Pre-detonation
Thread Starter
Cruising
Joined: May 2006
Posts: 14
Likes: 0
Pre-detonation
I have had a pre-detonation problem at high RPM's. I tried the Granatelli MAFS and got check engine lights. I read that the Granatelli is junk. I believe it. I knocked the honeycomb out of my factory MAFS and am wondering if that is why I am getting pre-detonation. I am putting an MSD Blaster (8 coils) pack in. Did I make a mistake by knocking the honeycomb out?????????
Le Mans Master
Joined: Mar 2006
Posts: 6,072
Likes: 196
From: Arizona
I'm not sure what you mean by 'pre-detonation.' Do you perhaps mean pre-ignition? If so, you have a very serious problem and you will destroy your engine quickly. Pre-ignition means fuel is exploding BEFORE piston travels past top dead center. You can imagine the devastation -- piston is traveling upwards and gets prematurely slammed back down by the ignited fuel charge. 
Perhaps you mean detonation or knock.
Perhaps you mean detonation or knock.
Team Owner
Joined: Feb 2003
Posts: 37,329
Likes: 12
From: Plano Texas
CI 6-7-8-9 Veteran
CI-VI Car Show Winner
St. Jude Donor '07-'08-'09-'10-'11-'12-'13
We'll need more information - detonation or knock.
As a noe - the Tech Section may be able to assist more so than General.
Lastly - take the Granatelli MAFS off the Vette and use it for a paper weight
As a noe - the Tech Section may be able to assist more so than General.
Lastly - take the Granatelli MAFS off the Vette and use it for a paper weight
Drifting
Joined: Aug 2006
Posts: 1,407
Likes: 46
From: Tampa FL
My 98Z28 had a descreened MAF when I bought it. The prev owner must have done it. It pinged when warm from the get go. I never noticed cause I moved to PA for a while. When I got back to FL it started pinging more often. I put EASE diags on it and found the LTRIMs were at 25%. Which means it was running lean. I thought the descreened MAF may be to blame so I bought an unmolested low mileage one for 45 bucks and the problem was gone!
The LTRIMs whent back down to 5% and there was NO pinging.
The LTRIMs whent back down to 5% and there was NO pinging.
Supporting Vendor
Joined: Jul 2003
Posts: 6,486
Likes: 2
From: http://www.mphparts.com 800-364-1975
I'm not sure what you mean by 'pre-detonation.' Do you perhaps mean pre-ignition? If so, you have a very serious problem and you will destroy your engine quickly. Pre-ignition means fuel is exploding BEFORE piston travels past top dead center. You can imagine the devastation -- piston is traveling upwards and gets prematurely slammed back down by the ignited fuel charge.
Perhaps you mean detonation or knock.
Perhaps you mean detonation or knock.
rockeynei, if you somehow damaged your MAF sensor to a point where it reads incorrectly (but not to the point that it's complete gone) that may be contributing to your pinging. The MAF is partly responsible for the fueling of your car, and if it tells the PCM that less air is entering the engine, the PCM will command less fuel from the injectors. There is logic that gives fueling authority to the VE tables instead of relying on data from the MAF, but only in situations where they disagree substantially on where fueling should be, or during throttle transitions, etc.
Easiest way to tell would be to get someone with a scanner to look at the signal coming from your MAF and see if it's within the expected ranges at idle, cruise, etc.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Cruising
Joined: May 2006
Posts: 14
Likes: 0
pre detonation.
I have a BBK intake manifold with an 80MM throttle body. Iridium plugs. MSD Ignition wires. MSD Blaster coil pack. Superchips power programmer and a 160 degree Thermostat. I am wondering if I need to go back to a stock MAF and see if my high rpm's ping goes away. What does any body think about that? Thanks for responding.