Help! I read an article somewhere on installing a manual fanswitch for a single fan--I have a 91 305 TBI Firebird. Per the article, I teed into a gray wire in a bundle going to what I thought was the fan relay on the firewall--other wires were, a big red wire, an orange wire, a black wire, a brown wire and, I think a green wire.

My teed in wire went to a switch, which was grounded at the battery negative. When I hooked up the battery, Positive then Negative, my fan came on (because my AC switch was on), and I heard a click. I turned off the AC, and noticed that my new switch didn't operate the fan. Also, now my fuel pump doesn't come on when I turn the key. She'll turn over but won't start. All other electrical seems to be working, and the fuses look fine too. Any suggestions?

Matt

 

I think you tee'd into the fuel pump relay by mistake.

 

I agree, think I did tee into the fuel pump relay--but how to get it going again? Wondering what I fried. Learned my lesson, don't guess with the wiring--if you are not sure, leave it alone. Great though, because I have a good excuse for taking the day off work tomorrow. !

 

The wire you want is a green/white wire, on the other relay. And don't worry too much, everyone here has done something like that, I know I have .

 

Thanks for the kind words. Okay, but even if I wire up my fan switch right, my fuel pump isn't working. Do I just need to find the fuse/fusible link? My fuses looked fine, and all the other electrical worked. Hoping for a simple fix.

 

I would say check the fuse under the dash first (if there is one, I can't remember). I am guessing you hooked the wire you teed into back up like stock, right? If not do that. When you have the car KOEO (key on, engine off), do you hear the relay click or fuel pump start to flow (it will sound like a drone from the rear of the car for about 3 to 4 seconds), you should. If not, I would say try a new relay. I'm not an electronics expert, though. If you can answer these questions I might can help you some more.

 

Thanks for the advice. When I turn the key on, I hear a faint click from up front, but no fuel pump noise. I took the relays (fan and fuel pump) off their mounts, and followed the wires.

The gray wire I teed into indeed goes into the fuel pump relay (I can tell because the other one has the fan wires going into it). So I was messing with the fuel pump relay. Also, when I first hooked up the battery, I forgot to attach a big red fusible link wire. I don't know if that helped.

Everything is put back the way it was, and I'm going to try a new relay tomorrow. Hopefully that will do it.

Also, when I reconnected my battery, (I had disconnected negative, then positive), I hooked up the positive, then the negative, so as not to spark the engine computer. Is that the right procedure? Thanks again.

91 Firebird 305 TBI Stang Duster
open air element
flowmaster 3" exhaust
aftermarket cat
auto trans rebuild
K&N racing oil filter
Slick 50
cobalt blue paintjob
weld style polished aluminum mags w/ fat meats
pine tree air freshener--"the smell of horsepower"
manual fanswitch and new fuel pump relay on the way

 

I think your using the right procedure for battery hook-up. I always disconnect negative first and reconnect negative last. Also, some auto parts stores don't list a fuel pump relay for our cars. If you can't get one, tell them you want a fan relay. The fan relay and the fuel pump relay are the same. I think the part number is MG44.

 

Put in a new fuel pump relay, still no fuel pump action. Could it be the ECM? I wish I knew what wire it was that I teed into--gray wire on fuel pump relay, and what effect that would have. Anyone have any ideas?

Matt

 

Lemme steal from Vader:



Put 12v to G, pump should go on.

Next check the fusible link thats just off the starter, you probably fried it depending on how you did the wiring.

 

May have toasted the 20 AMP in-line fuse located in the engine bay. Not sure of its exact location in the firebird. Should be somewhere near the battery. It blows, no fuel pump and no ecm.

 

Hi my name is moron, because when I hooked up the battery, I didn't see the red wire with the fuse on it, forgot to hook that back up. It's hooked up now, but it would appear that there was no fuse protection in my wiring job--straight juice directly to my fuel pump.

I tried to test the pump, and that terminal doesn't exist on my diagnostic plug. There's nothing there.

I have a wiring diagram that shows the gray wire going directly from the relay to the "fuel tank unit." No fuses in between. And I connected that wire to battery negative when I teed into it for my fan switch--so it could have gotten juice from the relay directly and fried the pump or sending unit?

Gray wire is not connected to ECM at all, just goes straight from the relay to the fuel tank.

Any other ways to test the fuel pump before replacing it? All your help is appreciated. And killer graphics, Trickster. Install an electronic exhaust cutout and your power will no longer be a secret!

Matt aka Poncho Villa, not to be confused with Juan Valdez the coffee guy.

Mods to my donkey include, carbon fiber horseshoes, direct port Red Bull injection, donkey steroids, and lots of beatings. Just kidding. I don't have a donkey, but if I did I could ride it to the auto parts store.

 

Oh yeah, and I checked the fuse by the battery, it's fine. I am going to be so happy when the car is running again. Haven't checked the fusible links yet--how do you check them anyway?

Pretty sure it's my fuel pump/sending unit.:rockon:

 

Aha, but before I go ripping out my gas tank--I noticed that with the key turned on, my check engine light doesn't come on--used to, with the brake light, etc.

Is this a sign my ECM is fried? My manual says that cranking without starting is likely an ECM problem.

 

More than likely it is your fusible links. Pull on each one and if they stretch any, replace them.

 

Thanks for the advice. I'm about ready to pay someone to look at the sled...Where are the fusible links? Found a couple by the battery, and looks like there are a couple more on pass side. They look kinda hard to reach.

Have been talking to a mobile mechanic, might have him fix it tomorrow or Monday--is ASC certified in auto electric. Have been gittin rides to work, and haven't played with the Bird since Tuesday. I am itchin to get her going though.

Will check the links I can find. Any advice is helpful.

Poncho Rider

 

They are down on the starter solenoid on the passenger side and to get to them, it helps to have the car firmly supported on jack stands or ramps for safety purposes. When working with them on the starter solenoid, make extra sure you disconnect the battery first.

 

Thanks for all your help. Yup, it was a fuse. A mobile mechanic came over, and I told him that I'd grounded out the fuel pump relay--he went right to a fat cable down by the battery, has a black cap on it, and inside a 20amp bus fuse that was fried. Not the inline fuse off the battery positive, mind you--this thing looks like a dead end for some option that wasn't installed, and it doesn't go to the battery, just dead ends there.

Actually, I saw it right a way, but didn't think there was a fuse in there. Oh well, I only paid a hundred bucks to find that out! Apparently, when juice to the fuel pump gets backed up, this is the fuse that goes. It's in a black plastic square shaped housing, on the end of a cable, hanging by the front fender on the pass side. The mechanic was smart as hell, and also owns a 91 RS Camaro, so I wrote down this site for him, and gave him some third genner tips.

Thanks again guys!

Matt