03 E450 ambulance no power

[jbarnett31]

Hey guys I have an 03 E450 with a 7.3 only builting around 8 psi boost. It has codes p0237, p0541 and p1105 in continuos memory. Fuel pressure is good, all pids are good except the map sensor pid which reads 0.00Hz and 14.57 psi. I have tried a new map sensor and nothing changed. I still dont have a lot of experience on 7.3's so I just wanted to see if anybody might have any help. Thanks.

[Bruce Amacker]

Map, Baro, and EBP should all read 14.7 KOEO at sea level so you're probably OK there. The MAP is not digital like the older 7.3 so 0Hz is correct. The code suggests a circuit problem so you should check the harness closely for rubs or loose pins. Use a push/pull Mityvac and apply pressure to the MAP KOEO and verify the pressure applied is the same as read in scan data. Use the "wiggle" test and wiggle the harness looking for circuit faults. (Does the IDS have the wiggle test (continuous monitor) or only the NGS? I can't remember on the 7.3)

 

A bad CMP can cause low boost, you might swap another one in to try. IPR should be 9-11% at hot idle, MFDES is usually 8-10 at a hot idle, if it's above 12 or so it's starving for fuel (low pressure or bad injectors).

 

Look for exhaust leaks on the up-pipes as they can cause low boost, and see what EBP reads at WOT in the shop and WOT on the road which might lead you to a plugged cat.

 

You did check FP on the road at 45MPH and WOT? It's really important to rule out plugged screens in the tank.

 

Bad injectors will also cause low power commonly, but not the circuit code. Check the air filters and inspect the turbo inlet looking for dirt abrasion on the impeller. If you don;t find anything else, fill the FF with Stanadyne and take it for a ride. If it acts better the injectors or fuel my be at fault.

 

Good Luck!