2L diesel fuel pressure (1 Viewer)

Mar 31, 2018
Hey guys, so i've got a 1988 pickup with a 1984 2L diesel in it, it runs awesome albeit slow..but it will crank for 30 seconds straight when starting from cold. It starts perfect once it's up to temperature. Valve clearances are perfect. There is NO PROBLEM with the glow plug system, I was going to pen it up as 'that's just how it is' until I bought a 91 Hiace that is identical running gear wise and that starts on the button even after being stood for weeks.

I have put clear fuel lines on it to make sure that I am not drawing air in anywhere, but tonight I put a clear line on the leak-off pipe from the injectors (the small 3/16" pipe), and even running the engine for over 5 minutes at varied revs, it still has not purged the air out of the leak off pipe, which leads me to believe that I might have a problem with fuel pressure...could anyone give me a way to measure it on this engine? I'm pulling my hair out at this! My Hiace is slightly worse on fuel but MUCH faster and torquier than this pickup, so there's definitely something wrong!






2LTE abuser
Mar 23, 2012
Victoria, BC, Canada
You can't judge fuel pressure by the nozzle leakage pipe. You're much better off monitoring for air in the hose from the filter/primer assembly to the injection pump. That said, look closely at the leackage pipe copper/aluminum washers, and make sure there are no diesel leaks. If there are, torque the retaining nut down a bit harder. I've almost always had to over-torque mine a little to get them to seal well.

Keep in mind, the injection pump draws fuel from the tank. There is no pump in the tank. The injection pump sends high pressure pulses of fuel to the injectors.

If your engine starts perfectly after 30 seconds, I'd be inclined to think there is an issue with the fuel cut solenoid in the pump. If your engine starts really rough with lots of missing, then I'd suggest the problem is related to an air leak. I'm assuming you have a mechanical pump. If its the electronic pump, then the problem could be with the spill valve solenoid, or ECU/electronics.

If it is an air leak, check your pump for leaking gaskets, and especially check or just replace your fuel primer unit. There are lots of decent knock off ones on ebay for cheap. It's common for the pump diaphragm to leak at this vintage.
Jul 22, 2003
Perth Western Australia
which leads me to believe that I might have a problem with fuel pressure.
An air leak is a 1000 times more common. Air gets in over night and it has to purge itself with the starter motor pumping the air out of the injector lines.
If you had a problem with fuel pressure, I think it would get worse as the engine warms up, and would be really bad at highway speed.

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