Thursday, August 31, 2023

1997 Ford Ranger Cranks/No-Start

 The engine cranks (starter engages and spins the engine) just fine so starter related system is fine. Fuel pressure is easy to test. Like the Sun slogan, we test - not guess. You don't have to use an expensive pressure tester but you do need an accurate one. Ideally with key on and engine cranking you want to see between 35 and 45 psi. of primary fuel pressure.



Primary fuel delivery is good. What about secondary? I just want to see if I'm getting injector pulse so a noid light is fine. During crank the noid light should flash at each pulse. I get no flashing noid light so I am seeing nothing to open fuel injectors. Instead of a video of a noid light not flashing I'll just use a picture of a noid light not flashing. VBG. 



Now I will assume I have power to the injector because it comes from the EEC Power Relay which also powers the Fuel Pump Relay and since my fuel pump is working I want to check I have spark at the plugs during crank. If I have spark but no injector pulse then I'm looking at fuel controls for problems but if I have no injector pulse and no spark then I'm looking at triggers, such as a crankshaft position sensor. 

I have no spark present at the spark plug wire during cranking.


If the computer isn't seeing an engine cranking condition it won't pulse injectors or fire ignition coils. It is a good time to use a scan tool to see that the computer is working and if it notices a fault. The computer is functional and it does have a memory code P0320 which indicates a problem determining engine rpm, which could also point at a bad crankshaft position signal.

If I watch the data pid for engine rpm while cranking I don't see activity. 


  The ECM connector is fairly east to access and I can check my crank sensor signal at the ECM. 


You can remove the connector cover for access to the wiring and backprobe or you can use a breakout box. 


I know which method I'll be using since I don't have a Ford OBDII breakout box.  I don't see a crank signal to the ECM during cranking so I'm going to access the crank position sensor. 



Not an easy area to access. The wiring near the connector was bad so I replace the sensor and repaired the wiring. 




Once finished, we have a crank signal and a start. On the road again. 

Kenny@ggauto.repair


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