86 5.0 efi runs terrible

[86 5.0 short box]

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]

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?

 

[86 5.0 short box]

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?

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]

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

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.

[85lebaront2]

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

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.

[Rusty_S85]

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.

[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.

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 12 Brutus]

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

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.

[86 5.0 short box]

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.

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

[Gary Lewis]

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

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.