Is a "spark knock" pinging normal?
#1
01-15-2000, 06:45 PM
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Is a "spark knock" pinging normal?
Have a 1999 5.4L that has had a "spark knock" pinging on accleration since about 1000 miles. Is this normal? Should I be concerned? Sounds almost like a manifold leak. I do get less than average gas mileage <10 mpg both hwy and city. Have had mass air flow sensor replaced. Vehicle has 10,000 miles on it now noise is always present on accel. now whirring noise when you release gas pedal (kinda like a metallic winding down noise) Any suggestions?
#2
01-17-2000, 06:20 PM
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Lemon,
It sounds to me as if your truck has a problem.
Certainly you've tried to use higher octane gas at this point, I assume, with no improvement. Like J-C, that would be the first thing I'd suggest. For various reasons, some vehicles simply require premium, regardless of where the timing is set.
Not quite sure how you relate a spark knock noise to manifold leak noise, though. They are two completely different noises, but the problems could easily be related.
A vacuum leak makes a hissing noise. If you have a vacuum leak, though, it could cause spark knock, since it would probably lean your truck's mixture radically, which would also make it run hotter. It would also affect gas mileage, which sounds like it really stinks right now, unless you're towing or carring huge loads around the city. You should average at least about 14 if you do "normal" driving.
Not sure exactly what a "whirring noise" on deceleration is, either, unless you have a leak in your air ("smog") pump system, if your truck is equipped with one.
A spark knock doesn't sound anything like the noises you've described. The best way I can describe it is like "pinging" a large metal object lightly (and usually repeatedly) with the ball of a hammer, which is why they call it "pinging." That's just what your're doing your pistons.
I assume you're under warranty. If your dealer won't give you satisfaction, try another one, or make an appointment to see Ford's regional rep and tell him (or her) about the noises and gas mileage. You gotta jump through their hoops to eventually get any satisfaction.
But don't let them tell you you don't have a problem if your truck makes noise and sucks gas. It should do neither.
Keep us updated!
John
------------------
On order (due week of 1/24): 2000 Lariat Flareside, Deep Wedgewood Blue monotone, gray leather, 5.4, trailer tow, 3.55 posi.
It sounds to me as if your truck has a problem.
Certainly you've tried to use higher octane gas at this point, I assume, with no improvement. Like J-C, that would be the first thing I'd suggest. For various reasons, some vehicles simply require premium, regardless of where the timing is set.
Not quite sure how you relate a spark knock noise to manifold leak noise, though. They are two completely different noises, but the problems could easily be related.
A vacuum leak makes a hissing noise. If you have a vacuum leak, though, it could cause spark knock, since it would probably lean your truck's mixture radically, which would also make it run hotter. It would also affect gas mileage, which sounds like it really stinks right now, unless you're towing or carring huge loads around the city. You should average at least about 14 if you do "normal" driving.
Not sure exactly what a "whirring noise" on deceleration is, either, unless you have a leak in your air ("smog") pump system, if your truck is equipped with one.
A spark knock doesn't sound anything like the noises you've described. The best way I can describe it is like "pinging" a large metal object lightly (and usually repeatedly) with the ball of a hammer, which is why they call it "pinging." That's just what your're doing your pistons.
I assume you're under warranty. If your dealer won't give you satisfaction, try another one, or make an appointment to see Ford's regional rep and tell him (or her) about the noises and gas mileage. You gotta jump through their hoops to eventually get any satisfaction.
But don't let them tell you you don't have a problem if your truck makes noise and sucks gas. It should do neither.
Keep us updated!
John
------------------
On order (due week of 1/24): 2000 Lariat Flareside, Deep Wedgewood Blue monotone, gray leather, 5.4, trailer tow, 3.55 posi.
#3
01-17-2000, 07:36 PM
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Big Easy,
I think he was refering to a leaking exhaust manifold. That sound, although unique, could be mistaken for "ping". I've only had one exhaust manifold leak in my life. It was an unforgettable sound. It was on the same car I had that would occasionally "ping" if I had a poor grade of 92 Octane. 10.5:1 pistons aggrevated that... I could run some brands of 92 without ping and any 93 or higher was OK.
I think he was refering to a leaking exhaust manifold. That sound, although unique, could be mistaken for "ping". I've only had one exhaust manifold leak in my life. It was an unforgettable sound. It was on the same car I had that would occasionally "ping" if I had a poor grade of 92 Octane. 10.5:1 pistons aggrevated that... I could run some brands of 92 without ping and any 93 or higher was OK.