Fire on one cylinder
#11
09-30-2018, 12:38 PM
Champion
And if it fires for all cylinders, then what's left is the wire to the cap, the rotor, and the other wires.
Nothing else.
And new? Did it come with a warranty? You know, if new was never bad out of box, you wouldn't need any kind of warranty.
And new can be bad out of box. Depending on the brand, it could be defective by "design".
Let's not also forget that if the cap is improperly installed, it might not be able to REACH any cylinder post than 4.
But let's go through all of that.
If the coil fires hard every spark event it should, that's probably not going to be the problem. But even if it was ... it wouldn't always be cylinder 4, now would it? If it's always 4, it's not random.
Funny thing about telling me that is, I do computers for a living. Not car ECUs, but computers.
And you're right; but rather than "corroded computers" I'd say "corroded contacts into a computer". But here's the thing there. The computer fires the coil for every spark event. The DISTRIBUTOR puts it out to the appropriate spark plug via the cap and rotor. So, once again, if the coil is firing every single spark event, the COMPUTER is doing ITS job, but the DISTRIBUTOR (cap and rotor)... isn't.
And once again, WHICH ground would case the coil to "fire hard" but the distributor to not, well, distribute?
Either you're not telling us what's actually happening, or it's the cap, rotor, or wires.
Try a inline spark tester ( such as as an example). Better yet, get two. Put one between the coil and distributor, and one at the #4 position. If the coil only fires when #4 fires, it's upstream of the distributor (and it could be some of what you're talking about); but do notice, that means the coil isn't hitting hard.
If the coil fires 8 times for every time #4 fires, well ... do the math. The ECU's doing ITS job, the MECHANICAL portion is not doing ITS job. That is, the cap and rotor and wiring from the coil to the plugs.
(Then try that at the cap for all the other four cylinders.)
Do be sure to triple check the spark plug wiring against the firing order of 1-8-4-3-6-5-7-2 . And if all else fails, but you get spark on all cylinders, check that the distributor isn't 180* out (happens to the best out there sometimes.)
RwP
Nothing else.
And new? Did it come with a warranty? You know, if new was never bad out of box, you wouldn't need any kind of warranty.
And new can be bad out of box. Depending on the brand, it could be defective by "design".
Let's not also forget that if the cap is improperly installed, it might not be able to REACH any cylinder post than 4.
But let's go through all of that.
If the coil fires hard every spark event it should, that's probably not going to be the problem. But even if it was ... it wouldn't always be cylinder 4, now would it? If it's always 4, it's not random.
Funny thing about telling me that is, I do computers for a living. Not car ECUs, but computers.
And you're right; but rather than "corroded computers" I'd say "corroded contacts into a computer". But here's the thing there. The computer fires the coil for every spark event. The DISTRIBUTOR puts it out to the appropriate spark plug via the cap and rotor. So, once again, if the coil is firing every single spark event, the COMPUTER is doing ITS job, but the DISTRIBUTOR (cap and rotor)... isn't.
And once again, WHICH ground would case the coil to "fire hard" but the distributor to not, well, distribute?
Either you're not telling us what's actually happening, or it's the cap, rotor, or wires.
Try a inline spark tester ( such as as an example). Better yet, get two. Put one between the coil and distributor, and one at the #4 position. If the coil only fires when #4 fires, it's upstream of the distributor (and it could be some of what you're talking about); but do notice, that means the coil isn't hitting hard.
If the coil fires 8 times for every time #4 fires, well ... do the math. The ECU's doing ITS job, the MECHANICAL portion is not doing ITS job. That is, the cap and rotor and wiring from the coil to the plugs.
(Then try that at the cap for all the other four cylinders.)
Do be sure to triple check the spark plug wiring against the firing order of 1-8-4-3-6-5-7-2 . And if all else fails, but you get spark on all cylinders, check that the distributor isn't 180* out (happens to the best out there sometimes.)
RwP
#12
09-30-2018, 10:41 PM
If you used dielectric grease on the plug wire contacts it may be letting the wire push itself off the tower on the Cap. I have had that happen on new wires when I used too much grease. You have to make sure they snap into place on the plug and the tower then watch to be sure it doesn't push itself back off. If that is not it and the wires are good the new cap or rotor is not working properly for one of the reasons Ralph has mentioned..
#13
10-03-2018, 10:42 AM
I'd definitely check your firing order. You aren't going to see spark at say the #6 cylinder if the number 1 cylinder is the one being fired. Odds of 7 wires going bad at once.... Possible but not likely. Double check your firing order first, try different wires from the other cylinders on number 4 and see if you get spark.
pull your #1 spark plug and get your engine on tdc on cylinder 1, pull the cap off and see where the rotor is pointing, it's possible your distributor is off.
If that's not it could be a defective cap, make sure you replace it with a cap that has brass terminals, replace the rotor too. If they're new they should have a warranty.
let us know how it goes
pull your #1 spark plug and get your engine on tdc on cylinder 1, pull the cap off and see where the rotor is pointing, it's possible your distributor is off.
If that's not it could be a defective cap, make sure you replace it with a cap that has brass terminals, replace the rotor too. If they're new they should have a warranty.
let us know how it goes