Supply voltage can be checked through the EEC relay. The FP and EEC relays are right next to the test connector, drivers side. The EEC must have more than 10.5 volts to operate properly. You can also test through any sensor. Turn key on, not engine and disconnect EVP connector. Top post on sensor is ground. leftmost is EVP signal and rightmost pin is VCC. Use this as a guide for the connector. VCC to ground should be 5 Volts.

Not very familiar with the FP relay, so hopefully someone can fill in here.

 

so if theres less than the approved voltage, does that mean the EEC is bad?

edit-- went out and checked input voltage to EVP sensor, its right at five volts...I am guessing that the FP relay and the EEC relay are the ones under the cover by the airbox? Which one is which?

 

Yes that is the relays, EEC Power and Fuel Pump. If the fuel pump relay is the one that came with it, it will be the one that is half green.

The EEC computer takes one side of the fuel pump relay coil to ground to turn on the fuel pumps (tan wire with a green stripe, EEC pin 22). The output of the fuel pump relay is then checked for near battery voltage and if the voltage is low then the computer gives a code 95 (brown wire, EEC pin 8).

A low voltage would mean that the contacts are bad on the fuel pump relay or the pump circuit is drawing to many amps.

Most of the time this turns out to be bad connections under the socket of the fuel pump relay, bad socket or dirty pins on the relay. A wire to the fuel pump relay may be just touching the socket also.

The loop on the battery ground cable that thomadm talked about bolts on to the body not the frame. The body ground is very important as it grounds all of the things in the cab and most lighting.

The frame is grounded for radio static, taillights and for a ground if you are pulling a trailer, these grounds of less importance.

The small black wire with a green stripe at the negative battery cable is the EEC computers ground (EEC pins 40 & 60) and will cause the engine to die if it comes off. This one is very important also.

Here is a diagram to help you out:
http://i54.photobucket.com/albums/g91/subford/Fuel/fuel-sel1987-89FSeries.gif

 

Thanks for coming on in......

How do I test the FP relay, I know what wires do what now thanks to the diagram, but I dont know which ones to test. The pins were clean, but what do you mean about a bad socket, or a wire touching the socket?

I found my original battery cable and it was bolted to the frame and then it went to the block.

Both small black wires coming from the neg. battery cable are plugged in and tight.

 

A bad socket might not make good contact with the pins from the relay.
I would look underneath the relay at the wires going to the relay and make sure they have a good connection to the relay pins.

Make sure the body is grounded, we do not care about the frame at this point. I know on an 87 van that loop bolts to the body, not the frame.

 

I also have been expiriencing a bad miss while driving and at idle. Sometimes it comes and goes..but it misses worse after it is warm.

I did a KOEO code pull and came up with this:

1. 212: Loss of IDM input to EEC or SPOUT circuit grounded.
2. 332: EGR valve opening not detected
3. 542: Fuel pump circuit failure
4. 565: Canister purge circuit failure

I'm just not exactly sure what any of this means.

*EDIT

BTW the truck is a 1995 F150 4X2 with a 5.0 in it.

 

After every thing is said and done it usually winds up being a bad PCM Computer.
Do the 5-Volt check above and listen to the fuel pumps and see if they time out in one second or run all the time.
If they run all of the time and the 5-volt reference voltage is off you have lost your caps in the computer, you can replace them or the computer.
If the PCM were bad I would say get one from a salvage yard from a truck the same year and every thing else is like your trucks engine and transmission. Or you can replace the caps, I can give you a URL that will show you how.

When done checking the above please start your own thread and we will help as much as we can.

 

is there a possibility that the FP relay is bad? Its only a couple bucks to replace.... The one in there is still the original green one, do you know which wires to test across to get that 10.5 voltage? My haynes manual tells me what to look for with the test (voltage, ohms, continuity) but it doesnt tell me which wires to test. Sorry for the trouble, and the ignorance, i'm still trying to get used to electrical and mechanical meshing together more than I'm used to.

edit-- since my output voltage to the EVP is right at 5 volts (test above) that means that my EEC isnt bad right?

