Power to EEC on Pin 1, no relay power out on pin 37

[68keyblr]

OK so I've followed jrichker's "Cranks OK but won't start" and found there's no power to fuel system. I can see power going into the EEC on pin 1, but no power coming out on Pin 37, which feeds the fuel inertia switch which then goes to the fuel pump relay. Am I correct in thinking I should get 12v on Pin 37 to power the injectors and fuel inertia switch?

Also - I've swapped in another computer and it's the same for both

Any ideas? Am I doing something wrong?

 

[dragnazz5.0]

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

according to this 37 should power lots of different things including injectors and maf. not sure if jrichker posted that but its helpful i think. obviously an open circuit somewhere. check the eec power relay

 

[68keyblr]

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

according to this 37 should power lots of different things including injectors and maf. not sure if jrichker posted that but its helpful i think. obviously an open circuit somewhere. check the eec power relay

So there should be 12v on that pin correct? Where is the EEC power relay?

 

[jrichker]

The EEC relay lives on top of the computer. The computer is under the passenger side kick
panel. You may find it useful to remove the passenger side dash speaker to see the EEC
relay. Making friends with someone who has small agile hands would be a good idea too.
There isn't much room to work in there.

Your problem has narrowed down to either a bad EEC relay or blown fuse link.
The fuse links live in the wiring harness up next to the starter solenoid.
See http://forums.stangnet.com/showthread.php?t=626395 for the story of someone else
with the same problems. I recommend you read this thread, as there is lots of good
information about troubleshooting fuse links.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds
(website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine

Diagram courtesy of Tmoss & Stang&2birds

Also see
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

 

[68keyblr]

jrichker, thanks for all of your help and information - you've proven to be invaluable!

I found that there is no power coming off of the top post on the starter solenoid, which feeds a Red/green wire which goes through a 20a fuse link with a blue wire coming out the other side of the fuse link up by the firewall. Could this be my problem?? A bad starter solenoid??

 

[jrichker]

All the wires for the starter solenoid except for the single large wire that goes directly to the starter should be on the battery side of the starter solenoid.

 

[68keyblr]

OK I jumped the blue wire with the 20a fuse link to + batt and the injectors came to life. I found that with the key on, if I grounded the tan/blue wire at either the fuel pump relay or the fuel pump test connector then the fuel pump relay would click and also a click would come from the tank (the pump I presume).

However, the pump doesn't sound like it's working (just a single click). Also, it appears that the ground wire (tan/blue) at the fuel pump relay is not continuous to the EEC.

Is there a simple explanation that would explain all of this or do I have (1) a bad fuel pump AND (2) a bad ground wire between the fuel pump relay and the EEC?

Seems like the chance of 3 things being hosed all at once is kinda remote Granted, the car has been sitting for 6 months...

Thanks for your help

 

[68keyblr]

OK I'm finally able to pull the codes! Here's what I get:

67 - Neutral drive switch drive or accelerator on (engine off)

85 - Canister purge (CANP) circuit fault

87 - Fuel pump circuit fault

I know what 87 is, gonna have to pull the carpet to find where the wire is broken.

What is the Canister Purge circuit and what is it for?

And what is the "Neutral Drive Switch drive or Accelerator on"?

 

[HISSIN50]

However, the pump doesn't sound like it's working (just a single click). Also, it appears that the ground wire (tan/blue) at the fuel pump relay is not continuous to the EEC.

Was this (see bold above) during the prime-out (without the test connector jumped)? If so, the ground should be present for a couple seconds and then go away. If you lost the ground while the test connector was jumped (which sounds like the case), that does indeed sound like an open circuit. Just confirming.

Good luck.

 

[jrichker]

Code 67 - clutch not depressed (5 speed) or car not in neutral or park (auto) or A/C in On position when codes where dumped. Possible neutral safety switch or wiring problem. This code may prevent you from running the Key On Engine On tests. You can generally ignore this code, since it has no effect on engine performance.

Code 85 - CANP solenoid - The Carbon Canister solenoid is inoperative. Check vacuum lines for leaks and cracks. Check electrical wiring for loose connections, damaged wiring and insulation. Check solenoid valve operation by grounding the gray/yellow wire to the solenoid and blowing through it.
The computer provides the ground for the solenoid. The red wire to the solenoid is always energized any time the ignition switch is in the run position.
The carbon canister vents fuel vapor into the intake manifold at cruse. This helps richen up the cruse mixture slightly. It also eliminates the gas stink when the car is closed up in the garage or other poorly ventilated place. Don’t park you car in the garage if you have a gas fired water heater, the fuel vapors are a potential explosive hazard.

If you have emissions testing in your area, plan on re-connecting it. You won't pass the visual inspection without it.

Code 87 – fuel pump primary circuit failure. The fuel pump lost power while the engine was running. Check fuel pump relay, check inertia switch, wiring to/from inertia switch, red wire going to inertia switch for +12volts. Check the other side of inertia switch for +12 volts.

To help troubleshoot the 87 code, follow this link for a wiring diagram for 89-93 cars http://www.autozone.com/servlet/UiB..._us/0900823d/80/19/59/5a/0900823d8019595a.jsp

For 79-88 cars use, http://www.autozone.com/servlet/UiB..._us/0900823d/80/16/71/3c/0900823d8016713c.jsp

 

[68keyblr]

Thanks again jrichker...u da man!

 

[68keyblr]

Was this (see bold above) during the prime-out (without the test connector jumped)? If so, the ground should be present for a couple seconds and then go away. If you lost the ground while the test connector was jumped (which sounds like the case), that does indeed sound like an open circuit. Just confirming.

Good luck.

OK so the ground goes away after it's primed? I guess that makes sense, shuts the pump down when the PSI is correct.

I'm not sure if that was the case since I don't think it actually primed, the Fuel Pump just clicked once

Thanks for the tip though

 

[HISSIN50]

OK so the ground goes away after it's primed? I guess that makes sense, shuts the pump down when the PSI is correct.

I'm not sure if that was the case since I don't think it actually primed, the Fuel Pump just clicked once

Thanks for the tip though

You got it. The pump primes initially but then the puter pulls the ground to the relay coil so if you leave it KOEO (without cranking or running), it's not pumping fuel for nothing. It's purely on a timed interval though - the computer doesnt have a clue what the pressure is (with an adequate pump, it is indeed plenty of time to gain correct pressure).

And as an aside, I have to agree with you - Jrichker is the man!

 

[68keyblr]

You got it. The pump primes initially but then the puter pulls the ground to the relay coil so if you leave it KOEO (without cranking or running), it's not pumping fuel for nothing. It's purely on a timed interval though - the computer doesnt have a clue what the pressure is (with an adequate pump, it is indeed plenty of time to gain correct pressure).

And as an aside, I have to agree with you - Jrichker is the man!

Thanks for the good info, that will help me this week as I get the rest of these bugs ironed out.

Jrichker deserves an award for the sheer number of people helped out....this site is the best!

 

[PaCemkr86]

thanks for the thread, just helped me fix a buddys mustang

 

[68keyblr]

thanks for the thread, just helped me fix a buddys mustang

Awesome! I never posted the final results of my process -

1. Bad Fuel Pump

2. Bad Ignition Switch

What turned out to be the problem with your buddy's Mustang?

 

[praugue]

Great info. I just got a pump problem. Now I get to dig in and find out why. All of this is helping. Odd that I've never heard the relay under the driver's seat. It must be quiet.