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hi dudes; im repairing a chevy van in the workshop, we changed spark plugs and delco distributor, iac cheked, temp sensor, o2 sensor... the problem is that only have pulse on one injector. we tested both injectors and work fine, its strange to only have pulse on one, we are thinking to replacing the ecu but here in spain its dificult to find one maybe ebay. another cuestion : at idle both injectors have to been spraying?
thak you very much, cheers from spain!!
 

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I had a similar problem once on my 93 TBI. It was connector or wiring, never knew which. I swapped plugs on injectors and problem followed the plug/wiring. Swapped back and it went away. Plugged, replugged many times after and did not happen again. Guessing it was resistance of plug and plugging, replugging cleaned it up.

I don’t know facts but would be surprised ECM was designed to pulse injectors independently or separately. If one is working kind of doubt it’s the ECM - but maybe someone with more knowledge or experience will comment on that.
good luck!
 

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I don’t know facts but would be surprised ECM was designed to pulse injectors independently or separately.
Actually they normally fire Synchronously meaning they alternate to fire in conjunction with the intake stroke which also happens alternately to coincide with the ports on the intake manifold. Each side of the intake manifold feeds 2 center ports on one side and the 2 outer ports on the opposite side.

The ECM grounds out the injector when it wants it to fire. The injectors are fed 12VDC constantly when the key is on.
 
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