Pump replace or missing somthing?

[Jgolden]

89 Cummins 5. 9 in a front engined Motorhome. 80,000 miles.

Just returned from a trip out west. Engine was getting harder to start for a while before I left. Stopping at a rest stop in western NY on returntrip no start. Starting fluid starts right up and it runs fulll power no problem. Stop for the night, no start in morning. Start fluid drive 100 miles to home no problem.



I have tried everything suggested by some smart folks. Checked for air leaks, fuel solenoid, see through lines, injectors checked and serviced, new filter, cleaned screen in Walbro pump, bypassed diaphram pump, bled lines, etc.

Pretty much down to yanking the VE pump , which is buried, up front. OK, good time to replace hoses etc.



My question is this, is it usual for a failing pump to cause a hard start or no start and still work well enough to move a 12,000 lb Motorhome down the road at 65 miles an hour?



Is there somthing to check that would cause what seems to be a no fuel at start deal? The slightest wiff of starting fluid will start it and it will run fine.

Thanks any info or opinions. Joe Golden



PS I did add an Intercooler last year.

 

[JLEONARD]

Mine acted up when the line comming out of the fuel tank rusted thru.

 

[cerberusiam]

Its one of the symptoms that can indicate a failing pump. Since you have a Walbro and are sure its getting fuel its down to the pump. Frequently what happens is case PR valve gets sticky or jammed with fuzz from the fuel and it won't build enough case pressure to start.

 

[TBartlett1]

I had an 89 D350 last year with a similar problem. The initial symptom was hard starting but ran fine once running. Eventually it had to be towed to start and would stall if allowed to idle. I pulled the pump with intentions of replacing it but decided to tear down & inspect.

I found the pump clean with no apparent problems so I pulled the head off the pump.

When I removed the 3 sided plug in the middle of the distributor head I found it hand tight.

The plug being loose allowed an internal fuel leak which prevented the injectors from firing. I tightened the plug securely, without any torque specks I felt that 50~60 lbft felt good. I reinstalled the pump, purged the lines and it started & ran fine.

My guess is that tightening the plug will solve your problems.

The plug is a very odd shape that is difficult to grasp securely. I used a socket that just fit over the plug and inserted pieces of welding rod between the socket and plug to get a purchase on it.



Hope this helps!!!

 

[ChrisWilliams]

I suspect you need to pull the VE, tear it down and go through it. Before you take this step, make certain you have positive fuel pressure to the VE.



I recommend you install a fuel pressure gauge if you don't have one already, just to make sure you don't have a fuel delivery problem (bad line) somewhere now or in the future. It's a cheap mod and a little piece of information that is nice to know. I lost a VE a couple years back due to a hole in a line. Started and ran fine, but would lose power on long hills under heavy load. The VE went out about 300 miles later. A $40 gauge would have saved me a grand plus a tow bill.

 

[Jgolden]

Thanks folks. I'll follow suggestions.

Jay, I did put a fule line direct from the walbro pump to the filter intake.



Tbartlett, what is described as a three corner bolt head is a standard bolt head on mine, maybe I'm looking at the wrong thing. Middle of the fule lines on the fuel distributer head? I'll check for tightness.



Cerb, I guess the stickyness can't be cured with out removal.



Chris, Fuel gauge shortly.



I do want to make syre the easy things have been done, and I think most have, but I'd hate to pull and replace and still have a problem.



Any other thoughts appreciated. hanks, Joe G.



PS Jay : Are you retired yet?

 

[Jgolden]

Its one of the symptoms that can indicate a failing pump. Since you have a Walbro and are sure its getting fuel its down to the pump. Frequently what happens is case PR valve gets sticky or jammed with fuzz from the fuel and it won't build enough case pressure to start.

Since the slightest wiff of starter fluid will start it and it seems to run fine with plenty of power what would be the down side of installing a "starting aid " injection port on the intake horn or intake manifold? Don't know if there is such a thing but it would be simple to make (or so I dream).



Thanks.

 

[cerberusiam]

Since the slightest wiff of starter fluid will start it and it seems to run fine with plenty of power what would be the down side of installing a "starting aid " injection port on the intake horn or intake manifold? Don't know if there is such a thing but it would be simple to make (or so I dream).



Thanks.

Grid heaters and starting fluid don't mix, big BOOM if you are not careful.



