Medium and Heavy Trucks
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Hi my name is***** will try to help. Verify you have good fuel pressure and no leaks or restrictions. Check your pressure regulator if the pump is good but low pressure. If ok verify cam sensor signal as injection will be disabled with no engine speed signal. Verify ICP pressure cranking. You should see around 870 PSI cranking and since this is an older model I believe around 500-550 PSI should be enough to start. Try unplugging the ICP sensor to put the ECM into a default status and see if it will start. If no leaks in the injector o rings or high pressure rail deadhead the IPR to full by applying 12V with a 5000PSI gauge in the ICP sensor port and you should see full ICP pressure up to 4000 PSI to test the pump. Let me know
The fuel pressure regulator is in the bowl. Have you removed the regulator and inspected the spring etc and checked for damage or debris causing it ti stick open?
What is your fuel pressure?
Also what was your ICP pressure when you checked it while cranking?
Fuel flow diagram. Check the screen and also according to this there should be some orifices as well
Click on this link. There are check valves going into the head as well. What is your fuel pressure? You should expect to see around 80PSI.
Sorry about any confusion.... There is a fuel pressure regulator and spring in the fuel bowl along with a screen that is known to get plugged.This is why I mentioned testing your fuel Pressure.I own a 95 7.3 and have already rebuilt my filter housing and regulator with a new stiffer spring. You also replace the rubber lines at the same time. Remove and rebuild your fuel bowl and regulator. Click this link for the details.
Thanks for the update. Go on E bay and they sell inexpensive diesel compression testers and then buy the glow plug adapter to run a compression test on all cylinders. You should expect to see around 400PSI average. If any are down around 350 or below it is a flag for a problem cylinder. I have never attempted to bypass the fuel bowl but HEUI injectors are very sensitive to contamination so I would not recommend it as locally these injectors are around 250 each and about half that for remans online.
Hi, Did you get this resolved?