tonybullitt Posted July 22, 2014 Share Posted July 22, 2014 Hi I have a way before my time ambulance here. The concern is at times will start fine then stall. Very hard restart after stall. If it doesnt stall it runs great and after it starts runs great. Any suggestions I have very little inj pump experience. Thanks Tony Quote Link to comment Share on other sites More sharing options...
Chase Posted July 22, 2014 Share Posted July 22, 2014 Sounds like air intrusion to me, check the return line caps for leakage, probably needs new caps, o-rings and lines. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 22, 2014 Share Posted July 22, 2014 Very common concern with these. There are many leak prone areas that allow air to enter the fuel supply system and the fuel injector return lines during shut down. When this happens the supply system and filter can drain so that when the engine is started it immediately ingests air in the injection pump and it loses prime - the engine stalls and is very hard to restart usually requiring purging to do so once this condition progresses. Inspect all of the fuel lines from the tank to the fuel pup on the right side of the engine block and then the lines up to the fuel filter housing. THen the rubber lines from the filter housing, pump and injector return lines and the collars at every injector. You m ight just be better off replacing parts on a truck this old. Parts meaning hoses, clamps and collars with new O-rings. Also the fuel pump can leak. I have attached (TSB 97-2-15) the diagnostic guides for the older engines in case you need them tsb97-02-15.pdf Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted July 22, 2014 Author Share Posted July 22, 2014 Thanks alot I will post what i find. Tony Quote Link to comment Share on other sites More sharing options...
8WA Sman Posted July 23, 2014 Share Posted July 23, 2014 IRC if you think it is the fuel pump bleeding back pinch off the return @ the pump the see if it starts fine. You can also buy the fuel return hose @ the injectors in bulk, I still have some in my toolbox that I will probably never use Quote Link to comment Share on other sites More sharing options...
BigWalt Posted July 23, 2014 Share Posted July 23, 2014 speaking of IDI diesel here.I have similar issue here.The lever on injector pump stuck between 1/2 throttle and wide open throttle...Does this means pump is defective? ...it is reman pump, comes with reman engine that we install three weeks ago. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 23, 2014 Share Posted July 23, 2014 speaking of IDI diesel here.I have similar issue here.The lever on injector pump stuck between 1/2 throttle and wide open throttle...Does this means pump is defective? ...it is reman pump, comes with reman engine that we install three weeks ago.Another common drivability concern I used to see was stalling after accelerating and returning to idle. The governors on these pumps do wear but as many diesel guys are, I would get curious and pull the cover off of the governor and have a look. More often than not there was a bit of rust and gook inside the housing. If I think really hard I may have seen one or two with a sticking throttle as well. It has been some time since I have put my hands on one of these now, but it's like riding a bike. Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted July 25, 2014 Author Share Posted July 25, 2014 I put clear hose in fuel filter vent line to fuel return line like the diag sheet showed. Let sit and started stumbled and ran like crap. I checked the hose and sure enough full of air. inspected fuel lines from tank to engine and inj return lines no concern found. The only thing i seen was a little weapage from lift pump told customer i would like to replace lift pump. Put lift pump in and upon removal got alot of fuel oil out of the weap hole. Test drove let sit and no air in my clear line. Its back at fire station and they will let me know if we need to dig further. Thanks for the help. Tony Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 26, 2014 Share Posted July 26, 2014 Tony the screwy thing about diagnosing this concern is that there may be no detectable external fuel leaks yet the system sucks in air when shut down. So yes - it sometimes takes a little trial and error to replace the right part or line to resolve it but you should not be getting fuel out of the weep hole. Sounds like you probably got it. As I recall, the o-rings in the steel line fittings and the rubber lift pump hoses were the biggest problems I encountered. Steel lines meaning the metal tube going to the fuel filter housing and from the housing to the injection pump. That rubber bleed off/return hose from the filter header as you mentioned is also a prime suspect. (pun intended) Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted July 29, 2014 Author Share Posted July 29, 2014 Just heard they had emergency call last night and my ambulance started stumbled ran rough then was good. So I am going to get estimate on the fuel line orings and rubber return lines. Quote Link to comment Share on other sites More sharing options...
