ok so here's my problem. I installed a later 70s 350 block into my 90 gmc 1500. Now i put my old intake and tbi unit from the 305 on it thinking it would work. My mistake... the motor can't idle and when I get it going in the higher RPMS it will run then just stall. What can I do to fix the problem??? I tried a computer and modules from a 350 same year and model as my truck and still am having problems. Is it just the fuel pump and regulator not being able to keep up?? What do I need to do.

there are no mods to the 350 motor.


thanks for reading and any help you can offer

Ben

 

A 350 probably has different injectors. I would think if you had injectors for a 350 and the right 350 prom it would run fine. All the stock sensors like the map are hooked up, right?

 

yeah all the sensors are hooked up, sorry the injectors are for a 350 as well. I just swapped a bunch of parts from a 350 tbi to mine, Still have problems with the fuel flow though.

 

I would say you need to get a fuel pressure gauge on it and see whats going on. Sounds like it could be a fuel pressure problem. Has it set any DTC's?

 

Did you change the prom chip?? if not i would, I would change that as well, they have different programs etc. Also did you change the knock sensor for a 350 specific one?? Just my thoughts. I just did the same swap a week ago and didnt have any major problems. I did the 350 injectors,prom,knock sensor. I put in an 80 block with mild cam and head work, airgap manifold and ultimate tbi mods as well. It runs great considering its on a stock tune. I did have to set my minimum air and make sure the timing was right. Now just waitning for my tuning hardware. Hope you get it figured out

 

installed a 350 tbi unit, computer, wiring, modules.

haven't tried changing the fuel pressure yet, need to buy a new regulator or try to grind out the solder to change the stock one. I haven't tried a different prom, thought the computer from the 350 would suffice. I can get it to idle now but really rough, and just wants to quit when it gear (timing is ok)