QuestionI have a 1991 Toyota Pickup with a 2.4L with Multi Port Fuel Injection. My engine cranks over, but does not start. I have a strong spark to the distributor and plugs. I then checked the fuel and have strong fuel pressure up to the rail. I don't have no fuel being dispensed from all four injectors. I checked the fuses and relays and they are all fine. I was wondering were the pulse sensor is that signals the ECU to dispense fuel to the injectors. Is it in the distributor? If it is, is there a way to test if the ECU is receiving a pulse signal? I'm almost on the verge of just changing the ECU, but if it's not the ECU I wouldn't be able to return it. So how would I test for the pulse or check the ECU?
Thanks for your time. Robert
AnswerThe fuel injectors are controlled directly by signals from the computer based on an rpm and ignition signal from the distributor, unless the computer has rpm and ignition confirmation the injectors will stay off.
The best way to check this is with a small special testlight available at most autoparts stores, it plugs directly into the injector connector, when cranking the engine the light will flash if the signal is ok, using a regular test light will not work.
Also check to see if if there are 12 volts supplied to each injector to one side of the connector with the key on, this is normal, the computer turns the injector on by grounding it through the other wire, if there is no steady voltage to one terminal of each injector it's a simple matter of tracing the wires to see where the voltage is supposed to come from, I believe on this engine it comes through the efi fuse.
If there is no pulse signal to the injectors I would suspect the distributor before the ECU as the cause.