 

YesYou should get about battery voltage to ground at the Yellow wire all the time and the Brown will have about the same when the relay is made. 10.5 sounds a little low to me.Well that means your 5 Volt regulator inside the EEC is good and you said the fuel pumps time out so the odds are that it is good, but that is no grantee that it is.

 

ok, so tested...yellow wire had 12 volts to it, tapped into the brown wire and turned the key, yet no voltage, but the pump still ran, so did I get the wrong wire and just not make a good connection? Either way, went and bought a new relay, plugged it in, rebooted comp, took for test drive, same thing happened, pulled codes again, got same....32,85,95

edit--
when I got back from my test drive, I let it idle for a bit, came down (700-800), then came down (to 400-500)farther and got a little rough, so just out of curiousity, took vacuum line off FPR and capped it, and the idle came back up to the 700-800 and smoothed out, is this part of my problem? I know I know, test FP, and tomorrow I will go and ask some of the parts stores if they have one to rent, but for now, just looking at possibilities. Thanks again everyone for your help

double edit--
Just so that I can rule it out, can I take my EEC out and take it to a parts store or maybe the dealership and see if they can test it to see if its bad for free?

 

OK after more research I think that the diagram is wrong that I sent you at the fuel pump relay.
The wire leaving the relay is Pink with a black trace on it. The 88 shop manual and the 88 Electrical & Vacuum Trouble-Shooting Manuals do not show that the wire has a feed back to pin #8 on 88 F series. The 1986 F series wiring diagram does not show this either.

Now I think we need more history of what you did to the truck in the change over. Namely what is the EEC computer out of, as a 95 code should not come from an 86-87 truck, as it does not test for power on the PK/BK wire.

I take it the brown wire is not hooked up on one end and the other end is going to the EEC computer pin #8. What year is the harness out of?

 

I do not know of anywhere that you can get one tested. There is a place that you can send it to and the will check it out and rebuild it and send it back to you. I think most auto parts stores can send it in for a rebuild also.

 

Here is a replacement diagram:
http://i54.photobucket.com/albums/g9...-88FSeries.gif

 

Ok, way back when (two years ago now) I swapped from a blown 302 to a 1994 351W. The harness is still the original 302 harness and the ECU is out of a 1989 F250 with a 351W and a 5spd trans from MustangGT221. I have had my share of problems with it, including a bad high idle that I fixed by unplugging the IAC valve for about 6 months. Last month, I swapped in a ZF S-42 transmission for an AOD, got tired of the AOD. A week or so later, I started having some more idle troubles as it idled extremely rough, turned out it was a bad EGR valve. Replaced said valve, and when I did, I noticed how dirty the top of my engine was. Wires were out of the looms since they werent taped, all the hoses had dirt embedded in them. As a general maintenance thing, I took off the throttle body, cleaned it, IAC, TPS, put in new gaskets and put it back. Wired everything back into it's respective looms and taped the ends. Worked fine for about a week, and now this problem showed up.

My Haynes manual (which I understand they have bad wiring diagrams) says that the 1987-1989 5.0, the 1988-1989 5.8 and the 1988-1989 7.5 all use basically the same wiring harness, with small differences. Didn't think it was a problem since everything's worked till now.

 

looking at my wiring diagram, the brown wire goes to the inertia shut-off, then from there, a pink/black wire goes to the high pressure fuel pump but yeah, no feed back to the #8 pin. (Is that why it's picking up that code? And can I run a jumper wire over to the #8 pin and make it like the 89 harness in that way) Yet your diagram shows pink/black to the inertia switch....gotta love haynes manuals. I was going to go back to look at your original diagram, but its not there anymore...???...

I notice though that the ground at the high pressure pump doesnt connect into the harness anywhere, but finds it's own ground with the other pumps, so I'll see if I can't crawl under there tomorrow and chase some wires.

I know I'm starting to sound like a broken record, but is there any reason that it just happens at random?

edit--haha, I was just thinking, what if this all is happening because of the spark plug wire touching thing (that I just forgot about and just remembered), and the code 95 is because of that wire not giving feedback to the #8 pin.......