Fuel relay switch?

1997 Oldsmobile Eighty Eight .

The fuel pump relay switch is located on the firewall under a plastic cover...It is a black plastic 1"x1"

switch...It is designed to operate the fuel pump for 3-8 seconds when you turn the ignition switch on, to prime the injector rail.

Fuel pump relay and cooling fan relay troubleshooting on 1997 ford thunderbird?

Fuel pump relay location for ford

Here is the fuse location (fuse 13) and also the constant control relay module location.The fuel pump relay is located in this module.

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The relay is located in the engine compartment in a relay box. It is a long narrow black plastic box with removable lid, and sits next to the radiator overflow/fill reservoir. 
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If your cooling fan is running(this is the default,if you disconnected the PCM and then turn the key to the run position the cooling fan will run) and your OBD2 scan tool is not linking up your PCM is not powering up.

When it is acting up check and see if you have power on the red wires on pin 71 and 97 at the PCM.This gets its power from the PCM relay on the ICRM(intergrated control relay module).

Here is a copy of the wiring schematic to help you.

Here is the connector at the PCM

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The relay control module is the one located on the radiator support that houses the relays for the PCM,Fuel Pump,AC,Cooling fans.

Here is a pic of the connector at the relay module.

Now how this works is looking at the wiring schematic I sent you the red/light wire on the right at pin 13 is the power feed for the coil side of the PCM relay,the black wire on pin 15 is the ground for the coil side of the relay. When power and ground are applied to the coil side of the relay,this creates a magnetic field which will pull the switch side of the relay closed.Looking at the left side of the schematic the switch side is the yellow wire on pin 8 and 10 which gets power from fuse 15L. when the switch is pulled closed power then can flow from the yellow wire to the red wire on pin 24 which feeds pins 71/97 of the PCM.

Now when it acts up if you have power at pins 71/97 then the problem is the PCM or one of the grounds to the PCM(look at the connector pic for which wires are ground).

If you do not have power to these 2 pins then your problem is either the wiring from the relay module to the PCM or the relay module itself.Most likely I would suspect the relay is sticking how ever a corroded wire or connection could also cause it.

The PCM is located behind the right kick panel. Here is a pic of the location

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OK NOW READ THIS SESSION AS FOLLOWS:----

THIS WILL GIVE YOU BETTER IDEA TO RESOLVE YOUR ISSUE:---

Yes, I've ordered a IRCM Intergated Relay Control Module yesterday, because I've been told by a Ford Mech. (retired) that these fail from the High Heat. It has been 95+ this last week, and I broke down and used my AC. Never use the AC much.

I reseated the gound cable from the Battery to the Radiator Support, removed and reseated the Connector on the IRCM that's mounted on the Rad. Sup. behind the Air Filter Box, reseated the Connectors by the ECM behind Pass. kick panel, Loosened ( didn't completley remove) the ECM Connector and retightened, reseated the Ground Cable that's next to the ECM. Replace the Relay in the Power Dist. Box for the Fuel Pump.

After all that the car started hard, and the Rad. Fan didn't run as it was before. I made it to work fine. At lunch it didn't run the fan, and wouldn't start, finely after several tries it started as normal. Started 4+ times after that during the hour. When I got ready to go home, it started hard, but did start. It was only 90 out that day.

Today went out to start it, 73 outside and cool. I turned on the ignition and heard the Rad. Fan runnning, Fuel Pump run for about 3 seconds. Cranks over never tried to fire.

On/ OFF the Key several times and still nothing.

QUESTION FOR TODAY: About the Grounds for the IRCM and the ECM. I know that the gounding of these items, especially the ECM are very important. Can you tell me how to check these and there LOCATIONS. Also can I use a 12V light probe to check the ECM for 12V? I do have a Fluke, light is easier.

To check the Voltages at the ECM, can I drop it down without causing any problem with ESD? Does it need to be grounded when I let it hang?

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You can just let the PCM hang down and check the wiring that way,the PCM does not have to be grounded.

Yes you can use a test light instead of a voltmeter.

You can check the grounds at the IRCM and PCM with your test light also just hook it to a power source and test the grounds that way. You should be able to use the connector view I sent you for the grounds. If you have one that is bad let me know which one it is and I will get you the location.

Are the Ground bus flat? About 1 1/2" X 2 1/2" X 1/4" thick? They are Clear white and have about 6 wires attached to each, and nothing else, expect the mounting screws. Because I'm seeing them under the hood and several places else.

As you have stated there are several grounds.But first make sure when the vehicle acts up that you have power on pins 71 and 97. You need to try and pin-point a starting point here.Just to give you an example the wiring schematics are 18 pages long for just the grounds. I can not upload all of this to you. If you can pin point the area I can upload that.

Start at the 2 power pins first lets make sure when the vehicle acts up that these are powering up. You can leave the PCM hanging down so you can easily access it and have your test light in the vehicle and the next time when you turn the key on and hear the cooling fan running check these 2 pins.

