4.3 cpi swap to 4.3 tbi engine
#1
4.3 cpi swap to 4.3 tbi engine
I pulled 4.3 cpi and trans from 1994 blazer put in 4.3 tbi and trans along with computer, engine wiring harness and fuel pump all from a running s10 truck 1991. Getting gas to thottle body but no spray from injectors. It will start if I pour some gas in thottle body anyone done this swap before. Did I miss something?
#2
Yup, your CPI truck has a running fuel pressure of around 60psi... The TBI engine needs 11-13psi... Swap the high pressure pump out for the TBI pump and you should be up and running. Your TBI injectors cannot open under the super high pressure like the CPI could.
Any reason for the step down in power? Most guys swap the other way... The CPI vortec has like 40 more HP than the TBI 4.3 did.
EDIT, sorry, reread that again and you did switch the pump... Stick a NOID light into the injector plugs and see if you are getting pulse from the PCM
Any reason for the step down in power? Most guys swap the other way... The CPI vortec has like 40 more HP than the TBI 4.3 did.
EDIT, sorry, reread that again and you did switch the pump... Stick a NOID light into the injector plugs and see if you are getting pulse from the PCM
Last edited by ohsofly; 10-22-2012 at 11:10 PM.
#3
Not getting fire to injectors. Didn't swap wiring under dash I was told I have to because tbi and cpi get power in a differnt way. Reason for swap is bought blazer with blown engine and bad injection the tbi I had in a wrecked truck
Thread
Thread Starter
Forum
Replies
Last Post
deathman
Full Size K5 (1969-1991) GMT415 (1992-1994) Tech
3
08-14-2011 11:25 PM
maverik78
Performance & Brainstorming
9
04-11-2010 10:05 PM
andrewhartley55
1st Generation S-series (1983-1994) Tech
13
11-30-2009 12:54 PM