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86 5.0 efi runs terrible

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86' 5.0 short box

86 5.0 efi runs terrible

Hi im new to this whole forum thing. I purchased a 1986 Ford f150 with the 302 V8 efi engine. The guy I bought it from said it was sitting for around 2 years and when we went to look at it, it would run for a couple of seconds and die. Since then I have put a new high pressure fuel pump, a fuel pressure regulator, a map sensor, timed and made sure I had spark and correct firing order, the pip sensor is good, replaced some gaskets, the injectors are working correctly, all valve train is in good operational shape, and it has good compression (160-185 psi) I have got it to run better and longer than when I got it but it still isn't firing on # 3&4 cylinders. Also the smog pump is removed and the catalytic converters are removed, I dont know what to do next, any and all info helps. Thanks

Gary Lewis

Re: 86 5.0 efi runs terrible

Administrator

Welcome to the forum. But before we get to your truck, you were asked to go to the New Members Start Here folder and post there. That's because the guidelines we hold people to very closely are there. So, since you didn't, please assure me you've read them?

And, my usual first question when someone gives an intro is to ask them where home is. That's because we have a map (Bullnose Forum/Member's Map in the menu) and we could put you on if we had a city or a zip.

On the engine, have you pulled the codes the ECU is throwing? That would be the first step.

But, there were two firing orders for the 302. They are:

1-5-4-2-6-3-7-8

1-3-7-2-6-5-4-8

Which one are you using?

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

86' 5.0 short box

Re: 86 5.0 efi runs terrible

Yes I read the terms of use my zip is 56340 and I am using 15426378 because I do not have the ho model engine my ecu is not throwing codes other than 11 for all good

Gary Lewis

Re: 86 5.0 efi runs terrible

Administrator

Ok, you are on the map.

Have you pulled the injectors to see if they are plugged? I don't know how to do that as I don't yet have an EFI engine, but it would seem that if you've verified that the plugs are good, the wiring is good, and you are getting spark that it must be a fuel problem.

Gary, AKA "Gary fellow": Profile

85lebaront2

Re: 86 5.0 efi runs terrible

Administrator

In reply to this post by 86' 5.0 short box

First rather obvious question, are the plug wires on the right side (1-4) on correctly. 2 through 4 wires were buried under the plenum if I remember my son's 1986 F150 correctly. If they are correct, and there isn't any obvious plug issue, I would run a compression test, if that is good, due to the lack of access on the right bank, I would try this little test. With coil wire disconnected from the distributor and grounded, crank the engine for a short time and pull #3 and #4 plugs, they should be wet with gas. If they are dry, then you have either an injector or injector wiring problem.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

Rusty_S85

Re: 86 5.0 efi runs terrible

In reply to this post by 86' 5.0 short box

sitting 2 years? Id replace your injectors cause if the tank wasnt replaced with fresh gas and pump and it was ran on what was in the tank, the turned ethanol blended fuel will stick the injectors. What you need to do is first verify there is injector pulse which I am sure there is but verify it anyways. Once you verify then its time to flush the fuel system out and replace the filter and the injectors cause the others may not be sticking now but it will be a matter of time before they stick again while sitting.

"Old Blue" - '56 Fairlane Town Sedan - 292-4V, Ford-O-Matic transmission, 3.22:1
'63 Belair 2dr sdn - 283-4V, Powerglide transmission, 4.56:1
'78 Cougar XR7 - 351-2V, FMX transmission, 2.75:1 9inch
"Bruno" - '82 F150 Flareside - 302-2V, C6 transmission, 2.75:1 9inch, 31x10.50-15 BFG KO2

86' 5.0 short box

Re: 86 5.0 efi runs terrible

Yes it has compression yes the plug wires are on the right plugs and I took off the whole plenum and pulled the injectors out of the intake manifold and turned the engine over with a spark plug stuck in the coil wire and I have nice even shots of gas out of all injectors and while I was in that deep I replaced the plenum gasket and the throttle gasket. It has great compression on all cylinders

86 1/2 Brutus

Re: 86 5.0 efi runs terrible

Check your fuel pump relay, it could possibly be sticking. You might also check the TFI module, if it is still stock and on the distributor, it could be bad, even though it starts then dies, the tfi could be bad. You might want to change it out this is a major issue with the TFI's. There is a modification to get the tfi on the fender well.

Nick and George
1986 1/2 F150 XLT Lariat 4X2 300 Six - C6 - 3:08 in a 8.8 - Fully Loaded - 8 Foot Box
Owned since new

86' 5.0 short box

Re: 86 5.0 efi runs terrible

Oh I forgot to say that I replaced the relay can you explain more about this sensor located on the distributor

Gary Lewis

Re: 86 5.0 efi runs terrible

Administrator

The TFI (Thick Film Ignition) is the aluminum module attached to the distributor. You might want to read up here on the results of the class-action suit won against Ford.

Basically, the module gets hot and fails, but when it cools the vehicle will run again. That write-up mentions 257 degrees F, but it isn't that precise. And, as the modules age the temp can easily come down - to the point the engine may only run a few seconds and then stall.

The fix is either to install a new module and hope it doesn't fail, or move the module to a cooler spot, like on the fender liner, like Ford did later.

Gary, AKA "Gary fellow": Profile

86' 5.0 short box

Re: 86 5.0 efi runs terrible

Can that tfi module cause the engine to run on only 6 cylinders?