As I stated earlier this is the default for no power to the PCM,if you were to unplug the PCM then turn the key on the cooling fan will run.

If you want to go ahead and check the grounds for right now check them right at the PCM connector with the PCM disconnected and make sure you have them all. If you do not then post back which one you do not have and I will upload that page and location for you.

I'm working on this tonight and tomorrow, trying to get as much info as possible before I start tearing it apart. I want to cover as much as possible so I don't have to spend days on line.

I am going to check the 71 and 97 for voltage at the PCM first as stated. Then all the grounds, in and around the PCM, IRCM, etc. I just want to be able to work on it without the lack of all steps needed to complete this troubleshooting and repair.

I studied the wiring schematics and there are really only 3 ground locations for the PCM and 1 for the ICRM that you really need to check.

The PCM ground are G200,G202,and G104 and the ICRM is G139.Here are pics of their locations,I have circled them in the pics.

Here are the rest of the wiring schematics for the PCM

Worked on it last night. Using a test light at the two power wires at the PCM 71 97, I had a bright light. I used the Green screw on a Ground bus for the ground. Didn't get actual Voltage at the PCM but check voltage at the IRCM and it was 12V+. Reseated as many of the Ground I could find. Except the one under the dash.

The Rad Fan fuse 10A in the covered holder on the pass. side, next to the Rad. Support was very corroded. I cleaned it up and replaced the fuse. It must be working,because the Fan Still Runs. Also now the Fuel Pump isn't working at all. I tried a new IRCM. The fan now doesn't come on, and still nothing, still no fuel pump.

Check all the fuses, PD box #13 20A which is the fuel pump it's okay.

Where do I go from here?

Just to make sure you know the fuel pump only runs about 2 secs when you turn the key on until the vehicle starts.

If it is not running for 2 secs when you turn the key on pull up the schematic page I sent you for the pump(024-2).When you have power on B which is the same wire that feeds pin 71/97 on the PCM,see the schematic page labeled (024-1) and the PCM grounds pin 18 LB/O wire this creates a magnetic field which then pulls the switch side closed so power from fuse 13 can go to pin 5 the PK/BK wire to the inertia switch and then to the pump.

Okay, I've checked the relay function inside the IRCM. I connected a ground lead to the bolt of the ground for the IRCM. Put my Fluke inline on Continuity check/ diode. Connected to the Pin 18 of the IRCM. When I turn on the Key, nothing. Doesn't go to ground like it should. I disconnected the IRCM and jumpered from Pin 5 for the pump to Pin 11, which is both sides of the Contacts of the Relay. The Fuel Pump does run and I have 40 PSI at the Shreder Valve.

Let me make sure I have understood what you have checked.You have power on 71/97,You have double checked the grounds to the PCM pins 33,25,24,76,51,77,and 103.

When you turn the key to run position the PCM is not providing a ground pin 18 LB/O wire for the coil side of the fuel pump relay at the ICRM? Have you also checked it at pin 80(see page 024-2) of the PCM just to make sure you are not fighting a bad wire?

If you have power on pin 71/97 and also 55 and all of your grounds are good at the PCM then take and ground pin 80 with the key on and everything connected and see if the pump runs.If so your problem is the PCM itself.

Power on pins 71 and 97. Also at 55 when key is on. I haven't checked the pin 80. I'll ground it and see what happens. I will do this with key on at the PCM.

. I DO KNOW that at the IRCM if I ground that wire the pump runs, so if it doesn't run when grounded at the PCM then it's wiring issue, more than likely. Since the pump ran when it first wouldn't start, now doesn't. Makes me believe it's something like wiring.

I unmounted the Power Dist. Box and Checked the Power to all fuses and outputs on them. Everything was okay. Reseated All connectors around the PDB, grounds, power etc.

I have 12V at the MAF Sensor, Ignition Module, IRCM and the PCM.

I have checked the Grounds at the Battery, at the Grnd.Buses at the Rad. Support for the battery and the IRCM, Data Link, and the PCM case, PCM bus and the two black wires mounted at the passanger kick panel.

ONLY Ground I can't find is the one behind the dash.

I found a Black 4" square Connector block under the dash, it has about 6 multiple color connectors going to it. Do you know the location of the Ground Bus at the dash? I know that you sent me a picture of the location, but I can't find it unless it's behind something, such as the above mentioned Black 4" block.

I've tried an Ignition Switch, IRCM, and a PCM, still the same thing.

Can the Igniton Module keep the Fuel Pump from running? If I check for spark at the coil packs, with the problems I'm having, will it still show spark? Someone said it would.

It sounds like you are putting the cart before the horse here so to speak. Remember what I told you if the PCM does not power up this is what it will do. Just to verify disconnect the connector on the PCM and turn the switch on and see if you see anything different than what you have now.

What I suggest you do since you have verified power to the PCM then take your test light or voltmeter which ever one you are using.Hook it to a power source then test each of the grounds I listed previously at the PCM connector itself. If they are good it will show 12V.

