Ok well to start off with I have a '86 Ford f150 302 v8 EFI 4x4, today while driving it after it warmed up, I was @ a stoplight I gave it gas and it was missing horribly, I mean it was barely enough power to move the truck, so I babied it up the road and pulled over, everything seemed ok started it and it was idling way low like 500 rpms, gave it gas same thing missing... I pulled the code by watching the blinking light and it keeps blinking 31, its EEC-IV I have no idea what this code could mean or if it has to do with the miss... needless to say it started running ok but if I whack the throttle open it will take off for like 5 seconds then start that miss again... I recently had the intake manifold off lower, the only thing I can think of is that maybe the ignition coil or distributor got screwed up... the distributor matched up with the lines I had marked and everything lined up... besides I though if I screwed it up a little the puter would compensate? Hey guys Im up a creek here any suggestions...? Im gonna let it cool down and see if it still does it while cool... Please

 

first question is how long since you've changed the fuel filters, you should have in the fuel line. my 98's is inside the frame rail below the driver door. if you have power off the line then it falls on it's face. sounds like a clogged or restricted fuel filter. they should be changed about every 30,000 miles.

but you could also run by autozone. they'll read your codes for free.

 

Unfortunately no autozone around here... I changed my fuel filter about 3 days ago, brand new gas tanks, brand new fuel pumps, brand new injectors, I think its safe to say it not the fuel... has to be something in ignition.... or something to do with that code... I just go tdone working on it and this was like the "test" drive if you will...Anyone else have any idea?

 

Unfortunately no autozone around here... I changed my fuel filter about 3 days ago, brand new gas tanks, brand new fuel pumps, brand new injectors, I think its safe to say it not the fuel... has to be something in ignition.... or something to do with that code... I just go done working on it and this was like the "test" drive if you will...Anyone else have any idea?

 

After all of the replacement parts went on and you replaced the dist. did you reset the computer. ( Did you have the battery disconnected when you were working on everything.) there is also a very structured way to reset the EEC-IV after you power them down. all accessories off, start and let idle. Let it go several minutes then peg the steering and hold it a few seconds. do this a couple of times. then put it in drive and let it idle agian for a few mintutes. The older setups don't pick things up as fast nor are they as adaptive as newer versions. Be sure that it is fully warmed up before you try the steering and putting it in drive also. EEC-IV takes quite a while to go into closed loop and that is what it sounds like to me. You can run fine in open loop but when the computer kicks in it goes bad. Never rule out a problem or part just because it is new or just replaced. I guarantee you will go crazy trying to fix things if you sucker for the new part working perfectly.

 

Well I didn't disconnect the battery when I did everything, I think you may be right about the closed loop, I think when it gets to closed loop thats when the problem begins... could it be the timing? Ill check it tomorrow... does the EGR system only operate in closed loop?, is there anyway I can just throw the puter into closed, loop like a procedure or something...? Thanks guys for the help.

 

Closed loop will only happen if the engine is fully warmed up and operating somewhat normally. If something is really out of wack then it will stay in open loop.

I would say checking the timing would be a good thing to do. I don't think it realtes much to the problem you discribed but it should be checked anyway. Don't forget to unplug the spout and follow the rpm rec's on the emmission decal.

I would first disconnect the battery and reset the computer. You already have a hard code so if you reset and lose it you can still find out what it meant. Maybe a reset will correct some of you rproblem and then the code will be a mute point


After reading you rother post about doing injectors, could you poss have an air leak in the intake system. Cold and open loop it might not be enough to cause too much trouble but after the computer leans thing out and the engine warms up it might be causing the fuel starvation symptoms you seem to be experencing..

 

hmm I dont think I have a vacuum leak anywhere... if I did have a vacuum leak wouldn't the idle be very erratic? the idle is actually very smoothe.... let me ask does the EGR valve solenoids only operate in closed loop? What Ill do is if I can duplicate the problem, Ill pull the vacuum line off the EGR valve and see if that fixes it... what do u think?

 

KMdstud; Replace the ignition module, they are cheap,get one at autozone.I went crazy looking for the problem on my 89 Bronco.the thing would start and run good at idle,But when I went for the gas,it would boog down and sputter.So I gave the module a shot .Worked like a champ.I think Autozone can also check the old one for you. Try this before you spend money looking....... good luck Oldgray

 

k Ill take it to napa and see if they can test it... no autozones around here....

 

ok well, ignition checks out, I just drove it 60 miles today and not a dam thing happened... I think it may have been the EGR valve stuck open, as this truck was sitting for about 3 yrs... Also would a bad egr position sensor cause it to stay open? Thanks guys

 

I had an 84 cougar with the same motor. I believe the EGR system is configured the same on it as it is your truck.

Carbon gets into the EGR on these engines. Ford used to have a carbon trap they could install to catch it before it got to the EGR. I am not sure where you would find one now days but it was made by TomCo.

I used to have to clean that EGR on the cougar daily until I got one of those.
It went with the Cougar or I would send it for you to try.

tom

 

Ok well, Ill see what I can dig up, let me ask could I just disconnect the vaccuum line and cap it, and leave it disconnected...? Would this hurt anything? besides what is the point of the EGR system..? besides the usual line of lowering intake manifold temperature. Thanks guys

 

I had a 1985 F-150 302EFI for many years and 170,000 miles. About every 50,000 miles my dealer recommended changing out the secondary fuel filter. There are two fuel filters on these trucks. I'm not sure where this one is located, but it is an in-line filter and the Motorcraft part comes with the filter fitted into the fuel line. Seems like it was not a particularly cheap part. If it has never been changed on your truck and that's a good possibility - this could be your problem.

 

ya know Napa and the Ford dealer told me the same thing that theres a secondary canister type fuel filter, needless to say I follow all the fuel lines from the tanks all the way to the fuel rail, and the only canister looking thing is the switcher valve which I tried to unscrew the bottom of and it broke, so I threw 200 bucks out the window... theres only one filter on this truck... the inline right after the fuel pump... not sure if someone modified it or not... but anyway so could I just disable the EGR system without any adverse effects?