robp823 Posted March 4, 2009 Share Posted March 4, 2009 got a 06 ambulance runs rough blueish smoke.Did fuel pressure test was way below spec with valve open 29 psi.had one contribution balance code.Replaced fuel pressure regalutor got fuel prerssure back in spec still running rough with bluish smoke not as bad.No FICM codes should i be diaging the FICM anyway??? power balance shows cylinder 4 has the worst one with fuel correction turned off but they are all dropping a decent amount as i watch idle.This is a cash job the ambulance has 150000 on it.Should i suggest all new injectors??? Is the damage already done from the low fuel pressure???Ive had this happen before where i replaced the regulator and the worst injectors viewed in power balance and had it come back a day or 2 later putting more injectors in.Or should i just replace the worst ones first??? Is there a better way to pinpoint faulty injectors than i am doing??? Quote Link to comment Share on other sites More sharing options...
Jeff_E Posted March 4, 2009 Share Posted March 4, 2009 do the modified "baloon" test by jumping the starter to crank it with the key off and secondary fuel filter cap and filter removed. If it bubbles from the standpipe you can take the lines off at the filter housing one at a time to isolate which bank. The last one I did failed the test miserably and got all 8 injectors. If this is what you find, make sure you correct the fuel pressure issues before returning it to the customer otherwise you'll be doing it all over again next week. Quote Link to comment Share on other sites More sharing options...
robp823 Posted March 4, 2009 Author Share Posted March 4, 2009 i got my fuel pressure issue starightened out but after reviewing power balance again it seems to be the whole left bank dropping cylinders in power balance. Quote Link to comment Share on other sites More sharing options...
Mekanik Posted March 5, 2009 Share Posted March 5, 2009 This sounds like combustion gas in the fuel rail. Probably caused by injector #4. I would do the modified baloon test as stated before and if this is the case replace all the injectors on that bank. I even had a hotline engineer suggest replacing all injectors on a bank when there is one letting combustion gas into the fuel rail. (This was with the understanding that the truck was out of warranty. ) Quote Link to comment Share on other sites More sharing options...
robp823 Posted March 5, 2009 Author Share Posted March 5, 2009 good call Quote Link to comment Share on other sites More sharing options...
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