vettething

is it normal to hear light pinging at full throttle for like two or three seconds from a l98 engine? i replace everything from maf sensor, ecm,prom,knock sensor, oxygen sensor, etc. i hope im just over reacting and this is normal for this type of engine. also i run 93 octane.

kimmer

If its at wot it could be the egr.

AirForceOne!

Here's some old posts with alot of good info on your problem, hope they help! They suggest checking your timing, plugs and wires to!

http://forums.corvetteforum.com/c4-t...25k-miles.html

Tom400CFI

How so? If the EGR is stuck open, it will reduce power, combustion temps and pinging...and idle poorly. If it's stuck closed, well, it is supposed to be closed at WOT.

It's not normal for and engine to be pinging at all. That is not normal or ideal operating conditions.

TommyFox

How many miles?

vettething

134000 miles and I replace egr a year ago. also did a full tune up 4 months ago. I hear its normal to get alittle ping when you floor it. that it takes time for the knock sensor to kick in. have any body ever heard of this before? this is driving me crazy

kleptopigdog

Do you get gas at the same place ?

Vette Daddy

Low octane

Put some premium in it

aboatguy

OP states 93 octane...

Base timing too advanced?
engine running lean?
deposits in combustion chamber?

vettething

no. shells or mobile only. my pops also have and l98 in his 1988 camaro. he got **** and toke his tune port off and put a carb on it. he tells me i need to do the same. lol.. but i be damn if i go back to the pass. ima fix this pinging issue one way or another and yes i run 93 octane

TommyFox

With that many miles you probably have some carbon build up causing the pinging. Use the additives to clean deposits. If you have not replaced the cat by now you need to. Or do what I did and take a pipe and gut the thing. Instant 5hp

dukeallen

The shell gas might be half your problem, I've never had much luck with their gas. And I used to work for them!
My dad's lawnmower even pinged on that crap!

aboatguy

That's odd shell is supposed to be a top tier gasoline.

I use Shell 93 octane in my 355 with no issues and my 355 is running a tad over 12:1 compression.



Mike

dukeallen

Maybe it's my area, but around here it's considered crap.

Frizlefrak

So let me get this straight....he's suggesting that you solve a detonation issue by removing an EFI system and putting a carburetor on it?

Don't.



Do you have any codes stored?

Run a compression test on all 8 lungs and post the readings. Set your BASE timing at 6 degrees BTDC with the ECM disconnected from the distributor. Next, test your knock sensor for operation. A rubber mallet and a timing light will do the trick.

There is absolutely no reason a TPI engine should be detonating.

Frizlefrak

Incidentally, I ran 10 degrees of base timing on my old CFI motor on 87 octane fuel, and it didn't ping in the least. Your timing is the first thing I'd check.

WW7

If you have access to a scanner you can check your egr for correct operation,also you can see if your car is running lean while driving... With a scanner hooked up you can also tap your exhaust manifold with a wrench to see if the timing is being pulled.( Friz gives another method above for checking operation with a timing light and hammer)...If the timing isn't being pulled it could be a bad knock sensor, spark control module, or very possibly the electical connector for the knock sensor.. The connector that goes on the knock sensor is very fragile and can become brittle over time causing it to break and loose contact, this is what happened to mine. I agree with the above , you should not hear any pinging at all if everything is working properly, the pinging should be detected instantly and timing pulled before being heard...WW

Frizlefrak

Wayne make a very good point....strong possibility the car is going lean on initial throttle up. Need to know fuel pressure when you lay the hammer down. Tape a gauge to the windshield. Would be good to know if you have a partially occluded injector(s) or malfunctioning regulator too.

If the ignition system, timing, and EGR check out, time to look at the fuel system.

383vett

As stated, thre first thing I would check if a motor is pinging is the timing.