Where is the cold start valve located and how would I test it? I am a novice at this. Thanks.
1. Connect fuel pressure tester in line between fuel pump and fuel supply lines. Remove injectors and cold start injector valve. Place pan under all injectors, to catch fuel being discharged. Turn on ignition and operate a remote starter switch. Check spray of all injectors. If any one injector does not operate, replace it and recheck.
2. If all injectors of either group do not spray, check trigger contacts of distributor, trigger contact wiring to ECU and wires from ECU to injectors. If wires and connections check okay, replace ECU and recheck. If defect is still present, replace all injectors in that group and recheck. If recheck still shows defect, try another ECU.
3. If none of the injectors operate, disconnect MPC sensor electrical connector. Connect ohmmeter across terminals No. 15 and 7 of sensor. Reading should be 90 ohms. Connect ohmmeter across terminals No. 8 and 10. Reading should be 350 ohms. Reading between terminal No. 7 and ground should be infinite. If any of these readings are not within specifications, replace MPC sensor.
4. Sticking injectors can be detected with engine running. Connect tachometer, run engine and disconnect electrical connector to one injector at a time. Note RPM decrease. It RPM drop from one cylinder differs from that of all other cylinders, a faulty injector is indicated. Replace that injector and recheck. If same injector still show a defect, replace ECU and recheck.
NOTE: Do not overlook possibility of restriction in fuel line or connection to that injector.
Cold start injector
Perform pressure test. See step 1 under Injectors in this article. If cold start injector leaks during test it is defective and must be replaced. Remove connector at thermotime switch. and ground wire. Cold start injector should spray fuel during engine cranking. If fuel does not spray, temperature is either above 95 F (35 C) or injector is defective.