I am new to posting but have been lurking and serarching For a while.

Recently I picked up an 86 F150 302 EFI Auto dual tank 2x4 supercab for my 15YO daughter as her first truck.

We are having a start stall issue we cant diagnose. I bought a equis diagnostic tool and cant get codes.

Truck starts after 2-4 seconds, runs 15-20 seconds then dies and wont restart. Does run very smooth till she dies.

This truck sat for 8 months front tank was dry so we are doing al our testing from that tank. Plugs are good. Wires are good. Fuel pump on the frame rail sounds normal. The fuel bowl reservoir has no filter in it and there is no fuel filter on the frame rail.

Truck has to sit for several hours before it will restart.

The pic attached is the obd1 port and where you see my thumb there is no pin on the port but there is one on the scan tool. I cant get any codes, not even and all clear.


I did pull the reservior bowl off and noticed when trying to start very little fuel was making it. Fuel is clear and does not smell.

Not sure where else to look? Is the pin in the pic above in the wrong place can it be moved so I can get codes?

 

Well I started trouble shooting and decided to bypass this reservior


I disconnected the line from this to the HP pump and placed it in a 5 gallon can, then hooked up 3/8 fuel line from the reservoir to another 5 gallon can. low and behold the truck started and ran until I shut it off. Hooked everything back up and it shut off again after 20 seconds.

Seems that is the issue. Luckily one came with the truck along with 2 gallons of the matching paint code.

Here is the $700 truck the day it was brought home,


Motor was replaced by ford in 2004 and has 40K on it since, tranny also by ford in 2005. Truck came with documentation from Westway ford in Irving, TX and we confirmed this before purchase. Body is straight except for a dent under passender side tail light.

By November the plan is to have the motor and tranny gone through. New brakes all the way around. Interior cleaned, truck painted (father in law is a painter) and new wheels and tires. Hoping I can do this for another $2000.00 doing the work myself. This truck should last her through college provided she doesnt wreck it first. this wont be as interesting as some other builds but I will post progress.

 

Your problem is the filter in the bottom of the reservoir you bypassed is clogged. If have a metal fuel filter between that and the engine, you can remove and discard that filter and reinstall the cup making sure the o ring is properly installed. If you don't have a metal filter, you can just replace the one in the cup. Be very careful with the cup taking it off. Use a strap type oil filter wrench to loosen it up. If you try pliers, you most likely will crack the cup, and then have to buy a complete unit (if you can still get one) from the dealer. 85 was the first year of fuel injection and around 86, the filter in the cup was redundant while also utilizing the metal filter.

 

thanks big bronc, I replaced that reservior Monday night and it ran good for about 10 minutes. Has to be bad gas so I am in the process of sipohing everything out. I will then replace the cartridge in the filter and see what she does.

Strange thing, the original reservior had no filter and there was no inline filter. Luckily the new one had a filter.

Again, appreciate the advice

 

That pin's there on the code reader because the reader also accommodates MCU's as well as EEC-IV. Did you connect the single pin connector as well? If you have a #3145, see pages 18 & 19 in your manual.

 

thanks ymeski, i've actually followed all the procedures. No codes not even an all clear. we've drained one tank and will drain the other tonight.

will report back once we get her right with and update

 

What to do if you can't get codes: http://www.fordfuelinjection.com/?p=44

 

Did that too, nada,

the problem has to be in the tanks so that is the next step. Either lift the bed or drop the tanks and clean them out.

Truck runs outstanding when you place the HP line into a 5 gallon can of gas and runs great after you re hook everything until the truck runs 2-3 minutes. Sounds like the socks are getting clogged.

 

See what happens if you remove the gas cap on that tank to make sure your not creating a vac. situation in the tank.

 

Finally got time to drop the back tank and talk about a mess. Sock was in pieces more rust than I care to work through. Gonna pick up new tank, sending units and pump for the back tank. That should solve that issue.

 

If the ECU goes, so goes injector function, which could lead you to believe you have a fuel problem. If you have pressure at the rail, it implies no injector function.

 

Well I spent so mucgh time getting this thing ready that I failed to keep up with the build. Below is a pic of how she looks now and up until recently ran very well and was reliable.

2 new tanks and pumps
new u joints carrier bearing
new brakes all around
new rubber
new (used rims) 000 steel wool and good aluminum polish works wonders
new paint
new fuel pump on rail
new starter and selonid
new cap, rotor, plugs and wires
new TFM
new TPS
new radius arm bushings (FUN)
new power steering pump
and finally new stereo



With all of that done and cleaning the throttle bodies all of the sudden she developed a hard idle and stall issue. Started out just stalling at a stop going down hill, now has an eratic idel.

No codes at all come up and I cant figure this one out, sprayed soapy water on vacuum lines..nada. Any direction would be helpful as she just sits now.

 

I'd start with the basics: compression, fuel pressure, timing chain slack, timing, plug wire routing, plug gap... If you don't find the problem, move on to testing things like TPS, IAC, ECT, ACT, oxygen sensor, EGR... The MAP can be difficult to test, but as old as that truck is, it might have the easy voltage-varying type. If it's frequency-varying (they're impossible to differentiate without testing), pick up a few spares from the JY to swap in. If one of them makes an improvement, buy a new one.

. . . . . .

It's worth noting that, even on modern vehicles, battery terminal & grounding problems can cause random symptoms, like poor idle or stalling. So it's worth removing & cleaning all of them, just in case. Read these captions:



Lastly:
Leaky vacuum lines pull air IN, so soapy water would create bubble INSIDE the lines, and you'd never see anything. To find a vacuum leak with the engine idling, use a mechanic's stethoscope with the probe removed (or a 3' piece of garden hose) to listen around the intake manifold and all vacuum components for an obvious hiss, similar to the normal hiss in the throttle body/air filter.

 

Thanks Steve 83
Well after tons of testing earlier this week and last weekend I found nada. I ended up taking it to a shop we trust. If they cant figure it out I will look at converting to carb as I no longer have to pass inspection here. Its not as reliable as a good running EFI set up but I can convert for $600-$800 and save the headaches and the current EFI isnt reliable.

 

The early EFIs had several problems, but they're easy & cheap to solve once you ID them. A MUCH-better option than going backward to a carb is jumping forward to a newer EFI. Take a look at these:

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The black '83 Bronco in my sig has a '95 engine; the tan '94 CV has a '00 engine.