hpfiend Posted June 17, 2008 Report Share Posted June 17, 2008 Apparently I have a lot of technical issues lately!!! 1987 F350 Pickup... 460 carb BBF with 35,000 original miles. The truck had a very loud and annoying exhaust leak, we found it to be coming from the manifold as one of the heads of the manifold bolts had rusted completely away. We tried to take the manifold off, broke 5 of 8 bolts off in the head. Removed intake, passenger side head, and manifold and had the bolts professionally drilled out and helicoils inserted where necessary. Reinstalled everything but the smog pump equipment (and tried to plug all the vacuum lines we could find going to it), after plugging the back of both heads (almost impossible on the car btw for the drivers head) and removing the fittings from the passenger manifold. We capped the other side. Also in the process of the tear down we foud the distributor to be seized so after trying various penetrating fluids for days we had to use a pipe wrench on it and tore it up pretty badly once we finally got it out... so we got a new advance auto distrib with the new vacuum advance.. We put it together and it runs great until bam something happens it seems like it is running on 4 instead of 8 cylinders or all the timing is pulled out, or the fuel pump is dying as basically has no power (both electric pumps have been replaced less than 2 years ago and probably 5000 miles, and it starts pretty quickly but we haven't checked the pressure)- so little power that it will not accelerate past 45-50 on the freeway in fourth all the way to the floor with an empty bed. We first came across this problem after our major repairs after driving around for a few short test trips, filling up with gas and it running fine we then loaded it completely up with scrap steel from around the farm and started to head to the scrap yard- on the roads aroud my dads house it started breaking up and low on power, we pulled over, unplugged all the wires, replugged them in thinking we had one loose, and tapped the then old ignition module, shut the hood, restarted it and it ran like champ, all the way to marion (from delaware) and back with 2 tons of scrap steel on the back which we dumped, and then drove all the way home with no problems until we got back to our local streets and it started acting up. Possible the "new" distributor is internally malfunctioning? We already put a new ignition module, new wires, distributor cap, rotor, new plugs on the side we messed with, all of the plugs were replaced less than 3000 miles ago but we thought maybe we cracked one on the side we took off, the EGR seems to have very little vacuum to it at idle with only slight at rev... barely reads on a vacuum gauge... there are these vacuum lines on the air cleaner that control the flapper that shuts off and causes it to suck hot air from the heatshield duct on the exhaust manifold rather than cold air from the grille... unplugging these lines seemed to remedy the problem and plugging them in would cause it to return but then nothing would make it better off or on (engine quite heat soaked at this point is the only thing we can guess)... Can this carburettor function without the air pump? My dad says it kind of feels like when the powervalve was bad in his 67 vette but he doesn't know what would cause it to be fail on the truck as he has not had any backfires and we dont want to tear the carb apart without reason.... That exhaust leak doesn't seem that annoying in retrospect! LOL THANKS!!!! Quote Link to comment Share on other sites More sharing options...
hpfiend Posted June 17, 2008 Author Report Share Posted June 17, 2008 Just found out this thing new only made 230 hp and 390 ft-lbs... thats pretty weak for 460 cubic inches... No wonder it can hardly pull its 7400 lb carcass around. Anyone ever build a BBF? I am smelling my first engine rebuild... Quote Link to comment Share on other sites More sharing options...
Miller Posted June 17, 2008 Report Share Posted June 17, 2008 Talk to rob. And that motor has a lot of ability when treated correctly. Quote Link to comment Share on other sites More sharing options...
hpfiend Posted June 17, 2008 Author Report Share Posted June 17, 2008 rob gearhead or rob lasota? Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted June 18, 2008 Report Share Posted June 18, 2008 me.....those engine are retarded! head suck. but can be made better. timing chains are -8 degrees retarded and so on..... now back to reading you long post to see whats going wrong here Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted June 18, 2008 Report Share Posted June 18, 2008 first you say you took the upper intake off? is this fuel injected? or carbed? sounds like the converter is plugged up. how does it run cold? need more info. you should have my number or pm yours. Quote Link to comment Share on other sites More sharing options...
Dave1647545494 Posted June 18, 2008 Report Share Posted June 18, 2008 bad converter or your new module puked on you I put six modules on my old 5.0 ranger one day before I got one that would last more than a couple miles..... Quote Link to comment Share on other sites More sharing options...
hpfiend Posted June 18, 2008 Author Report Share Posted June 18, 2008 bad converter or your new module puked on you I put six modules on my old 5.0 ranger one day before I got one that would last more than a couple miles..... I can't take this... every way we go crappy parts- I guess I better start going back to the manufacturer when I can afford it and its available. We will see if another box fixes it. Our old one supposedly tested fine but we questioned the diagnostic abilities of the guy at the store. Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted June 18, 2008 Report Share Posted June 18, 2008 i have seen the dura spark box's cause this issue aswell! Quote Link to comment Share on other sites More sharing options...
hpfiend Posted July 17, 2008 Author Report Share Posted July 17, 2008 Ok guys here is what we have done so far... 1. Swapped out dura spark ignition module for another. 2. Checked fuel pressure on both pumps to be around 3.5 psi- passed 16 oz in 10 second volume test as well. 3. Vacuum as tapped into line going to vacuum advance, 20 inches at idle, drops with increased throttle/load to about 5 psi when it runs really crappy. At 0 vacuum at WOT it seems to run much better 4. We have run one tank empty so we are now going to get a new tank of gas (possibly bad gas?) 5. New spark plug wires, plugs, cap and rotor 6. Verified that choke is not randomly closing off the carb.... we have not manually rigged it to make sure but when we stop and remove the air cleaner it has been open. We are hypothesizing that the new distributor we got is bad internally or we have the wrong vacuum advance module that came with it... the weird thing is that it is intermittent though. It is also possible that when we removed the smog pump and tried to redo the vacuum lines we hooked a source somewhere that it should not be but you would think the problem would always be present as well. We may have to go with a race carb to fix this.... Damn this sucks- we need this truck to haul equipment- may have to bring it to the pros with an EGT or engine analyzer. Quote Link to comment Share on other sites More sharing options...
hpfiend Posted July 18, 2008 Author Report Share Posted July 18, 2008 Not bad gas. Filled up rear tank with Shell and same problems. Pulling distributor next. Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted July 19, 2008 Report Share Posted July 19, 2008 vacuum or carb issue. Quote Link to comment Share on other sites More sharing options...
hpfiend Posted July 19, 2008 Author Report Share Posted July 19, 2008 yep thats what we think as well- we are changing the power valve today. Quote Link to comment Share on other sites More sharing options...
hpfiend Posted July 19, 2008 Author Report Share Posted July 19, 2008 Not the powervalve :-( Could mixture cause this rpm window of crapiness? Changing distributor monday. Quote Link to comment Share on other sites More sharing options...
Guest Removed Posted July 20, 2008 Report Share Posted July 20, 2008 ? Changing distributor monday. why? the only thing in it is a pickup that either works or it dont. Quote Link to comment Share on other sites More sharing options...
hpfiend Posted July 20, 2008 Author Report Share Posted July 20, 2008 well- what controls mid rpm advance? Maybe the vacuum advance that came with it is bad... it is very crappy in the midrange but if you can power through it it runs pretty good... decent down low as well. Quote Link to comment Share on other sites More sharing options...
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