Hey guys, I got a question for ya, I have a 87 f150 with a Fuel injected 302 that has one hell of a lope to it, it hesitates, sputters, shakes, and overall runs like a bag of crap. Ive changed the cap,rotor,plugs,wires,coil and still cylinders 7 & 8 will not fire, or at least not heating up because I sprayed a little water on the headers and cylinders 5 & 6 steam but 7&8 theres nothing, im at my wits end with this engine and I need this truck for school, so if anybody has any ideas of where i could check next that would be awesome ! many thanks in advance

 

Maybe you interchanged the wires at the cap.
Cyl 7 & 8 are next to each other.

Here's a pic:



And if this is not the case, then check the fuel injectors - maybe they are clogged or broken.

If that doesn't help, the next step would be to check the compression pressure.
When two cyinders next to each other have no internal pressure, the most probable explanation would be a blown head gasket.

 

ok ill check the injectors, I hope its not the head gaskets, cause im not getting any back pressure from the cooling system, my spark plugs arent white or suspiciously clean

 

When one of my fuel injectors got clogged, the engine had a bad lope, and I felt an obvious power loss. But it did not sputter or shake; it ran surprisingly smoothly. This was on a 1987 5.0 HO in a Mustang.

Did you try pulling the spark plug wires for 7 and 8 and hold them near their plugs to see if they actually sparked?

 

I pulled them at the distributor and it sparked, ill try at the plugs tomorrow, but i would say when i gave the engine some gas it would hesitate, then shake horribly when i revved it (probabally all because of the 2 not firing cylinders) but Im gonna compression test it tomorrow, along with pulling the fuel rails and see if they're spraying ill let you guys know what happens tomorrow

 

Are 7 & 8 plugs wet? Injectors would be pulsing, if plugs are wet. Can you hear them clicking when pulsing? If not, then no go. If plugs are dry, I say pull injectors and.check them.

Need a testlight and check 7 & 8 when turning engine over, check for flashing from those 2 injector connectors.

 

I think he's already mentioned that the plugs aren't white or clean. If they're getting fuel and not burning, then the telltale sign would be if they're wet.

It's hard to hear the injectors clicking when the engine is turning. You would need to rig up a test harness to activate the injector with a 12v battery, with nothing else going on, in order to hear it clicking.

 

No, it isn't

Or at least with a little trick

Just take a screwdriver, hold the metal tip against the injector and the handle to your ear.

 

ok so I got the truck running on all cylinders but now itll run for only a second then stall and wont start

 

Since you changed so many ignition parts.....hows the Fuel pump?

Once it quits, find the Schrader valve on the fuel rail and push it. Does any fuel come out? No? Then you have fuel pump issue. When you turn the key to ON, do you hear the pump cycle on/off?

If you get fuel from the Schrader valve, then you still have ignition problems.

 

I put a new fuel pump in the tank about 4 months ago
And im getting fuel to the rail but It seems like its not as much as it should be because shouldnt fuel spray out and hit the hood if everythings good? Cause it mainly trickles for me

 

Have you tried to start the engine with some - I don't know the right translation - starthelper spray?

It's an ether based aerosol that you spray into the air filter or intake manifold.

If it starts and dies shortly after - you have a fuel problem.
If there's no attempt to start, then you have an ignition problem.

 

its called eather but i have none but my buddies dad said its probabally a sensor or something because im getting spark and fuel to all cylinders itll start for a second then stall out could it possibly be a map sensor ? or something stupid that im overlooking like the tfi module and supposedly the engine is a reman that was built 10or so years ago im losing my dang mind over it ive tried everything i can think of

 

Does your Truck have the dual-tanks or just a single tank?

Mine has a similiar problem, the fuel tank selector valve is stuck, so it can't run on the front tank.
When I change the lines, it runs on the front, but not on the back tank anymore

When I switch to the "blocked" tank, it stalls and dies shortly after.

And by the way: How old is the fuel filter?

 

The fuel filter was put in back in august but I left the truck sitting for 4 months with fuel in it is there any way I could of gummed up the fuel lines?