6.4 runs like crap at times

GregKneupper · October 14, 2009

I have a 2008 6.4 F-350 ambulance here that I need some help on. This vehicle has a very extensive history at other dealers and now has been put off on me. While driving at times it will start to cut out and lose power. There are no codes. The concern happens anywhere from half to 3/4 throttle. It starts to lose power and at times will start knocking and then just clear up. Under wot you can feel it surging but it is still running ok until you let up on the throttle and then it will start to lose power. Fuel pressure is good and fuel is clean. I took a recording and the egr valve starts to do all sorts of strange things. It is slamming open and closed during wot and you can feel it in the truck. Also when it falls flat on its face you can watch the egr valve go wide open during the concern and then when it slams shut it regains power. The egr valve is new. I have inspected the harness and cannot find any chafes. The pcm has been updated to latest calibration. Just a list of items replaced: both turbos, turbo actuator, ebp and tube, all lh injectors, map sensor, both turbo up pipes, rh exhaust manifold, egr valve, all egt sensors, dpf filter and the doc. I think that is all. Any advice would be appreciated.

Aaron · October 15, 2009

What is the EGT sensor in the RH up pipe doing during the concern?

joshbuys · October 15, 2009

What is the EGT sensor in the RH up pipe doing during the concern?

^^^^IIRC this is the EGRT SENSOR A

Aaron · October 15, 2009

I can never remember lol

LARRY BRUDZYNSKI · October 15, 2009

First off, problem one 6.4 F series built as a ambulance package. It will continue to have problems due to the fact that when they come screaming in to the hospitals they have to shut down upon parking. Hot shut downs with these and the earlier 6.0's are a killer. Second the fire houses like to let them idle on runs. Killer number 2. Their Diesels they need a load to run at optimal effiency. I'm seing more and more class 8's doing the same and having problems. Only bigger ones, Turbos, Fan clutches and A/C compressors are the big failures. The class 8's have decided to try to quiet them down by insulating the engines and engine compartments more and more, giving no room for ventilation and keeping engine heat under the hoods. Horton was having a hell of a time dealing with it until they came out with their 2 speed conversions on the DM clutches. I have been telling the fleets with these to pull the fender liners out and give them some breathing room. The oe's are putting rubber liners on the hoods and covering the frame rails and closing off any place the heat could come out. Could go on, Sorry about the Hi-Jack but I think you get the idea. 1 the 6.4 runs to hot and needs to be run with a load. 2 ambulances are the wrong application for these engines.