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Daniel Wilson
Daniel Wilson,
Category: Medium and Heavy Trucks
Satisfied Customers: 5412
Experience:  Owner at DJ Wilson
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Working on a 1995 international with a 7.3L diesel with a no

Customer Question

Working on a 1995 international with a 7.3L diesel with a no start condition. I'm working a flowchart for this condition but I need an expert to help sort this out. Fuel tanks full. Lift pump will fill the fuel bowl but I have no pressure at the schrader valve on the fuel bowl after cranking.
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Daniel Wilson replied 1 year ago.

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

Customer: replied 1 year ago.
All the simple, basic stuff has been tried. CPS has been changed.New fuel filter Tried to start with default ICP signal, unplugged. We need to go back to the beginning, I believe. Lift pump will carry fuel to the fuel bowl and fill it up. Where does fuel go next? There appears to be no fuel pressure at the bowl despite the lift pump working
Expert:  Daniel Wilson replied 1 year ago.

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?

Expert:  Daniel Wilson replied 1 year ago.

What is your fuel pressure?

Expert:  Daniel Wilson replied 1 year ago.

Also what was your ICP pressure when you checked it while cranking?

Customer: replied 1 year ago.
Nothing obvious at the FPR after taking it apart but it came apart on the bench and i am assuming i got it back together properly? FPR has a Schrader valve and it does not appear to be building any pressure but I haven't taken a pressure reading just no fuel squirting out when depressed
Expert:  Daniel Wilson replied 1 year ago.

Fuel flow diagram. Check the screen and also according to this there should be some orifices as well

Expert:  Daniel Wilson replied 1 year ago.

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.

Customer: replied 1 year ago.
I think my problem is somewhere in the fuel bowl. Can we zero in on this area? The first file seems relevant. The second one does not. My pump is mechanical. I have no electronics on the fuel bowl. Heater, etc.
Expert:  Daniel Wilson replied 1 year ago.

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.

https://www.youtube.com/watch?v=gUYvbO04WGM

Customer: replied 1 year ago.
Still working on rebuilding the fuel bowl but is there a way to bypass it? Maybe an electric pump and regulator? Rumor has it that this truck has a bad motor but I refuse to believe it as it will start with a shot of juice down the intake
Expert:  Daniel Wilson replied 1 year ago.

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.

Expert:  Daniel Wilson replied 1 year ago.

Hi, Did you get this resolved?