im stuck between fuel injection and carb . im scared of all the wiring involved with fuel injection, if i want to keep my factory 4 speed manuel tranny, tack, air, cruise, how many wires am i going to have to deal with ?, i need some one whos done this to speak up here . ive read all the stuf in alternative fiero and have seen ed parks bit on his 700 doller harness , im shure i can make one but i would like to know what im lookin at . so is it hell or what??

the average person would spend 50+ hours wiring it.

It takes time and accuracy. It is only one wire at a time. AND MUST have Rockcrawls PROM, if not don't!

Pete

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so then a carb mod would be better suted for me than i guess . only does any one know how much loss hp and torque would there be???

I agree with PBJ, don't even attempt it without Rockcrawl's PROM and wiring diagrams.

Good luck!

The wiring need for installing a 4.9 in a Fiero is not as bad (in my opinon) as most of these people make it out to be. I did my wiring harness while the engine was still out of the car. The key to it is to take your time and remember that the wiring harness you are creating is basically the Cadillac hareness with the outputs to the Instrument panel, fuel pump for the Fireo grafted to it. I used extra wire that I just cut off several wrecks at my local Pull-N-Save with crimp type butt splices and shink tube to protect the splices to lengthen wires as needed (because the hareness has to come off the engine from the other side). When I was all done the only wiring problem that I had was getting the VSS circuit working (from Rockcrawl's site). I can not comment on a carbed version, but my Fuel Injected Computer Controlled 4.9 runs great! You will need to get Rockcrawl to reprogram your Memcal pack, if you go with the computer controlled, he is very reasonable and it makes a world of differerence. You should also think about using a 5 Speed tranny instead of the 4 speed unless you plan on using it as drag racer, with a 4 speed you will end up using it like a 3 speed because 1st gear is so low.

Good Luck which ever way you go.

Joe Sokol
85 Se 5 Speed 2.8 V6
88 Formula/GT 5 Speed 4.9 Caddy

If you're afraid of the wiring, or just don't want to do it, Ed Parks sells a pre-fab wiring harness for 4.9 conversions. It's $700, I believe. But consider your time when evaluating that price. If I were doing a 4.9 swap, I'd keep the FI and use Ed's mounts and wiring harness.

Now if someone will only make a prefab harness for 3800SC swaps....

Just a note: people want to go the carb route to avoid the wiring, but you still have to do some wiring with the carb engine. With all points considered you need to splice in almost as many wires with a carb engine as with the fuel injection. Sure the fuel injection has more wires, but most of them you do not need to touch (ex: wiring for the fuel rails, you just leave them as they are, unless you have to lengthen/shorten them - but you will need to identify them). The only real time consuming part is identifying the wires and removing what you dont need (ex: transmission wires if you are going with a standard).

Best thing to do, when you get the motor tag all the plugs before you disconnect them - same for the Fiero motor when you pull it. Take your time and do one wire at a time and you will be fine. There have been enough people on here that have done this swap to ask for help. Maybe someone can take Rockcrawls diagrams in mark/highlight which wires are needed, and highlight in a different color what may be needed depending on your options (Cruise, auto tranny, etc)?

Electric current seems to be a hard thing for people to grasp, but think of as a water hose. The hose is the wire, and the water is the current. You need to water grass in front of your house from the back, you connect the hose in the back and take the other end to the front - same for electric current, you need power/signal from the battery to the light, you connect the battery to the light (one thing to remember is you always need 2 'hoses' to allow the current to flow. A positive and a negative. On a car, the 'negative' is the ground and some parts may be connected to this through the case so there will only be 1 wire (oxygen sensor is an example).

Not sure if that helps or not.

Tim

what im thinking of doing is to go with the carb to start , that way i can do every thing in my shop .then maybe in a year or so i would put in the fuel injection , this way it will breakup the project a bit. another reson i might go this way is that i understand a carbed engen better,,so if i get into running problems it wont be a big deal. one thing im not clear on is that you have to get distibuter parts from an olds to make a disributer for the 4.9,, i understand how to meld everything together to get a working unit, but which olds do you harvest parts from ,, more directly which engen ??? help on this matter would be greatly apreceated!!!!! thanx for your input ,,,every thing helps

ok well im glad you guys put out these responses because this is my dilema too......BUT!!! i read that one of you guys said "mostly to gauges..." or something (cant remember already) what if i am putting in ALL aftermarket gauges?? i wont need any of the wires from the caddy harness for the gauges so will it be pretty easy?? is there an EASY to read diagram for me to look at? i have my fiero harness out and was tempted to sell it cause i was gonna go carbed due to too much wiring, but there are alot of extras you need w/carbed too....... so to get back to the point, if im using ALL aftermarket gauges(custom dash) will the wiring be pretty easy????

