any help will help--
well after washing engine carparment (which i have done many times before with no problems) and this was a cold engine, i fired up the car to pull it into my shop, well next day car would not start, checked the number 1 plug no fire-- humm, fuel gage read 1/2 tank ok, took a pressure hose and blew out each connection, still no fire, been monkeying around with it and found #11 fuse blown all the rest ok even the ones under the hood, replaced #11 fuse a 20 amp 5 times kept blowing the last time i heard a slight pop from behind the glove box -- humm but the fuse was still good everything working but engine will not start after going futher found the car was completely out of gas- ok possibly bad sensor, filled it up and no fuel pump running, hot jumped the fuel pump from the aux primer line under the hood and it primed will not come on using just the key, checked the fuel pump relay its fine also, now this is a 95 lt1 and has a obd2 connector but the system is obd1, found that out after connecting a obd2 tester to it and would not read any codes, well any advise is welcome, is their a way of testing the obd1 ecm, could this be the bcm ? kinda sounds like something in the bcm may have blown while swapping fuses, will that stop the fuel pump and ignition ? thanks dan-k,

 

Wet opti.

 

humm, wet opti, ok and how would that effect the fuel pump the schematics i have gone over does not appear to be interlinked with the optical reader, rather one system is not linked to the other on obd1 if im wrong once again any help is welcome,

 

Geez, I can't believe I wrote that last night. I didn't even notice about the fuel pump. In order to scan the PCM, which you found out is OBDI, you will need an OBDI scanner with the OBDII connector. I think Shoebox has on his site a way to use jumpers to connect to an OBDI scan tool. Is it possible the fuel pump is actually dead, due to running out of gas?

 

no the fuel pump has (on 95 model f body's) a gray wire just off of the wireing harness that the ecm module uses just next to the dual plugs on the passenger side of the car, this wire hang loose and has no where to plug in, it is a primer wire for the fuel pump to prime the system you must hot jump off the battery to activate it and I have done that to verify that the pump is good, she is up and running and pressurizing the system so im still at square 1 fuel pump will not activate by turning key on and no spark to ignition, have tested the icu/coil at local shop and they are good still no spark or fuel when key is turned on I think I may pull the distributor today but gut feeling tells me its going to be ok, the question i am unsure of is the bcm, or ecm, being bad, but that just dont seem right either, this is week 2 on this puppy, also this is not a daily driver car and it is totally stock no mods, and will burn the tires through all three gears, I already have 78 t/a drag car 750hp so no need to use this one for anything but a toy!! oh well any advice will be helpful where else to look thanks in advance.

 

Take a look at Shoebox's website.... his car is a 95, so he has an unbelievable amount of info regarding all LT1's, but the 95 in particular. Wiring diagrams are there, the info mentioned about about jumpnig the pins on an OBD-I scanner, etc. Fuse #11 supports the power supply to the coil and IC Module.

http://shbox.com/1/4th_gen_tech1.html

Lack of the low res pulse from the Opti (DTC 16) will cause the PCM to shut down the fuel system, including the injetors and the fuel pump. It does that by not sending the control signal from pin A7 of the PCM to the relay. However, even if you have DTC 16, the PCM should allow the fuel pump to start on the initial move of the key from off to run, then shut it down after 2 seconds when it can't find the pulse pattern from the Opti.

Have you checked fuse #5 in the dash panel, which is the source of +12V power for the fuel pump relay? That also supports the theft deterent relay, the MAF and power to the PCM.

 

yes I have replaced all fuses with new and double checked with a ohm meter all fuse in car and under hood are good, and most are now new I have a pretty well equipped shop, unfortunatally it has been used for the older trans-ams I have a 78 drag car and a ultra rare 78 gold edition packard pontiac trans am, with a can am racing kit sporting a 455ci, this puppy is never driven as parts are impossible to get any more only 28 were produced, well back to the 95 and thanks, any help is useful