86 f150 issues - Ford Truck Enthusiasts Forums

Notices
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks Discuss the Early Eighties Bullnose Ford Truck

86 f150 issues

  #1  
Old 09-03-2018, 03:31 PM
jcris
jcris is offline
Freshman User
Thread Starter
Join Date: Jul 2015
Posts: 27
jcris is starting off with a positive reputation.
86 f150 issues

Hello group,
Been working on my brother in-laws 86 F150 4wd. History is it has not run in a few years. The 351W was swapped out for a 91 injected 302 long before I worked on it. This truck will be used off road only.I had been trying to troubleshoot a no start issue which led to replacement of the starter relay (on the fender well) and was greeted by the contacts welding together on the relay. I thought bad (china) relay so replaced with motorcraft. Same problem occurred which led to a refresh of all grounds, ignition switch, neutral safety switch, and both positive and negative battery cables and problem has not resurfaced. Battery is also new and alternator is charging normally. Once that was solved fuel pressure at the rail was very bad which led to inspection of entire fuel system. We decided to replace the side mount (19 gal) tank with a 38 gal rear mount. Both high pressure pump on frame and low pressure pump in tank were complete junk. I mounted the new tank, repositioned the fuel fill, installed new low pressure pump in tank and modified it to account for deeper tank, replaced both vent and pressure fuel hoses up to first filter (the black plastic one mounted on frame referred to as a reservoir ) and installed new filter element in that housing which was not there to begin with. The hi pressure pump was also replaced as was the filter that leads up to the rail. The fuel pressure regulator was also replaced. I need to verify fuel pressure with a gauge but before it would only dribble out the Schrader valve on the rail and now pressure is consistent and appears normal. I will be checking that soon and report back. So now after all this work I find I'm not getting spark which leads to the replacement of the ignition control module on the distributor. I suspect that when we were having issues with the starter relay welding that took out the ICM. Not 100% thats possible but sure seems likely. So now I have spark and the motor starts but only stays running for a minute and slowly rpms drop and it stalls. It will stall right away if I try to give it any gas. The plugs are motorcraft, gapped at .054 . The plugs that came out originally were ac delco gapped at .044. They were also coated with carbon and were wet with fuel. The motorcraft plugs I've pulled to inspect and are not carbon fouled and also not wet with fuel . They look normal to me. Maybe the poor functioning fuel system and small plug gap contributed to the poor state of those plugs? The wires, coil and distributor are all new. I'm going to pull the ECU(computer) and check for any obvious signs of problems ( burnt traces bad caps) .What else can I check? I pulled the idle air control valve and it looks good and it tests ok electrically. Could a fouled 02 sensor cause the motor to flood out and stall? With an all new fuel system it seems unlikely one of the pumps could be bad. I did pull the tank pump to check it and it is working normally and I can clearly hear the high pressure pump cycle with key on not running.I also pulled the fuel regulator at the rail to verify that the return line was not clogged all the way back to the new tank.I know conventional wisdom is to pull the injectors and send them out for cleaning but that has not been done yet. What am I missing ? The last time I had it running, after the whole starter relay scenario it would idle fine. I was able to set base timing and idle was solid. Throttle response was good. Now this whole scenario has occurred and I'm thinking besides the fuel system being so crappy there must be other gremlins. Everything on this chassis is very rusty, I'm doing this to help my brother in law with something that has emotional attachment. I just want to get it to idle. I have yet to pull codes, I know big mistake. What do you think? Could a clogged catalytic cause it to stall? What about a stuck open EGR?
THANKS
I should also mention this truck is 6 hours south of where I live so I'm trying to send parts to my brother in law and figure out whats going on before I drive there.
Were close, just want to get it idling
 
  #2  
Old 09-04-2018, 02:27 PM
Franklin2's Avatar
Franklin2
Franklin2 is offline
Moderator
Join Date: Jan 2001
Location: New Market, VA
Posts: 42,032
Franklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant future
Have you ever looked at all those wires, sensors and the engine computer and wonder if it's all working or not? How would you know? There is a way. The computer will talk to you, and tell you anything it see's that is obviously not right and it's not happy with. All you do is pull the codes from the computer. Here's how to do it with a testlight or old needle type voltmeter.

