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1986 F-150 XLT "Ellie"

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Wesley

1986 F-150 XLT "Ellie"

Starting a thread to detail progress fixing up my truck.

A little history: Bought in 2008, drove it until 2010 or so. Had to park it when I started college, but kept it running until around 2015. Had it towed to my mechanic a couple weeks ago and asked them to get it turning over and safe to make it a few miles home. Will post a few more pictures when I finish cleaning it up.

Just serviced:

Fuel injectors

Fuel lines

Fuel tank, forward

Master cylinder

Brake lines

Tires

To do soon:

Replace some light bulbs

V belts

Radiator hoses

Heater hoses

Diagnose high/oscillating idle

To do eventually:

Deal with cab rust

Repaint

Work on interior

Wesley
---
"Ellie" / 1986 Ford F-150 XLT Lariat / 302 / AOD

Gary Lewis

Re: 1986 F-150 XLT "Ellie"

Administrator

I call "shotgun" for this ride.

If you've had that much done to it then it should be about to turn the corner to reliability. But the idle issue could be a problem. Sometimes those are tricky to diagnose.

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

salans7

Re: 1986 F-150 XLT "Ellie"

Props to you for keeping it all this time! I bought a truck in 2008 as well, but unfortunately lost interest briefly, and made the decision to sell it in 2017. There will always be a part of me that wishes I had tried a little harder to regain interest.

I hope you'll stick around and keep us updated on the truck.

Wesley

Re: 1986 F-150 XLT "Ellie"

This post was updated on .

In reply to this post by Gary Lewis

Thanks!

And as for the idle, it's not a problem I recall having before. It runs high for a minute after starting, then when it tries to find normal idle, it falls and then revs back up again. I don't have a tachometer so I can't give numbers. Would welcome suggestions! Wondering about the IAC or the vacuum lines.

Wesley
---
"Ellie" / 1986 Ford F-150 XLT Lariat / 302 / AOD

ArdWrknTrk

Re: 1986 F-150 XLT "Ellie"

Administrator

IAC, or the MAP sensor by the starter relay.

But does it always hunt at idle, or only when cold?

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Wesley

Re: 1986 F-150 XLT "Ellie"

Hey Jim, pretty sure I've let it warm up and it continues. Going to pull codes today.

Wesley
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"Ellie" / 1986 Ford F-150 XLT Lariat / 302 / AOD

Wesley

Re: 1986 F-150 XLT "Ellie"

In reply to this post by Wesley

Pulled error codes today and got:

41
34
13

The last one is strange (idle out of range - low) because I'd swear by the sound of it the idle is too high. 41 indicates the engine is running lean. And 34 indicates something wrong with the EGR circuit/sensor or the EVAP control system. Plan to test the EGR valve and vacuum lines to see if I can find the issue.

Wesley
---
"Ellie" / 1986 Ford F-150 XLT Lariat / 302 / AOD

ArdWrknTrk

Re: 1986 F-150 XLT "Ellie"

Administrator

Let me tell you something about OBD1 codes.
There's a hierarchy to them

Always start with the lowest number first.
They are set up so lower numbers are often the root cause of higher error codes.

And I would think that your truck thinks the rpm's are too low, and that's why the IAC has it revving high.

Resolve that.
Reset and check later for codes.
They may very well not come back.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

ArdWrknTrk

Re: 1986 F-150 XLT "Ellie"

Administrator

If you have an evap code it may well be a vacuum leak.

But I think you should check into why you're getting a code for 'idle too low' when it's really too high.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

FuzzFace2

Re: 1986 F-150 XLT "Ellie"

ArdWrknTrk wrote

If you have an evap code it may well be a vacuum leak.

But I think you should check into why you're getting a code for 'idle too low' when it's really too high.

Would a TPS out of adjustment cause this?
Wait maybe not as it would be reading the RPM from the IGN system right?

