jjjosh

Swapped 305 tbi from 91 rs in to my 72 rs.. i have yet tune for better results,,but it runs well after it starts,,,stock tune. . problem i have is i gotta pour flammable liquids down her throat to start. (the injectors are stock and they do not spray as i try cranking ) once forced feed it cranks n runs. The injectors are spraying like they should and engine runs well ,,,,any ideas of that issue also no trouble codes thanks fer all help

RBob

iTrader: (1)

Two things come to mind, VATs and no power to injectors during cranking. The VATs is anti-theft and the stock '91 RS ECM is looking for the signal from the VATs module. Otherwise the ECM won't fire the injectors.

The other, no power to injectors during cranking is a common issue on swaps. Simple enough to check for, while cranking the engine use a DVM to see if the +12 volts to the injectors remains.

RBob.

jjjosh

Ecm is from a mid 80s van that had a 305 and it did not have vats,,,, there isnt 12 vollts during cranking to injectors. (left out that thursday night was first fire up and she cranked and run with no problem as i stated ),, didnt have to force feed her ,,cranked several times repeatedly and ran. set timing and looked everything over . friday morning she wants to be forced feed on every start now.... so we know it doesnt have 12 volts,, what could be causing that

RBob

iTrader: (1)

The ignition switch provides 2 power feeds. One is accessory for items such as the radio. This is hot with ignition on, but cold while cranking (ever notice the radio turns off during cranking).

The other ignition feed is hot with ignition on, and while cranking. This is the one that the distributor, ignition coil, and injectors need to be on.

The easiest check is to see if the power feed has power when the key is turned backwards to the accessory position. If there is power, then it will be cold during cranking.

RBob.