Jditlfm

iTrader: (26)

Well i just got scan master for my car to help diagnosis why it breaks up on top end and i found that i have 40 degrees timing at 2500 and up and then i have 5 degrees retard and knock counts that are in the 1000's My car has a madz28 tune mail order tune and i haven't had any problems in the past 6 months until i moved to Florida. The car will pull to 6k when my cutout is closed but when its open i get the feeling of detonation and it wont pull up top.

car has:
New ac delco optispark
New ac delco plugs
new ac delco o2 sensors
New autolight spark plug wires
new Coil
new ignition control modual
Egr is tuned out of the pcm and all vacum lines capped off but egr is still on intake manifold
Long tube headers
madz28 tune
cutout
new fuel filter
Cleaned maf
newer K&N filter

the_merv

iTrader: (88)

Are you a stock Cam? If so, that is your problem, you took the EGR out and it is detonating. The EGR helps keep the Cylinder temps down. With a Cam, the duration helps with that also, it bleeds out the combustion chamber pressure. The stock Cam needs the EGR to do this, otherwise you get detonation..

MEAN LT1

iTrader: (2)

Only way to figure out if its real is to put in some race gas and see if its real or not. More than likely its faulse. What your feeling up top is timing being taken out. When the knock sensor detect what it thinks to be knock it will decrease the amount of timing the motor see's there for decline in performance.

MEAN LT1

iTrader: (2)

Hmmm, I guess you learn something new everyday. I had no idea the exuast gas recycler(sp) did that?.

the_merv

iTrader: (88)

I blew a Head Gasket cause of it, ran too lean with the EGR still functional. I installed the LT4 Hotcam, got it tuned a little rich, and managed to blow the Gasket. We couldn't figure out why..cause after research was the EGR still functional. Removed the EGR, and it ran like a champ. Then tuned it a hair richer just incase.
That is my theory. Sounds like a good running Engine, just that Cam is holding you back.

ZFan88

iTrader: (4)

That sounds like a weird problem just from removing EGR. I've never heard about it before?

the_merv

iTrader: (88)

We couldn't figure out why I blew the Gasket, it went at a stop sign. After researching the **** out of it, that is what we came up with. I say the Cam has a factor in it cause of an article in here..
http://www.grandsportregistry.com/lt1vslt4.htm

Jditlfm

iTrader: (26)

yes i am on the stock cam, the vacuum still goes to the egr i just have it caped off, and the codes are deleted from the pcm. I can hook it back up tommorrow and try it out. I dont understand how it is effecting my wot peroformance, i thought the EGR was disabled under WOT?

the_merv

iTrader: (88)

It is dis-abled under WOT, I got rid of mine just incase. If you still detonate, richen it up a hair..