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View Full Version : new crate motor tbi need help no fuel


sheldonbaker1973
04-09-2013, 10:46 PM
well here we go ,,, changed motors , bought a new 350 tbi crate motor ,, before i pulled the old one out i started it up all works injectors fuel pump and so on .....new motor old intake and tbi had to be used on the new motor ,, u can here the fuel pump come on the is fuel to the tbi ,, the injectors will not spray ,, i have pulled the injector wire caps and tested the wire one on each injector has power ,, i can put gas down the tbi and the motor will fire ,, they worked befor so what can i look for ....

MLA
04-10-2013, 08:51 AM
On those engines, the injectors are fed a switched B+ when keyed up. When the ECM senses ignition, as in the engine is spinning over and the ignition is pusling, the ecm with start to pulse the ground side of the injector. You can buy an LED test light or injector tester to test for both the B+ and pulsing ground.

Since the old engine fired right before the swap, i will assume all was working in regards to the ignition and fuel system. I would look for a plug/connector that is not connected, look for a pinched or cut harness, test for spark on the coil wire where it would connect to the top of the distributor cap. Im betting you will not see spark.

sheldonbaker1973
04-10-2013, 06:43 PM
u can pour gas down the tbi and it will fire off the lil gas u dump in so that tells me I have spark right

sheldonbaker1973
04-10-2013, 06:48 PM
I have power to the injectors . I hae tested the for wire there is power to them . and I bought the injector light but no flash or light up .. I can't see it being the computer I took the batt out befor we even started the swop ?

jmw
04-10-2013, 06:48 PM
u can pour gas down the tbi and it will fire off the lil gas u dump in so that tells me I have spark right

yes, if it fires up and runs by pouring gas you have spark...

MLA
04-10-2013, 07:37 PM
Yes, that indicates secondary ignition. The lack of pulse with the presence of B+ at the injector connector indicates that the ECM is not pulsing the injectors or theres an undone connector. Other possible cause could be wide open TPS signal placing the ECM in clear-flood mode. This means no fuel needed, so no injector pulse. These are basics bases on the TBI system as it works in a truck. There may be some additional reasons for the ECM to interrupt the injector pulse that are strictly marine.

sheldonbaker1973
04-11-2013, 01:33 AM
well this is what i did bought a new crate motor ,, and used my old intake and tbi ... so i used carb cleaner on the tbi it was in need of a good cleaning it allways worked very well never pulled the tbi from the intake i used a wire will to clean the ports and stuff blow the tbi clean with air not a lot of air at all ... there is power to the injectors but no pusling going on