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Ron
Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 33438
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
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Not duplicate, pls do not close. I have a 99 F150. Drove it

Customer Question

Not duplicate, pls do not close.
I have a 99 F150. Drove it in October, parked it then it wouldn't start. It has a few leaking issues. The gauges sweep back and forth and I only get about 7 volts to the fuel pump.
Submitted: 1 year ago.
Category: Ford
Expert:  Ron replied 1 year ago.
Hello, my name is ***** ***** I am a professional here at Just Answer. I have noticed that your question was not getting a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.
Dose the engine crank over normally and it just will not fire up and run, what is the engine cranking voltage at the inertia switch while cranking. Post back with the results and we can work from there.
Customer: replied 1 year ago.
New battery, Turns over but won't start. Not getting the initial 12 volts for a couple of seconds at the inertia switch when I first turn on the key. If you can read the original question and responses, it may get you up to date with the situation. Thanks for responding.
Expert:  Ron replied 1 year ago.

The fuel pump is controlled by the fuel pump relay through ground switch from the PCM (computer) .If you take your 12 volt test light and or volt meter do you have key on power at the FP relay on pins 86 and 30?

Customer: replied 1 year ago.
I can check that. I know that when I turn the key on, the relay clicks. I also replaced the relay and tried swapping it with the PCM Relay that i think is the same size. Should I place the Black connector on the volt meter to a ground and then try pins 30 and 86 individually? Also, should the key be on or do this as I turn the key on? It will be this afternoon before I can check this. The truck leaks just a bit and I suspected a grounding issue all along, but I haven't found any water around the dash or the PCM. Thanks again.
Expert:  Ron replied 1 year ago.

Check the two power pins first to be sure you have key on voltage to them with the black power probe on ground and the red probe on the pins at the connector and if so then see if you have battery voltage out of the relay while cranking the engine over on the dark green /yellow (pin 87) wire that feed the pump circuit. Also try jumping pin 30 to pin 87 (green/yellow) and see if the pump will now run.

Customer: replied 1 year ago.
OK, sorry for the delay. Pin number 30 has 12 volts in the key on position or the key run position. Pin number 86 has 12 volts only in the run position. Jumping 30 and 87 causes the fuel pump to run.I wasn't sure where i could find the dark green/yellow wire, but at the the inertia switch I get about 6 volts when I turn the key on or in the cranking position. I do not get an initial 12 volts when I first turn on the key.
Expert:  Ron replied 1 year ago.

Okay you need 12 volts while cranking at the inertia switch and if the pump runs with the pins jumped then I have to suspect the PCM is not grounding the relay on the orange/blue wire at the relay, if you supply a ground to the relay on pin 85 does the pump run and will it start?

Customer: replied 1 year ago.
Okay, I ran a ground wire from by ground battery terminal to the unplugged relay at pin 85, The pump didn't run and I stll only registered 6 volts at the inertia switch. I also tried it with placing the ground wire in the 85 pin and plugging in the relay and still no change.
Expert:  Ron replied 1 year ago.

Thew relay needs to be in place to complete the circuit, was that the case?

Expert:  Ron replied 1 year ago.

If the pump runs with pin 30 and 87 jumped then the circuit from the relay to the pump is fine, will the engine start with the pump running?

Customer: replied 1 year ago.
I had to run out for a bit I will check later may be tomorrow before I get a response back to you
Customer: replied 1 year ago.
Some progress perhaps. First I picked up a multi pack of fuses and replaced fuses 1-22 or 24 under the hood with new ones just to be safe .I ran a ground wire into the 85 pin slot and plugged in the relay. I also had a voltmeter at the Dark Green/yellow wire in the inertia switch. I turned on the key and started getting 12 volts to the inertia switch and the fuel pump ran.You can probably explain what that means. The truck still turned over, but would not start and the gauges are still bouncing and the lights are all flashing.
Expert:  Ron replied 1 year ago.
Has the computer been scanned and are there any fault codes?
Customer: replied 1 year ago.
I had rented a scanner early in the process, but I don't recall that there was a code. When I had the locksmith out a while back to see if the Keys needed to be reprogrammed for the PATS, he claimed that he couldn't connect to the computer. Should I try rentinf a scanner again. At Autozone, you buy it and then get a refund when you return it.
Expert:  Ron replied 1 year ago.

The fact that the fuel pump will only run when you supply a ground points towards a failed computer since the computer controls ground switch to the relay but if the engine will still not start with the pump running that means you likely do not have injector pulse as well. Have you checked to see if you are lacking injector pulse as well? If you are lacking injector pulse you could very will be dealing with a PATs concern as well.

