gravedigger472

to me it looks like the fuel is sputtering rather than spraying in a fine cone like i have heard described. around .08 seconds in the video look at how the fuel comes out the side of the TB.

http://www.youtube.com/watch?v=SJ7amuQ-Aw4

This is in my 1989 K2500. I swapped in a 454 last month. I originally bought a tow master chip from brian to put in the 7747ecm. ran real rich and stumbled. I checked a bunch of stuff and that did not work, so i had Brian pull some fuel. still the same, yada yada. before
i have been chasing down a really rich condition, it stumbles like crazy. so far i have put new o-rings/gaskets in the injector pod, new regulator, replaced 02, CTS, MAP, TPS, IAC, coil, ignition module, cap, rotor, plugs, wires, etc....

my plan is to have the injectors cleaned and whatnot, but i want to know is thats what i need to do first of all.

im getting way too much fuel dumped in. it blows smoke like crazy, smells awuful, and gets terrible MPG, even for a big block.

thomas1976

Not sure, but wenn spraying the pattern looks ok. The drops could be too much fuel for the injectors to control at low rpm, or eventually a leacking o ring, in this case probably the first.
What injectors are you using and @ what fuel pressure?

I guess a VRFPR and a decent tune will solve the problem, though I dont know if your ecm can control a Vacuum Referenced Fuel Pressure Regulator.

If you need a coustom chip and your ecm does not support a VRFPR/VAFPR you are better off upgrading to EBL http://dynamicefi.com/.

gravedigger472

id love to upgrade to the EBL when i get a cam and stuff, but for now the motor is completely stock so i shouldn't need a VRFPR.

they are the stock 454 80lb injectors at 13psi, so that should not be an issue of too much fuel pressure.

RBob

iTrader: (1)

I must have watched the video about a dozen times. Can' t figure for the life of me what would cause the erratic firing of the injectors. At some points it appears as though the PW is so small that the injector barely gets the fuel flowing. Then at other times it suddenly gets enough of a PW to produce the proper cone shape of the flow.

If you have a stock chip, even if from a 305 or 350, try it and see what happens. It may throw a code 43 (ESC) if the 454 doesn't have a knock set up on it (many don't). But see if the injector issue goes away.

The other thing is to check the wiring to the injectors. On some harnesses the injector wires are spliced in about a foot from the TBI unit.

I've had them break at the splice which provides an intermittent injector firing.

On a properly running set up at idle the eye sees the injector flow as a continuous stream. It appears as a steady cone shape of fuel flow into the TBI unit.

I wonder if maybe the calibration is flipping in and out of async mode.

RBob.

gravedigger472

according to my laptop, it never goes into asynchronous fueling mode.

i have put in a 350 chip, and it runs alot better with no stumbles, but i have not looked at the fuel cones with the 350 chip in it, ill have to do that.

gravedigger472

well i bought new injectors and out em in, and the new ones have the same spray pattern as before and runs mostly the same, but throttle response seems a little better, so not a complete waste. been reading a ton more, thinking that maybe a leak on the EGR or something.

xX89RSXx

iTrader: (1)

You could also send your injectors out to be tested and cleaned. I sent mine to Witch hunter performance, I should have them back in a few days.

southbay08

you can send your injectors to us...we will put them on the bench to check them for you at no charge to you.

www.southbayfuelinjectjors.com
516-492-6504

gravedigger472

i probably would have sent them to somewhere to be cleaned, but its my DD and i just wanted to get it done. even though it the injectors didn't solve the problem i at least was not out of a car for a few days

Yuffie55

hey you maybe want to check your pick-up coil in you dist you will have to wire from it. one withres the computer to fire your fuel inj cheked it with a O meter your pick -up

RBob

iTrader: (1)

Have you tried this to see if it clears things up?

RBob.