batmantech Posted July 29, 2014 Share Posted July 29, 2014 Tony, What town is still running that old of an ambulance? Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted July 29, 2014 Author Share Posted July 29, 2014 Goodhue Mn fire dept first responder. In Zumbrota there are 3 newer ambulances for rural goodhue co. Unfortunately I have had both to my house. A little over a year ago on a saturday I was at work trying to catch up. My wife and mother in law were doing a garage sale. My at the time 4 year old crawled up a unfastened cattle gate and leaned backwards and had it fall on him. Lucky it was dirt were he hit not cement. He was bruised good and got a cut on his head. They hauled him to mayo in Rochester and stitched him up checked him over no concern. Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted July 29, 2014 Author Share Posted July 29, 2014 Here is picture of the 2011 super duty ambulance leaving my house. Quote Link to comment Share on other sites More sharing options...
batmantech Posted July 29, 2014 Share Posted July 29, 2014 Our fire department does have some old stuff also. Its something to work on an ambulance after you have had them respond to your house, family. I know for me having them hauling my daughter a couple times it changed me. Glad to hear your son was ok. Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted July 29, 2014 Author Share Posted July 29, 2014 Here is a picture of the 1993 ambulance on my 18k hoist. Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted July 31, 2014 Author Share Posted July 31, 2014 I am working on resealing this idi fuel system and upon removal of fuel filter housing found fuel heater leaking fuel into connector anyone have a fuel heater connector part # by chance. Thanks Tony Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted August 4, 2014 Author Share Posted August 4, 2014 We found a way to get a pigtail for fuel heater. It shares connector with the 94-97 di fuel heater and fuel bowl harness is available yet. Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted August 4, 2014 Author Share Posted August 4, 2014 Here is a picture Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted August 8, 2014 Author Share Posted August 8, 2014 Got this truck fixed after replacing the lift pump, fuel heater, fuel return lines and seals on metal lines. I let this sit 2 days without being touched. She runs great when started and driven after sitting now. Thanks for the help. Tony Quote Link to comment Share on other sites More sharing options...
batmantech Posted August 9, 2014 Share Posted August 9, 2014 Way to go Tony! Quote Link to comment Share on other sites More sharing options...
tuff57 Posted September 4, 2014 Share Posted September 4, 2014 running into the same issue with my fathers truck, haven't had the time to go over there and look at it yet, replaced all the return lines last year, and some how the kit i bought, the line wasn't diesel compatible and collapsed, replaced all the lines with marine diesel line, and half the bank of injector o-rings, ran good for a while, now he called me up saying the filters dry and the truck won't start. As simple as the old trucks are, it's tough putting my brain in "old" mode after playing with 6.0s, 6.4s, and 6.7s all day. Can't even ask for advice as I haven't even looked at the truck yet Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted September 4, 2014 Share Posted September 4, 2014 Joe - if it were me doing this job I would have gone ahead and installed new o-rings on all of the injectors while I was there. I remember going round and round with several trucks back in the day. In an earlier post I eluded to replacing hoses and seals. Specifically, the rubber seals inside the fittings of the steel line that runs from the fuel filter housing to the injector pump and any other line up there might need to be replaced. They are just large square cut runner rings that compress around the tube and spread inside the fitting to seal. They can dry rot and crack, compress and suck air on shut down. Anything on that system that is not high pressure is suspect - anything on that filter or housing that can be removed, inspected and or resealed is worthy of your attention. Don't think I have ever heard of a pump causing this. Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted September 5, 2014 Author Share Posted September 5, 2014 The rubber seals inside the steel lines were in terrible shape on the ambulance i started this post about. Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted September 5, 2014 Author Share Posted September 5, 2014 ? for you guys that know these engines. The steel line from filter to high pressure pump was different size then the line from lift pump to filter housing. My parts guy got me same size seals for both lines and i looked at parts pictures with him. I was able to get the seals on both lines and it worked fine but they were very tight inside of the smaller line. Does that seem normal or were we missing something in the parts picture? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted September 5, 2014 Share Posted September 5, 2014 There is a service kit for the early 7.3L PSD engines that contains several different sizes of the seals. More than you need for the IDI engines but you will get what you need. Toss the extras in your parts drawer as you never know when you might need one. The part number is F81Z-9C387-BA Quote Link to comment Share on other sites More sharing options...
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