Customer: replied 1 year ago.
How do i check injector pulse? I last mechanic said that that a PATS issue could cause the injectors and fuel pump not to work and suggested that I bring out a locksmith to reprogram new keys to the PATS. The locksmith told me that it could be the transceiver so I had one just in case. When the locksmith's machine couldn't talk to the PCM, he went ahead and replaced the transceiver. He still couldn't talk to the PCM and just said it was probably bad.
Expert:  Ron replied 1 year ago.

The injector pulse can be checked with a standard 12 volt test light by placing the test end in to the power side of the injector connector and the ground end on the other wire at the injector connector and then cranking the engine over. If you have pulse then the light should flash with cranking the engine over.

Customer: replied 1 year ago.
I don't have a test light, but can go pick one up. Any chance a voltmeter will work? Can you also tell me where the injector connector is located?
Expert:  Ron replied 1 year ago.

No you need a test light to watch the flash. I suspect you are going to find you have no pulse and if the scanner will not communicate with the PCM and there is no injector pulse and or fuel pump operation you are likely going to find you have either a failed computer and you you do not have power to it. I have enclosed the steps in the link below to check the power supply to the PCM as well. Copy and paste the link to your browser to open and view the steps.

https://dl.dropboxusercontent.com/u/104923897/Scanner%20com%20AUg%2014.pdf

Customer: replied 1 year ago.
Thanks. I will check this afternoon. I will buy a test light and rent a code scanner on the way home. I really appreciate your help.
Expert:  Ron replied 1 year ago.

Okay good luck.

Customer: replied 1 year ago.
A couple of questions, do I unplug the injector and test if in the plug or do I push the probe into the wire with it plugged in.
With respect to the attachment on step 2, how do I check the PCM for power and ground?
Expert:  Ron replied 1 year ago.

No the injector stay connected and you need to check the signal while cranking the engine. Power and ground are checked with the steps I sent you.

Customer: replied 1 year ago.
Do I need to leave a ground wire that I put in place yesterday that made the fuel pump run for these tests
Expert:  Ron replied 1 year ago.

No, you have already proved the fuel pump circuit is okay from the relay to the pump , your just not getting a ground from the PCM , remove any add on wiring and test the injector as I instructed you to.

Customer: replied 1 year ago.
The code scan didn't shoe any codes. It said no codes since last reset. It may have reset when I sent it away for testing
Expert:  Ron replied 1 year ago.

Well did you ever check for injector pulse?

Customer: replied 1 year ago.
I think my response did not go through. The only injector I could really get to was the one on the passenger front. I put the clip on the black wire from the probe on the ground source and then pressed the probe into the front wire. I got a light with a key on but when we attempted to crank at the light went off. I seem to have the same result when trying to press into the back wire. But to be honest it was very hard to get to and maybe the only one I can get to. When the light was old and it turned off it actually seem like it tried to fire a time or two
Expert:  Ron replied 1 year ago.

That would indicate you do not have injector pulse and if the fuel pump will not run and with no injector pulse and no ability to communicate with the PCM, I am at a point where I can not fix this for you online. At this point you are going to need some hands on testing which unfortunately I can not do from here.

Customer: replied 1 year ago.
I ordered a replacement PCM today I gave them my VIN number for them to program it in I will see if that helps if not I can return it for a restocking fee
Expert:  Ron replied 1 year ago.

Okay, hope fully that the problem and not just the key have lost there programming. Replacing it will tell either way.

Customer: replied 1 year ago.
I may unplug the PCM tomorrow double check the connections make sure there's not a bent pin Or something but I wouldn't expect it to this was doing it well before I took it out the last time. Are there any particular grounds for the PCM or power to the PCM that I should be looking for other than the list you've already sent I'll get back to the list in the morning
Expert:  Ron replied 1 year ago.

No, the list I sent you is the correct list , its not like you have bent pins if the connector was installed correctly.

Customer: replied 1 year ago.
Update. I spent some time Saturday trying to troubleshoot and I needed to put the interior parts around the steering wheel. I saw where there were some fuses related to parts of the PCM in the interior fuse box. I replaced all of the PCM related fuses. I was hoping that perhaps one of them was bad, but no change.Then under the hood I rechecked the fuses and replaced the PCM relay as well. I then discovered that their are 2 Diodes, one for the ACH clutch and one for the PCM Power. I checked both with a fuse tester and only the AC Clutch diode lit up. I checked with Autozone and the local dealer and neither had the L shaped Diode. I tried swapping the two and nothing changed. Any idea if the two Diodes are the same or the part number? I am trying to find the part online and not having much luck. I hope to have the new PCM by Wednesday.
Expert:  Ron replied 1 year ago.
I believe the diodes are the same but I do not have a part number. I would think if there are replaceable the dealer should have the part numbers.

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