hey guys new to the message boards, but lived at ls1tech.com
well i have a question concerning my 1989 formula 350 tpi, it has sat about 5 years now and finally put in the new motor and turbo 350 tranny. now to the point, i cranked the car last saturday and the car ran fine, i adjusted the tps, timing, fuel pressure, and installed a new intank pump. i have been running the car everyday this past week in the garage and it has run fine. now friday night i had it running and one of my ls1 injectors in the car was leaking so i decided to put in my stock injectors. well the car would not start. i thought maybe my stock injectors were not working correctly so again i removed the stock injectors and replaced them with accel 30lb injectors brand new. i tried starting the car again, and the same thing, it did not start. since then i have checked the spark to the coil and plugs and i am getting fire to both, i checked the timing and it is dead on. after that i checked my fuel to the rails, turn the key on and hear the pump, walk to the front of the car to check the pressure at the fuel rail and there was no pressure. i then did a search and clamped off the return line going back to the tank. i then turned on the key hear the pump and check the pressure and now the fuel rail has pressure. my question is after checking this out does this mean i need a new pressure regulator because it is not holding pressure at the rails. i have already checked the voltage of the injector wires and they pulse when turning over the engine so i know its getting a signal and the car is getting fire. anyone have any ideas if the regulator has gone bad. it is a tpis regulator but its about 5 years old and has been sitting without use since the car has been down. any help would be awesome. i know its something small because the car has ran fine all week until i changed the injectors stock and accel 30lbs. my thought is this i think with the ls1 injectors leaking it didnt build enough pressure to blowout the regulator, but when i installed the new injectors and the system was sealed it ruptured the inside of the regulator. thanks for your help, sorry its so long i just wanted to fill you in incase you have went thru this already. the mods i have justify the larger injectors

 

Welcome Aboard!

If the vacuum pilot diaphragm of the FPR had failed, you would get fuel pouring from the vacuum hose connection when the pump is running. That's relatively easy to test.

If the regulator has debris in the valve disc/seat, it will not allow pressure to build. Do you have a pressure test guage?

 

yes i have a pressure guage, as soon as i turn the key on the pump comes on and the pressure goes up but as soon as the pump stops the pressure is gone. also i blocked the return line and the rails held pressure, plus there is no fuel coming from the vacuum line coming off the regulator which is good.

 

does the holley regulator come with the star head tool to remove the old regulator?

 

what's the pressure after the pumps shuts down while the return line is blocked? If it doesn't hold, the check valve at the output of the pump is failing.

 

well i dunno after i blocked the return line the second time the fuel leaked from the afpr base and out the vacuum line, so i ordered a holley afpr. anyone know the fuel rail o-rings part number? i would like to replace all of these while i have it apart.

 

Here is a post that has some o-ring numbers in it.

https://www.thirdgen.org/techbb2/sho...ail+blue+oring

Here are a few pages from a search for the following terms
fuel o-ring

https://www.thirdgen.org/techbb2/sea...der=descending

 

thanks that helped

 

Some of those are old, so I would call your local dealer for current price, part numbers, and availibility.

 

i went to autozone today and got a fuel rail oring rebuild kit for $2.99, this included all the o-rings to rebuilt the fuel rail. i am surprised autozone had them and that they were so cheap. so no picking thru o-rings to find the right ones. i found a peice of injector o-ring stuck under the valve in my afpr. i guess when taking out the ls1 injectors part of the o-ring got pushed thru and lodged into the afpr. so now i know why it wouldn't hold pressure. i ordered the holley unit. so now i hope all is well i will see wednesday. at least i know my fuel system is all new as i have replaced all rubber hoses from the tank to the fuel rail, installed a new pump, and rebuilt my fuel rail, and replace all o-rings on the injectors. so now i have a new motor, new trans, new interior, and changed fluid in my rear. now i have to replace all the brakes and get a paintjob. then i can say my 15 year old formula 350 will be total restored.

 

Do you have a part number handy for the kit you got from autozone?

 

http://www.autozone.com/servlet/UiBr...EFUEL+INJECTOR