EEC IV Self Test hookup

When you checked and set the timing, what was the procedure you followed? This truck is fuel injected, there is a special wiring plug you have to remove to set the timing.
 
  #3  
Old 09-05-2018, 11:20 AM
jcris
jcris is offline
Freshman User
Thread Starter
Join Date: Jul 2015
Posts: 27
jcris is starting off with a positive reputation.
Hello Dave F,
When I had the truck running after solving/getting past the whole starter relay issue I did set the timing. I removed the plug/jumper you referred too and set base timing at 10 degrees.
I will run the EEC4 self test again as soon as I can. I do recall pulling codes 18 and 31 but I'll double check those readings to be sure. This truck is several hours from me or I'd check the codes again now.
Thanks so much for the help
 
  #4  
Old 09-05-2018, 07:37 PM
ctubutis's Avatar
ctubutis
ctubutis is offline
Moderator
Join Date: Nov 2007
Location: Denver Metro Area, CO
Posts: 21,319
ctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputation
Remember to do all the sets of codes:

KOEO
CM
KOER

The engine should be warmed up a bit before running the tests.
 
  #5  
Old 09-06-2018, 02:27 PM
jcris
jcris is offline
Freshman User
Thread Starter
Join Date: Jul 2015
Posts: 27
jcris is starting off with a positive reputation.
At this point I can't get the motor to idle for more than a minute. I can restart it but the crank time seems a bit longer each time. It always dies as if it just ran out of gas. Thats just the way it sounds to me. We are going to double check the codes sometime this week. Maybe the codes will point to a component that is in need of replacement but we'll see. Once codes have been dealt with maybe then I'll be able to use the EEC test for a running motor and then find other issues. I'm wondering if there is a way to more accurately measure the intensity of the spark. It still appears more orange but with these old eyes its very difficult to tell. I also need to verify fuel pressure. The Schrader valve on the rail releases a pretty good amount of fuel to depressurize the system. Does that seem right? I mean shouldn't the return line release most of the pressure back to the tank? I really want to pull the rail and injectors cuz there is no history on them ever being serviced, at least back to somewhere after 91' when the motor swap was done. And theres no info on what was done during the swap. This was a running motor a couple years ago but that doesn't mean the injectors were in decent shape even then. When I get the codes and fuel pressure reading I'll get back.
Thanks for looking in
Jcris
 
  #6  
Old 09-06-2018, 02:29 PM
jcris
jcris is offline
Freshman User
Thread Starter
Join Date: Jul 2015
Posts: 27
jcris is starting off with a positive reputation.
When I get it to idle I'll be able to more thoroughly run the tests. At this point it runs for about a minute and stalls like its running outta gas.
 
  #7  
Old 09-06-2018, 04:30 PM
Franklin2's Avatar
Franklin2
Franklin2 is offline
Moderator
Join Date: Jan 2001
Location: New Market, VA
Posts: 42,032
Franklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant future
You can at least do the Key On Engine Off tests without running the engine. The computer will look around and see what's going on, and it will also generate any memory codes from when it last ran.
 
  #8  
Old 09-06-2018, 04:36 PM
Franklin2's Avatar
Franklin2
Franklin2 is offline
Moderator
Join Date: Jan 2001
Location: New Market, VA
Posts: 42,032
Franklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant future
If you want to do a poor man's fuel pressure test, get a regular pressure guage of any sort, you are going to be reading around 38-40lbs, so don't get a 1000 psi guage, try to get something that will give you a decent reading, a small 150 lb air pressure gauge will work.

Relieve the pressure at the schrader valve, then get one of those removal tools and take the guts out of the schrader. A lot of times those two wheel carts will have a removal tool on one of their valve stems. Once you have removed the guts, get a 3/8 or so hose and a small hose clamp and clamp it around the schrader valve, and then run that up to your gauge, using a hose barb or whatever you need to hook the hose to the gauge. I have even used this setup with a longer hose and ran it out of the back of the hood and taped it to the windshield to do road tests with a load on the engine and check fuel pressure under those conditions.
 
