89 F-250 5.8L W HD


I don't get it. After my full rebuild my engine still lacks just as much power as it did when it was burning oil. Even after ported heads and a TQ cam. I set the timing at 10 or 11 degrees BTC and it will barely idle. I advance it more and it runs smoother, but not a healthy mood. I drove it on 10 degrees first and it would stall everytime I let off of the gas. Would not restart because I have a charging problem, I'll get into that soon. So yeah, with advance it will not stall but still doesn't have any power at all. New TPS sensor in today to make sure that wasn't it. It lacks even more power when you put the gas pedal down more then 1/4 throttle. Starts to bog. Tried to take off of a light fast, not a chance. Runs like a wore out 89 truck should. This is not right at all. Newer plugs and wires/rotor and cap. What do you think could cause this? Fuel regulator? Injectors? How do you know when they're bad? The fuel filter is new. Fuel pump is priming. New oxygen sensor. Any ides are welcome, this is rediculous performance.

Alternator was checked today and has a brand new battery in it. It runs at 14volts on the dash when it's running but as soon as you shut it off and try to start it again, it turns over the starter but will not start without a charger.
The ECM isn't getting enough juice to run. Now obviously this person before me ducted taped the alternator wires for some odd reason. My guess is that the wires are bad, so I'll work on those. But I never had the starting problem before the rebuild, always started up.. just lacked lots of power. I'm lost over this. Help!!

 

Clogged Cats? Past that, I'm clueless. Sorry I couldn't be much more help, but my '87 is kinda like that too, mine will pull a load really well, but accelaration sucks from 40+, I've got 2 friends with F150's with 302's and they will both blow me off the road, so I know somethings not quite right, so I'm about to cut my cats when I get some spare time.

 

You say FULL rebuild.

Is it possible you have the timing chain off a notch ??

 

Good guess Netscaner... I've seen the exact same problem with a fresh 302.

Does your new camshaft have any timing alterations?

 

how does your fuel pressure regulator and fuel pump is ? are they good?

 

No cat, timing chain is right, fuel pressure and regulator I have no clue about how they are. But the fuel pump primes now. Runs better with more timing so maybe it's running too rich.

 

Without going in to double check, how do you know the timing chain is installed correctly?

 

Because it ran like this with the stock timing chain. Anywho, I think this might be a fuel problem because it won't start right after you drive it. It fired right up this morning no problem. Started 1st break, lunch, and when I left work. But when I got home into the driveway I shut it off and tried to start it but nothing. Buddy of mine says he's got a bad regulator on this 95 460 and his won't start recently after it has been running. His also lacks power. I'm gonna try getting a new regulator and see what happens.

 

How's your exhaust smell? Rich possibly? Any sort of smoke?

 

I have a 4.6L and have the same problem when i remove the air tube to the filter I get a poping like a valve is open but it runs smoth at idel but when u gas it it dies ? with the sohc could i have the crank off a tooth or two?

 

This sounds like a fuel issue to me.

But just because it ran crappy before doesn't mean the timing chains is installed correctly.
It probably was stretched out before, causing poor running, and now it's out of time.
I would check that, IAC, FPR, and a few other things.

If you just did a complete rebuild though, and used old sensors.
Swat the back of your head for me.
New build - New Sensors. That way you know they will not effect your running when you break the engine in.

It's sounding like you have fuel pump or timing issues.

 

Well, it will not start until 20-30 minutes after I drive it now. Otherwise it starts. Put a new fuel pressure regulator in. With Long tube headers, Ported heads, and a TQ cam you would think it would idle fine. But, I have the timing set at like 20 degrees BTC and that's the only way it will run fine. But anything less or more will not run the motor right. I'm at the best I can get right now. I think mass air is neccissary now wouldn't you think. Or should I just fix my alternator wires and drive the damn thing for another 190,000. Plenty of time for a mass air conversion. If you put bigger injectors on a SD is there anyway it will run richer?

 

Engine coolant sensor, or air temp sensor. They should read 37K ohms at room temp.

 

if your 20 BTDC, sounds like your timeing is off to me...

 

Something else to check would be your engine ground, battery terminals (but you said its a new battery), and the connection to the alternator. Make sure they are clean so you are getting good conductivity. Battery might be showing 14 Volts but if you have a bad engine ground then it could be lower at the engine due to poor contact.