crazy cat 3116 problem?? - Diesel Forum

4wheelfurry · 10-08-2009, 02:10 PM

Have a 3116 pusher in a coach that is driving me nuts! The engine runs great and accelerates fine but when it reaches about 40 it dies out and pours black smoke and the turbo spools down. After just a few seconds it clears up and the turbo picks back up and accelerates up, then after a few seconds it goes back down then back up and so on... This is not a miss or even starving for air it feels exactly like I'm letting off the gass then mashing it again and it is very consistant. I can set my watch to it so I think that rules out injectors. It free revs out great and won't it do it in manual 1 or 2ed so it doesn't appear to be RPM related but this engnie is non-electronic so a speed limiter isn't causing it either.

So far I've changed the turbo, exhause mani and gaskets and all intercooler fittings. All new filters and such but nothing has made any difference. This problem is limiting the speed to about 60 and it takes a LONG time to get there from the up/down of how its running.

I've taken it to two different dealerships and they have both said the engine is old and worn out but it only has 65k miles on it so I'm not buying that pluss it pulls really hard until it starts this nonsence. Anyone run across this problem before?? I'm at whits end on this one...

LTFFNREMTP · 10-08-2009, 09:01 PM

Have you checked the wastegate itself plus linkage and sensing line?

4wheelfurry · 10-09-2009, 06:51 AM

Yes its new also but I even tied it shut to temp bypass it and it made no change.

Oh and I also replaced the injector pump with a new one from cat, no change either...

nevrenufhp · 10-09-2009, 10:38 AM

This may sound like a strange idea, but there could be something floating in the fuel tank and catching on the suction tube.