I just finished everything last night except for my custom dual exhaust. Its basically open headers right now but everything else is done. It lopes pretty bad with the new CAM i have, but i havent had it tuned. It backfires like every 4 or 5 seconds. Is it possible that the opti was put in wrong by one of the 3 inserts........
just a timing issue.......
no backpressure.....causing super amounts of fuel to be dumped into the cycle
thing is, it didnt back fire before when i ran open headers just messin around in the garage
also you guys with mezeire electric water pump.....anyone have any issues with theirs....i used to hear it run with just key-forward....but i dont think its working now

 

Anyone have any insight

is it possible that a spark plug could not be firing

I also have th Delteq System Equiped on the LT1

 

I had the same thing when I went to LT's and crossed up two spark plug wires. It would idle a bit rough but "backfire" while idling. Just an idea... good luck finding the culprit!

 

Check all your plug wires first, make sure thier not crossed.

Check to be sure that the injectors are measuring the correct Ohm's. It should be 12.X I think Or right around 12 volts. You could have a bad injector ? But i doubt it.

Does it smell like raw fuel? Like stronger than usual in an open header situation?

Also, I know it sucks but for testing the motor out, your gonna have to quiet the exhaust some so you can hear the engine well.

It is possible to put the opti on wrong, but I would think that it would barely even want to start if it was off by that drastic of an amount.

Check plugs and wires first. Dont forget the coil wire

 

How can i check the injector resistance.... black wire on a ground and positive wire on 1 of the 2 injector prongs...?????


i will run over everything today....plus i will put my x pipes on....i know %150 that im dumping fuel with an open header

 

I kinda agree with you about the opti...because i have put it in worng b4 and it would just crank crank sput...in that cycle

 

Running open headers causes problems with the O2 sensors. The exhaust mixes with the air at the collectors and throws the O2 sensors off, causing it to run excessively rich. Could that possibly explain it..... lots of raw fuel and air in the collectors?

You check injector resistance by removing the harness connector, and probing the injector across the 2 contacts. 12-15 ohms is OK. Then check the pink wire on each injector harness connector. That's where you want 12V. The other wire on the connector supplies the ground from the PCM to fire the injector.

 

Thats right...the pink wire = power
its coming back to me just like when i did the v8 swap

and yes i know about the o2 excessively dumping fuel
but i dont know if this is causing my problem

 

Wheres the experts on this pump
it was making a very strange noise last night at least i think it was te water pump

all the coolant go sucked down into the radiator and in the engine, but i think it might just be the vacuum......

 

Mine did the same thing, come to find out i had 2 wires crossed on the opti.

 

Adjust the rockers for 3 hours, then check the wires at the opti.....

Worked for us.

 

Hopefully that is my problem too, but i have this delteq system that cuts that opti sh*t out
Delteq only uses the opti for the signal from the camshaft
Fire comes from 4 dual terminal coils----2 cylinders per coil

 

Is your car tuned for the 30lb injectors? If not try backing down the fuel pressure that could be a band aid till you get a tune.

 

Arghh.....
Simple fix

6+8 were crossed
backfires gone

exhaust is on too...... has a lil chop + some vibration

but this meziere pump doesnt seem to be working
all fuses and the relay snaps on with key forward so
this

i used to be able to hear this thing run.......

 

Congrats..... in fact, they were the same two wires that we had crossed!