robp823 Posted July 1, 2009 Share Posted July 1, 2009 Got an 08 f-450 with low compression on cylinder 8 and SFT +18 on cylinder 6. So i tear the head off and cylinder 8 the cross hatch is gone and the walls arent to bad and there is almost like a star pattern burnt into the piston.What causes this overfueling??Someone a while back said that running a programmer will do that but it doesnt have this on any other pistons on the bank. As for SFT +18 on cylinder 6 i think that this was just a bad injector because everything looks fine there.Also when i turned the corrective fuel strategy off it was still firing but barely. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 1, 2009 Share Posted July 1, 2009 Did you actually run a manual compression test? I got sucker punched by using the IDS relative compression test. What was your fuel trim for cylinder #8? According to Ford anything over +10% indicates a problem with the cylinder/injector. As for the star pattern it is normal to see that to some degree and it will vary from engine to engine. If you have one cylinder that has a star pattern with a distinctly different appearance I would think that is an indication of an injector problem. Remember, we have an active FSA on injectors. Is this truck involved? Quote Link to comment Share on other sites More sharing options...
robp823 Posted July 1, 2009 Author Share Posted July 1, 2009 No, truck is not involved with FSA.As for compression test i dont trust relative compression on these as far as i can throw the IDS.So i triple checked it and kept getting the same reading for cylinder 8, which was 6%.So i did a manual compression test with all cylinders reading 370-380 psi except for cylinder 8. Cylinder 8 read only 320 psi and i know that anything 25 psi difference indicates a problem, also watching valve train while cranking couldnt see any evident problem so it was time for head to come off. Quote Link to comment Share on other sites More sharing options...
joshbuys Posted July 1, 2009 Share Posted July 1, 2009 I've found that the relative compression test is JUNK on the 6.4. I had one with a bent connecting rod on cyl. 8, Power balance showed cylinder 8 around -40, relative compression showed 0% varriance on all cylinders except #5 was 2% low. manual compression on the other hand showed around 350-360 psi on all cylinders except cylinder 8 was 250 psi. How can relative compression possibly show it 0% different when in reality it is like 26% different?!?! CAN WE SAY WORTHLESS TIMEWASTING TEST?!?!?!?! Quote Link to comment Share on other sites More sharing options...
Aaron Posted July 1, 2009 Share Posted July 1, 2009 I could probably throw the IDS pretty far.... Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted July 2, 2009 Share Posted July 2, 2009 While wearing your Power Stroke jacket???? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted July 2, 2009 Share Posted July 2, 2009 You guys don't realize how good you have it with the IDS. No other scan tool I've used comes even close to its ease and power. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted July 2, 2009 Share Posted July 2, 2009 I concur. Quote Link to comment Share on other sites More sharing options...
Aaron Posted July 2, 2009 Share Posted July 2, 2009 Don't get me wrong, IDS ROCKS. I think it's, in my case, more an issue of the computer it's being run on, rather than the software/hardware. Now that they have the cables sorted out. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted July 2, 2009 Share Posted July 2, 2009 We finally went wireless and I love it, although now I don't get as much exercise due to the lack of playing "jump rope" while working with it around the car. Quote Link to comment Share on other sites More sharing options...
robp823 Posted July 2, 2009 Author Share Posted July 2, 2009 Im ready for Bruce to give the ole you kids today dont know how good you got it speech ahahahah Quote Link to comment Share on other sites More sharing options...
robp823 Posted July 20, 2009 Author Share Posted July 20, 2009 Well when i pulled the piston out of cylinder 8 for this thing i found that the intermediate ring was stuck in the ring groove.Both other rings when pulling the piston out immediately uncompressed.Heavy soot build up too on piston. Quote Link to comment Share on other sites More sharing options...
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