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-   -   Power not up to par (https://www.ford-trucks.com/forums/70454-power-not-up-to-par.html)

madcitymike 01-08-2001 11:46 PM

Power not up to par
 
I recently picked up an 88 F250 w/ EFI 460 and although it seems to run fine it doesn't have nearly the amount of power the my carbed 87 F250 w/ 460 had. This truck is a manual truck and I can't spin the tires, which was easy in the 87 and that was an auto truck. I'm using the same tires from the 87, and the axle ratio's are the same at 3.55. The truck also has no guts trying to accelerate on an on-ramp or trying to pass.

I just did some easy stuff like replace the air filter, plugs, wires, cap & rotor, and that didn't seem to make any difference. I've also replaced all 3 fuel pumps (each tank + high pressure) and the fuel filter. The computer has no stored codes, I have yet to do a compression check, but the truck has hardly any blowby coming out the pcv hole while running.

One thing to note is that the stock oil pressure guage is pegged on the high side and stays there after it's warmed up, and when idling.. I just replaced the oil with 10w30 Synthetic and it made no difference. I've never put a whole lot of faith into the stock guages, so I'm going to put a mechanical guage in, but if the guage is correct, what could cause high oil pressure, and is it a sign of impending doom??

The carbed 87 460 seemed to really wake up when I put a straight up timing chain in it, and I was wondering if it's possible to do this on a EFI motor without screwing up the computer, because I'm sure it's probably about due for a new chain. If I'm going to have to tear the front apart to do the timing chain, I figure it'd be a good time to throw an RV cam of some sort in there as well. Does anyone make a Speed Density compatible cam for a 460 that would help out in the lower end torque department? I mainly use my trucks for towing an 8000 lb trailer, and I have yet to try pulling with this truck.

What else should I look for to be the cause of why this truck seems so anemic??



bb79ranch 01-09-2001 09:45 PM

Power not up to par
 
Could the exhaust system be partially clogged. Check ignition timing. I don't think a straight up timing set will adversely affect the computer, but I don't know about a cam change. The dual intake runners have a "necked down" area that needs to be removed, some say power increase? Check fuel pressure when idling and with load if possible. Try some fuel system cleaner, the GOOD STUFF, not the repackaged diesel fuel. When Ford changed the 460 over to EFI they changed the head design. The intake ports and valves are smaller to take advantage of airflow velocities. The exhausts were changed as well. Which may account for somewhat sluggish performance compared to your earlier truck. I hope this helps in any way.

Todd
BB79RANCH

DeenHylton 01-10-2001 07:10 AM

Power not up to par
 
My 89 F250 had minimal power too when I first bought it. My fuel milage was low also but after changing the O-2 sensor, the air-charge sensor,and the engine-coolant sensor (NOT the water-temp sensor)I picked up some power and my milage went back to normal...11 MPG unloaded. None of these sensors showed up as a computer code problem. Next I installed headers and dual exhaust, this increased my towing speed on steep hills around 5 MPH. I am in the process of rebuilding my 460 with a special grind "towing" cam...I should be able to tell you how it works with the computer
in the next week or two (the cam is being installed with a "straight up" timing chain set).
One other thing...I believe the throttle plates are so large on the injected 460s that they will never have the high flow velocities at low engine speed that a carb 460 would have. I have been 4 wheeling, sand drag racing and drag racing for the last 25 years and have seen time and again that a small carbed engine will out perform a large carb engine up to around 5,500 RPM. Deen

madcitymike 01-12-2001 02:30 PM

Power not up to par
 
Please do let me know how it works out for you.


cobrajet 01-20-2001 01:25 AM

Power not up to par
 

DeenHylton 01-25-2001 07:16 AM

Power not up to par
 
>Please do let me know how
>it works out for you.
>

Madcitymike, just wanted to let you know that the new "torque" cam and straight up timing gear does not seem to effect the computer. The engine runs, drives, and idles fine. It will be awhile before I get enough miles on it to be "broken in" before I floor it or take it out to tow my 9,000 lb. trailer. Deen


mrlaserboy 03-11-2001 02:01 AM

Power not up to par
 
Deen,

Do you have any updates on the EFI 460 performance with the new timing set and cam? I've got an '90 460 on the way to be swapped into my '88 Bronco and I would like to pick up some better power and mileage over stock. Can you provide any part numbers for the EEC compatible items?