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-Bobadoo Funk-

http://bobadoofunk.tripod.com/funksfunkyfiero/index.html

Even with aftermarket guages you still need to connect them up to something

Speedo, tach, oil pressure, temp, etc still need to be wired into the caddy harness at some point.

Tim

For the wiring you are talking about for a carb, and you want to leave the stock wiring harness in, like Oreif described for his 3.4, you just need one hot feed for your electric choke.

The rest doesn't count because the carbed engine doesn't use the computer.

You can rewire, like I am going to do (or more correctly PBJ), or you can just leave the ECM in place like a boat anchor.

I don't subscribe to the school of thought that complicated is better.
I also do not accept the mistaken notion that carbs don't produce torque monsters.

Just ask Master Tuner Akimoto.

I wouldn't hesitate a moment to do the carb. I would most certainly ask Master Tuner what kind of carb is best for the 4.9.

By the way, I have a sweet racing Moroso aircleaner in the Mall. Just what you need.

Arn

quote Originally posted by collinwestphal: the average person would spend 50+ hours wiring it.

I respectfully disagree!

I did my harness in about 30 hours and i knew next to nothing about EFI at the time.

Ed

quote Originally posted by PBJ: It takes time and accuracy. It is only one wire at a time. AND MUST have Rockcrawls PROM, if not don't! Pete

I totally agree with the above statement, When i did my harness
i wound up with three codes on start-up:

1. # 19 Low voltage or short circuit on fuel pump circuit (my bad, i made a wiring mistake)
2. # 47 BCM to ECM (Caddy computer could not "see" Caddy BCM in my Fiero) Jon
erased that one for me.
3. # 52 I don't remember what it is called, but when you disconnect the battery on
a Caddy this code shows up. (my scanner erases that one)

This were the only problems i had with the wiring part of my conversion.
(it was my first time tackling something of this magnitude)

Ed

[This message has been edited by ED's85GT (edited 03-16-2004).]

quote Originally posted by Formula88: If you're afraid of the wiring, or just don't want to do it, Ed Parks sells a pre-fab wiring harness for 4.9 conversions. It's $700, I believe. But consider your time when evaluating that price. If I were doing a 4.9 swap, I'd keep the FI and use Ed's mounts and wiring harness. Now if someone will only make a prefab harness for 3800SC swaps....

If you have the money, and don't have the time that is the way to go, for me it was the
opposite, i had the time but the checking account was low (it allways is)

I'm glad that i tackled my harness, it taught me how to read schematics, how
EFI works and i feel very confident that i will be able to properly troubleshoot
my EFI instead of guessing and or throwing parts/money at it when the need arises.
Plus i'm very competent(sp) with a soldering iron now.

Ed

so uh which olds did you get your distributer from??

quote Originally posted by Mickey_Moose: Even with aftermarket guages you still need to connect them up to something Speedo, tach, oil pressure, temp, etc still need to be wired into the caddy harness at some point. Tim

actually i already have aftermarket speedo and tach that dont touch the rest of the wiring harness (digital if that helps)i dont think ANY of the gauges im gettin will need to go into the caddy harness..........so if i just leave the caddy harness on the engine and correctly wire it to the PROM + ECM ill be ok? (of course ill use rockcrawls chip!)
it wont be too bad will it? im just a backyard mechanic (but took mechanics and electronics and may switch schools to major in automechanics..) but my skills aren't great..id say a little above average so will the wiring be that bad?

well, im gonna do the PFI on my 4.9 swap. i cant believe that it is that hard to sort thru 20 odd wires (at the most). all of the descriptions/directions of the harness makeup seem to me to be convoluted - i guess because the writers already know what they are doing - can anybody write harness buildup for dummies (me)? i guess this is also complicated by the prediliction of the carmakers to change things all the time - arent there several colors of wires in the various years/models of fiero wiring harnesses? there are at least 3 or4 different color codes for the caddy wiring harnesses. lets see that makes between 9 and 16 permutations for donor/donee harness buildups. i am going to buy the haynes manuel and begin studying the caddy diagrams as i cant seem to make heads or tails out of bubbajoes or rockcrawls - remember im a dummy!