Never mind me I don't know what I talk about

That is why my truck dose not have a computer, I make all the adjustments.
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

Wesley

Re: 1986 F-150 XLT "Ellie"

I've got a CD with the shop manual on its way for my truck, but a quick search on a Code 13 indicates I should check for a vacuum leak and then the air bypass valve. Need to pick up a propane torch for that.

I replaced the IAC and TPS on the first go-round (10-odd years ago) but who knows what sitting might have done.

Wesley
---
"Ellie" / 1986 Ford F-150 XLT Lariat / 302 / AOD

Wesley

Re: 1986 F-150 XLT "Ellie"

Quick clarification -- the Chilton guide indicates a Code 13 actually means the engine couldn't reach its lower RPM limit, NOT that the RPMs are too low. So at least I'm not imagining things.

Wesley
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"Ellie" / 1986 Ford F-150 XLT Lariat / 302 / AOD

ArdWrknTrk

Re: 1986 F-150 XLT "Ellie"

Administrator

Ok.
But that would suggest that the computer doesn't recognize the actual rpm's.
I understand that V-8 tachs need to be grounded and I-6 engines not.

Perhaps the issue starts there?

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Wesley

Re: 1986 F-150 XLT "Ellie"

My F-150 didn't come with a tachometer, but I'd assume the electronics are all there?

Wesley
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"Ellie" / 1986 Ford F-150 XLT Lariat / 302 / AOD

Wesley

Re: 1986 F-150 XLT "Ellie"

Belts replaced today, and it turns out my ears aren't as reliable as I thought. Tested for vacuum leaks and didn't find any, then recorded and analyzed audio of my engine at idle. If I did it correctly, I'm estimating an idle RPM in the neighborhood of 600. The idle seems to have stabilized too.

Still throwing those codes though, and I would like to try to resolve them soon-ish. To be continued.

Wesley
---
"Ellie" / 1986 Ford F-150 XLT Lariat / 302 / AOD

Gary Lewis

Re: 1986 F-150 XLT "Ellie"

Administrator

In reply to this post by Wesley

Electronics no. Wiring yes. Trucks w/o gauges, meaning those with idiot lights, didn't have the wiring for a tach. But in '86 Ford dropped the idiot lights, so you should have gauges and the wiring should be there. You just need the tach and, maybe, the flex circuit on the back of the gauges.

Gary, AKA "Gary fellow": Profile

Wesley

Re: 1986 F-150 XLT "Ellie"

In reply to this post by Wesley

Hoses, thermostat, front brake pads, wiper blades replaced. Cleaned the air filter (K&N). Truck is overheating, and since the fan is running I suspect it's the water pump? No coolant leak.

The idle issue seems to have resolved itself. Reset the computer, so I'll try pulling codes again and see if they're still there.

A few more odds and ends should make it driveable.

Wesley
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"Ellie" / 1986 Ford F-150 XLT Lariat / 302 / AOD

FuzzFace2

Re: 1986 F-150 XLT "Ellie"

Keep plugging away and before you know it it will be done.

How do you know it is over heating?
Dash gauge or after market gauge or temp gun to get temps and if so from where?
Dave ----

Wesley

Re: 1986 F-150 XLT "Ellie"

Aftermarket gauge I installed when the dash gauge failed. After replacing the thermostat and coolant I started it up and the temp was holding steady at about 190. Drove it around the neighborhood and it rose steadily up to 220-230 before I got it back.

Wesley
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"Ellie" / 1986 Ford F-150 XLT Lariat / 302 / AOD

old55pete

Re: 1986 F-150 XLT "Ellie"

With the engine running, take off the raidator cap. After the engine comes up to temp, you should be able to see the coolant flowing out of the end of the tubes.

I have seen a radiator plug with coolant in the past. The test I am giving will only tell you it you have flow, thats all. The thermostat being in backwards will also make it not flow.

All I am saying is do some testing before you start changing parts.

Steve
86 Bronco, XLT, 5.0 EFI, EEC IV, AOD, IFS, limited slip front and rear, 3.08 gears, Tilt steering, factory AC