Thanks,
Dustin Siebert
mrlaserboy(No Email Addresses In Posts!)
Registry: http://www.superford.org/cgi-bin/sf.cgi?uid=default&vr2=1&ID=201
Home Page: http://www.superford.org/users/ylobronc/index.html
'88 Bronco XLT 302EFI/AOD/BW1356/44IFS with 8 lugs(open)/10.25 FF(Lockright locker)/4.56/6" Superlift/2" BL/35's-street/38.5's-trails
2 BIG BRONCOS 4X4 CLUB - GREAT LAKES CHAPTER http://www.2bigbroncos.org


DeenHylton 03-11-2001 08:38 AM

Power not up to par
 
Dustin, I should be able to tell you how it tows by the end of this month, we start racing the 24th so I haven't towed anything yet. I have only put on 100 miles since the truck was rebuilt, but my wife took it to the coast this weekend since her car has problems. When she gets back today the truck should have 500+ miles on it and should be "broke in". My wife called last night and said the truck drove like a dream to the coast but she noticed it idled "rough" when sitting in "park". I myself noticed it seems to "hunt" when idleing about a 100 RPM up and down but drives great...it's probably the computer trying to compensate for the cam at idle.
The cam is a Competition Cams special grind #FF 5440/5128 H12+4
Duration at .050" is 206 intake, 211 exhaust
Lift is .499 intake, .510 exhaust.
When I called to order the cam I told them I wanted a cam strictly for towing with maximum torque/H.P. to be in the range of 2,400-2,800 RPM...I tow at around 2,600 RPM (about 60 MPH).
I'll update you the end of the month. Deen



Deen Hylton
Ford F250 460 C-6, K&N, Headers, Dual Exh.,Comp. Cams,Shift Kit
Pioneer CD w/Bose Speakers.
Other Passion: Blown 77 Corvette (Sorry Guys/Gals)
How I can afford to Drive the above: 93 GEO Metro

mrlaserboy 03-12-2001 12:48 AM

Power not up to par
 
Thanks for the info, Deen. About that idle hunting, have you thought about installing the IAC valve spacer from Ford. The spacer was designed to correct idling problems and costs $15-20. I have the part number somewhere if you'd like it.

Dustin Siebert
mrlaserboy(No Email Addresses In Posts!)
Registry: http://www.superford.org/cgi-bin/sf.cgi?uid=default&vr2=1&ID=201
Home Page: http://www.superford.org/users/ylobronc/index.html
'88 Bronco XLT 302EFI/AOD/BW1356/44IFS with 8 lugs(open)/10.25 FF(Lockright locker)/4.56/6" Superlift/2" BL/35's-street/38.5's-trails
2 BIG BRONCOS 4X4 CLUB - GREAT LAKES CHAPTER http://www.2bigbroncos.org

DeenHylton 03-12-2001 07:30 AM

Power not up to par
 
Ya Dustin,I would like the part number if you have it handy. Thanks, Deen


Deen Hylton
Ford F250 460 C-6, K&N, Headers, Dual Exh.,Comp. Cams,Shift Kit
Pioneer CD w/Bose Speakers.
Other Passion: Blown 77 Corvette (Sorry Guys/Gals)
How I can afford to Drive the above: 93 GEO Metro

mrlaserboy 03-12-2001 08:12 PM

Power not up to par
 
Ah, dug around a bit and found it- F2PZ9F939A . It's a very simple aluminum spacer about 1/2" thick and has two idle adjusting screws. Doesn't take long to put on but I haven't gotten around to putting it on my 302 yet.

