90 f150 5.0 injector problems .... testing
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Joined: Jan 2001
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90 f150 5.0 injector problems .... testing
I think I have a bad injector, but cant tell which one it is. I've got the fuel pressure tester hooked up. Some one please explain how to test. I've read the clymer book and I get the same reading on all injectors. KOn pressure up to 42psi. KOff Starts to bleed off immediately. What am I missing ? Its got to be simple . Here is what I've done. Key on, Key off , disable pump, crank for 2 sec., read pressure drop after 5 sec. What am I missing???? Thanks
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Joined: Jul 1999
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90 f150 5.0 injector problems .... testing
How fast is the pressure bleeding off ? You can do a cylinder balance check to see which injector is not contributing if in fact thats what the problem is with your engine . To enter the test , depress & release the throttle within 2 mins of the Engine Running codes being displayed . The idle speed will be fixed , now fuel will be shut off , on the 5.0L it will be on the No 8 injector . What the Ecu will do is compare the rpm when the injector was on & when it was shut off . The whole process will be repeated down the line to each injector , dont touch the throttle until the test is complete . If the Ecu detects no problems , Code 90 will be displayed . If its detects no or little rpm changes on a particular injector it will display a code for that cylinder IE: Code 30 = injector 3
You can repeat the whole test 3 times , depressing & releasing the throttle within 2 mins of the last code being displayed . Each subsequent test the Ecu uses a lower % of rpm drop to measure . First test 150 Rpm x 65% = 98 rpm , Next test its 43% and finally 20% .
You can repeat the whole test 3 times , depressing & releasing the throttle within 2 mins of the last code being displayed . Each subsequent test the Ecu uses a lower % of rpm drop to measure . First test 150 Rpm x 65% = 98 rpm , Next test its 43% and finally 20% .
Postmaster
Joined: Jul 1999
Posts: 3,172
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90 f150 5.0 injector problems .... testing
[font size="1" color="#FF0000"]LAST EDITED ON 10-Jan-01 AT 02:38 PM (EST)[/font][p] If you cant get the engine to run then check to make sure you got the distributor in correctly . Bring the engine up to Tdc on the crank & Check that the rotor is pointing to No 1 on the dist cap . No 1 should be indicated on the cap . The firing order is 15426378 . Also , remove the SPOUT Connector when checking the timing .
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