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ok guys here's the story have a 1970 f350 2x4 with a straight 6 300 4.9 engine was driving it one day parked in a parking lot came out truck hasent started since (has no spark) to make a long story short I have changed everything plugs wires cap rotor points condenser coil and even the distributer itself and got to the point of a very faint spark but not enough to fire although every so often it would spark nice and bright (on the spark tester) and want to fire I have gaped the points plugs and even jumped the coil positive side to the battery just to see if than would help no difference no I have gone back and forth between the old parts and new parts just in case one of the new parts was bad to and to try to see what part maybe is the problem but no matter what I do I stay in the same boat cranks but to little spark to fire and when I did the distributer I made sure the timing was right with number 1 piston tdc and the rotor was pointing to #1 wire this thing has everyone o know stumped so if anyone has any more ideas I'm all ears thanks
Welcome aboard, pal. We will help you.
You say you have a weak spark. Do you have a voltmeter with a 0-15 volt scale? Can you make a measurement at the + side of the coil with the ignition switch on and the points closed? You should see 7-8 volts with points closed, battery voltage with points open.
Orich will be in with his hotwire test in a little bit.
Hmm you say you jumped the coil to the battery and no go.
I don't know so I'll ask is the carb getting gas for sure.'
Body grounding can be a problem with these old wires.
Many times the rear engine to body ground had been left off or loose/broken.
Have you taken a look at you ign. switch as these has a common problem
with the starting circuit over heating the round small pin contacts that I'll
post a pix of
By putting a jumper wire from the batt+ to the coil+ bypasses the ign. switch starting circuit and engine will start with it hot wired.
Also I'm assuming you removed the spark plug and put your thumb over the plug hole and cranked engine over until the compression blow your thumb off then lined up on #1 Guessing that your on true TDC can fool the best guessers an have it at 180* off .
So if you not sure put your timing light on it crank the engine by jumping the solenoid so eng. will crank you may need to have the key.
Most guys change over to the flat blade ign. switch
Orich
Sure sounds like a poor ground. Clean up the ground terminals. You should have one at the rear of the engine that goes to the metal firewall. Check (or add one) from the battery to the engine, engine to frame, and one engine to fender. That way the whole area is grounded in a circuit. Don't forget to check the small ground wire inside the dist. If it's not a ground problem then, possibly a break in the "pink" resistance wire. If you have a wiring diagram follow it and check it for damage. If you don't have a diagram, just google it. If those two things don't fix it, then I'd check the ign. switch, like Orich stated. Welcome to the forum!!
I had a very similar thing happen with my truck last year --very weak spark, engine wouldn't start, no spark coming out of the plug wires.
Turned out to be the condenser, even though the condenser at the time was only 4 months old.
Condensers for points ignitions these days are of very poor quality. Don't rule out the possibility that that new condenser might be bad, right out of the box.
Thanks for all the quick responses I'll have to check out all those grounds that were mentioned as far as the ignition switch I have also replaced that as well when switching out parts so I'll check the grounds and get back thanks
Thanks for all the quick responses I'll have to check out all those grounds that were mentioned as far as the ignition switch I have also replaced that as well when switching out parts so I'll check the grounds and get back thanks
If you have the round pin ign. switch it the plug that is the main problem of over heating the small contacts will show signs of over heating or burnt discoloring form heat.
Orich
just to update everyone I got the truck running I ended up getting the electronic ignition for it and that seamed to solve my problem so it does seam that todays points and condensers are crap since I did change those before converting thanks for all the help and suggestions
just to update everyone I got the truck running I ended up getting the electronic ignition for it and that seamed to solve my problem so it does seam that todays points and condensers are crap since I did change those before converting thanks for all the help and suggestions
Most likely the condenser was the culprit. At least you have the engine running now.
just to update everyone I got the truck running I ended up getting the electronic ignition for it and that seamed to solve my problem so it does seam that todays points and condensers are crap since I did change those before converting thanks for all the help and suggestions
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