Crank no start
- Thread starter steveo1
- Start date
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And remember truck will run and idle smooth on starting fluid momentarily as if there were no issues
Does anyone else seem to hear the HIGH spot in the crank cycle? Or am I just being fooled?
It does appear that the light isn't getting a proper or strong signal. It also appears as though that circuit is being affected by the cranking cycle - watch the light flicker with crank start and end. I wonder if the PCM has an issue for the injector driver. Either that or it's input is bad or weak.
One last thought I have based on the high spot in the cranking test. Have you checked compression on the cylinders? If it's out of time, it should show up as low compression. 90-130 psi after 3 hits is normal from what I've seen historically. You'll need a second set of hands unless you have a long hose for the tester.
But, you did say that the plugs are dry when removed after cranking. Which means no injector pulse to open. You also said that you have good flow from the pump, so supply isn't an issue. I'm not too well versed on what can keep the injectors from firing computer wise though. Would need a bidirectional scanner to perform tests and see real time data.
It does appear that the light isn't getting a proper or strong signal. It also appears as though that circuit is being affected by the cranking cycle - watch the light flicker with crank start and end. I wonder if the PCM has an issue for the injector driver. Either that or it's input is bad or weak.
One last thought I have based on the high spot in the cranking test. Have you checked compression on the cylinders? If it's out of time, it should show up as low compression. 90-130 psi after 3 hits is normal from what I've seen historically. You'll need a second set of hands unless you have a long hose for the tester.
But, you did say that the plugs are dry when removed after cranking. Which means no injector pulse to open. You also said that you have good flow from the pump, so supply isn't an issue. I'm not too well versed on what can keep the injectors from firing computer wise though. Would need a bidirectional scanner to perform tests and see real time data.
rockola1971
Full Access Member
That spark is orange. That is not right. It should be a pretty blue color. Orange or white is a NO GO. Starter sounds weak too. Whats your battery voltage at DURING CRANKING, measured at battery?
Last edited:
972sparky
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Could be a really bad tank of fuel. I would take the fuel line off just past the filter and run the pump into a glass jar and verify the flow rate and check the fuel for water/debris. Could have plugged all the injectors with junk from the first bad pump and old filter or just bad fuel. There was a gas station near me that got a trash load of fuel and ruined several car's fuel systems, the symptoms were similar to those you described before the first pump replacement. Cost the station a lot of $$$ to fix all the cars that broke. They had to clean all their tanks, lines, filters and pumps as well. It sure seems to be a fuel issue.
SWAG: pull the two PCM/ECM connectors and check for cleanliness and good fitment, and water migration.
Reinstall the old crank position sensor.
Test for fuel volume and quality at one of the injectors.
Temporarily ground engine block to negative battery connection. As @rockola1971 asked, what is the voltage on this new battery while cranking?
Reinstall the old crank position sensor.
Test for fuel volume and quality at one of the injectors.
Temporarily ground engine block to negative battery connection. As @rockola1971 asked, what is the voltage on this new battery while cranking?
