Went cheap and it shows

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Apr 28, 2008 | 11:42 AM

DUBI

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From: Dix Hills NY

Went cheap and it shows

I just bought a tank full of 87 octane in my 91 vert. Now I have a ping machine. Is this normal or is this a definite knock sensor inop alert???

Apr 28, 2008 | 12:23 PM

c4cruiser

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From: Lacey WA RVN 68-69

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The pinging is due to too low an octane for the engine. It probably won't hurt anything as long as you don't constantly hammer on the engine.

Assuming the knock sensor is working properly, it will pick up the ping and the ECM should retard timing a bit. That will reduce engine performance some.

I would just go thru about half of the tank and top off with premium grade. Have you tried the middle grade gas? That might work a bit better.

Apr 28, 2008 | 12:45 PM

hexane

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From: Kathleen FL

If it pings, I would retard the base timing from the stock 6 to 4 degrees. Back when my L98 was stock, this was apparently a solution to my problem when I decided to cheap out on the 87 octane.

Apr 28, 2008 | 01:28 PM

Demonic85

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From: sw Ohio

I run 87 with no pinging and mine is modified. My compression ratio is about 9.65 to 1. I think the '91 had a higher compression ratio and I bet thats why yours is pinging.

Apr 28, 2008 | 02:13 PM

DUBI

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From: Dix Hills NY

cheapo

Thanks Guys

for the info!!!

Apr 28, 2008 | 02:31 PM

CFI-EFI

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From: The Top of Utah

You shouldn't hear much, if any, pinging, if the octane is really too low for your car. The ESC should retard the timing to prevent the pinging. The first thing I would do is check for codes. You nay have an ESC problem. There is no need to alter the base timing. At the very worse, keep your foot out of it until you make room for higher octane gasoline to mix with it.

RACE ON!!!

Apr 28, 2008 | 03:02 PM

Firevette

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From: Conroe TEXAS!

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Quote:

Originally Posted by Demonic85

I run 87 with no pinging and mine is modified. My compression ratio is about 9.65 to 1. I think the '91 had a higher compression ratio and I bet thats why yours is pinging.

91 = 10:5:1