'74 GMC won't start..
mdunlap13
01-18-2004, 06:58 PM
:banghead: My father has a '74 GMC that has been sitting since '96. It turns, but will not fire. I took the shotgun approach of fixing the thing since dad was footing the bill. I have replace the coil, all plugs and wires, the distributor cap, rotor and have also replaced the points and condensor on the distributor. Plugs were gapped at .035 and the points were gapped at .019. Fire makes it into the distributor, but does not come out. Well, let me back up. This was tested with an analog mulitmeter, not a light or digital meter. Maybe analog won't read the spike, but I'm fairly certain no power is coming out of the distributor. Any suggestions? Why no fire? Marc
webelnn
01-19-2004, 11:38 PM
Mark
This may sound simple but have you pulled a wire at the plugs to see if spark is there, and the coil wire? Check your points again to make sure they are set at the high spot on the nut. Some times we all forget to put the rotor back in as well, my boss (55) still does this at times. Be sure to recheck all conections. And recheck firing order 1 8 4 3 6 5 7 2 And sometimes we all do get a bad part, quality control what can you say. I believe in test lights, no meters for plug wires, unless you check look at ohms with the wires off the vehicle. No movement means a bad wire, full scale is a good wire.
I have gotten so tired of the point ign that i usually put in the hei dist. A real easy install, pull out the old one, drop in the hei and hook up one wire to your fuse box (some are marked ign or to an accesory splade lug,) a new set of wires. Recheck firing order, set the timing, and enjoy the new found power from the hei.
Hope it helps Jim
This may sound simple but have you pulled a wire at the plugs to see if spark is there, and the coil wire? Check your points again to make sure they are set at the high spot on the nut. Some times we all forget to put the rotor back in as well, my boss (55) still does this at times. Be sure to recheck all conections. And recheck firing order 1 8 4 3 6 5 7 2 And sometimes we all do get a bad part, quality control what can you say. I believe in test lights, no meters for plug wires, unless you check look at ohms with the wires off the vehicle. No movement means a bad wire, full scale is a good wire.
I have gotten so tired of the point ign that i usually put in the hei dist. A real easy install, pull out the old one, drop in the hei and hook up one wire to your fuse box (some are marked ign or to an accesory splade lug,) a new set of wires. Recheck firing order, set the timing, and enjoy the new found power from the hei.
Hope it helps Jim
herefordman
01-20-2004, 01:51 AM
Mark,
The gap on the points is too big, .014"-.015" is closer to a decent working gap on the older engines, and I'm in agreement with Jim, dump the points and go breakerless, a lot less of a headache.
The gap on the points is too big, .014"-.015" is closer to a decent working gap on the older engines, and I'm in agreement with Jim, dump the points and go breakerless, a lot less of a headache.
mdunlap13
01-21-2004, 01:03 AM
Great advice. Especially the part about the hei. I think I'll just get the hei and replace everything around it. :naughty:
I have, in the past forgot to put the rotor back on, but not this time. Seriously, I don't want to put any more money in it. There is more rust on this thing than true metal. The wood slats in the bed have rotted out. It's in pretty bad shape. Dad wants it running so I will get it running if it takes me the rest of the year. By the way, its the 250ci straight six. I'll let you know how it turns out. Thanks again. Marc
I have, in the past forgot to put the rotor back on, but not this time. Seriously, I don't want to put any more money in it. There is more rust on this thing than true metal. The wood slats in the bed have rotted out. It's in pretty bad shape. Dad wants it running so I will get it running if it takes me the rest of the year. By the way, its the 250ci straight six. I'll let you know how it turns out. Thanks again. Marc
stwin4
01-14-2005, 05:49 AM
I agree,I replaced my point ign. with a H.E.I years ago in my '74 truck and have never had a problem just replaced my wires to the specs of a '86 blazer and your in like flint.Oh it also makes it easier to hook a tach up in your vehicle.
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