  #9  
Old 09-09-2018, 11:21 AM
jcris
jcris is offline
Freshman User
Thread Starter
Join Date: Jul 2015
Posts: 27
jcris is starting off with a positive reputation.
Finally got to checking fuel pressure at the rail. I have no pressure showing at all. Hereís what Iíve done :
i noticed the fuel pump relay connector was damaged as in part of the plastic was broken. So I rigged it to make the connection. Whatís strange is the relay has 5 pins and only 4 wires? I donít get that. Iím unsure whether the inertia switch is working properly so I just jumpered it out. Is that a mistake? Work will continue today. Iím going to pull the ecu for a look see. And then Iím going to start over from scratch rechecking everything Including the eec4 relay , the fuel pump relay, Iíll report what else I find
 
  #10  
Old 09-09-2018, 11:45 AM
Franklin2's Avatar
Franklin2
Franklin2 is offline
Moderator
Join Date: Jan 2001
Location: New Market, VA
Posts: 42,032
Franklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant future
Some relays have a normally closed pin that is not used.

Is pulling the codes from the computer intimidating? You are not the first person we have had on here who had a computerized control system on their engine, and just flatly refused to pull the codes, they would rather replace every sensor on the engine rather than pull the codes from the computer. Pulling the codes may reveal nothing, but it's another very important tool for you to use to find out what the problem is.
 
  #11  
Old 09-09-2018, 11:48 AM
ctubutis's Avatar
ctubutis
ctubutis is offline
Moderator
Join Date: Nov 2007
Location: Denver Metro Area, CO
Posts: 21,319
ctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputationctubutis has a superb reputation
And they need to be pulled before the battery is disconnected to get the in-memory codes. It's not difficult to do and is quite honestly the #1 thing to do in my mind.
 
  #12  
Old 09-09-2018, 06:38 PM
jcris
jcris is offline
Freshman User
Thread Starter
Join Date: Jul 2015
Posts: 27
jcris is starting off with a positive reputation.
Pulled codes and this is what Iím getting
31, 18,63
and still showing no fuel pressure
these are new pumps the hi pressure is not working
i can hear the rear working.
I put a new socket on the fuel pump relay and it tests good
whats next
 
  #13  
Old 09-09-2018, 07:14 PM
Franklin2's Avatar
Franklin2
Franklin2 is offline
Moderator
Join Date: Jan 2001
Location: New Market, VA
Posts: 42,032
Franklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant future
Code 31 is a EGR code. Don't worry about it for now, but the EGR can cause it not to want to idle (big vacuum leak). You can block it off with a piece of metal from a pop can and worry about it later.

Code 18 is somewhat serious, the computer is not able to send signals to the distributor. The easiest solution to this would be someone has left the spout connector off. Do you know what the spout connector is? Has anyone ever checked the timing or moved the distributor on this truck?

Code 63 is a problem with the throttle position sensor.

You need to attack these problems by priority, I thought you had the fuel pressure problem fixed. That would be the first problem to fix.

Here is the fuel pump circuit. You will need a meter or testlight.

 
  #14  
Old 09-09-2018, 07:16 PM
Franklin2's Avatar
Franklin2
Franklin2 is offline
Moderator
Join Date: Jan 2001
Location: New Market, VA
Posts: 42,032
Franklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant futureFranklin2 has a brilliant future
I would go the easiest place to get to and measure to see when and if you have voltage. One spot would be the inertia switch. Put your meter there, and when you cycle the key, do you have voltage there? It should prime the pumps and then shut off.
 
  #15  
Old 09-10-2018, 04:39 AM
jcris
jcris is offline
Freshman User
Thread Starter
Join Date: Jul 2015
Posts: 27
jcris is starting off with a positive reputation.
Thanks franklin,
I will check the inertia switch I did jumper it out to eliminate it as potential problem. I will review that fuel system print tomorrow The distributor is new, installed last year. This motor was running with that distributor and idled smooth. I know about the spout as itís part of setting base timing. Itís a simple jumper if Iím remembering corrrectly . Without it you canít canít give it throttle or it stalls. I know the jumper is in place but Iíll recheck the wiring. The PIP is also new . I just replaced it a couple days ago after which it would actually start but consistently stall. Thatís when I put a fuel gage on the rail and have yet to see anything beyond 12 psi. More later today
 

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2018 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.