I just purchased an 87 GT fastback....low miles....great shape....with a few minor issues.....Anyway, To activate the fuel pump the guy has an on/off toggle switch wired from the + battery terminal to one of the relays (not too up to speed on the ferio electrical yet). So you turn on the switch and the pump runs continous, turn the key...car starts....away you go....once you turn off the car you have to turn off the toggle switch to turn off the pump....he mounted it in the engine bay???. He told me he had replaced the fuel pump and that he believed that he must have knocked a wire of the pump assemble....he did not relize this until the tank was in and so he ran this wire so he would not have to pull the tank again......So guys could that be in fact true or should I look at some other issue?.....Also where the hell is the horn located....it don't work......cheers and thanks in advance/.....John

Welcome to the Forum!

That switch story does not make any sense. Where did he hook it up if he did not drop the tank? It sounds to me that you have a bad relay. I think it's a bad idea to leave the switch there if your memory is as bad as mine.

edit to add:....wow...you live way out there! How many Fieros are around you?

[This message has been edited by Gall757 (edited 10-20-2011).]

If he had knocked a wire out of the fuel pump assembly, nothing outside the tank would have fixed it. It is possible the relay failed and he effectively bypassed it. Could you get a picture of how exactly it is wired into the relay?

Normally when you turn the key to "Run" the first time, before starting the car, the ECM will trigger that relay and keep it active for about two seconds. During that time the pump should run and prime the fuel system. Once the car is running the fuel pump should remain running. When you turn the key to Run now, without flipping that switch, do you hear a "click" in the engine bay followed by another one about two seconds later?

Having a switch like that is somewhat unsafe as you will be unable to gain control of a fuel leak should a fire start, definitely worth getting it working properly.

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No he said he had the tank out and when he put it in he had this problem and do not want to drop the tank again....maybe he didn't do anything but the bolts for the straps look like they have been work on...
When I tun the key I get no click no sound at all...I have all winter and spring to mess with it inside, but trying to get my head around it. No not too many ferios left out here on the island, that and the condition of the car is why I bought it....it's originally from mainland Canada....This guy bought it 15yrs ago with 75K kms, now it's got 104K kms...so it's my turn to keep it for awhile......I'll get a few pics posted soonest....oh yes and thjere is a fuse in that wire as well.....thanks, John

Is the original wire still there? The relay is behind the air filter box under the window.

Maybe this will help you out.
The fuel pump is powered two ways. The output from the ECM supplies 10-12V to the FP relay to normally run the pump. As a backup there is also a contact in the oil pressure sender that can also power the pump. (although you don't want to run it this way all the time as you have to crank the engine more and the switch tends to fail over time.)
The relay is behind the drivers head in the engine bay and has an AC relay next to it if you have AC.
From the pump in the tank there is a connector in the middle of the firewall so you can unplug the wires to the tank. It's hard to see or get to.
Commen points of failure are the relay going bad or once in a great while the ecm output. Other then that broken wires.
You need to figure out what he wired the switch to. If he wired right to the pump or is running the relay.
At any rate I'd sure fix it.. You need to measure the volages on the wires at the fuel pump relay and see what you have..

[This message has been edited by Dodgerunner (edited 10-20-2011).]

Thanks for all the quick answers.....I'll check these tips out in the next few days and let you know when I need more help...I'll try and add some pics then as well.

John

Ok had a good look at the bypass that the PO did.....wire from the + terminal of the battery, to a toggle switch...then a 10 amp inline fuse.....plugged into the the connector where the pump relay should be....It is plugged into the center of the 3 with a fourth up higher...I guess a 4 prong relay???? I found 2 5 blade relays in the car, they plug in but no fuel pump sound......is there a way to test the 2 relays I found?...or any idea why it would be wired that way??? I put a new 10 amp fuse in the fuse box as well...any ideas?????

John

According to Dodgerunner's schematic, you are still using the 'B' connection at the relay, so A, C, or D must be open.....bad wire or bad connection...

Any fuse needs to be at the head of the circuit, or it doesn't protect the entire circuit.

From the switch, you can see where the wire runs to the pump right?

So somewhere along there do you see the old wire that came from the relay, just cut off? Like near the place where he spliced in his new bypass hack wire?

phonedawgz
The PO just ran a wire from the + terminal on the battery.....to a toggle on/off switch....then a 10amp fuse....then to the relay harness...the wire he ran is plugged into the center of the relay harness where the 3 connectors are straight across with a 4th connector up the side.......he remove the relay only (I hope). I am not in a big hurry as I just put the car inside to work on over the fall/winter/spring months.....but hell if I can figure it out.

The Tan/White wire runs to the fuel pump

The Orange/Black wire come from the fuse box and has +12v on it key on or key off.

If you connect those two wires with a test wire between the two terminals the fuel pump should run.

