First off let me tell you a little about the car. Its a formula firebird that came with a 350 and tuned port. The motor has been changed and they used a edelbrock mpfi unit. The edelbrock unit is ran using the facory ecu. the car has a cam headers and no smog equipment except o2 sensor and a catalytic converter.

The car is slow roughly a 17 second car maybe slower.

When i first start it and rev it the motor sounds really powerful. After that initial rev its a gutless pig. The car doesn't want to pull past 5k and has no upper rpm power. it has 70 camaro z28 heads roller rockers etc.

Can a plugged catalytic converter do this?

I had to time the engine by ear anything lower than 15 degres initial it backfires through the intake. At 17 degrees it still backfires through the intake if i nail the gas when cold! I checked the cam timing and its good. i want to say the total timing is mid 30's but i'm not sure. I read on this forumn a good spot to have the total timing and i set there. My car also wants to heat up but i'm thinking that is the thermostat.

I'm ballin on a budget so i cant take the car to a mechanic or afford to have it dyno tuned. I have basic tools and am going to work on it saturday. Any direction where to go 1st would really be helpful

 

Backfires through the intake is usually fuel pressure, or spark. Check that first it's a simple fix.

 

there isn't a port to check the fuel pressure on the edelbrock parts and i've put new taylor plugwires and new plugs. cap and rotor appear to be good. really i'm trying to figure out why after one rev it would run like garbage

 

The only way to find out is to put a port or check valve on the fuel rail line. If you don't start with the basics first your car will be scrap.

 

ok i'll try that what kind of fuel psi should i be showing it's a tpi

 

55-60psi for the LT1, L98 and ls1.

 

In that case pull the codes and see if anything shows up

https://www.thirdgen.org/forums/tech...s-dumbies.html

You are wasting your time until you can set the timing correctly and know what it is

Does the ECM have a custom tune to suit the mods ?
Do you know the cam specs , some cams are not compatible with EFI

 

i have no idea the specs on the car as i bought it this way. I dont get a ses light which is weird because all of the smog equipment is removed and all the smog wires are unplugged! Should it not throw a light for that?

If i try to time it to factory specs it backfires through the intake really bad and wont run. hooked up a vacuume guage to time it and used a timing light where you can see the total advance with a ****. The timing is the best i can get it and dont think my problem is there.

The ecu has a sticker that says it was remanufactured but doesn't mention a tune and appears to be a stock ecu.

I'm really leaning torwards the cat being plugged or something with fuel pressure. I'm going to throw a vacuume guage on it in the morning and will post my results.

 

Does the light actually work?
There is no feedback to the ECM to tell it if the smog stuff is in place or not.
There is feedback if the EGR is not working ( or removed ) and a code will be present unless a custom tune is installed with the EGR deleted

That is only the part # of the ECM.The one ECM may be used on many different engines .The tune programmed on the memcal ( chip ) inside determines what it is setup for
You have to remove the cover and see what is written on the memcal
Stock memcals look like this ( the blue thing ) and a 3 or 4 letter ID code

 

Do you have the ESC connector disconnected when you are adjusting the timing ?

 

yes i do have the esc connector disconnected.
I put a vacuume guage on it today and found the cat is good.
I am showing 13 inches of vacuume with a steady needle. I live at 5500 feet and have a cam installed but tdont know the specs.
It does idle around 800 rpm with some lope and i am using a factory stall conveter and rear gears.
does the ssending unit that tells the guage the coolent temp also signal the ecm? I found that guage is reading way wrong by about 60 degrees hotter than the car is actually running!
I'm still yet to check fuel psi as i havent built a test port for it yet, hopefully tomorrow if i can find time!

 

also the service engine light does come on when i initially start the car. So i'm guesing there must be some sort of tune then? It does have a blue chip in it. I will pull it tomorrow and see what it says on it.

 

No