Dustin Siebert
mrlaserboy(No Email Addresses In Posts!)
Registry: http://www.superford.org/cgi-bin/sf.cgi?uid=default&vr2=1&ID=201
Home Page: http://www.superford.org/users/ylobronc/index.html
'88 Bronco XLT 302EFI/AOD/BW1356/44IFS with 8 lugs(open)/10.25 FF(Lockright locker)/4.56/6" Superlift/2" BL/35's-street/38.5's-trails
2 BIG BRONCOS 4X4 CLUB - GREAT LAKES CHAPTER http://www.2bigbroncos.org


mrlaserboy 04-03-2001 10:41 PM

Power not up to par
 
Deen,

How'd you do at your races? Hope you did good. Any updates on your EFI 460 mods? My engine is coming in this Friday or Monday and hopefully going into my Bronco by the end of this month. What mileage did you get while towing and unloaded? I just did a 1600 mile road trip this last weekend and got the best mpg average I've had in the last 10 months- 9.5 mpg (EFI 302).


Dustin Siebert
mrlaserboy(No Email Addresses In Posts!)
Registry: http://www.superford.org/cgi-bin/sf.cgi?uid=default&vr2=1&ID=201
Home Page: http://www.superford.org/users/ylobronc/index.html
'88 Bronco XLT 302EFI/AOD/BW1356/44IFS with 8 lugs(open)/10.25 FF(Lockright locker)/4.56/6" Superlift/2" BL/35's-street/38.5's-trails
2 BIG BRONCOS 4X4 CLUB - GREAT LAKES CHAPTER http://www.2bigbroncos.org


DeenHylton 04-04-2001 06:10 AM

Power not up to par
 
>Deen,
>
>How'd you do at your races?
> Hope you did good.
> Any updates on your
>EFI 460 mods? My
>engine is coming in this
>Friday or Monday and hopefully
>going into my Bronco by
>the end of this month.
> What mileage did you
>get while towing and unloaded?
> I just did a
>1600 mile road trip this
>last weekend and got the
>best mpg average I've had
>in the last 10 months-
>9.5 mpg (EFI 302).
>
>
>Dustin Siebert
>mrlaserboy(No Email Addresses In Posts!)
>Registry: http://www.superford.org/cgi-bin/sf.cgi?uid=default&vr2=1&ID=201
>Home Page: http://www.superford.org/users/ylobronc/index.html
>'88 Bronco XLT 302EFI/AOD/BW1356/44IFS with
>8 lugs(open)/10.25 FF(Lockright locker)/4.56/6" Superlift/2"
>BL/35's-street/38.5's-trails
>2 BIG BRONCOS 4X4 CLUB -
>GREAT LAKES CHAPTER http://www.2bigbroncos.org
>
Hi Dustin,
I have 1,000 miles on the truck now but have only towed once and that was with a partially loaded trailer (5,000 lbs.). My mileage is down a little...7 MPG towing, 11.16 empty. I did not notice any difference going up the steep grades, but on the level I had to keep letting off the throttle since I kept going over the speed limit...kinda looks like I have more HP at cruising speed (2600 RPM @60-62 MPH). Keep us informed on your engine swap. Deen

Deen Hylton
Ford F250 460 C-6, K&N, Headers, Dual Exh.,Comp. Cams,Shift Kit
Pioneer CD w/Bose Speakers.
Other Passion: Blown 77 Corvette (Sorry Guys/Gals)
How I can afford to Drive the above: 93 GEO Metro

doggish460 04-04-2001 01:58 PM

Power not up to par
 
I own a 89 1 ton stakebody with a 460 i bought brand new it only has 38,500 miles on but is in need of some T L C have you tried to remove the catalytic converter and run a better exhaust because it seems to restruct exhust flow if so, what can it do to vavle train or computer, sensors etc.

DeenHylton 04-05-2001 06:21 AM

Power not up to par
 
>I own a 89 1 ton
>stakebody with a 460 i
>bought brand new it only
>has 38,500 miles on but
>is in need of some
>T L C have you
>tried to remove the catalytic
>converter and run a better
>exhaust because it seems to
>restruct exhust flow if so,
>what can it do to
>vavle train or computer, sensors
>etc.
It can be done...but your breaking Federal law no matter where you live. Make sure you reinstall the O-2 sensor if you change out to dual exhaust since it gives input to the computer to fine tune fuel flow to the injectors.

Deen Hylton
Ford F250 460 C-6, K&N, Headers, Dual Exh.,Comp. Cams,Shift Kit
Pioneer CD w/Bose Speakers.
Other Passion: Blown 77 Corvette (Sorry Guys/Gals)
How I can afford to Drive the above: 93 GEO Metro


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