New motor, 383.

Ever since I installed it, I cannot get cylinder 1 to fire. My EGT's for cylinder 1 are half of every other cylinder. Ive swapped injectors, swapped plugs, plug wires, checked compression, readjusted the valves..Im clueless..

Runs great at WOT, backfires and misses horribly at part throttle, but idles ok.. Atleast it seems to, I cant tell if its missing or cam surge at idle..

I got tired of ****ing with it and let it sit about 2 years ago.. Im feeling the itch to mess with it again.. Opti is a brand new Delco unit from Chevy..

Any ideas?

 

If the EGT for that cyl is even half of the others, it must be firing sometimes, or weakly.

Basics first: Test that injector and make sure it's actually squirting fuel, with similar pattern and volume to the others. You can just pull the injector rail and use the fuel pump prime wire. Stick a plug in that wire and see if it sparks. Don't start a fire.

 

Do you actually have 8 EGT thermocouples installed, or are you reading the temp with a non-contact IR meter?

 

Non contact meter..

JP, switched injectors, switched plugs, switched wires, can feel the injector firing..

Possible that the injector isnt firing at the same rate, but Im not sure why it would be the only one doing so being as its a batch fire system..Wiring maybe..

 

My 93, does the same thing. I also used a non-contact meter. Swapped injectors, new opti, new wires/plugs, never solved the issue. It actually made me use a open-loop tune only, as I could never figure the split BLM issue with it.

In the end, I blamed it on the fact that it gets the most benefits from the cooling fans.

Runs good in WOT/Part Trottle. My vaccumm was best @32 timing/950 RPM idle.

355 cid, XE230/236, Ported Head car.

Someone once told that the 93 specific intake was to blame for it poor air distribution.

 

Make sure you don't have a crack in the spark plug ceramic insulator. It might be hard to see - might try a fresh plug if you have one handy.

 

I guess I forgot to mention, I put a 95 ported intake on the motor when I built it. It also has the 95+ Opti...


I dunno....this is the reason I quit messing with it 2 years ago..

 

TTT for ya man.

 

I am going to bring this back up...
was there ever a resolve for this? Could there be a possible blow by issue? or a valve issue.
Just curious on this one. I Know a guy off here that is having a similar problem and went through the same stages done here...(injectors, bought new ones and switched them around, put in new plugs which actually helped for a couple miles, and then it went bad again,)
going to do a compression test and a leak down test to see if that leads to something,

 

I gave up, ive had 8 different F-bodies, ive had this car for almost 10 years, had several different motor combos in it, and I guess its just age that has lots of different things failing on the car lately..I dont have the patience or time for it anymore and it just sits.. Im pulling the motor and selling the shell.. Ill tear the motor down and sell it piece by piece. I'm done with F-bodies...

 

Sorry couldn't help but notice a few things that seemed odd.

Does the Accel DFI drive low impedance injectors?

Once you switched over to the Accel unit for fuel and spark control why would you use it in batch mode as you mentioned above?

How did you arrive at the need for 96Lb injectors?

Did you check spark and compression on the cylinder in question compared with another cylinder?

Did you try swapping an injector from another cylinder?

Who's injectors are you using?