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1989 firebird formula engine swap from 305 to 350 wont start


kicknbird
03-11-2009, 09:48 PM
i recently did a engine swap from a 305 tbi to a 350 tpi complete from computer up i can only get it to turn over will not start been asking around was told the chip in the key has to match the other ecm i,m using how do i get one or is there some way to bypass it this is driving me nuts :banghead: any help in the right direction would be great :biggrin: thanks the motor and everything else is new i used the intake heads and ecm plus wiring harness from a 1988 it has good spark to plugs but the fuel pump does not prime when you turn on the key i noticed on the harness by the ecm there is another electrical connector with wire colors similar to the fuel pump if you put power to the fuel pump by the back seat it will run i took the harness and other stuff off along time ago so i don't remember if anything was pluged in there the car is a 1989 and the old harness or original one did not have this connector on it im not sure what it is

Morley
03-13-2009, 02:17 AM
If the engine cranks over it is NOt a VATS issue. Vats only prevents the starter from engaging.
Not sure what would have been plugged into that harness you describe...The 85's had a MAS module down there but that was the ONLY year to have it.

kicknbird
03-13-2009, 02:32 PM
If the engine cranks over it is NOt a VATS issue. Vats only prevents the starter from engaging.
Not sure what would have been plugged into that harness you describe...The 85's had a MAS module down there but that was the ONLY year to have it.
thanks for your help at least that saves me the hassel of the dealer in town that will not provide any help on this they want me to bring it in so they can over charge me with no garantee they can fix it someone was telling me about a body control module do ya know anything about that? i was thinking of getting a handheld dianostic com to see if somthing missing from the system trying not to keep spending money with no results thanks again found awsome site chevythunder.com found out the plug i did not know is for fuel injectors i went from a tbi to a tpi so i have nothing to connect have to fuse over to ignition were old ones are this should solve my problem anything any one wants to know about L98 tpi,s in or out of f-bodies go to chevythunder.com unlimited info awsome site:iceslolan

Morley
03-15-2009, 02:44 AM
Well, THAT makes a difference, going from TBI to TPI.
There is no body control module on the 2nd gens..The key here is that the pump won't prime. Check all the wiring to the relay and see if it is cut anywhere.
Depending on how you did on installing the harness try this step.
Apply +12 DC to pin G on the ALDL, this will "hot wire" the pump and make it run.
If it does run then you have a problem from the relay to the ECM/ignition switch. If it still won't run, then there is the possibility thatthe relay is bad or you have some bad wiring from it to the pump or a bad pump.

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