posted
All of a sudden while driving to work I started losing power. I can still drive but I have to feather the gas pedal to accelerate and I can't get the engine to rev. I checked the fuel pump and the carb and both seem to be okay. My distributor is a stock rebuilt for a 1964 390 with a Pertronix ignitor and a pertronix flame thrower coil. I completely disassembled the dist and put it all back together and it seems fine. No matter what I do I can't accelerate at a normal pace without the engine stumbling and hesitating, like I said the only way I can accelerate is very slowly while feathering the pedal. Any ideas, I suspect the dist.but I can't pin point. Also swapped in another coil no difference. I swapped in a set of points and the problem seemed to go away up to 80mph then when I took my foot off the gas the problem came right back so I put the Pertronix back in. Do I need a resistor for the points the pertronix coil has 1.5 to 2.0 ohms already I wonder if I burnt out the points and the pertronix is bad.
-------------------- 79 F250 Ranger with 67 390/NP435/NP205!
From: Lincoln, Nebraska | Registered: Aug 2002
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posted
I'm going to look further at fuel supply today but yesterday I did pull the fuel line off of the Holley 4 barrel ran the line into a bottle and cranked it with a remote starter and their was no shortage of gas pumping out. Nothing was in the Holley filter screen I use a clear fuel filter and I dumped a bottle of gas treatment in, in case of water. Also forgot to mention that it idles just fine and revs in neutral/clutch in with no problem only does this while driving.
-------------------- 79 F250 Ranger with 67 390/NP435/NP205!
From: Lincoln, Nebraska | Registered: Aug 2002
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posted
Well this morning I drove without the gas cap, no change. I replaced the short piece of fuel line between the two metal pieces along the frame, I shortened the fuel line between the metal line and the pump(seemed long to me), I replaced the fuel filter and while the fuel line was apart I blew air through it(not through the fuel pump or into the tank though).I also tested volts coming into the coil at 13v. Again, when I push the gas the truck slows and bogs, push in the clutch its fine, I can get up to speed by lightly tapping the gas and shifting into 3rd and 4th. Then it bogs and I lift my foot off the gas the bog goes away and I can slowly accelerate. Thats the best I can explain it. Morning traffic is going to be a blast!
-------------------- 79 F250 Ranger with 67 390/NP435/NP205!
From: Lincoln, Nebraska | Registered: Aug 2002
| IP: Logged |
posted
Where does a timing light say your timing is? It sounds like the engine runs fine but it doesn't generate any power, like it's timing is really retarded. Only possible places for that to happen are ignition module (especially adj advance modules), dizzy, or timing chain.
posted
My timing is @ 14 no pinging so I leave it their. Idle @7oo vac @ 17". No ignition module even though its a 79, when the original owner put in the 67 390 the module was removed and he installed a dual point Mallory, I removed the Mallory and installed a stock rebuilt 67 dist took out the points and put in the pertronix. This combo has been working flawlessly for the past year or so. Just started out of the blue. I still suspect the pertronix after what happened when I installed points. I still need to know if the points need more than 1.5 ohms resistance and I will get another set and put them in and see if this solves it.
-------------------- 79 F250 Ranger with 67 390/NP435/NP205!
From: Lincoln, Nebraska | Registered: Aug 2002
| IP: Logged |
posted
Check the accelerator pump on your Holley. The engine needs a solid stream of fuel as the throttle plates open, otherwise it will stumble for lack of fuel.
From: Missouri | Registered: Mar 2003
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Well made it to work today. In second gear I could get to 1000rpm in 3rd 1500rpm 4th gear could slowly do the rest. I noticed that while bogging down when I would take my foot off of the gas I would get a little surge forward and the engine would sound normal. Also when going up hills the truck ran almost as normal would accelerate fine. Could I be getting too much gas, like a stuck float? Any way I can check this without taking the holley apart?
-------------------- 79 F250 Ranger with 67 390/NP435/NP205!
From: Lincoln, Nebraska | Registered: Aug 2002
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posted
On level ground... check your float levels in both fuel bowls. Sounds like it could be low level, since high level usually bogs down and doesn't even want to idle. On level ground, fuel should *just* seep out from the lower edge of the fuel level site hole. If you don't see fuel like this, unlock the screw on the front fuel level and turn the lower hex one flat side counter clockwise... then see where it pumps the fuel up too. Note - if engine running it should start to spew fuel once you unlock the screw but should stop when you snug it down again. Search for Holley fuel level adjustment online and I'm sure you can find better instructions.
As the Old Goat states, accel pump could also be a problem... low fuel could also inpact this.
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Interesting, I just went out and raised the float level per Holleys instructions and it did help. The problems not gone but better. Tomorrow I will pull the front fuel bowl off so I can check the accelerator pump diaphram and make sure I don't have a "water logged" float, that carb has been on there since 1980. I took it apart last year but only for a quick clean and inspection.
-------------------- 79 F250 Ranger with 67 390/NP435/NP205!
From: Lincoln, Nebraska | Registered: Aug 2002
| IP: Logged |
posted
If the accel pump diaphram isn't orange or green, but black, it could have dried out and isn't giving and accel shot... this is especially a problem with alcohol blended gas.
posted
Found most of my problem today. I removed the front fuel bowl to find a piece of rubber o-ring stuck in one of my jets! The exploded view of my carb shows a "tube and o-ring" where I found the degraded o-ring, but of course the rebuild kit didn't come with those o-rings! Great rebuild kit! The o-ring was still mostly intact so I cleaned everything and put it back together. Runs great! I guess I will have to contact Holley for the o-rings. I still have a small spark problem but I think its that pertronix. If anyone can answer my question about how many ohms of resistance needed for points I would appreciate it. My current coil has 1.5 ohms. Thanks for all of the help!
-------------------- 79 F250 Ranger with 67 390/NP435/NP205!
From: Lincoln, Nebraska | Registered: Aug 2002
| IP: Logged |
quote:Originally posted by holl: ...... If anyone can answer my question about how many ohms of resistance needed for points I would appreciate it. My current coil has 1.5 ohms. Thanks for all of the help!
Holl, that is a low resistance coil, and you need about 3.2 to 4 total ohms for the points and coil. I'd measure the total voltage on the + coil wire and see if it's in the 6-7 volt range, or over 12 volts. If it's over 12, then wire in an external resistor in the coil wire circuit. That should give you enough total resistance for the coil and points ignition. Check this link out for more info..... http://www.classictruckshop.com/clubs/earlyburbs/projects/trouble/ignition.htm
-------------------- 78 Bronco Ranger XLT, Trailer Special with FreeWheeling package, 351M, NP435, 10.50 BFG's on Ford 7.5" alloys, Moroso/Imco hybrid exhaust, Survivor w/44K actual miles.
From: Southeast USA | Registered: Jan 2001
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