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1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

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Rusty_S85

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

Gary Lewis wrote

Yes, .6 ohm is almost a dead short. Zero ohms would be a dead short, but I'll bet if you touch the leads of your DVM together it only comes down to .2 or .1 ohms. In that case you are seeing the resistance of the leads - or a meter that hasn't been zeroed.

Your truck may well be like many others - an onion you'll have to peel and cry, peel and cry. But eventually you'll have enough for a mess of onion rings!

Seriously, you will need to sort out that wiring. It is ok for the wire to be the wrong color as long as it goes from the right place to the right place(s) and nowhere else. So get the injector wiring sorted and then, once the engine will run, work on the next layer of the onion.

How he can check for a short is to unplug the harness completely for that circuit then check the circuit to ground and then check the circuit to positive with it completely disconnected and isolated it should show up NA or OL. If there is any reading then it is confirmed shorted to either ground or voltage.

Its a fairly basic test us technicans do at work to isolate circuits and verify a short to ground or power.

Lets say the wire is from connector 1 to connector 3. You unplug connector 1 and unplug connector 3. You then probe the wire at connector one and at connector three check resistance. Then remove one of the probes and touch it to chassis ground or negative battery cable (battery should be disconnected for any resistance tests) if you get a reading with the wire isolated it is shorted to ground. Do the same thing to the positive cable, if any reading then its shorted to power. Once you confirm this you can unwrap that leg of wire and find the short.

It is quite possible the reading he is getting is "normal" in a sense and may not be an actual short. Its also quite possible the short isnt in the wire itself but is in the ECM itself internally which you wouldnt know unless you unplug the circuit to isolate it from everything else.

"Old Blue" - '56 Fairlane Town Sedan - 292-4V, Ford-O-Matic transmission, 3.22:1
'63 Belair 2dr sdn - 283-4V, Powerglide transmission, 4.56:1
'78 Cougar XR7 - 351-2V, FMX transmission, 2.75:1 9inch
"Bruno" - '82 F150 Flareside - 302-2V, C6 transmission, 2.75:1 9inch, 31x10.50-15 BFG KO2

Gary Lewis

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

Administrator

Axe - Rusty is right, your readings look normal, but you really aren't testing correctly. Try the way he suggested - test to ground, which seems to be the problem you were having. Having said that, I don't think your problem is in that harness. I think it is in the one going to the computer. And you don't want to be testing with the computer plugged into the harness.

So I suggest you unplug the computer and then test the wire that is supposed to go to pin 58. You should see nothing when testing to ground or to power. I think you may find that it shows low resistance to ground.

Rusty - I think he's already tested with another computer and gotten the same results, so it must not be the computer.

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

axe2011

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

I think I made some progress tonight. We took a test light and found that pin 58 wire had a diode spliced into it that goes to the drivers side of the truck. When I unplugged the connector on the other side of the diode it stopped grounding the injectors. I then looked at pin 30 and found that it didn’t go to a diode like it was supposed in the diagram to but rather straight to a unused plug on the passengers side of the truck. We cut the grounding wire off the pin 58 wire and we’re going to test it out….but of course in the process of pulling in and out injectors I messed up an oring….so gotta pick up some of those now. Fingers crossed I have the first layer figured out and I can rewrap some wires.

1986 F150 RWD Automatic 5.0 EFI

Gary Lewis

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

Administrator

Yippee!!! That is great progress! I'll bet the thing will run once you get the o-ring replaced. If so, you have one layer peeled.

Gary, AKA "Gary fellow": Profile

axe2011

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

I got some o-rings and put the rail back on. The truck started and ran!! In the process I may have killed off a sensor that sticks into the side near injector 6 and 7. I have to figure out what that is and get a new one, but I was able to start it. I let it run for a few minutes and then went up and down the driveway. I didn't have temp reading so I turned it off because I didn't want to have it overheat and me not know. I appreciate everyone's help with this first issue! I am sure I will find more as I try to figure out what happened to the old girls wiring.

