Well, my '88 F-250 is acting up a bit after putting a new EFI 460 in it. Ever since then, about 5 months now, I've been having trouble with the darn thing running right. Two of the possible causes that I can think of is that the left manifold is leaking at the y-pipe, and the cat is completely blown out. At first I was just having trouble with a miss at idle, but now the symptoms that its having are as follows:

-Low (500rpm) and rough/slightly missing idle
-feels like its going to die on deceleration
-mushy thottle responce
-occasionally on acceleration it feels like its running out of gas
-gas mileage has dropped from 13-14mpg to 9-10mpg.

The truck did already have a 460 in it when I swapped this new one in, and the old one wasn't having any of these problems(except buring a quart of oil per 100 mi and terrible compression).

When I put the new motor in I also putin a new fuel filter, spark plugs, wires, distributor, O2 sensor, etc. It is however running the factory 16yr old injectors. Anyone have any suggestions, its really starting to drive me crazy.

Thanks for the help,

Matt

 

I would double check the timing, verify you don't have a vacuum leak in any of the hoses, and all the connectors are on tightly.

I'd also check out the 02 sensor, I'd start the truck and clip on a volt meter to verify its swinging in voltage.

I'd also check fuel pressure with a mechanical gauge, maybe the fuel pumps aren't pumping as much as you need, things do wear out unfortunately.

If all that checks out, I'd do a dry/wet compression test, just to be sure the engine was rebuilt correctly.

Not to scare you, many years ago I bought a "professionally rebuilt engine) that had tremendous piston slap. I couldn't even break it in, it was that bad. I took the engine back out only to find the engine rebuilder FORGOT TO PUT IN PISTON RINGS

While extremely uncommon, everyone can make mistakes. But start with the easy stuff first...

A 460 should have nice "snap" when you blip the throttle, and your **** should feel it in the seat.

 

Thanks for the quick responce. This was a Ford factory re-man, so I would hope that it would be ok, but you never know. My grandfather had an old Allis Chalmers tractor that came brand new from the factory w/o any rings, lol, needless to say it was sent back.

I'll check into those things that you've mentioned, and hopfully I'll be able to work this mess out. With the old 460 that I had in there (before it went to pot), when you would mat the throttle it would almost toss you in the back seat. This one certainly doesn't seem up to par.

 

No problem, just happened to be reading the forums while you posted.

Yeah, I'm about to struggle with the same thing. My crewcab has a 351 thats very tired, and is noticably more tired every day I start the truck, so I may not make it to late spring which is about when I'll have all the 460 swap bits setup, tested, and on the run stand. So I might have to swap in a 351W as a temporary measure just to keep my daily driver, drivable.

The local ford dealer wants $1950 for a remanufactured engine, with a $200 core charge, whereas most of the local machine shops want about $500 less than that. I do know that Ford doesn't actually do the remanufacturing themselves, they outsource it, but they do provide a strong warranty (36K, 3 yrs). But the problem for me is which shop, which price. With all the local shopping around I've done I haven't really gotten a good explaination as to who will do what and what really gets replaced.

I have a friend in Arkansas who rebuilds engines out of his garage as his sole income, but add in the shipping costs and the price is in line with everyone else, so I might go with him since I've known him for a very long time.

Maybe I'll turbocharge the 351W instead. Then what do I do with the 460 sitting on my run stand now.

heh-heh. Another day, another project.

 

I searched arround a lot, and finally got mine from ford for $1750 for a reman long block. I also had ford drop the motor in for me and get everything running right(BIG MISTAKE). I really wish that I had done it myself now. They didn't even bother cleaning the parts before they put them on the new motor, and PUT THE USED OIL FILTER BACK ON THE NEW MOTOR. These are only a couple of the things that they did wrong, needless to say I was Irate. I spent the better half of a day in and out of the ford garage trying to get them to fix various things, and they always found a way to wiesel out of it. Even after talking with the manager I only got marginal service. I guess the warrenty is only as good as the company that stands behind it. I would have been almost better off to have bult the motor myself(and the way I wanted it built) than to have sprung for the 3/36 warrenty. Oh well, live and learn.

 

Pull codes.

A bad knock sensor can cause that. More so than O2 sensor.

 

Thank you. I've been investigating my options for a while now, and I'm about 90% sure I'm buying a shortblock 500cid stroker bottom end from a friend who machines engines for a living, and slap on my about-to-be-extremely-ported 460 EFI heads, and slap all that into the truck.

Still trying to find the elusive, 460 bell ZF 5-sp. Hard to find, ridiculously overpriced when I do.

At least to feel like I've done something I bought all the materials from a steel supplier as well as a junkyard to make the engine test stand.

If it were me, I'd be finding the owner of that Ford Dealership and demonstrating how good a supposivetory that used filter makes. On his/her ***, not yours of course.

From the dealer, I expect no mistakes like that. None. Zero. Putting a fuel filter backwards underneath a truck where its dark, anyone can do. Using an old filter on a brand new engine is insane.

Maybe you'll be pleased to know that Ford doesn't reman their engines. They use several larger engine reman companies around the country and the warranty can be executed anywhere if necessary, even at a non-ford dealer type service station.

Thats the one thing that attracted me to Ford for a reman engine, the warranty. But at the same time, with stories like yours (and trust me, yours is not the first I've heard), I'm starting to wonder why bother with the warranty anyway. With all the turbocharging and EFI experimentation that I do, its kinda moot anyway.

So I'm leaning much more towards building the 500cid stroker and calling it a day. Then I can dump this 460 block on e-bay and keep the heads once I get the snapped exhaust bolt out of one of them.

Grrrrrrrrrr.