smoke and runs bad hard accel.

[duff]

I have a 1992 e-van non turbo under hard accel. vehicle will start to knock - missfire - heavy smoke blueish in color -  after coming to a stop smoke will stop and motor starts to smooth out  -runs fine at normal driving. fuel pressure at filter adapter 4-5 psi idle raise rpm drops 1-2 psi - return line has 1-2 psi at 2500 rpm - attempted to crack fuel lines at injectors to find missfire they all seem to drop same rpm and good fuel flow -- during idle - any ideas for further testing possibly fuel pick up intank plugged ? thanks

[Brad Clayton]

Them things can suck air, you can bypass the chassis and just run a jug of diesel fuel to the lift pump and see what happens as long as test results are valid in your bay.

 

Sounds like you could also have a leaking injector tip. You need the old school injector tester to check them accurately though. oddly enough we have two of them. Our shop is a living museum.

 

http://www.toolsource.com/nozlrater-diesel-fuel-injector-nozzle-tester-d93l9000a-p-62578.html?osCsid=9m6tib3f203feg3qp60snjfq00

[Brad Clayton]

When in doubt on these old ass engines.......run a manual compression test. It can give you volumes of information on the state of health before going any further.

[Mekanik]

I used to install a clear hose at the injector pump spliced into the return line.  If the fuel system is sucking in air, you'll see it there.

[duff]

ALL EIGHT INJECTORS HAVE BEEN REPLACED - INJ. PUMP REPL. - RUNS FINE AROUND TOWN - AT HIGHWAY SPEEDS STARTS TO RUN ROUGH SMOKE HEAVILY LET OFF ACCEL. AND SLOW DOWN CLEARS OUT AND SOME ROUGHNESS

[Aaron]

What's your fuel pressure at highway speed, how about volume? Clear hose on the pump return side to look for bubbles? Inlet restriction on the feed side, with the motor running at the governor?