1986 F150 RWD Automatic 5.0 EFI

Gary Lewis

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

Administrator

Excellent!!! You really solved a tough problem. Well done!

On the sensor, there may be a number on it. Let me know what that is and I should be able to figure it out.

Or give me the color of the wires if there is no number.

Gary, AKA "Gary fellow": Profile

Rusty_S85

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

In reply to this post by Gary Lewis

Gary Lewis wrote

Axe - Rusty is right, your readings look normal, but you really aren't testing correctly. Try the way he suggested - test to ground, which seems to be the problem you were having. Having said that, I don't think your problem is in that harness. I think it is in the one going to the computer. And you don't want to be testing with the computer plugged into the harness.

So I suggest you unplug the computer and then test the wire that is supposed to go to pin 58. You should see nothing when testing to ground or to power. I think you may find that it shows low resistance to ground.

Rusty - I think he's already tested with another computer and gotten the same results, so it must not be the computer.

When it comes to electrical systems you kind of have to view the component as possibly bad even if it isnt. Ive seen brand new electrical parts fresh out of the box be bad so I try not to write a new part off as good.

I went through that with an alternator on my '63, it took 4 alternators to get one that actually charged, the guy at the parts house told me that he wont give me another one cause if this one doesnt fix it then its something wrong with my car and not the alternators. I told him the old one was charging it had a bad diode trio resulting in a short to positive and a dead battery over night. The 4th alternator fixed it but those previous 3 so called new/remanufactured alternators were defective out of the box.

axe2011

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

In reply to this post by Gary Lewis

Left town for a couple days I’ll try to get on number on it Thursday or Friday depending when I get back from my work trip. Again thanks so much for your help!

1986 F150 RWD Automatic 5.0 EFI

85lebaront2

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

Administrator

In reply to this post by Gary Lewis

Gary, that should be the knock sensor, 1985/86 it is driver's side center of the lower intake. So it is between 6 and 7.

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

I’ll have to check it out. When I was kneeling on the front tracing wires I slipped and broke it off.

I noticed that they deleted the coolant lines that go through the throttle body. The top one is fine and I see the hose that is clamped that I can hook back up, but the bottom hose port has been smushed and soldered shut. It looks like it is separate of the throttle body and could be threaded out and replaced possibly. I live in Iowa so it does get cold here. Is it worth fixing? Anyone know what this part is called and where I could get one?

1986 F150 RWD Automatic 5.0 EFI

Gary Lewis

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

Administrator

Bill - Thanks.

Axe - I think I know the part you are talking about with the little coolant hoses, but don't see it in the illustration. Am I missing it?

Also, on the part that you broke, if it is the knock sensor it is surely this one: E3AZ 12A699-A Sensor assy, (engine spark knock intensity) and it will be marked #E3AF 12A699-AA. I say that because all of the '86 5.0L engines with a knock sensor appear to have used that one. But the trucks with a C6 don't appear to have one. Your truck has the AOD, which means the gear shift lever has a OD position?

Gary, AKA "Gary fellow": Profile

axe2011

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

It does have the od gear. I’ll have to check once I get back.

I don’t see the coolant tubes either on the diagram but it exists!

1986 F150 RWD Automatic 5.0 EFI

85lebaront2

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

Administrator

In reply to this post by Gary Lewis

Gary, those may only show under cooling system. I have yet to figure out what logic is used in parts catalogs. Mercedes-Benz Diesel cars have a "snubber" mount on the front of the engine, to find it you have to look in the front suspension section.

Bill AKA "LOBO" Profile

Gary Lewis

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

Administrator

Yeah, I'd thought of that as well, but here's the closest illustration to a 5.0L EFI cooling system, and it doesn't show that stuff either.

