1986 F150 RWD Automatic 5.0 EFI. - Injector Problems

[Gary Lewis]

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?

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?

[axe2011]

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?

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!

[85lebaront2]

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, 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.

[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.

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

[axe2011]

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

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.

[85lebaront2]

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.

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.

[axe2011]

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.

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.

[Gary Lewis]

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.

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?

[axe2011]

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?

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?

[Gary Lewis]

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?

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.