85lebaront2

Re: 86 5.0 efi runs terrible

Administrator

I don't think so, however, back when vehicles still had breaker points, I have seen a worn advance cam or bad bushings cause cylinders to not fire.

Try using your timing light on #3 and #4 plug wires to see if they are firing, if not, closely examine the distributor cap for cracks or carbon tracks. You don't mention plug wires, how old are they? Old rule I used in my shop was anything over 3 years by the date code was suspect.

If all this checks, with the cap and rotor removed, take the shutter (cup shaped with 8 vanes) off and check the vanes for signs of damage. The narrow vane is for #1 cylinder, then go counterclockwise viewed from the top to #4 and #3 and see if there are any obvious differences in them.

Bill AKA "LOBO" Profile

Gary Lewis

Re: 86 5.0 efi runs terrible

Administrator

In reply to this post by 86' 5.0 short box

I doubt it. The TFI failure mode is usually "on" or "off", meaning that it either works or doesn't.

But I suppose that if the teeth of the reluctor wheel in the distributor for those two cylinders were shorter, meaning that they didn't come quite as close to the pickup as the others, it might not fire on those cylinders. In that case I think the pickup module in the distributor would be the culprit. That module provides the signal to the TFI module that tells it to fire, and the TFI doesn't know which cylinder it is firing. But the pickup module does because each cylinder has its on tooth on the reluctor wheel.

Gary, AKA "Gary fellow": Profile

Gary Lewis

Re: 86 5.0 efi runs terrible

Administrator

In reply to this post by 85lebaront2

Bill beat me to it. But we are on the same page. His "shutter" is my "reluctor wheel". And his idea of placing your timing light on 3 & 4 is a good one.

Gary, AKA "Gary fellow": Profile

86' 5.0 short box

Re: 86 5.0 efi runs terrible

In reply to this post by 85lebaront2

I have excellent spark on all plugs and that would tell me the plug wires are good correct?

85lebaront2

Re: 86 5.0 efi runs terrible

Administrator

Maybe, under load they may act differently. Quick question, what spark plugs are you running? I have seen some strange behavior from plugs, particularly Bosch Platinum in Fords. I personally stick with Motorcraft for my Fords and Champion in the Chrysler.

Bill AKA "LOBO" Profile

Rusty_S85

Re: 86 5.0 efi runs terrible

In reply to this post by 86' 5.0 short box

not running on two cylinders can only be a few things. No fuel to those cylinders, no compression to those cylinders, no spark to those cylinders, or mechanical failure such as broken rocker arms, bent or broken push rods, or a distributor cap with those two terminals heavily damaged, or the reluctor in your distributor is damaged on those two cylinders and not providing a signal to fire.

The TFI module is basically the ignition module that controls the coil it either fires the coil or it doesnt it wouldnt pick and choose

86 1/2 Brutus

Re: 86 5.0 efi runs terrible

I've seen the TFI do some strange things in the past which is why i brought it up. They act different under load. Also check the reluctor wheel in the distributor, i'm not saying this is definatly your problem, but you do need to start somewhere. Things act differently under load. I know i can do this in Brutus, but he has an electronic carburetor and not efi. But you can at least in Brutus, disconnect the computer and the truck will go into limp mode, the truck will run enough to get you home, and this is also how you adjust the carburetor. The engine computer takes care of your timing and spark advance, but like i said, i dont know anything about efi, but may be worth a check. I have all the books on the 86, if you need any info, ill be glad to send it to you. In the meantime, here is brutus with the tfi on the fender

Nick and George
1986 1/2 F150 XLT Lariat 4X2 300 Six - C6 - 3:08 in a 8.8 - Fully Loaded - 8 Foot Box
Owned since new

old55pete

Re: 86 5.0 efi runs terrible

In reply to this post by 86' 5.0 short box

One of the things I have noticed with my 5.0 EFI Bronco over the years, 34 years, There are two different ignition rotors for that engine, One the parts stores call " The California rotor "( it was also used in New York, New Jersie and one other state). I remember doing a tune up while stationed at Ft Bragg went to the local NAPA and bought cap, rotor, wires, plugs and filters. After the tune up was finished, it ran worse and I want to say that it was missing on 3 & 4. Because I was in NC and nobody asked I ended up with the wrong rotor, the 46 state rotor. After some digging at the NAPA, the finnaly asked if it was from California. They gave me the correct rotor and the miss went away.

Are you sure you have the correct rotor? look up your engine calibration number and see if you have the right one. They will both fit, but the Cal. one has a long tail on it with a pin on the bottom of the tail that goes through a hole in the Hallefect sensor cover.

The NAPA part number for the" Ca rotor" is MPE FA152SB, the 46 state rotor is MPE FA144SB.

Just a thought and a blast from the past.

Steve
86 Bronco, XLT, 5.0 EFI, EEC IV, AOD, IFS, limited slip front and rear, 3.08 gears, Tilt steering, factory AC

86 1/2 Brutus

Re: 86 5.0 efi runs terrible

Steve, i forgot about that one. Good thought

Nick and George
1986 1/2 F150 XLT Lariat 4X2 300 Six - C6 - 3:08 in a 8.8 - Fully Loaded - 8 Foot Box
Owned since new