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Topic: Starting issue with 1995 U300 with Cat 3176 (Read 362 times) previous topic - next topic

Starting issue with 1995 U300 with Cat 3176

When we bought our 1995 U300 last year from an auto auction on EBay, the guy that sold it to us said they had to spray starting fluid in it to get it to start.
We had to do that the first couple stops on the way back from California to Ohio but then it ran fine.
Every time it sits a month or two we have to use starting fluid again.
It then runs fine the rest of the time we are on a trip.
Yesterday it finally warmed up a little in Ohio, we got it started with starting fluid, let it run awhile and when we shut it off, Bob noticed a small amount of diesel coming out of one of the lines in the back.
We never see white smoke come out when it starts.
He's wondering if that leak is letting air into the lines causing the hard starting issue.
It doesn't seem to leak after it's running.
Any ideas?
Susan and Bob
1995 U320CSE
40'
Cummins M11
Coach build #4730
Previous Foretravel's 1996 U280, 1995 U300

Motorcade # 17974

Re: Starting issue with 1995 U300 with Cat 3176

Reply #1 –
Quote from: Rocky1down –
When we bought our 1995 U300 last year from an auto auction on EBay, the guy that sold it to us said they had to spray starting fluid in it to get it to start.
We had to do that the first couple stops on the way back from California to Ohio but then it ran fine.
Every time it sits a month or two we have to use starting fluid again.
It then runs fine the rest of the time we are on a trip.
Yesterday it finally warmed up a little in Ohio, we got it started with starting fluid, let it run awhile and when we shut it off, Bob noticed a small amount of diesel coming out of one of the lines in the back.
We never see white smoke come out when it starts.
He's wondering if that leak is letting air into the lines causing the hard starting issue.
It doesn't seem to leak after it's running.
Any ideas?
Yes, probably where air is being introduced into the fuel system. I does not take much air to cause a starting problem.  Fix the line with the leak first and then check for starting issues the next day.

Perhaps not the easiest but you can take the fuel return line and place it in a container and watch for bubbles while the engine is running. It's easy to do on our generator but harder to reach the return line at the tank but might be easier at your engine.

White smoke is usually the sign that fuel is being injected but not exploding due to high altitude, cold temperatures or low compression. Does not sound like this is a problem on your engine.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Starting issue with 1995 U300 with Cat 3176

Reply #2 –
IF you have the Caterpillar manual primer pump (don't know if the 3176 has one) before trying to start if after sitting, pump it.

If immediately hard to pump, you still have fuel pressure.  If easy, either air getting in OR the check valve in the return line (again, having not worked on this series Cat, I don't know if it has one or where it is located.  On the smaller Cat engines, it is on the back of the head and the fuel return line goes from there.

Other possibility would be  a bad intake manifold heater or relay not pre-heating the engine.

Someone with first hand experience with the 3176 could certainly point you in the right direction on both fuel system and intake manifold heater on your engine.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020
 

Re: Starting issue with 1995 U300 with Cat 3176

Reply #3 –
Quote from: wolfe10 –
IF you have the Caterpillar manual primer pump (don't know if the 3176 has one) before trying to start if after sitting, pump it.

If immediately hard to pump, you still have fuel pressure.  If easy, either air getting in OR the check valve in the return line (again, having not worked on this series Cat, I don't know if it has one or where it is located.  On the smaller Cat engines, it is on the back of the head and the fuel return line goes from there.

Other possibility would be  a bad intake manifold heater or relay not pre-heating the engine.

Someone with first hand experience with the 3176 could certainly point you in the right direction on both fuel system and intake manifold heater on your engine.
3176B in our coach the primer pump is located midblock on passenger side just past the aircompressor d2 unit ,primer  has a knurled knob.
Hope that helps
Hans
Hans & Marjet
1995 U300 "Ben" (#4719)
3176B Cat,4060HD,Jake
SKP#139131
Motorcade#17579
2006 Honda Element (towed)