A little help ASAP please

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A little help ASAP please

November 20, 2014, 03:08:31 PM

Just replaced the fuel pump in my 1987 tc and the fuel pump is still running for more then 2 seconds when you click it to the on position is there any thing I need to do to fix that? Any help would be thankful.

A little help ASAP please

Reply #1 – November 20, 2014, 04:26:52 PM

The EEC will command a prime on the fuel pump when the key is put into the "ON" position for about 5 seconds. IF the pump continues to prime then do some digging on the Mustang sites and you will come up with stuff like this:

http://www.allfordmustangs.com/forums/5-0l-tech/230560-fuel-pump-diagnosis-101-1986-1993-mustangs.html

Darren

A little help ASAP please

Reply #2 – November 20, 2014, 04:45:20 PM

So, you're saying that when you turn the key to the on position with the engine off the fuel pump continually runs, correct?

First two things I would check are the fuel pump relay followed by the ignition switch.

A little help ASAP please

Reply #3 – November 21, 2014, 12:22:12 AM

This could mean the EEC is in LOS (limited output strategy) mode. The EEC is broke to the point where the software has stopped running.
If you try to pull codes you should get nothing. No error codes, no good 11 codes. The self tests will not run.

A little help ASAP please

Reply #4 – November 21, 2014, 01:34:42 AM

If the EEC is good, replace the ignition switch. Not where the key goes, that's merely a lock. The switch itself is under the plastic on the column. 4 phillips screws, pull the plastic off, and you'll see it.

Even if it's not the issue, it likely needs replaced. If you have some other wonky electrical issues, it may very well be bad. Worst case scenario? Your car burns down.

Otherwise, it's the relay. All simple, easy fixes. Good luck.

A little help ASAP please

Reply #5 – November 21, 2014, 08:34:04 AM

So, you're saying that when you turn the key to the on position with the engine off the fuel pump continually runs. Yes that is what I'm saying. I went and talked to a ford master tech yesterday and he said it is the new style fuel pumps and they are all doing that. I don't know what to believe any more. So I'm going to take a look at it this moring. I'll check the relay and the thing under the stearing wheel.

A little help ASAP please

Reply #6 – November 21, 2014, 09:13:01 AM

The crew here on the forums know these cars better than anyone. If you were to drop it off at a Ford garage, they would probably scratch their heads as these cars are as old as half the mechanics there. We, as a collective group, have addressed nearly every imaginable issue that these cars can have.

A little help ASAP please

Reply #7 – November 21, 2014, 02:21:18 PM

I understand I changed the relay and the thing under the steering wheel and it's doing the same thing still. I know what you mean about the people not knowing very much about these cars. That is why with every car that I had I always find fourms for it.

A little help ASAP please

Reply #8 – November 21, 2014, 03:35:27 PM

See if it stays running with the relay disconnected. I had one car where the previous owner bypassed the relay with some home-made hackery... If the pump doesn't run with the relay disconnected, at least you will know the wiring is probably OK, and it might be an ECM issue.

If it continues to run with the relay missing, you've been visited by the Duct Tape Fairy.

A little help ASAP please

Reply #9 – November 21, 2014, 03:50:14 PM

That Master Tech is a Master of Bullshiznit. It's not the pump that controls when it comes on and off it is the EEC through the fuel pump relay. If the fuel pump is staying running with the key in the "ON" position then you have a problem which you understand. Since you have replaced the fuel pump relay and the ignition switch then that narrows things down a bit. I would do as CoogarXR suggests and unplug the relay an see what happens.

If the pump does not run with the relay disconnected then I would try this next. Find the wire that latches the coil in the fuel pump relay at the EEC connector. When you find it get a DVM (digital volt meter) and see if the wire is continuous from the EEC plug to the relay. I do this on my DVM by selecting what I believe is a diode test which if you touch the two DVM leads to each other the DVM will beep. If it is contiguous from one end to the other then keep the EEC connector unplugged and turn the key on to see if all of a sudden there is voltage on it which would mean someone spliced into it. If it is not contiguous (i.e. no tone) but you are getting voltage at the relay then my guess is that someone cut it and wired it to keyed hot as CoogarXR is suggesting.

Darren

A little help ASAP please

Reply #10 – November 21, 2014, 03:56:20 PM

Have you read and followed through with the link Aerocoupe posted?

The ECU controls the Fuel Pump Relay. If the relay is good, then you either have a wiring fault somewhere or the ECU is ping out and never shutting off the signal (ground, actually) to the FP relay. See Pin 22.
http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/06/bb/ce/large/0900c1528006bbce.gif

It's actually not too complicated, which is a good thing!

A little help ASAP please

Reply #11 – November 21, 2014, 04:17:21 PM

Simply put the pump does not control the run time the ECM does. It applies a run signal for a pre determined time if the ecm does not see an RPM signal then times out. If in fact the pump continues to run for more than a set amount of time i think it is 20 seconds not 100% on the time the ECM is defective. BUT!!!! I have seen this happen and it does not effect anything if the car runs correctly. Sounds like your ECM is KAPUT!! That is in re-guard to the pump control.

A little help ASAP please

Reply #12 – November 23, 2014, 01:08:24 PM

short and easy end to topic...

someone was trouble shooting back at the trunk fuel pump relay.
they injected 12vdc up the tan / light green wire.

this is the eec ground control signal to the coil of the fuel pump relay

the eec is broke,,,,, point blank.

however..... I have had running perfectly for several years an eec I broke doing this myself before I knew what I had done wrong.

the car ran fine.

the disadvantage here is that if you are in an accident, the pump will continue to run,, that could be a problem depending on the magnitude of the collision.

EEC is damaged , pin 22 on the eec,, which is also parallel and arrives at your eec self test connector.

the damage could also occur to the eec if the codes were pulled incorrectly at the self test connector.

A little help ASAP please

Reply #13 – November 23, 2014, 01:10:32 PM

Quote from: TOM Renzo;440826

Simply put the pump does not control the run time the ECM does. It applies a run signal for a pre determined time if the ecm does not see an RPM signal then times out. If in fact the pump continues to run for more than a set amount of time i think it is 20 seconds not 100% on the time the ECM is defective. BUT!!!! I have seen this happen and it does not effect anything if the car runs correctly. Sounds like your ECM is KAPUT!! That is in re-guard to the pump control.

about 1 or 2 seconds max

A little help ASAP please

Reply #14 – November 23, 2014, 06:34:46 PM

Ok 1 or 2 seconds Max. Now i have to time it JAY. Just thrown that in as a guess of the time frame. By the way Jay the enertia switch can be the savior if the ecm is Kaput. Another words it will shut down the pump in a crash. By the way the best one is from a RANGE ROVER. Just saying if you want one that works real well. Peace Guys