler in either a flowmaster or magnaflow. The magnaflow looks to be super long and probably wont fit but i don't really want to go with the flowmaster since its baffled. Guess i will keep looking around. Im really not looking for anything loud or that "oldschool V8 sound"

also built a solid dogbone that connects the left cylinder head to the subframe to help with the engine movement.

Overall i think im pretty lucky to be swapping this a second time since i learned so much the first time. Seems like the 87 is going to be a cleaner swap since it already has a good space for a larger intake tube, the coolant heater core routing is one hose instead of 2, and getting the AC hooked up will be 10x easier and out of the way. Besides all that, everything on this car works already! I did buy a getrag shift cable from rodney and i will say it sure is quality as well as the shifter rebuild kit which was much needed!

You will like the LS1 computer and the flexibility it gives you with HP Tuners, etc....

You might want to consider using 4 engine mounts: two forward, two back. I have 4 engine mounts on both the 88 GT manual 5 speed, 85GT automatic and the 88 Coupe N* swaps. No movement or vibration using poly. I have dodge 318 rubber on the 85GT and its fine also. I do have a doggone strut on the manual 5 speed swap but I came to realize that it isn't necessary.

If your cutting the trunk out, then you can use a truck muffler from an older GM 350 pickup. Its very quiet until you open it up. For the full size trunk (not cutting it out) on the 5 speed N*, I used an 80 series flow master. However, everyone loves the sound, but its too loud for my liking. But, loud is fun.

Your 87 has a little more room between the strut tower and the head.

Looking forward to hearing more...pics...pics...pics!

The strut towers are further apart on the 87? Thats good news if so! Ill get around to posting some picks soon, i just got a new phone and haven't had my laptop that runs windows to get the program running. As far as mounts go yours sure do look a heck of a lot better than mine. I pretty well got them set up now. I used an older jeep cherokee engine mount that should actually hold up and they make poly aftermarket ones if there is any issues there.

Also looks like i took a lot more out of the passenger side of the subframe than most people, but i was paranoid about it sitting flush/parallel with the trunk rail when looking at it from the back.

Great news the ECU showed up today so im very excited for that. I did buy a muffler part number 12158 magnaflow. should be able to fit in the stock location with a 14" body. id like to keep all of my trunk. I think the flowmaster would definitely be too loud for me and i really didnt want anything with baffles

lots of updates to post and took some pictures i can post tomorrow. Im currently stuck on something unexpected with the intake manifold swap... i was installing the new gasket for the obd2 intake and realized there will be nothing covering the old slits in each cylinder head intake port for the EGR system on the 94. looks like i will have to plug it and seal it somehow but im also concerned with this type of newer gasket and the fact that it will only be using 2 bolts per side instead of 5. just another bump in the road i guess