If th epump is good and the temp is anywhere above zero thes engines normally fir eon the first cylinder up, if they don't its a good indication of a problem that might get you in the middle of no where. I don't mean a no start either, I mean a no RUN and that wil be expensive.



If you have positive fuel pressure to the pump and everyhting else has been done its a good bet there something not quite right. Since this is a MH I'll bet it sits a lot and that seems to make things worse.



You could try fillling the fuel filter with Sea Foam and start if for a few seconds to run it into the pump then let it soak for a while. Might tell you more about the problem.

 

[TBartlett1]

The bolt head you see in the middle of the injector lines is the plug you pull to insert an adaptor for timing purposes, this small plug is threaded into the 3 sided plug I'm talking about.

You may need to remove the injector lines on the pump to have enough clearance for a socket.

I strongly suggest that you check the plug before condeming the pump, the 3 sided plug is approx 1inch in dia if that helps!



I'll watch for other posts.

 

[Jgolden]

The bolt head you see in the middle of the injector lines is the plug you pull to insert an adaptor for timing purposes, this small plug is threaded into the 3 sided plug I'm talking about.

You may need to remove the injector lines on the pump to have enough clearance for a socket.

I strongly suggest that you check the plug before condeming the pump, the 3 sided plug is approx 1inch in dia if that helps!



I'll watch for other posts.

Thanks, I see what you mean now.

 

[Jgolden]

Grid heaters and starting fluid don't mix, big BOOM if you are not careful.



If th epump is good and the temp is anywhere above zero thes engines normally fir eon the first cylinder up, if they don't its a good indication of a problem that might get you in the middle of no where. I don't mean a no start either, I mean a no RUN and that wil be expensive.



If you have positive fuel pressure to the pump and everyhting else has been done its a good bet there something not quite right. Since this is a MH I'll bet it sits a lot and that seems to make things worse.



You could try fillling the fuel filter with Sea Foam and start if for a few seconds to run it into the pump then let it soak for a while. Might tell you more about the problem.

Thanks. Yes it does sit. 80,000 miles in 20 years. No grid heater so less chance of boom. I realize there is agood chance it's the pump.

 

[JLEONARD]

PS Jay : Are you retired yet?

Not yet but working on it. The plan is to have the summer of 2011 to cruise full time.

 

[Jgolden]

As info to all who contributed good information and advice to the problems listed in my first post:



In the end I had the injectors rebuilt and put in a new pump. Slow process because I had to remove much of the front of the motorhome. Extra thanks to Peter Toombs who talked (emailed) me through pump removal and replacement as well as putting me on to a good pump rebuild shop.



Now I realize that my 5. 9 never started well as long as I owned it. The pump was weak from the start and turning it up gave me a few extra years. It gradually got worse until it would not start.



It now starts as soon as it cranks. I'm not an expert but I think longer crank time is a great clue on pump health (I know lots of people know that but I'm a slow learner). Like most folks I had to climb the learning curve, check leaks, injectors etc. Lots of people told me it was the pump and they were right.

Thanks again to all who posted as well as those who posted over the years to build the "search" files.



Now all I have to do is bolt the front back on and get in a road test. J Golden

 

[DVolk]

I got a weird issue going on my 93 engine . It ran fine the other day but i go to fire it up to go to down it stumbles for a minute i rev it up it clears its throat no big deal . Get in the truck on way up it acts up even more and wants to die I keep it running on the way home get it home it dies . When it starts it revs way up and sounds sick . I drained the fuel filter and it looks good in clean the fuel that drained i have not switched the filter out (napa in town wants 21. 00) i can get a better filter down the road for 15. 00 .

I replaced the pump a turned up pump with the spring and i beleive a fuel pin mod says turned up pump from Diesel Care of Millington , TN it has between a 1/4 and a 1/2 tank of fuel any ideas ?it acts like its running out of fuel but i dont know dont see any leaks in the lines . Any idas ??????????????????

 

[cojhl2]

I had something like that once, plus it would run out of power on a hard pull.

What it turned out to be was the flexible line(s) on top of the tank. They either suck air(no visible leak) or pinch shut at the 90deg bend.

 

[DVolk]

What is the best way to fix that problem in the tank area ?

 

[JLEONARD]

Replace the line. I had mine done when it rusted thru.