1986 emissions nightmare
 

My 1986 F-150, with the 4.9 motor, has been ruthless to fix and I was seeking some guidance as I'm attempting to keep the stock fuel system. I bought a "direct fit" MagnaFlow catalytic convertor w/ pipe and attempting to join the 12" stem to what I have left to connect the smog pump. I don't have a welder and was hoping to use some sort of coupler to join the 2 (outside diameter of both steel pipes is 3/4"). As the connection will be hot, I was thinking of perhaps buying a piece of copper pipe and using clamps, such as cable clamps, to make it air tight.... thoughts?

Now for the whopper. I've tried running the codes with my reader and have been unable to get them. I've cleaned the connections on the red multi-pronged connection and the single connection on the red/white wire. I, of course, have the key on, and even put the manual transmission in neutral while holding the clutch in (after powering up the reader and pressing test/hold). I even took apart the computer and saw no breaks on the back of the board. What I have not done, however, is start the truck, let it run for 10 minutes, turn the ignition off, turn the key back on and run the "engine off key on" procedure; I'm wanting to get it running decent before torching the brand new cat with a super rich mixture. Is it possible to get codes without warming the truck up?

I'm wanting to keep the stock emission system as all components are present and appear to be in good shape... but a fried computer may end up being the straw that results in my bully getting durasparked.

Thank you in advance for your help with this... Ray

Do you have emissions testing?

I don't but am trying to get the best possible fuel economy. My last bully had half the emissions stuff missing so durasparking it was an easy choice. This one has low miles and is bone stock... so it's tougher for me to trash the emissions.

Still no codes
 

I am very grateful to those who have helped with my silly questions on this forum... everybody's feedback is helping me make the most reasonable decisions moving forward.

So, I bolted on a 4 foot pipe to the manifold and left the catalytic convertor off and the air pump line disconnected (neighbors aren't too happy with me). I did find a Walker kit to properly connect said smog/air pump. However, I'm stumped on getting codes still.

I did warm the truck up and felt the outlet of the air pump and there was zero pressure and/or airflow. I tried following the procedure for the code reader to a T; hooked up reader (as seen in picture), made sure reader off, started truck, warmed it up, turned ignition completely off, waited 10 seconds and turned ignition on to observe "emissions light" cycle on/off, turned reader on and pressed test/hold, got back in truck and held clutch in with tranny in neutral... no codes and nothing in the memory.

(1) Is it safe to assume the smog pump is not properly working as it is not blowing out the outlet?

(2) Is it safe to assume computer is not working as no codes are being read?

Thanks again for helping folks
https://cimg5.ibsrv.net/gimg/www.for...71aa7d1f5b.jpg

I have never used one of those all-in-one readers before. I have always used the testlight or old analog voltmeter like in this link.

EEC IV Self Test hookup

If you look at the connection diagrams in the above link, you will see the indication device, whether it is a testlight or old voltmeter, uses the battery + for power, and the computer grounds terminal #4 to give the code indication. How does your little code reader get power? It needs to get power from somewhere to get an code indication. If it gets power from the plug somewhere, maybe yours is missing power. I see that it has numbers on the screen, does it take a internal battery in the reader?

Why don't you try the method in the above link and see what you get?

The reader I have is battery powered and works good on my 89 as it records the 4 or so codes that my Ranger spits. But, the old 86 F150, might do good with a test light as I just want to make sure the computer is working... that's a good idea and I'll definetely try it. Thanks much!

There have been other posts of members not being able to use readers for the same reason, just would not work and think they all used the test light.
Dave ----

I followed the test light instructions and got no flashes... making me more convinced there is a wiring and/or computer issue. Also, as can be seen in attached pics, there is a wire that the previous owner(s) have disconnected as well as a vacuum line that has been plugged. I suppose I could shell out another $100 for a computer but I'm leaning heavy towards buying a new carb off Amazon, the "painless" harness, new distributor and coil... and durasparking this beast.

Thanks again all for your help, I've given it a valiant effort to keep this stock but think I might have to make er simple and easy to work on.
https://cimg6.ibsrv.net/gimg/www.for...6081b5e3b0.jpg
Disconnected wire above valve cover and next to carb
https://cimg8.ibsrv.net/gimg/www.for...6817877928.jpg
Blocked vacuum line running to \"tree"

I applaud you for trying to take the high road, but your plan B is what I would do. That painless harness is awfully expensive, I would go junkyarding and see what you can find. For the blue plastic module and wiring to the distributor, any Ford or Mercury car or truck, any size engine would work from the late 70's to the early 80's. Just make sure there is blue plastic where the wires come out of the module. You will need a 4.9 distributor, you need one with the vacuum line going to it.

If you want to do this in small steps, it will run ok with the retro fit distributor system and the feedback carb, till you can get an older carb for it.

If your truck is a manual it will not send codes unless the clutch is depressed. depress the clutch either with a helper or an approtate sized 2x4 or by pass the clutch interlock switch then turn on the igntion and retrieve the codes.... The Clutch has to be depressed before you turn on the code reader....

Grateful for help
 

Thank you all for helping with this.. I am grateful for your time. I have been pushing in the clutch and still no codes. Also, I did check all the fuses and all seems good. Last time I had the truck running, I didn't feel air coming out through the line leading to the cat but did feel air coming out a hole in the back of the pump (perhaps the pump is working and a solenoid is bypassing air out another path as the engine is cold?).

I live in Medford, Oregon and was thinking of maybe running my truck out to a mechanic to help as I'm on the edge of wanting to Duraspark it. This could be a problem, though, as the other time I converted an 86 Bronco to Duraspark the wiring was fairly stock; I simply spliced in the 2 factory ignition wires to the 79 harness I bought at a junkyard, spliced in a one ohm resistor and connected the "run" wire to the positive side of the coil... I ran that Bronco for years that way. However, my current project has some "special" additions including non-stock wires leading to/from a removable security chip that when removed in the cab renders the truck inoperable (the starter relay is far from stock with spliced in wires).

I feel compelled to keep at this project by purchasing Painless Wiring part #30812 and starting over but am hesitant to cut/splice the red/white wires coming from the ignition control module. I have been unable to find a junkyard that has a Duraspark harness for sale.

Since rebuilding the carb, the truck does seem to run better and I suppose I might drive it for a while and think things over...

Thank you all again. Seems every time I find another bullnose, I battle with the previous owner's modifications :)

I think the security chip mod is the reason you're not getting codes. Or a Dead ICM. But we need to verify it is getting power. See attached photo. Remove ICM and measure VDC to ground. Are you getting 12V at pin 37 (keep alive power?) with engine on or off? Are you getting 12V at pin 57 (ICM power) when key on/start?

Also sometimes these code readers don't work for whatever reason, have you tried the simple test light method to read codes? See bottom illustration for reading codes with a $4 light. Also, If you choose to go to a shop, make sure they know old fords before you waste money.
https://cimg3.ibsrv.net/gimg/www.for...3e2402b164.jpg
https://cimg7.ibsrv.net/gimg/www.for...a5ce6e118d.gif

I just realized these pinouts may be for the 5.0, but you get the point. Used 4.9 ECMs are 20-50 bucks free shipping on ePay. Maybe buy a new one at the store and swap it in and see if that fixes it, if not return it.
Either way, I'd troubleshoot with the VOM and test light as noted first.

Im willing to bet the solution will cost very little, just a loose wire or something.

https://cimg8.ibsrv.net/gimg/www.for...e55035d830.jpg
Maybe try this arrangement