The Green/White wire comes from the ECM and turns on the relay.

Can you check to see if shorting the orange/black to the tan/white makes the fuel pump run?

Can you check for +12v on the green/white for two seconds after you turn the key to on? Note - the high current requirments of the fuel pump means you CAN NOT just connect the Green/White wire to the fuel pump wire. It will either blow the ECM fuse, or blow the ECM itself.

A simple 12v test light works great for testing for the presence of the +12v signal. They cost about $4.00.

Ok I looked at the wires...I need to replace the connector as well as the relay....looks beat up......any way I checked the orange/black wire.....not getting any voltage. (there is supposed to be 2 of them right)
I jumped the tan/white to the orange black.....no worky
the green/white gave me 12Vbut it is constant, not just for 2 sec.
I tried to reground the black/white....still nothing.
the fuse in the box is good.
Is there a way to test the relays once they are removed????


ok my relay harnes has 4 connectors....2 x the orange/black on the top, below that 3 along the bottom one is green/white.....then tan/white in the middle....then the black/white....does that sound right?
Any other ideas guys??????

Yep that is right.

You are SURE the fuel pump fuse is good in the fusebox?? The fuse box swings down (squeeze the latches on the sides and push up slightly)

Under the console at your right elbow is a connector. It is right in the crotch of the firewall & console, right under the ECM box. There is a connector there - C203. On that connector the orange black wire of the body harness connects to the orange black wire of the engine harness. Check for power there.

There is an orange black wire that runs from the fuse box directly to C203. There is an orange black wire in the engine harness that runs from C203 to the relay. The other orange black wire connected to the relay terminal runs down to the oil pressure switch.

The oil pressure switch can ALSO turn on the fuel pump, along with the relay. The tan/white wire also runs to the oil pressure switch.

I'll replace the fuse again......I'll pick up some new ones just to be sure.....didn't know the fuse box came down.....Do I have to completely remove the center console to get at the C203??

thanks for all the help....eventually with help I'll get to the problem.


cheers,

John

Pull the two ash trays. Take out the four 9/32" (or metric) screws under them.

You can unscrew the knob (manual) or take out the clip and pull the handle (automatic), but actually you don't have to. Then take out the two screws that hold the arm rest.
Unscrew the two T15 torx screws that hold the cig lighter panel in, and then unscrew the cig lighter base (phillips). Then open the glove box and unscrew the two 9/32" screws that hold the arm rest to the firewall bracket. Then lift out the back portion of the arm rest.

C203 is the connector engine side clear - body harness side black - A double connector on one side but a single on the other side, located under the ECM.

[This message has been edited by phonedawgz (edited 10-23-2011).]

@ phonedawgz,

I installed the relay harness you sent me, track down the orn/blk wire (it was cracked somewhere)...replaced it...so now I get a solid 12V to the relay, but looks like the grn/wht is not getting any power....tested it on initial key turn...no 2 sec 12v....Does that wire go directly from the ecm, or is there a junction for it somewhere in between?.....I'm wondering should I swap out the ecm and give it a try.....I do have a second ecm I got at the mall....but it has a preformance chip....I don't want to sawp chips unti I'm sure that the ecm is bad.......any ideas??

[This message has been edited by wraith13 (edited 12-03-2011).]

Swap ECMs with the chip still in it. You can unbolt the ECM and pull the Secondary Pin Assurance clips off of the ECM connectors. Then probe the Green/White wire on pin A1 of C2 (2.8 ECM) to see if you are getting the +12v there. The wire runs directly from the ECM to the relay. With the relay and ECM unplugged check to make sure the wire is open to ground. You could even 'hotwire" +12v to the unplugged connector to the Green/White wire and see that the relay activates (relay plugged in).

phonedawgz,

ran through all the info you pm'd me and once I swapped out the ecm....it's alive again (thanks so much)...Now one more question...I promise.....I installed the ecm that I got at the mall, has a superchip in it (from what I understand, it don't help the 2.8)...I also have an ecm from a 1986 V-6, 4 spd std, that being said could I swap out the prom from the broken 87 ecm and put it into the 4 spd one....or should I just buy another v6-auto one?

[This message has been edited by wraith13 (edited 12-04-2011).]

86-88 2.8 ECMs were all the same SERV # - 1227170. So the wiring is the same for all those years. You can use any prom from those years in those ECMs

However - you can't use a auto prom in a stick and vice versa. The output of the ECM that locks up the torque converter on the Auto is the same circuit that turns on the shift light on the stick. So if you put a stick chip in your auto, the ECM will lock up the torque converter when the shift light would have come on, and won't lock it up when you are on the highway.

Here is a chart of ECM types and the chips used in them

http://www.exatorq.com/ludis_obd1/fieroprom.html