york1181

Hi guys,

First the intro. The name's Jeremy and I'm from sunny Manitoba in Canada. English, but been over here for the last 7 years. Have been a member since 09 but not got around to any posts (till now).

Now the problem. I bought a 96 F150 XL 302 5.0 last year. Didn't get around to using it much at the time. This year I wanted to use it as a runaround. The truck starts good and runs good till I get to around 50 then it loses power and the speed drops to around 40. When I increase the gas it will remain at 40 for a second or two then take off.

I took it to the stealership to have it checked out. They said it was a misfiring engine and the engine would need to be replaced. Why? Because someone in the past has changed the engine from a 96 302 to a 93 302. They also said that the problem was because the computer is sending signals to the engine but not having those signals picked up.

Is this right? Is a new(er) engine on the cards or is there a way around it? I'm no mechanic, so layman's terms would be appreciated. Hoping someone out there can help me out.

I drive truck for a living and can't always get the internet. Will get back to you asap though.

Thanks guys.

FORD TUFF

The big difference is the firing order changed in 94. The computer reads the EGO sensors to control the fuel injector timing. (yea yea,other sensors too ) Because of the wrong firing order,the computer is sending the signals to the wrong injectors.This will confuse it from the readings from the EGOs... The only way to fix this is to change the camshaft with the right firing order. Thats my thoughts on it anyways

sdmartin65

The 96 is HO firing order and a 93 truck engine is non HO firing order but a 93 engine from a Ford car would be HO firing order. Regardless i don't think non HO firing order engine would even run in your 96 unless it had the cam replaced.
Since the 96 is obd11 I believe it has a crankshaft position sensor. This sensor and hardware might not have been transferred to the new motor. The 96 harmonic balancer has a ring that the sensor reads. If something along This line is the problem it wouldn't be too hard of a fix.
The first thing the dealer tech would do is plug in a scanner so this makes sense.

Chris_1

iTrader: (1)

Everything above is right. The 96 has a ring on the harmonic balancer that you need to feed your computer a signal. And you need the HO camshaft because it opens and closes different valves in a different order. all the electronics on your truck are set up for the HO order.

FORD TUFF

Sure it would run fine in open loop ,, when it goes into closed loop (at cruise speeds) it would lose its mind trying to adjust the pulse widths to the wrong injectors ,,hence the reference to the EGO sensors . When he steps on it, it goes back to open loop and away it goes again, just like he says it does.

york1181

Thanks guys. To get it right, I need to change the camshaft, but get one 94 or newer. Is that the general consensus?

Chris_1

iTrader: (1)

95 and 96 5.0 has the HO cam. You need one from an F150. It's also a roller lifter cam. You will also need the lifters, dogbones, spider plate, rocker arms and the gear off the bottom of the distributor.
This stuff will go into a 92 engine, they're all roller cam capable all the way back to 87, they just put flat tappet cams in till about 93.
You may even already have a roller cam, just the wrong one.

sdmartin65

Just seems like if the cam was running non HO firing order and then fuel injection is pulsing an HO firing order the truck would barely start, want to backfire ect... The OP should check the wires and see if they match the hood label or not, that would be an easy start to trouble shooting.

FORD TUFF

Well, He says "The truck starts good and runs good till I get around 50 then it loses power and speed drops to 40.... " . The injectors really don`t matter till it goes into closed loop.. Backfiring is caused by an ignition problem or a valve problem. Getting codes would be the best start .

FORD TUFF

My 94 has the HO firing order...He doesn`t have to make it a roller if it isn`t already . I would think a flat tap cam with the proper grind could be found or made.