Bullnose Enthusiasts Forum

1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Classic

List

Threaded

74 messages Options

1234

axe2011

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Well....when it rains it pours. I thought since I had ruled out the wiring harness in the injectors I should retape and wrap it. Got it all wrapped back up and put back on the truck and now I have a new issue. With the key turned on and engine off I can hear the fuel pump turn on but it never turns off. I immediately pulled the injector rail to see if it was spraying fuel back into the motor again, but that wasn't the issue. When I push the relief valve on the rail gas sprays out so its pressurized. I can hear a hissing noise while the pump is running, which I thought was spraying, but I can't find any leak anywhere. I tried replacing the relay and it still stays on constantly. Any ideas what I should check next? It has a new hp pump and fuel filter and the front tank is full.

On a plus side after tearing though about 50 old F150/250s at a junk yard in Garber, Iowa I was able to find the coolant tree, and a couple of the other parts I needed. I also was able to source an fuel rail from Idaho which should be a match as well, its in the mail! Hopefully I can get these parts on and have some success.

1986 F150 RWD Automatic 5.0 EFI

Gary Lewis

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Administrator

I think you have a ground on the Tan/Light Green wire.

In the Page 60, below, you can see that power goes to the fuel pump relay via the Red wire at ZZ. Then on Page 103 it comes into the fuel pump relay and then goes out on the Tan/Light Green wire via YY. And on Page 62 it comes in to the computer, the ECA, on the T/LG wire.

The ECA is supposed to ground the T/LG wire when you turn the key on, and I think it is supposed to take the ground away after a few seconds unless the engine starts. But if you have a ground on that wire the relay will stay engaged and the pump will continue to run.

I would pull the relay to see that it does stop at that point. If so I'd find the ground, which may be in the self-test connector or its wiring.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

85lebaront2

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Administrator

In reply to this post by axe2011

The hissing noise is the fuel going through the pressure regulator and returning to the tank.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

axe2011

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

In reply to this post by Gary Lewis

Thanks for your help Gary. I decided yesterday I was going to trace every wire from the EEC to its destination in order to ensure they actually go where they are supposed to. So far between the kids, wife, and chores I have made it to pin 22.
I found today that Pin 17 and Pin 48 (shown on page 62 of the diagrams you provided) were actually flip flopped, not sure if this would have cause the issues, but it will probably help me if I ever want to pull codes in the future. Like I said earlier in this thread I believe someone replaced the harness as it has two splice points along it on either side of the motor.
I am slowly winning the war on this truck. Is there a chart of what the Connections look like. I assume C171 is the grey connector right next to the C168 connector that in my truck is red and is right behind the battery.
So far on this project I have learned how to use a test light, somewhat how to use multimeter, and how to solder, so if nothing else I am learning a lot fast! It will all be worth it when I can cruise around in the old girl.
I will look tomorrow night If I can find any issues off the pin 22 on the EEC and try to follow it all through the fuel pump control diagram. Again thanks, I definitely would be lost without your help!

1986 F150 RWD Automatic 5.0 EFI

axe2011

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

In reply to this post by 85lebaront2

I thought that might be it too, I bought another regulator, but I couldn’t get the mangled fuel rail to seat again and not leak. So currently I have the old mangled rail off and another one in the mail From Idaho. Hopefully in a few days I’ll be able to put it all back together and finger crossed it was just that part!

1986 F150 RWD Automatic 5.0 EFI

Gary Lewis

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Administrator

In reply to this post by axe2011

I wouldn't think that having 17 and 48 reversed would cause a problem as long as nothing is plugged into the STI. But if there is something plugged in then it might cause problems. I'd fix it were I you.

And there is a table at the back of each section of the EVTM. Here's the one from the section that includes most of what we've been talking about:

Gary, AKA "Gary fellow": Profile

axe2011

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Do you know what a infrared mileage sensor is? There is a plug under the dash but nothing in it, should it have something or does it matter?

1986 F150 RWD Automatic 5.0 EFI

Gary Lewis

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Administrator

It is actually an "inferred" mileage system, and you can read about it at Documentation/Emissions/Inferred Mileage System. If the writeup is accurate then w/o that the ECA (computer) is going to think it is in a brand new vehicle and will probably give the engine a richer air/fuel ratio to account for an assumed tight engine.