If you ground pin 80 with the key on and the pump runs then this further verifies that the PCM is not powering up.

If all the grounds at the PCM connector check good there is no need tracing them back.

If all the grounds and powers are good at the PCM then the PCM is bad.

Last night I checked all the grounds at the PCM. The 7 u listed. Using the 12Volts from the interior lights power. Everything was fine, even the case was grounded. I shorted the Blue/ Orange wire Pin 80 I believe,and the Fuel Pump runs.

Just for the heck of it I hooked my OBDII scaner to the Data Link and turned on the key, it tried to read the codes, said didn't have any, so I'm assuming that it was seening the computer. No codes, obviously, cause I've had the battery disconnected.

Does the Ignition Module have anything to do with the Computer NOT turning on the Fuel Pump? I have 12V at the ICM when the key is on, and also at the MAF.

What is the cooling fan doing now?

If the PCM is powering up cooling fan should be off and the fuel pump should run about 2 seconds then shut off until engine actually starts.It should do this every time you cycle the key from off to on.

You do not have a chip installed on the back PCM.I was just working with a guy on here with the exact problem and he had a super chip installed,when he removed it problem was solved.

reply

Same as original problem.

No modifications, to PCM.

You have a bad PCM unless you have a chip installed on it and in that case remove the chip.

I've tried a new PCM. It's doing the same thing. Is it possible that something else is influencing the PCM not to run? Possible a bad PCM? Does the Ignition Control Module or the Crank Position Sensor possibly have anything to do with a signal not getting to the computer?

That should not effect the cooling fan and the fuel pump,but try and unhook the ignition module then cycle the key and see what they do(cooling fan and fuel pump).

Where did you get the PCM was it programmed to the car? Or was it a used one of of a like vehicle?

Picked up the PCM from Advance Auto, Cardone brand. 78-6137 part number. It's one that is programmed for the Calibration sticker on my door jam. Calibration 5-18B-R00.

If the PCM you got was brand new then it is blank and has to be programmed to the vehicle. If your local dealer has the adapter cable they can program it off of the car but if they don't they will need the vehicle.Here is a TSB about programming it off of the car.

TSB 99-4-3	REPROGRAMMING POWERTRAIN CONTROL MODULES (PCMS) - OUT-OF-VEHICLE - EEC V VEHICLES ONLY
Publication Date: FEBRUARY 19, 1999

FORD:	1994-1997 THUNDERBIRD 1994-1999 MUSTANG 1995-1999 CROWN VICTORIA 1996-1997 PROBE 1996-1999 CONTOUR, ESCORT, TAURUS
LINCOLN-MERCURY:	1994-1997 COUGAR 1995-1999 CONTINENTAL, GRAND MARQUIS, TOWN CAR 1996-1998 MARK VIII 1996-1999 MYSTIQUE, SABLE, TRACER 1999 COUGAR
LIGHT TRUCK:	1994-1997 F SUPER DUTY, F-250 HD, F-350 1995-1999 ECONOLINE, RANGER, WINDSTAR 1996 BRONCO 1996-1997 AEROSTAR 1996-1999 EXPLORER, F-150, F-250 LD 1997-1999 EXPEDITION, MOUNTAINEER 1998-1999 NAVIGATOR 1999 SUPER DUTY F SERIES

This TSB article is being republished in its entirety to update the affected vehicles and to include an Application Chart for the affected vehicles.

ISSUE:

The Federal Environmental Protection Agency (EPA) has mandated that all aftermarket service centers shall be able to either reprogram Powertrain Control Modules (PCMs) or obtain reasonably priced, timely PCM programming services at dealerships. Ford has released an out-of-vehicle EEC V reprogramming cable to support this requirement. Also, PCMs are reprogrammable to update calibration levels or to reprogram a common hardware type to a new calibration in order to fill a service need without ordering a new PCM.

ACTION:

Refer to the Application Chart in this article to use the new 15- to 104-Pin Flash Cable to handle all necessary out-of-vehicle programming of EEC V modules in the vehicles listed. This may allow added flexibility in servicing aftermarket and fleet accounts as well as provide the ability to have modules updated to new calibrations through the Parts Department instead of ordering new parts.

Currently, EEC V modules must be installed in a vehicle to reprogram a new calibration in the module. An aftermarket service center may bring a module to a dealership for a calibration update or may request an updated calibration be installed to a new service part. The EPA regulations require "reasonably priced, timely service" be provided by the dealer. The new 15- to 104-Pin Flash Cable works with the New Generation Star (NGS) Tester to provide the capability to reprogram a calibration on a PCM out of the vehicle.

The 15- to 104-Pin Flash Cable connects between the NGS Tester and PCM 104-pin connector. The proper calibration must be downloaded to the Data Transfer Card through Service Bay Technical System (SBTS). Once the card is inserted into the NGS Tester and the cable is connected, follow the calibration download instructions displayed on the NGS screen.

The 15- to 104-Pin Flash Cable (007-00587) can be ordered from Rotunda by calling 1-800-ROTUNDA.