gjh2916 Posted September 4 Share Posted September 4 According to Cummins QuickServe Online my 2001 8.3 Cummins ISC Caps engine does not have a fuel shut off solenoid. How does the engine shut down when I turn the key off? I am having a hard start issue sometimes. Forums I have read says the fuel shut off solenoid could be sticking, but I don't have one. I've have a Fass fuel system and my pressure gauge is at 20psi when key is turned on. Before I install the Fass system a couple of years ago I had a hard start issue , it was the lift pump leaking and loosing it's prime. I replaced the lift pump and hard start issue went away. Little while later I installed the Fass fuel system and everything worked fine for a couple years. Now the hard start problem is back. Sometimes it starts fine and other times it don't. It always starts but only after a lot of engine cranking with pumping fuel throttle peddle. I've replaced fuel filters, chassis battery (8D) and installed a Blue Seas ML-ACR to keep batteries charged. Anyone one ever have an issue like this? Link to comment Share on other sites More sharing options...
Superpro14 Posted September 4 Share Posted September 4 did you leave the original lift pump in place and have the fuel running through it, if so could be sucking air at the lift pump again 1 Link to comment Share on other sites More sharing options...
Rikadoo Posted September 4 Share Posted September 4 Replace the ignition switch! Short while after buying my new to me rig an before i installed the fass system it would crank alot before it would fire, i replaced the switch an it has not had a issue since 2 Link to comment Share on other sites More sharing options...
Dr4Film Posted September 4 Share Posted September 4 I really don't think "pumping fuel throttle peddle" will help you since it is a fuel injected engine plus the peddle is not mechanical like it was when vehicles had carburetors. Sure sounds like it could be electrical and not mechanical. 3 Link to comment Share on other sites More sharing options...
Tom Cherry Posted September 4 Share Posted September 4 4 minutes ago, Dr4Film said: I really don't think "pumping fuel throttle peddle" will help you since it is a fuel injected engine plus the peddle is not mechanical like it was when vehicles had carburetors. Sure sounds like it could be electrical and not mechanical. DOUBLE DITTO. In the days of a CARBURETOR....there was an ACCELERATOR PUMP (diapghram) in EVERY CARBURETOR....or for CARS. I know... I was the Engineering Manager for a company that supplied Ford with 25,000 carburetors PER DAY. SO, there ain't NO CARB and ain't NO Accelerator Pump. As to the HARD STARTING and the IGNITION switch. Sometimes YES....sometimes NO. When the switch fails...it USUALLY has other symptoms. You can wiggle it. You can watch the displays or such that are IGNITION ON. Frequently ONE or some of them will NOT DISPLAY...like the Aladdin. If you PUSH the key in one direction or two DIFFERENT positions, it will USUALLY start. BUT, if the Engine is TURNING OVER and the Displays ALL LIGHT UP and no "gee, maybe later" ON's...then I would be less inclined to throw $$ at it without a REAL diagnosis and troubleshooting. Since the comment was...."AFTER a LOT of cranking"....that would appear to eliminate the Chassis Battery. The fact that it CRANKED....means that the Ignition switch is providing the START signal. The DRIVE BY WIRE or the Accelerator mechanism on the older Monaco's is obselete There are several threads on them here...and the upgrade/replacement is not cheap. I do NOT know if there is any interaction between the Throttle Control Sensor (the "potentionometer" that controls the activator on the engine. Maybe someone can chime in here. HOPE NOT... Wish I could add more...but logically troubleshooting and not throwing parts and money is something that is stressed here... Good Luck. Link to comment Share on other sites More sharing options...
gjh2916 Posted September 4 Author Share Posted September 4 4 hours ago, Superpro14 said: did you leave the original lift pump in place and have the fuel running through it, if so could be sucking air at the lift pump again Yes I left Lift pump in place, and disconnected the wiring. There is no leaks at lift pump, all the connections are completely dry. Link to comment Share on other sites More sharing options...
timaz996 Posted September 4 Share Posted September 4 3 hours ago, gjh2916 said: Yes I left Lift pump in place, and disconnected the wiring. There is no leaks at lift pump, all the connections are completely dry. Leaving the lift pump in place is fine, but you need to bypass it with the fuel lines and that is easily done. Just disconnect the inlet and outlet lines from the pump and connect them together with a coupler. Otherwise you’re just pushing fuel through a pump that’s not operating. Link to comment Share on other sites More sharing options...
jacwjames Posted September 5 Share Posted September 5 One suggestion I have is to disconnect the fuel hose at the secondary filter if you left it in place and check the flow rate of the FASS pump, put the hose in a 5 gallon button, turn the ignition on for 30 seconds and check volume of fuel pumped. My FASS is a 100 gph, so in 30 seconds it should pump ~1 gallon. Eyeball it and if it is close that means the pump is putting enough fuel out. If not there is a restriction either on the suction side or on the pressure side. If fuel is not an issue then it might be 12 volt circuit, check connections at starter. Link to comment Share on other sites More sharing options...
gjh2916 Posted September 5 Author Share Posted September 5 On 9/4/2024 at 12:28 PM, timaz996 said: Leaving the lift pump in place is fine, but you need to bypass it with the fuel lines and that is easily done. Just disconnect the inlet and outlet lines from the pump and connect them together with a coupler. Otherwise you’re just pushing fuel through a pump that’s not operating. See the diagram this how I piped up the fuel lines, so I could utilize the return to the tank Link to comment Share on other sites More sharing options...
