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Discussion Starter #1
K, story goes:

Ford F-250 89 pickup, original 302 motor was shot, we had a 5.0 out of a mustang GT and redid it, and just did a straight wire for wire swap, everything kept from the 302 already in truck. its a manual.

Pretty much has no power, has terrible trouble getting over 2000 RPM, and I've gotten stuck on highway @ 60 mph in overdrive @ 2.2k rpm, stepping on gas does just about nothing.

Personally me and my father dont know anything on the computer side of these motors or electronics, hes considering switching the motor over to Carbureted to fix it, but I'm coming here first to see some suggestions on what to look at.
We did notice sparking coming out of the plug wires when looked at @ night in the dark, we are buying new plug wires today.
We can also sorta start the truck, turn it off immediatly and then restart it, and it seems to be able to get to 6000 RPM easy for a tiny bit before running like crap again.
 

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I think the trucks used a diff firing order than the mustangs. Depending on the year I would call the parts house and ask them for the firing order for the truck.
 

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The 5.0HO uses a different cam so the firing order is different. The mustang uses the same order as the 5.8L. The truck doesn't. So you may have to re-pin the injectors and definitely check the firing order.
 

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1-3-7-2-6-5-4-8 I believe is the 5.0 HO firing order. 1-5-4-2
-6-3-7-8 is the firing order for 5.0 trucks(Im reading this is for an 86, not sure about an 89). Ya'll might be on to something here.
 

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What year mustang did the 5.0 motor come out of? If newer than like 82 I think, it should be an HO motor.
 

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Discussion Starter #7
The motor is 90 something, it is HO, but we did the modifications i think to match the firing order to the 302, when my father rebuilt it.

We want this engine fixed up, cause we have plans to after its served its purpose in this truck, to transfer it to a 1965 mustang.
 

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You would have had to change the camshaft to change from an HO motor to an non-HO motor firing order.

You sure you changed it?
 

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Discussion Starter #9
Yes, we did.

I talked to my dad today, about if it could be the firing order problem, but he assured me that he knew about the different orders and changed the cam.

My dad owned a mechanic shop when he was alot younger, but he left the line of work, he knows to plug **** in and match certain things, but he doesnt really like EFI, much perfers carbs, and right now hes about to buy a intake/carb combo for 230$ and swap afew things to make it run off that, to see if that fixes our problem.
 

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Discussion Starter #10
P.S

Before he goes and does something major like swapping off of EFI, i was hopeing to get some ideas on what to check on.
 

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Discussion Starter #11
/Bumping post from lack of replies, also wanted to add to the list of issues with the engine, that it only gets about 6 MPG.
 

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K, story goes:

Ford F-250 89 pickup, original 302 motor was shot, we had a 5.0 out of a mustang GT and redid it, and just did a straight wire for wire swap, everything kept from the 302 already in truck. its a manual.

Pretty much has no power, has terrible trouble getting over 2000 RPM, and I've gotten stuck on highway @ 60 mph in overdrive @ 2.2k rpm, stepping on gas does just about nothing.

Personally me and my father dont know anything on the computer side of these motors or electronics, hes considering switching the motor over to Carbureted to fix it, but I'm coming here first to see some suggestions on what to look at.
We did notice sparking coming out of the plug wires when looked at @ night in the dark, we are buying new plug wires today.
We can also sorta start the truck, turn it off immediatly and then restart it, and it seems to be able to get to 6000 RPM easy for a tiny bit before running like crap again.
What was the original engine doing to decide it was shot?
You put in the original truck cam into the new HO block?
Have you done the plug wires to eliminate any voltage leaks?
Double and triple checked the firing order (stock) assuming you are using the stock F250 cam?
Distributor indexed correctly upon re install?

Does the engine have low vacuum like 15in hg?
I did an engine swap on an 89 F150 because the owner thought the engine was shot, but it just needed a map sensor.

Map sensor is on the firewall, little black box about the size of a deck of cards with a larger than normal black plastic and rubber vacuum line connected to it. make sure that that line has no leaks in it, if not then take off the vacuum line to the sensor, and with a vacuum pump, apply 20 in hg of vacuum to the sensor with the engine running. If the truck dies, replace the map sensor and see if that corrects your concern.

Next check fuel pressure while driving and assure that the pressure goes up and NOT down when on the throttle.
If it goes down when you get on the gas, you have a fuel system concern.

If all checks pass, then I would suspect the pickup in the distributor.
 

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Discussion Starter #13
K heres a quick update, we replaced plug wires and now the truck:
Still runs like crap at startup.
BUT when we are rolling down the road and stall the truck, and restart after about 1 or 2 seconds its fires right up, and can reach 3-3.5 RPM with alil power, feels like running on 6 or 7 still, but its better then a normal start.

what could cause this? why does doing this restart help the truck run better?
 
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