I've got a 97 Z28 A4 with a 383 stoker motor, cc306 cam, 11.5:1, ported stock heads, electric water pump, 30lb injectors, MSD6AL, NGK tr6s, OBD1 out of a 95 Caprice w/ knock sensor.

My first run on the dyno ran lean and it wouldnt allow for any tuning, it pulled 336rwhp. It would drive fine and felt like it had power down low, it just wouldnt turn up. So I brought it home to switch fuel pumps and now it has seems to have lost what power it did have. Wont even spin the tires over. The alternator is knocking real bad, but i wouldnt think it would cause it to loose this much power. New one will be on tomorrow. SES light is also coming on as soon as the switch is turned on w/o even cranking after it has been reset.

Jon

you sure the knoking is the alternator and not the engine

jusitn

It's without a doubt coming from the alternator. I dont really see any reason that it would be actually knocking at idle. It runs cool and it hasnt really been tuned in perfectly yet, so it runs a little rich at idle but according to the guy who was tuning it after a certain point it just leans out beleived to be cause by my stock fuel pump. But again at idle it was running real good, and I could just ease on the gas and spin the tires, but not anymore. Thanks.

Jon

do you have posi??? jk.

that engine seems pretty sound, should generate some good power, is your cam solid? Maybe you have some problems in your drivetrain somewhere, whats ur rear end gear ratio?

I'm thinking your knock sensors are picking up the noise from the alt. and retarding your timing seriously, but I would think you could still spin the tires

Its got a 2500 stall and stock 3.23s. Drive train is fine it just doesnt have the power. False knock is a possibility I'll see it I cant get it scanned to determine if thats the case, but like u said I would think that this motor would have some power even with some retard. The way it is it would be no match for a stock LT1, not even close. It seemed just fine to start with but fell off in less than a week. Thanks.

Jon

Are you saying you dyno'd it with an SES light? Who did the initial tuning program? Have you done anything at all to the programming to account for the displacement, injectors, heads and cam? Do you at least have some idea why the SES light is on? What did your fuel pressure look like at WOT?

It's almost a waste of time to even speculate on the cause of the problem until the basic questions are answered. Get it scanned and solve the basic problems.

On an administrative note - is there some particular reason you posted this in "Advanced Tech", rather than "LT1 Tech" where it belongs?

I had a crapped out PI Vigilante and the joker was stalling to 3600 but absolutely no torque multiplication. So it may not be the engine.

If compression is good, valve timing is right, fueling/air is correct and the exhaust emmision show good combustion, time to look at a bad cat converter or tranny/TC problem

try pulling the serpentine belt and running it. That should weed out that problem to see if there are any others. If you still have a problem with no enough power with the serp. belt off, then at least you will know for sure it isn't the alternator.

Like Injuneer said. What have you done programming wise? I have a stock bottom end motor and pulled 335 rwhp with a hot cam and a noname set of ported heads.

-Tony

Alrighty, i think this has gone down hill long enough.

1- All unnecessary posts that are either a cutdown/contain profanity/or dont contribute have been deleted.

2- Yes the discription for this forum says Stroker Motors. It ALSO says Advanced. You do the math.

3- I am locking this since it is not helping fix a problem, or providing good info anymore. Jon if you would like to repost this in LT1 Tech, you are more than welcome to.

Sorry to sound harsh but sometimes you just have to.