I have no idea of what is up with my 92Z? With the stock engine and supercharger 8psi i ran 12.9. I rebuilt the engine with a ZZ3 cam, svo 24lb injectors, crane hi-6s ignition, SLP intake runners, TES headers with 3in cat back, AFR 190 heads and I ran the same et's and trap speed of 109mph...SAME Cat's are new too?

Last year after the rebuild, it ran like stock without the supercharger, then after 3 weeks, i was getting onto the freeway and it seemed to open up? Then it was really fast! I later put on the supercharger and blew a head gasket and fuel psi regulator. I replaced the gaskets and a new fuel psi set at 45. Now it's sluggish again. No vacume leaks, ignition and wires are correct, idles fine, sounds fine but seems like it is back to a stock engine again. I am stumped? valves are lashed at 1/3 lash and timming is at 6deg adv. I have moved the initial timming around but no change and i am at my whit's end!

Any Ideas?

 

if your 190 AFR heads are not ported then get them ported by a good porter like GTP. also try to scan your computer to see what is going on and go to a dyno shop to check your car's rwhp.

 

Get it scanned to see if any trouble codes are popping up.

Mike

 

BTW, this should have been posted in LT1 Tech.

Mike

 

no codes! Sorry about the location, however, i thought this could be considered advanced because I have no idea what is up and no one else i have spoken to does either? Good spark, fuel psi is @ 45 under load????

 

Osmosis, This should be posted in a regular tech forum, since you have a 92 ill get this over to 3rd Gen.

Thanks bud.

 

I think this all boils down to fine tuning and PCM calibration.

What injectors are you running? What PROM?

I would start by getting a good air/fuel ratio gauge and checking the base a/f ratio. The next thing is to put it on a scanner and check for knock retard. I think that if you're using the stock injectors you may be running lean and losing power. U really need to get it on a dyno and dialed in.

 

I burned my own chip and have 24lb injectors. No codes either? It was really wierd! After the rebuld, it was acting just like it is now for only 3 weeks, then i went around a corner onto the freeway and it opened up...BOOM like something was plugged up or a wire was not grounded? Now it runs like the first 3 weeks after teh rebuild but has not opend up? I plan to take it to a dyno soon.

 

anybody

 

Are you running a FMU, or just 24# injectors at 45 PSI? Have you tried running the new combination with the stock programming? Your engine is not nearly modded enough that the stock chip shouldn't be able to produce good power, you obviously can make more power with a well tuned chip but that is if you have the skills to make one.

 

Yep, got the super FMU and burn my own chips. BLM's are between 16-128. It's strange because after i rebult the engine, it was similar to the stock power for about 3 weeks N/A. Then, it opened up? Do not know what the heck was going on??? Anyway, put the supercharger on, and blew a fuel psi reg and head gasket. After i fixed it, it's running like the first three weeks of the new engine? When I did open up, WOW! It was as fast with out the supercharger as the stock engine was with teh supercharger? Now, I have no idea what's going on? Currenlty making a wide band O2 but have work crap going on so it will have to wait a few weeks? Any ideas?

 

Was your stock engine with the charger running a stock chip or one of your burnt ones?

 

The stock engine I was running the stock chip except for the fact that i changed the injector constant from the 22lb to the 24 lbs and did 4 burns to get the BLMs in the ball park. And to turn the fans on @ 180ish. Other than that, i have yet to really tune the car via the chip due to this problem. I have tried to mess with the chip to see if that was the problem but nothing seems to work? So to answer your question, not really & still running the stock chip except for fans on @ 180deg and chaged the injector constant from 22 to 24. I'm stumped

 

What I was trying to get at is that your new combo is really not that far off of your old set up as far as the parts are concerned. You have a very minor cam, with higher flowing heads, neither of which would cause such a decline in performance if you kept the same programming as you had when you were running the old set up. Without the charger on that engine you could run in the twelves with a stock 305 chip. There are just too many factors to take in to account to make an acurate guess on what your problem is. Have you tried reverting back to the stock ignition? Whenever you have a problem that should be your first move. If that is Ok, this problem is probably going to be something that you have to go through step by step. If the engine is in proper condition, your chip is burned correctly, and your ignition is firing properly, then you must have missed something during the re-installation of your engine, be it a ground wire or whatever, you changed a variable that is going to be very hard to diagnose with out seeing the car. Also, if your psi is staying at 45 all the time your FMU is not doing it's job. You should see higher psi as your boost increases, what kind of charger kit are you running?

 

I agree! It is not too far off than stock and should be running 12's with out the supercharger! I know some one on TGO who runs mid 12's! The only difference is that he as a superram. He runs NA 12's! Anyway, I keep think Spark Air Fuel, my fuel psi is at 45 NA, supercharger and fmu is 90ish under boost. I have tried stock ignition, increasing fuel psi, no vacume leaks. Me and all of my friends are .... Lost on this issue. When it did open up that one time, it was like a wire grounded or a rock shot out the exhaust and it was running free? What wire could cause this? It Idles perfect! Sounds like it runs perfect? just lack of power.

Thanks for your help on this issue!