Boudleaux (My 1985 F-150 XL)

Hello fellow Bullnose enthusiasts.  I've had Boudleaux for 2 years.  He is VERY cranky and at this point I don't know what to do with him.  As you can see, he's very very good looking but looks ain't everything. Here's my problem (this month) After warming up (about 20 minutes) he will COMPLETELY lose acceleration  (like it's not getting enough gas or something).  So when you're driving 45 miles an hour it feels like a lunge then it collects itself again and then it loses it's momentum again. I will admit, I am not a very good mechanic but I've taken him to the same guy for 2 years and even he can't figure it out.  Does this sound like a common problem with this year with the introduction of Fuel Injectors?  I will list out just what's been done to the truck since I bought it and you can see at this point, It's like I just rolled it off the lot with what I put into it which is why this problem is so frustrating.



Brand new motor/mounts
New flywheel
Timing cover/set
Distributor/wires/plugs
Alternator/Regulator
Battery
Cooling Fan Clutch
Radiator
Idle air control valve
Ignition condensors
ALL NEW WIRING for God's sake
Coolant Temp Sensor
Ignition Coil
Fuel Gas shut off inertia and connector
Control computer
fuel pump

Any help and I mean ANYthing you got I'm willing to listen to.  I've spent close to $10,000 at this point and this truck just seems to have a curse lol

Luke

Also here's a link to a video of when I bought it 2 years ago.  If that helps.  Keep in mind, most everything you see under the hood has been replaced.

 https://www.youtube.com/watch?v=8JT1dxgovlc&list=TLGGtwH-653NxHkwOTA5MjAyMQ&t=5s

That's a beautiful truck Luke, sorry for your problems. I'm not real familiar with the FI vehicles but someone will likely be responding soon. Good luck!

Welcome aboard Luke!

And another thumbs-up for a very good looking rig!

There are a lot of very knowledgeable and helpful people here so hopefully it can get sorted out.  

Frankly, I’m working on a very similar problem to yours with my 1985 F-150 5.0L EFI, dual tanks. Very similar situation, running nicely then started to have a similar symptom of starving for gas. Currently a work-in-progress so parked in the garage with the plan to change out the gas tanks; however, the outside projects have priority at the moment.

Welcome!

Yes nice looking truck.

I would say the first thing is to hunt down if it is a fuel or IGN issue.
I would hook up a fuel psi gauge and place it so it can be seen and take it for a ride.
When it happens see if the psi drops off if not I would say most likely not a fuel issue but you are only checking the psi to the injectors.

Even if the computer is different dose not mean it is good and with todays parts its a crap shoot if you get a good one or not so keep that in mind.

I think as a test I would also drop the EXH system before the cat.
A plugged cat or muffler will kill power as the air coming in cant get out.
If that helps then you need to figure if it is the cat or muffler or just replace everything?
Dave ----

THat is a beauty!  I have no idea on your issues, but I know I read that description a LOT, especially on FB groups.   I don't think you are alone.  Wish I could help.

Thanks!  And thank y'all for the kind words!

Sorry I'm late to the game, but that sure does look like a nice truck.  Too bad it doesn't run well.

When you say you replaced the distributor did that include the TFI module?  That's the aluminum piece sticking off the side of it.  Those are known to have problems, and even if you did replace it you might have gotten a bad one.

Very nice truck! The problem you described sounds almost exactly like the one I'm having. Mine is also a 1985 5.0 with fuel injection. I'm betting they cut the video right when it started having trouble staying running.

I haven't replaced as much as you have, but I'm wary of replacing anything else until I've had more of a chance to troubleshoot.

Someone in here mentioned installing a fuel pressure gauge. I've noticed on my truck that there is no test port such as is found on later model fuel injection vehicles.

I suspect that my issue is fuel-related. I'm in the planning stages of upgrading to the 1990-up single in-tank high pressure fuel pump system. I already have the lines and fuel rail forward of the filter along with the filter bracket and a support bracket for the fuel lines. The only problem is that my truck is an odd ball: a long bed with a single amidship tank. Almost every truck I've found at the yards is a dual tank truck. I'm either going to have to figure something out with the fuel lines (they have a t-manifold on the later trucks where the rear tank meets the amidship tank lines) or hopefully find another truck with a single tank like mine.

I'm also going to be looking into vacuum leaks. I'm probably going to just get a whole bunch of bulk vacuum hose and run all new lines. I recently redid the exhaust and eliminated that cats. The problem is still there.

In my experience, fuel injected vehicles are more reliable, but they're way more of a pain to troubleshoot. Good luck!

We're replacing the TFI today, I'll let you know how it works!  Thanks for the advice!

Just as a follow up in case anyone ever reads this thread and has the same problem, it was the Engine Control Computer.  

I got your replay in a notification and had to go back and see what we were talking about.  

Glad you have it fixed.   These really can be great trucks.   But the most particular person to ever work on it will be you.   Sometimes you just have to learn to do it yourself.  

Hope it works out for you.

Glad you got it figured out.  Is the truck running well now?