okay, 90 TA, 350 tpi, speed density
mild cam, swapped heads
took the 32lb accel injectors out and the 58mm bbk throttle body off thinking this would improve the drivability of the car (packing a hypertech chip so you can guess how it was running lol)
after the injector swap back to the stockers it was running better
today swapped the t.b. and still have a bad off idle bog and to make it worse an occassional backfire
any ideas, I will check fuel pressure as soon as I can beg/borrow/buy a gauge
no cross wires, no vacuum leaks
any ideas of things to check, I have yet to check the tps voltage either but with the stock t.b. back on should that even be considered?

one last ?, someone put a vacuum reserve can on the car, I think they mistook all the tuning it needed for too big of a cam and a vacuum loss, opinions?

ok tpi gurus where are you? help your lt1 familiar tpi unfamiliar brother out

 

I am having the same thing happen on my 90 Formula 350 newly rebuilt. I think you need to check the timing. I beleive that is why it is backfiring, hopefully someone else will verify this.
Gary

 

it probably means your retarded...












seriously tho, your timing is probably retarded

 

Isn't the TPS bolted onto the TB of the LT1 like the TPI's? If so then you WILL have to reset the TPS, you moved it from one TB to the other, right? Even if it already had one on it, when you put the stock TB back on the throttle position could have easily changed due to different gaskets (thiner or thicker). I would also check minimum air on it too, then TPS.

 

okay, the tps is @ .536 or so (I remember reading .54 is the desired value)
will check timing this afternoon

my problem is the tpi has "q-jet bog" hit the gas and 4 seconds later the engine revs and BACKFIRES!!!
HELP!!!!!

I adjusted the iac up a little and it helped w/ the backfire so the possibility of retarded timing still stands

anyone have any other help for me

thanks as always