timaz996 Posted September 5 Share Posted September 5 (edited) I also mounted my FASS pump in the department, but I bypass the stock lift pump with the stock fuel lines using a coupler. I ran a completely new return line because the stock return line cannot handle the extra volume of the FASS pump. At least I was told the stock return line could not handle that much fuel going back to the tank. But I’m not sure that would cause your problem of hard starting the engine. Edited September 5 by timaz996 Link to comment Share on other sites More sharing options...
jacwjames Posted September 6 Share Posted September 6 5 hours ago, timaz996 said: I also mounted my FASS pump in the department, but I bypass the stock lift pump with the stock fuel lines using a coupler. I ran a completely new return line because the stock return line cannot handle the extra volume of the FASS pump. At least I was told the stock return line could not handle that much fuel going back to the tank. But I’m not sure that would cause your problem of hard starting the engine. I mounted my FASS up at the fuel tank making the return line easy and I used the original fuel supply suction line from the FASS to the engine. I also bypassed the the original transfer pump, didn't want to take a chance and there has been some reports of the original transfer pump stopping up. So why take the chance. I also abandoned the original primary filter but I did keep the secondary filter and that is where I mounted my pressure sending unit. 1 Link to comment Share on other sites More sharing options...
BennieH Posted September 6 Share Posted September 6 You do not need the lift pump in the fuel circuit with the Fass. I have a set of photos with labels on the lift pump. You can simply bypass the pump only and the fuel returns built into it will function normally. In the link below, go to the last post and it details the lift pump and mounting assembly. the Banjo connections for the fuel return have no connection to the pump other than they are part of a common unit. Link to comment Share on other sites More sharing options...
cbr046 Posted September 6 Share Posted September 6 Back to the original issue . . . . . If there is *ANY* pressure at the input to the CAPS pump it should start. If the flow isn't sufficient it wouldn't run well under load, losing boost in the process, but it would idle just fine. I'm starting to suspect something electrical . . . . are the injectors electrically or mechanically driven on a CAPS pump? Maybe the fuel gelled inside the CAPS pump? Or the pump shaft broke? Is there a way to crack the connectors to the injectors and see if they "leak"? - bob Link to comment Share on other sites More sharing options...
gjh2916 Posted September 6 Author Share Posted September 6 I think I might have found the problem. Several of the connections on the fuel lines connected to the filters were a little loose. Maybe it was loosing its prime. The hard start issue was only 50% of the time. Once engine starts it runs fine and idles fine, my boost is about 20psi under load. I tightened fittings now time will tell if this corrected the problem. 2 hours ago, BennieH said: You do not need the lift pump in the fuel circuit with the Fass. I have a set of photos with labels on the lift pump. You can simply bypass the pump only and the fuel returns built into it will function normally. In the link below, go to the last post and it details the lift pump and mounting assembly. the Banjo connections for the fuel return have no connection to the pump other than they are part of a common unit. MY installation is very similar to yours except I cap the lines where I disconnected them from the filters and left them connected to the lift pump. Added new lines to install lift pump. I also bought my kit from Ultra RV products. This problem I'm having just started a couple of months ago, up until them Fass system worked fine for 3 years. Link to comment Share on other sites More sharing options...
gjh2916 Posted September 6 Author Share Posted September 6 59 minutes ago, gjh2916 said: I think I might have found the problem. Several of the connections on the fuel lines connected to the filters were a little loose. Maybe it was loosing its prime. The hard start issue was only 50% of the time. Once engine starts it runs fine and idles fine, my boost is about 20psi under load. I tightened fittings now time will tell if this corrected the problem. MY installation is very similar to yours except I cap the lines where I disconnected them from the filters and left them connected to the lift pump. Added new lines to install lift pump. I also bought my kit from Ultra RV products. This problem I'm having just started a couple of months ago, up until them Fass system worked fine for 3 years. My bad that was suppose to say added new lines to install Fass Pump Link to comment Share on other sites More sharing options...
jacwjames Posted September 6 Share Posted September 6 Keep an eye on any problems associated with the CAPS pump. I know with the OEM transfer pump leaking problem and then sucking air when it was running caused many CAPS pump failures. Do you have any type of monitoring system that will show fault codes. Link to comment Share on other sites More sharing options...
BennieH Posted September 6 Share Posted September 6 3 hours ago, gjh2916 said: I think I might have found the problem. Several of the connections on the fuel lines connected to the filters were a little loose. Maybe it was loosing its prime. The hard start issue was only 50% of the time. Once engine starts it runs fine and idles fine, my boost is about 20psi under load. I tightened fittings now time will tell if this corrected the problem. MY installation is very similar to yours except I cap the lines where I disconnected them from the filters and left them connected to the lift pump. Added new lines to install lift pump. I also bought my kit from Ultra RV products. This problem I'm having just started a couple of months ago, up until them Fass system worked fine for 3 years. Glad you got it figured out. Link to comment Share on other sites More sharing options...
gjh2916 Posted September 6 Author Share Posted September 6 1 hour ago, jacwjames said: Keep an eye on any problems associated with the CAPS pump. I know with the OEM transfer pump leaking problem and then sucking air when it was running caused many CAPS pump failures. Do you have any type of monitoring system that will show fault codes. Yes I have a code scanner and no codes were thrown Link to comment Share on other sites More sharing options...
gjh2916 Posted September 7 Author Share Posted September 7 20 hours ago, BennieH said: Glad you got it figured out. So far 5 attempts to start and 5 successful starts Link to comment Share on other sites More sharing options...
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