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iTrader: (6)

I have been putting this off but I must take care of whatever is happening now.
Car is a 1998 Formula with lid, catback and LS6 intake and at WOT around 5k RPM+ I have this sound of pebbles/bb's. This is the only time it happens. I do not get into those high of RPM's very often but when I do it sounds horrible. And it does it in just about every gear.

I am running German Castrol 0-30 but this has been going on since I purchased the car bone stock.

I did search and I read something similar about detonation? I do belive my fuel pump is almost out the door. I hope this is nothing internal motor related? Please give me suggestions if you have any ideas. Thanks

BOTTLEFED383

my formula did the same to me a month after i got it i took it to the track ran it 14.2 and it ran fine then i swapped my buddys air box and mass air 14.1and it did it after i got home i checked my fuel filter bitch was plugged tryed it again ran like a champ look at the simple stuff first

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iTrader: (6)

About 3k miles ago I did plugs (NGK TR5's), new crap Autozone Wires (AC Delco), new fuel filter, seafoam and oil change.

So the fuel filter is not that old, the one I pulled out was nasty though.

And my only time to the track I ran a 13.4 @ 107 before the LS6 intake. So she runs decent for what is done and being a 98, just that at WOT (above 5k RPM) she seems to fall on her face.

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iTrader: (6)

TTT Anyone else?

shoemike

iTrader: (25)

detonation

hammertime

iTrader: (1)

Some have found that a badly clogged fuel filter allowed debris into the fuel rail where it blocked the flow of fuel to certain cylinders (#7 perhaps?).

At any rate, that noise is very bad for your car. What did the plugs look like when you removed them? Did any one of them stand out as badly worn?

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iTrader: (6)

I will check that next time. And with the cheap cost of a fuel filter I will replace it and see if that helps any.

s346k

iTrader: (4)

spark knock

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iTrader: (6)

After doing some old searching of posts I read something about unplugging the MAF sensor to make the car run rich? So I left work, unplugged the MAF and the noise went away in WOT through 1st and 2nd gear. Any ideas what this means?

I have also been thinking that the cheap Autozone spark plug wires may not be enough for my car?

Hennytime

iTrader: (33)

clean the maf

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iTrader: (6)

I think my MAF is pretty clean actually. I will try to buy the cleaner from Autozone and clean it out and see what happens. Anyone think my problem may be something else?

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iTrader: (6)

So I have since plugged the MAF back in and the knocking has went away. Maybe it did something when it was unplugged, I will still try to clean it soon! Any other ideas? Thanks

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iTrader: (6)

Update to my thread:

I bought the CRC *Sp* MAF cleaner last night at the auto parts store. Claims 4hp or on bottle from cleaning MAF! BS!! Either way I cleaned the MAF as well as replaced my tranny mount and went out for a drive and it still was doing it some. It did not seem AS bad, but still visible.

Any ideas why when I unplugged my MAF and at WOT it seemed to go away? Am I running lean. Detonantion = Lean? Correct?

SidewayzOZ

iTrader: (11)

Unplugging the MAF will put you on to the low timing table, and that's likely why it went away. I dont think it really changes your A/F ratio.

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iTrader: (6)

Hmm well unplugging the MAF made the noise stop by made my car run pretty weak and sluggish.

I also was reading about PCV problems and knock sensors being a big problem with detonantion. Can anyone enlighten me on these things? I recently did my LS6 intake and fixed my torn PCV hose if that helps any!

hammertime

iTrader: (1)

Retarding the timing will give up some of the power over the High Octane Table. Also, if you had a tear in the PCV hose between the valve and the intake, then you were probably getting un-metered air, so yes the A/F ratio could have been off for that reason. If you just did the repair, you may want to drive it some to see if that resolved the problem.

Something else you may want to consider is doing a top engine clean. The PCV runs dirty on these cars, usually pulling oil into the combustion chamber. Once you get enough soot in the chambers, you can get some hot spots that cause detonation. Look for the Seafoam sticky elsewhere in the forum.

If all of that fails, there is a slight possiblilty that you could benefit from a tune after the LS6 manifold. That seems rather low, though.

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iTrader: (6)

What is a top engine clean? Searching led me to nothing!

And the PCV hose is now fixed but I capped off the hose that ran to the passenger side valve cover.

hammertime

iTrader: (1)

From the general maintenance & repair section
How To Seafoam Your Car

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iTrader: (6)

Update to this thread:

A local guy hooked my car up to his laptop today (HP tuners?) and went out for a drive. The small details I am not sure of on numbers (maybe he will chime in). But I do know that my "knock" starts somewhere around 4.5k and extends until redline.

At WOT my KR is at 4 which I have read that is a big problem with the 98's, and we are needing too replace the Knock sensor with a 99+. That sounds like the problem but also I must add that once we unplug the MAF, the knock goes away completely. It does get a bit sluggish at WOT but it does not do it. Upon leaving his house I got on WOT several times and the sound and gone away, yet still sluggish now only at 5k or so (MAF plugged back in.) He told me that he thinks the MAF has to recalibrate it's self? So maybe when I go for a drive later it will do it again.

I am now in the process of finding someone to let me swap MAF's with a good MAF and see if that helps. (I cleaned it once with CRC cleaner as noted in another post) I am hoping this is the problem. Any input would be great. Thanks

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iTrader: (6)

Another update tonight:

Went and swapped MAF's with a buddys 01 z28. Seemed to make the knock go away completely and pulled like crazy! So now I am searching for a screened MAF. Anyone think my 4 degrees of KR is a bad thing at WOT? Thanks