runaway engine after injectors

[randyco]

wondering if anyone has had a problem with engine runaway after installing injectors. since my fuel screw is bottomed and it still dropped to idle instantly. im wondering if the increase of fuel from pod's/edm's could cause a runaway condition. and if so should i turn down the fuel screw before i fire for the first time.



93. 5 le w250 cc, 247k, 354's, auto, hx35/14 32psi, tweaked pump, 4"ex, old smokey pin, 4" lift 35's

 

[1stgen4evr]

I would be extremely surprised if injector work ever caused a runaway. The injectors merely do the spritz that the pump provides. Pump work on the other hand has been known to result in runaway.



My two cents.



James

 

[Greenleaf]

No, I don't believe you will have a problem. If your fuel screw is in "all the way" there are still internal pump adjuatments that will far more effect your fuel setting than simply turning a screw. The POD's will warrent you turning in the screw you speek of due to a change in pop off pressure and flow rate.



Be sure to compensate for this by bumping up your timing as well.



Scott

 

[cerberusiam]

Depends on what you mean by fuel screw "bottomed". If your bottomed on the lock collar its probably not an issue, however, bottomed in the case could cause issues with larger injectors and the same pop off pressures.



The full power screw controls the amount of fuel delivered on the injection cycle by returning part of the fuel thru a port. When you move the piston far enough the bleed port is closed of sooner and more fuel is injected. Only so much fuel can be injected thru a stock injector so increasing the size of the injector can make a difference. Each pump is a little different and the fuel curve may not be the same so what works on one may cause a runaway on another.



If you know where the stock setting is backing the screw out to that point would be the careful thing to do. Good luck.

 

[BushWakr - RIP]

Here is a quick test proceedure...



After the install start the truck and let it warm a bit. Then with someone under the hood on the manual shutoff lever, slowly depress the throttle... keep going slowly towards about 2000 RPM - 2200 RPM.

When you get to 2000 stop and hold that throttle position for a few seconds... if the RPM still continue to climb you are about ready to go to runaway... if you have no problem at 2000 then do the same thing when you hit 2200... . again watch the tach while holding the throttle still... again, if it climbs on it's own you're near trouble.

Usually you can get away with this test up to around 2500 RPM.

If all is well at that point you should be ok.

Be very aware as you do this. . listen for any signs/sounds of changes... this will be your first clue.



pastor bob... .