'84 302 CFI - no fuel pumps, injectors not firing

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'84 302 CFI - no fuel pumps, injectors not firing

December 21, 2009, 06:22:17 PM

Any ideas? It sounds like a faulty relay to me, a disconnected sensor, or a bad/disconnected ground.

We just completed an engine swap so everything is a possibility.

When you pour gas down the throttle body, the car fires right up, so ignition is not an issue.

The pumps would not come on with the key, so we hard-wired them with 30' of wire. That made the pumps come on (and there was pressure at the TB) but the two injectors would not squirt.

Everything inside the car is functional. There are no blown fuses.

So my assumption is that both of these fuel delivery issues are related, but don't know where to begin diagnosing the problem. There are a series of connectors on the driver side engine compartment that I believe are for EEC diagnostics, but there is one that looks suspiciously un-plugged. It has four wires in a square connector; one of the wires is a large white/yellow that looks like a power lead.

Thanks for any help, I appreciate it.
Danny

'84 302 CFI - no fuel pumps, injectors not firing

Reply #1 – December 21, 2009, 06:36:21 PM

Photos would help but i belive the wiring you're looking at under the hood is the diagnostic test port. Sounds like it could be a fuel pump relay to me. Now at the same time ill display my ignorance. Does the car have a fuel pump inertia switch???

'84 302 CFI - no fuel pumps, injectors not firing

Reply #2 – December 21, 2009, 06:39:50 PM

Yes, I figured pictures would help but I'm not near it at the moment. :)

Yes it has the inertia relay. It is in the trunk if I remember correctly. The car was driven into the work area, so I would assume it has not been "shocked" to set the inertia relay. But that is a good suggestion and I will check it.

Does this also control the injectors firing? I thought it was just the pump(s). Thank you.

'84 302 CFI - no fuel pumps, injectors not firing

Reply #3 – December 21, 2009, 06:48:50 PM

Your inertia switch doesnt control injector firing. However you really arent getting good atomization by dumping fuel down the TB. By far im no expert im just tossing ideas out there that are no cost. As far as the rogue injectors, make sure they are plugged in all the way, or worse that mighta got schmegmaed up and are blocked.

'84 302 CFI - no fuel pumps, injectors not firing

Reply #4 – December 21, 2009, 07:35:29 PM

I'd bet it's a relay, I had a very similar problem when I swapped an HO into my '88.
Of course, I wasn't able to dump gas in it, but as soon as I got the correct relay in the connector, she roared to life.

I have no diagrams or info on an '84, but perhaps someone who does will post something.

'84 302 CFI - no fuel pumps, injectors not firing

Reply #5 – December 22, 2009, 02:13:09 AM

ground the tan / light green wire at the eec self test connector under the hood.

turn on key

does fuel pump run constant?
no= go to next step
yes- report back

ground tan / light green wire at the relay with relay installed.
turn on key

does fuel pup run constant?
no- bad eec (someone has been ing with the fuel pump relay and screwed up)
yes- report back.

this fuel pump drill has repeated itself many times. What I want to know is do you have one or two fuel pumps.

I hope you have only one in tank pump. if you have two, then the second will be mounted along the rail near the fuel filter and softtouch (member) has all that information.

'84 302 CFI - no fuel pumps, injectors not firing

Reply #6 – December 22, 2009, 10:22:33 AM

I will try that. The car has two fuel pumps, one in the tank and one inline under the back seat on the passenger side.

'84 302 CFI - no fuel pumps, injectors not firing

Reply #7 – December 22, 2009, 10:46:05 AM

IF the pumps run OK when hard wired, problem is with the computer, inertia switch isn't the problem...

Likely you have a power issue for the computer(fuse link, relay, etc), or possibly it's not receiving the firing pulse from the TFI(wiring issue)... I'd guess one of the first suggestions are the most likely... You can verify by checking to see if there is voltage being supplied to pins 37 & 57 of the computer...

One other possibility is the injectors are gummed up from setting(been there have a T-shirt), but that'd likely only be a issue if they were unused a couple months or more... You can use a test light(preferably LED, they are made just for such testing) to see if the injectors are receiving a pulse, if so they are your problem...

'84 302 CFI - no fuel pumps, injectors not firing

Reply #8 – December 22, 2009, 11:43:56 AM

You said you did an engine swap...care to clarify more? What was swapped? What was changed?

Obviously something didn't get reconnected, but who's to say what.

It's hard for us to guess when you don't give us all the details.

'84 302 CFI - no fuel pumps, injectors not firing

Reply #9 – December 22, 2009, 02:04:00 PM

I will test the injector pulse with a test light, thanks.

Quote from: Chuck W;303545

You said you did an engine swap...care to clarify more? What was swapped? What was changed?

The original 302 long block that had a rod knocking was replaced with a good 1986 302 long block. The car's original accessories, transmission, exhaust, and CFI system were retained.

Quote

Obviously something didn't get reconnected, but who's to say what.

It's hard for us to guess when you don't give us all the details.

I'm asking if there is any one connection / device that controls both the pumps, and the injectors. Since these are the only two things that are not working on the car, my assumption is that they are both not working for the same reason. And of course I could be wrong.

Let me turn it around. If you had a car that wasn't getting power to the fuel pumps and the injectors weren't firing, where would you begin looking?

I don't have any wiring diagrams handy, so if anyone has an EEC-III CFI diagram they could post, I would appreciate it. Thanks.

'84 302 CFI - no fuel pumps, injectors not firing

Reply #10 – December 22, 2009, 02:35:18 PM

It has EEC-III??? Thought the '84s were EEC-IV...( hope I haven screwed up and ruined a otherwise perfect year)...

'84 302 CFI - no fuel pumps, injectors not firing

Reply #11 – December 22, 2009, 02:55:25 PM

Quote from: TurboCoupe50;303566

Thought the '84s were EEC-IV...

As did I, and according to FFI, it is.. http://www.fordfuelinjection.com/?p=3

To the o.p., this site may be helpful, if you didn't already know of it

http://www.fordfuelinjection.com

And you're welcome :D

'84 302 CFI - no fuel pumps, injectors not firing

Reply #12 – December 22, 2009, 03:02:09 PM

Gotcha. I thought EEC-IV debuted along with port fuel injection, apparently I was wrong. Thank you very much for the link.

'84 302 CFI - no fuel pumps, injectors not firing

Reply #13 – December 22, 2009, 03:21:30 PM

Are you sure you're getting power to the ECU?

The FP relay doesn't get tripped unless the ECU relay is. At start, the TFI is controlling the spark, and doesn't need input from the ECU.

One test to see if the TFI/ECU/FP/injectors are talking to each other is to rotate the distributor while the engine is off with the key in the "RUN" position.

As you rotate it, you should hear the FP's run and the injectors click as the Hall Effect sensor is tripped. Sounds like that is not happening though.

I'd look to ECU power first. There should be a big yellow or grey/yellow wire that enters the firewall right near where the ECU harness does. That is the wire that leads to the ECU and FP relays IIRC.

'84 302 CFI - no fuel pumps, injectors not firing

Reply #14 – December 22, 2009, 04:53:30 PM

+1 for what ChuckW says.
The ECU has to power-up so it can provide the ground for the fuel pump relay and operate the injectors.

There is a small pig-tail wire on the negative battery cable. This is the ground for the ECU computer. Make sure it is connected.

The ignition switch picks the ECU power relay. This relay is behind the dash a little to the right of center. The relay has a 5 second delay on its' drop out. When you turn the key off, listen and see if you can hear it drop out 5 seconds after you turn the key off.