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Soaking a FI assembly to dissolve crud?

Hello,

I have a small problem with my car, a suzuki import. It's currently at 181k miles. I checked the fuel pressure and it is much lower than normal. Normal is 23-31 psi, and at idle it registers 17psi.

I performed the diagnostic procedures in the manual, and when I pinched the fuel return line, the pressure increased dramatically. The manual said this means it's a faulty fuel pressure regulator. The filter was also replaced a few weeks ago, with no change in pressure.

The regulator is a non-removable part of the entire FI housing and assembly, but it's fairly easy to remove the entire thing from the vehicle. I have a spare FI assembly from the salvage yard, but I was wondering if I could soak my original assembly in something like alcohol to clean out the crud. Is there such a thing as a concentrated FI cleaner that I could soak the entire assembly in? I've already tried all the "system cleaner" fluids and they don't change the psi one bit.

Thanks for any help, Dan

Reply to
dstvns
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Are you sure you're measuring the fuel pressure correctly? If the spec is a "dead-head" measurement and you're measuring at idle, your measurement will be low because the fuel pressure will drop with increasing engine vacuum.

Reply to
Robert Hancock

It sounds like you have a throttle body injector with a built in regulator. Why do you think "crud" is the source of the problem? If it's vacuum operated then perhaps the source of vacuum is leaking. Otherwise perhaps the internal spring is weak or the diaphragm is ruptured. No solvent is going to fix these conditions. I think I'd put the junk yard assembly on and see how it works before I started playing around with the original one. If the junk yard one works OK you can take more aggressive action with the old one, but it sounds like a mechanical malfunction.

Reply to
MaxAluminum

If he is measuring at idle, which I think he is, that should sound right. How will vacuum increase at idle? Not sure what is "dead-head." Indi

Reply to
Indian Summer

If the vacuum is leaking wouldn't this increase his fuel pressure? It's a good idea to replace with the salvage yard, but someone should explain why three out of four FPR I got from the salvage yard, sitting there for months dry of fuel, won't work - zero PSI. But the one that worked came from a car has pressurized fuel still on them. I got squirted. Ab

Reply to
Abner Lewis

The gauge is built into the dash, but I forgot to give the full-throttle reading in the original post. The reading at full throttle (zero vacuum...I also have a vacuum gauge) is 23 psi...the bare minimum. I've checked the line repeated times for leaks and haven't found any, nor any smell of gas leaking.

The car activates the fuel pump for 5 seconds and pressurizes the fuel line when the key is in the ON position, just before I crank and start. When the pump is working, and the car is OFF, it temporarily reaches 23psi, then comes down and stays at 17. When I pinched the fuel return line with vice grips, it rose to about 30psi. During accelerations and decelerations the pressure ranges between 17 and

23psi. It only reaches 23 when the pedal is at the floor.

Dan

Reply to
dstvns

Are you checking this with the engine running, or Key On Engine Off? Most specifications are for KOEO.

You also don't mention any type of problem that you are trying to correct. Are you just curious? Year, Make and Model would help.

Reply to
saeengineer

Unless it says otherwise, the spec is probably for fuel pump running and engine NOT running (zero vacuum). That will probably be a bit more than at WOT because of the lack of fuel demand bringing the pressure down somewhat despite the regulator. If the spec is 23-30 psi, that sounds alright to me..

Reply to
Robert Hancock

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