by biggibbo on Sat Jul 25, 2015 4:48 pm
Finally fixed it. Thanks to Tony for all his patience and respond to my emails.
Been having a problem where it wouldn't rev much past 3000rpm, then over the last few weeks it's been surging around 2000rpm and running crap. Boost and ultra guages were both showing healthy boost levels, and holding nicely, so Tony and I were both thinking Fuel restriction somewhere, but where? The fuel limiter was replaced a few years ago with a billet, and wasn't leaking, so couldn't be that. The fuel rail pressure was dropping from 18000psi to 8000psi, at 3000rpm, so has to be fuel system related.
Did the usual stuff, tried extra 2t in the fuel, tried a fuel system cleaner, cleaned the air filter cleaned the MAF, changed the fuel filter., yanked the SCV and gave it a polish up, all to no avail. Pulled the MAP sensor lines off and gave them a clean- bit oily but nothing sinister looking.
After a few mechanics visits, and a trip to the dealer, everyone has been scratching their heads-no faults displaying. No help there. Rang Berrima Diesel and booked it in for the 4th August to get a specialist to look at it out of frustration.
Yesterday the surging got so bad it was almost undriveable. I was wondering how the hell am I going to get it to Berrima to get it looked at.
So yesterday I Bit the bullet, and decided to replace the SCV and see if that would fix it. It solved the surging issue but it still wouldn't rev past 3000rpm. Replaced the hose clamps on the fuel lines and pulled them all off checking for air leaks-nothing.
While replacing the SCV I knocked some wiring to the boost gauge. When I was tracing the wiring fault, the MAP sensor was staring me in the face, so decided to yank it off and see if I could clean it.
Grabbed the MAF cleaner with the long tube and decide to hit it with a few squirts. Black oily crap started coming out. Kept hitting it till it ran clear and left it dry. Re-installed and eureka! I now have a ute that pulls all the way to 4500 if I hammer it, and there is noticeably less smoke on take off. Loads more power than I've seen in ages.
So stoked! Not sure how long the fix will last on the MAP sensor, but atleast if it plays up again I know what to replace.
Maybe mods can post this in the Surging and rev posts for others to think about.