still, even with the problems, it seems a lot easier than modifying a distributor and plugging the holes in the fuel rail! and what power to understand the electronics of the chosen motor in ones favorite ride! i already feel enormously empowered by the good folks on this forum helping me get my long dormant fiero on the road again - and now to drop the cradle to replace the throwout bearing - what would this cost for a mechanic to do it? a LOT! seems to me that this 4.9 engine swap and wiring harness will just be more empowerment over ones ride (and by extension other cars that one might own). power to the fiero owners (in more ways than one)!

the thing i fear most is my soldering (in)ability - i have a LONG history of soldering failures - when i tried to solder my extended cables for my front battery relocation, i discovered that there was some sort of crud on the outside of the wires - and stripping them farther back didnt help - ever try to solder crud?

jon
thanks for also suggesting that we consider this basically as the caddy engine harness (with a few fiero wires soldered in) - that is what i had concluded

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Im the original owner of a white 84 2M4 purchased Dec 10, 1983. "It is better to remain quiet and have people think you are a fool, than to speak and remove all doubt" - Abe Lincoln

The wiring is very very easy, If you can read a diagram or read then the wiring will be easy, It's time consuming but easy. And to the person that said ppl avoid the PFI because afraid of wires, That is not the case with me I chose carb because that's what I wanted With no emmesion laws in florida I wanted the carb, In my opinion I always liked how the carb setups looked and the aftermarket for carb holley ect.

The only disavantage to carb is having to wait for the motor to warm up But I can live with a 18 second deley in going were I have to go to do the setup I liked.

Anyway I liked the carb setup sooo much I gave away my PFI crap

But in my opinion doing the wiring yourself will save you the price of buying a carb.

For the dist setup with the carb do not use the 4.9 dist but infact you go to a 4.5 or 4.1 dist then you need the internals from a late 70s to early 80s olds

How to tell if you got the wrong one or right one The olds motor has the dist on the right side of the cam as you are standingin front of the car.
The chev motor has the dist on the left side of the cam as you are standing in front of the car.

Another way to tell the difference (maybe easier) is that Chevrolet distribuitors turn
clockwise where the olds dist turns counterclockwise.

You will know quick if you have the wrong one sure it will rev fine and all but when you decide to put it in gear your dead in the water

[This message has been edited by 86fieroEarl (edited 03-17-2004).]

A lot of it depends on what you want to do. In some cases you are not able to alter it due to sniffer laws. I will be doing carb for 1 main reason, I HATE Computers in Cars!!! I can live with Electronic Ignition boxes but not the full ECM. I hate the empty wallet light! Plus it will be much simpler for me to run 5 or 6 wires to my new gauges in my custom dash. Plus I wanted less clutter.

Point is You need to do what You want to and drive on.

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http://home.cfl.rr.com/fierose
Central Florida Fieroshttp://www.centralfloridafieros.com

BobadooFunk: Guages: the tach still gets connected to the caddy motor, as does the temp and oil guages.

longjonsilver: the Haynes manual that I have seen is not very good for the diagrams - all you really need is what is on Rockcrawls site. The ECM pinout diagrams tells you what each pin is on each connector, the other diagrams just kind of show you how it's hooked up. For the most part you do not need touch the needed wires on the caddy harness. All that is needed is to identify which wires to keep and which ones you need to splice into the Fiero C203 and C500 harness. The rest of the wires in the caddy harness can be removed from the plugs or just left there (ex: cooling fan relay #2 pin B8 can be removed as you only use the one fan output). BTW, I would not rely on wire colors, the ECM connectors are marked to which one they are as well as the pin numbers.

Soldering: best way: heat the wire from the 'bottom' and touch the solder to the 'top' of the wire. The solder will melt into the wire once it reaches the correct temp. This method allows the solder to flow into the wire and make a good connection vs solder just the outside layer of the wires. If done correctly you should still be able to see the strands of wires in the solder. For dirty wire, use a brass brush to clean it. Strip off the insulation for what you need, lay the strands on a block of wood (or an hard surface that you don't mind scratching) and 'brush' them out towards the end of the wire (only go the one direction), turning the wire as you go. Solder paste will also work, but you usually need a fair amount of it and lots heat to clean the wire strands.

Tim