But, they do sorta show on the 460's illustration, although the base part number is just for a connection, not anything specific to EFI. In fact, 9C789 doesn't show in the 1980 - 89 Master Parts Catalog nor the 1986 Standard And Utility Parts Catalog. Assuming the 302 takes the same ones as the 460 I see three solutions:

Drive w/o the heat, which may work fine as Ford dropped it in later years

Find a hose fitting that will press into the throttle body at that point and replace the smushed one - assuming the smushed one will come out of the throttle body.

Replace the throttle body with one that has the proper connections

Gary, AKA "Gary fellow": Profile

axe2011

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

Back from my trip. I took some photos!

Here you can see the smushed port in the bottom right. It seems to be separate on a coolant tree…not sure if that’s the right terminology.

This is that sensor I broke. I tried googling that number printed on it and didn’t have much luck yet.

1986 F150 RWD Automatic 5.0 EFI

85lebaront2

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

Administrator

Ok, the coolant lines are mainly for heat for anti icing in cool damp conditions (35-38°F). If there is enough meat in that area of the throttle body maybe a screw in fitting will work. If not, the basic TB assembly was used through 1996 on the 302 and 1997 on the 351.

Knock sensor PN is: E3AZ-12A699-A but it shows as discontinued. In 1987 it was moved to the back, top of the block behind the intake manifold. Maybe the later, 1987-1995 would work. You might try Green Sales Company, I couldn't even find one on eBay.

Bill AKA "LOBO" Profile

axe2011

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

Well here's an update.

Firstly the coolant lines. The coolant lines ports on the throttle body are fine, its the one on some kind of coolant tree on the motor that is pinched shut. Its a few inches towards the drivers side of the motor, seems to have a sensor that goes into the bottom of this "tree" and then above that is a port that I believe a short hose goes from to the bottom of the throttle body.

I found the knock sensor on Ebay (15.00) and have that ordered.

Now for the bad news. The fuel rail is bent, bad enough that the injectors don't particularly seat well, with a lot of manipulation I was able to get them to seat long enough to drive 2 miles. This is when I discovered my next issue.....:(

I believe that I may have a blown head gasket. My buddy has a tester that looks for vapors that he is going to bring over, but we believe that the coolant systems is over pressurized as it gets hot and then boils over out of the reservoir tank. So my quest to get this old truck going may be getting extended.

So now I think I may be tearing into this engine to fix this issue. Meanwhile I need to keep looking for parts such as the fuel rail.

If anyone has any suggestions or opinions about this I would love to hear them.

1986 F150 RWD Automatic 5.0 EFI

Gary Lewis

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

Administrator

I saw the post looking for a fuel rail. I don't have one, but hope you can find one.

As for the head gasket, if you find that you have a blown one then I would do a leak-down test before pulling the heads. A leak-down test can determine if you have bad valves, and if you do you'll want to have them fixed while the heads are off.

A leak-down test will also tell you how bad the rings are, which helps you understand how much money you want to sink into the engine. In other words, if you have several bad valves and the rings are leaking profusely they do you really want to just put a new head gasket on it?

Gary, AKA "Gary fellow": Profile

axe2011

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

Hey Gary, so good news. We tested the cooling systems with the chemical that changes colors if it finds fumes in the coolant and it didn’t have any. We think it might have had a bubble in the coolant system as we had recently changed the coolant. I added some more and drove it again and it didn’t boil over. So I think the head gasket is ok!

I will have to keep looking for a injector rail, I have seen some 5.0 mustang ones on eBay; they look similar, not sure if they would bolt up the same.

When driving I was able to drive around 55 mph on the back road by my house. It kind of cut out a little while going any faster than that. Not sure what would cause that yet. Maybe a vacuum issue?

1986 F150 RWD Automatic 5.0 EFI

Gary Lewis

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

Administrator

That's great news!

Yes, a vacuum leak could cause all sorts of problems. One way to find vacuum leaks is with the "smoke test" or, as David phrased it, Vacuum leak detection - effective and inexpensive.

Gary, AKA "Gary fellow": Profile

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