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engine knocking????????


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saleens281
Novice

Apr 24, 2010, 4:19 PM

Post #1 of 10 (3138 views)
engine knocking???????? Sign In

thanks for looking at my post. i am no gearhead but i love cars and this spring my motor has started knocking after i took it out of storage. i should start off by saying it is a 2000 mustang saleen s281. it is a supercharged 281 with 20000 miles. now my wife thought she was doing me a favor by filling my tank to full a day b4 i planned on storing it. it has been in storage for 4 to 5 months and the knocking is worrying me. i initially topped off the oil with a quart of duralube and dumped a can of seafoam into the fuel tank. i then drove it for 10 min and nothing changed! i think i need to syphon my gas and refill with a fuel cleaner as well. does anyone think this is what i should do? is it a lifter or a misfire in the cylinder due to bad gas? any suggestions would be very appreciative.Unsure this knocking is obviously slower at low rpm's and faster at higher.....not sure if that helps but thought i would throw it out there anyway.


jayvie2000
New User

Apr 25, 2010, 4:58 AM

Post #2 of 10 (3128 views)
Re: engine knocking???????? Sign In

 
I suggest you run the car (easily) until you've used up this tank of gas, then put fresh premium in from a Mobil or Sunoco station. Add a bottle of Redline fuel cleaner. I would change the oil, too. I'll bet it clears up.


saleens281
Novice

Apr 25, 2010, 11:55 AM

Post #3 of 10 (3122 views)
Re: engine knocking???????? Sign In

you dont think this will make the problem worse? does anyone know what makes the knocking? and if i should take the safer approach and just suck out the gas. this is not just an ordinary mustang and i am worried that running the motor will put more stress on whatever is knocking.


jayvie2000
New User

Apr 25, 2010, 12:04 PM

Post #4 of 10 (3118 views)
Re: engine knocking???????? Sign In

 
I assumed you meant the sort of knocking as in "pinging and knocking" you get with bad or low-grade gas. An experienced mechanic can tell you quickly if it is another sort of knock, one that is more serious. I'd have a mechanic listen to it.

Its unlikely that 5 months of storage did anything bad to the engine.

If you change the oil, save some of it and see if there is gas in it (you'll smell it). Gas-thinned oil might make your engine knock.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Apr 25, 2010, 2:17 PM

Post #5 of 10 (3116 views)
Re: engine knocking???????? Sign In

Stale gas isn't going to cause a knock or a ping. You first have to determine exactly what the noise is before anyone can tell you what to do about it. It could be a stuck lifter. In that case, changing the oil and driving it would be the best thing for it. It could also be something more ominous.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



saleens281
Novice

Apr 25, 2010, 8:49 PM

Post #6 of 10 (3107 views)
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i changed the oil last fall before i stored it which is why this is weird. i only use synthetic since i bought the car. if it is a lifter should i dump some seafoam in my crankcase? it says it will free up lifters. or is there another product you recommend. i plan on taking it to my mechanic soon but even he says he is not comfortable working on my saleen. i appreciate the help and will update my progress hopefully this week.


Tom Greenleaf
Ultimate Carjunky / Moderator
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Apr 26, 2010, 6:24 AM

Post #7 of 10 (3102 views)
Re: engine knocking???????? Sign In

I like SeaFoam for certain issues but not for this - yet. 5 months is nothing! First diagnose what the noise is before trashing the oil with SeaFoam which I don't suggest leaving in oil. If a fresh synthetic oil change it probably isn't a lifter noise at all. Could be sounding like it but could be something like a flat spot on a belt or who knows?

Is oil suddenly over filled and you didn't possibly do that? Fuel getting in oil will cause problems. If worried enough get this to a tech or a tech to it to isolate what is making the noise,

T



saleens281
Novice

Apr 29, 2010, 6:30 PM

Post #8 of 10 (3088 views)
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well i decided to try and burn off the gas after 2 syphon attempts failed. i tried 2 different pumps and one would not fit and the other would not get deep enough into the gas..........skrew it, took em back so no $ spent.........i figured it wouldn't work anyway. so after 6 hours i am down to half a tank and now my "check engine" light came on...........i think this is a good thing, at least for narrowing down the problem. it still knocks while idling and if i rev the motor, there is a considerable amount of smoke out of my tailpipe. i plan on burning thru another 3 hours of gas this weekend and taking it to my mechanic to see what the scanner says. i hope that the smoke is not a headgasket and is related to the gas? the car has 20k miles so i am guessing that the scanner will say there is a misfire on one or more cylinders, but i will have to wait till next week. Unsure once i get to 1/4 tank i plan on refueling with premium and dumping an octane booster in as well so i can see if the gas is the cause. is this a good idea or should i see what the light is on for ASAP?


Tom Greenleaf
Ultimate Carjunky / Moderator
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Apr 29, 2010, 7:33 PM

Post #9 of 10 (3081 views)
Re: engine knocking???????? Sign In

">>there is a considerable amount of smoke out of my tailpipe.<<"

That would cause a CEL and mislead you as O2 sensors wont like smoke out tailpipe and cats will bedestroyed soon if not already.

Get a professional ear to hear this noise and isolate it first. Any operating malfunction is going to throw codes and sure go get them but I wouldn't be hasty with that info. Find and fix the noise as now it's clearly the problem,

T



saleens281
Novice

May 1, 2010, 9:39 PM

Post #10 of 10 (3064 views)
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got the scanner on it and there is a misfire on #3. at first it sounds like a lifter but took the stethascope out and nothing on top. it sounds like it is coming from below!!!!!!! my mechanic will pull the plugs on wednesday and see what he can do. we also seen smoke out the oil res while running. i am prepared for the worse........cracked ring etc. my buddie thinks it may be a coil? i think he is trying to raise my spirits. i will update next week.Frown
at this point i think i can rule out the "bad gas" theory.


(This post was edited by saleens281 on May 1, 2010, 9:42 PM)






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