Headers, Timing

[MY90GT]

Just had the stock exhaust replaced. Installed MAC headers, HighFlow Cats,
and Flowmaster mufflers. I had been running the timing at 18 degrees BTC.
When I got the car back, I thought I had an exhaust leak. You couldn't hear it at idle or when you revved the engine, but when you drove the car you could hear a pinging sound. I took it to two muffler shops and they couldn't find a leak, they said it sounded like header ping?????
Well, I dropped the timing back to 10 degrees BTC and the ping is not as bad,
but the car doesn't run as well. I use 93 octane gas.
Any ideas??????

 

[ECU5.0]

put 87 in it and see if that helps. it sounds like detonation to me....most detonation only occurs when there is a load on the engine (like when youre driving). higher octane isnt going to help. check all your sensors and make sure they are good

 

[blkstangman88]

dont put cheap **** in it, it will just clog ur whole fuel system, theres a reason the cheap gas is cheap and the other more expensive.......it just ur timing, u need to play with it.....anywere between 8 to 18 timing is good, just start at 9 or 10 and go up one degree at a time untill the pinging stops, everytime u change the timing, u need to "race" the car to actualy tell if the pinging has stopped.

 

[Foxwolfe]

cheap gas isnt cheap because it "clogs your ****", its cheap because its a lesser octane, the difference between octanes is how quickly they burn.

 

[MY90GT]

I also put new plugs in when I put the new headers on.
Could it be the plugs?

 

[ECU5.0]

dont put cheap **** in it, it will just clog ur whole fuel system, theres a reason the cheap gas is cheap and the other more expensive.......it just ur timing, u need to play with it.....anywere between 8 to 18 timing is good, just start at 9 or 10 and go up one degree at a time untill the pinging stops, everytime u change the timing, u need to "race" the car to actualy tell if the pinging has stopped.

yeah, that was the worst statement ive ever heard. its just lower octane....and if you read a manual that came with our cars you would see that they are supposed to run 87 octane. im running 87 with 14* timing and no detonation. its all in how you tune it with fuel pressure and timing

 

[MY90GT]

OK, I removed the timing advance chip (not sure what it's called) reset the timing from 2 degrees BTC, to 12 BTC (which is where I had it before). After I put the chip back in, timing jumped to 18 degrees BTC. The car runs a lot better but the ping is louder. I could still hear it at 2 degrees, but not as loud. I have always run 93 octane, and have a full tank, so it will be a couple of days before I can put lower octane in. I had also put new plugs in when I put the headers on. Plugs gapped at 0.050. And they were the same ones I had run before.

 

[ECU5.0]

try disconnecting your battery for half an hour or so...and let the computer learn the new settings. ive also heard you can just unhook both battery cables and touch them together to reset the computer instantly. go try that and see how it runs

 

[blkstangman88]

i ran regular in my car for a year, then it started sputtering and hesitating, changed all the filters and screens and had the injecters cleaned and it runs fine, been putting 93 octane in it since and no problems. thats been 4 years since.

 

[MY90GT]

I cleared the computer of errors, and left the battery disconnected overnight.
Changing the timing really does not change the ping that much. I'm going to pull the plugs this weekend, regap. I've checked for vacuum leaks and found none.