69 302 running on 4 cylinders
2/16/12, 12:15 PM
#1
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69 302 running on 4 cylinders
Iv got a 65 coupe with a very unusual problem, is only running on cylinders2,3,5 and 8. 1,4,6 and 7 are sparkin, compressing good and getting fuel.but not firing at all.
1 5 4 2 6 3 7 8 being the firing order note every second in sequence is workin and nothing from 1 4 6 and 7.
Anyone out there ever heard of this one cos im out of ideas and all ears!
1 5 4 2 6 3 7 8 being the firing order note every second in sequence is workin and nothing from 1 4 6 and 7.
Anyone out there ever heard of this one cos im out of ideas and all ears!
2/16/12, 01:16 PM
#2
Mach 1 Member
Welcome to TMS!!!
You say they spark but get no fire? Have you checked the cap/rotor/distributor/points for damage and play? My 69 FE had a lot of play in the distributor, but I didn't realize how bad it was until I replaced it and it mad a world of a difference.
Does it still have the points in it? Just a theory, but maybe the bounce (or lack thereof) from the points may be firing so far off that the spark is useless or detrimental. Maybe a lack of grease on the rotor lobes?
You say they spark but get no fire? Have you checked the cap/rotor/distributor/points for damage and play? My 69 FE had a lot of play in the distributor, but I didn't realize how bad it was until I replaced it and it mad a world of a difference.
Does it still have the points in it? Just a theory, but maybe the bounce (or lack thereof) from the points may be firing so far off that the spark is useless or detrimental. Maybe a lack of grease on the rotor lobes?
2/16/12, 07:52 PM
#3
Legacy TMS Member
Since the cylinders in question are getting fuel, spark, and compression, then the only thing this can possibly be is the spark is completely off. There is no other explanation, except a catastrophic failure... and that would have shown up as no compression.
Be sure your spark plugs are gapped correctly. Incorrect gap will cause the cylinder not to fire... well, I wouldn't expect *FOUR* of them not to fire, but still, I'd be checking.
Barring that, it sounds like someone was walking the wires on the distributor and got them messed up. Like this:
6-5-7-2-1-3-4-8
That would produce a car that only ran on the four cylinders pretty quickly, as all of the affected cylinders:
1---4---6---7--
Wouldn't get their spark on correctly... Heck, it might just backfire somehow. I dunno, it may be another pattern. I doubt it's the HO pattern:
1-3-7-2-6-5-4-8
as that would really leave other cylinders out, not the exact every other one...
Therefore, excepting the whole "new points, rotor, cap, wires, plugs' thing, make sure that the timing is correct, *mechanically* speaking. Don't use the timing light, get the engine to TDC, and then set your rotor. It will all magically start working after that, most likely.
I also have to ask, how are you determining that the fuel is getting into the cylinders in question? Just curious on that.
/I claim not to be any expert... more thinking out loud kind of throwing stuff at a wall sort of thing, and knowing just enough to be semi-dangerous or something... so don't shoot me for speakin' up, k? Thanks so much!
Be sure your spark plugs are gapped correctly. Incorrect gap will cause the cylinder not to fire... well, I wouldn't expect *FOUR* of them not to fire, but still, I'd be checking.
Barring that, it sounds like someone was walking the wires on the distributor and got them messed up. Like this:
6-5-7-2-1-3-4-8
That would produce a car that only ran on the four cylinders pretty quickly, as all of the affected cylinders:
1---4---6---7--
Wouldn't get their spark on correctly... Heck, it might just backfire somehow. I dunno, it may be another pattern. I doubt it's the HO pattern:
1-3-7-2-6-5-4-8
as that would really leave other cylinders out, not the exact every other one...
Therefore, excepting the whole "new points, rotor, cap, wires, plugs' thing, make sure that the timing is correct, *mechanically* speaking. Don't use the timing light, get the engine to TDC, and then set your rotor. It will all magically start working after that, most likely.
I also have to ask, how are you determining that the fuel is getting into the cylinders in question? Just curious on that.
/I claim not to be any expert... more thinking out loud kind of throwing stuff at a wall sort of thing, and knowing just enough to be semi-dangerous or something... so don't shoot me for speakin' up, k? Thanks so much!
2/20/12, 03:15 PM
#7
Legacy TMS Member
I would start with making sure your firing order is correct, as stated above start by bringing number one piston to TDC on compression stroke and go from there. You have a very odd problem there.
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