So when you get the truck going well and it seems like it is still running a bit rich, that might be the culprit. And it would seem that just placing power on the T/LG wire would solve the problem, but I don't know that for sure.

Gary, AKA "Gary fellow": Profile

Gary Lewis

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Administrator

Actually, your system is slightly more complex than the one shown on the page referenced. You can see the inferred mileage system in the lower left of the schematic below:

Gary, AKA "Gary fellow": Profile

axe2011

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Got it all back together and running again! Seems to be idling pretty high, but when I shift into a gear it drops in rpm to what seems more normal. Maybe a vacuum issue, not sure yet. Slow progress!

1986 F150 RWD Automatic 5.0 EFI

Gary Lewis

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Administrator

Excellent! You are making progress, and as Jim says, progress is good!

Gary, AKA "Gary fellow": Profile

FuzzFace2

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

In reply to this post by axe2011

Good to hear it is running again

What was the fix or we have not got that far because of the mangled fuel rail?
I did see something about pin 17 & 48 but nothing about swapping them around, was that the cause?
Dave ----

Dave G.
81 F100 flare side 300 six / AA OD / NP435 / 2.75 gear
http://cars.grantskingdom1.com/index.php/1980-Ford-F100?page=1
81 F100 style side 300 six/SROD parts truck -RIP
http://cars.grantskingdom1.com/index.php/1981-Ford-F100

axe2011

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Well the mangled rail was causing all kinds of problems. There was a wire spliced into one of the injector banks which was grounding out the system and making it spray fuel all the tie into the motor. After I fixed that I had an issue with the pressure regulator, after changing that I was unable to get the mangled fuel rail to seat without leaking, so that put me on hold. Finally got a new rail and put it all together and it runs! Figured out the high idle…some dummy (me) forgot to plug the pcv hose back in. That made a huge difference. So now I’m down to trying to figure out a couple last wires. One is a orange wire from pin 49 on the computer, I don’t understand how it hooks into the o2 sensor. Pin 29 goes to it and it’s plugged in and seems to be a single blade connector so not sure how that works. The other wire I’m trying to decipher goes to a plug that ends behind the battery. Right now I have it rolled up, not sure where this should pop into the harness.

1986 F150 RWD Automatic 5.0 EFI

85lebaront2

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Administrator

Orange wire is the O2 sensor ground. It should have a pretty good sized lug on the end of it and I believe went on the rear right (passenger side) intake manifold bolt (will have a stud on the top for it).

Bill AKA "LOBO" Profile

Gary Lewis

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Administrator

In reply to this post by axe2011

You are making really good progress! I'm impressed!

Is that wire you are holding all green? I can't tell, but I might be able to find it in the EVTM if I knew its color(s) and what other wires are in that connector.

Gary, AKA "Gary fellow": Profile

axe2011

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

In reply to this post by 85lebaront2

This is what confuses me. The wire from pin 29 exists and it has the connector to the O2 sensor which is a single wire sensor and wire. I don’t get how the orange one hooks in

1986 F150 RWD Automatic 5.0 EFI

Gary Lewis

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Administrator

I think your truck is more like the '85 EFI, shown on the left, than the '86 EFI which is on the right. If you only have the one wire (DG/P) and no orange wire then that seems to prove it. But, does your harness have the orange wire going to pin 49?

And, do you have the calibration code for your engine? Label on the valve cover? Or, what's the # on the computer? If we have some of that info I may be able to figure out what you have.

Gary, AKA "Gary fellow": Profile

axe2011

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

The Orange wire is just hanging there right now near the firewall. It’s currently capped. I’ll have to look around for the code when I get home.

1986 F150 RWD Automatic 5.0 EFI

Gary Lewis

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Administrator

Check to see if the orange wire does go to the computer on 49. And look for #'s on the valve cover and the computer.

I think your truck is a combination of parts - that don't completely mesh.

Gary, AKA "Gary fellow": Profile

axe2011

Re: 1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

Sorry about the delay, wife’s starter went out today so I was baking in the sun in the gravel fighting that. I have attached a picture of that plug with the wire I don’t know where it goes.

The orange wire does in fact go to pin 49 on the ecc.

The stickers on the valve covers are gone so all I have is the computer. The one pictured is the old one, I have a new one in it but it was supposed to be a direct replacement.

1986 F150 RWD Automatic 5.0 EFI

1234