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6.5TD motorhome starting problem

B

Bezzer

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Hi Fellows...too long getting back to you. I have the motorhome with the 6.5 TD.
As you all have recommended I installed the fuel pressure gauge. I did find a gauge set up on Leroy Diesel where I bought the parts and bought the pressure gauge at O'Reilly.
My problem still is the first start up of the new day.
I have done some more reading and found two possible problems.
One is the oil pressure switch and the other is the fuel pump that is mounted on the frame.

#1. The oil pressure switch .... reads 40 lbs. when driving and 20 lbs. at idle. I believe that switch is OK.

#2. The fuel pump sitting at idle reads 4 lbs. and after the engine is turned off it reads 5 lbs..

What should be the correct fuel pump pressure?
 
Bezzer said:
Hi Fellows...too long getting back to you. I have the motorhome with the 6.5 TD.
As you all have recommended I installed the fuel pressure gauge. I did find a gauge set up on Leroy Diesel where I bought the parts and bought the pressure gauge at O'Reilly.
My problem still is the first start up of the new day.
I have done some more reading and found two possible problems.
One is the oil pressure switch and the other is the fuel pump that is mounted on the frame.

#1. The oil pressure switch .... reads 40 lbs. when driving and 20 lbs. at idle. I believe that switch is OK.

#2. The fuel pump sitting at idle reads 4 lbs. and after the engine is turned off it reads 5 lbs..

What should be the correct fuel pump pressure?
Click to expand...
What does the fuel pressure read with key on, while the glow plugs cycle?

Did you install a lift pump relay upgrade with the prime feature, so the lift pump runs with the glow plugs?

If you have fuel pressure with the truck running. Your fuel pressure sending unit is working.
 
please fill out your signature line with details of the rv. We need to know if db2 or ds4. There is several folks with 6.5 RVs and a few of each type.

Anything in the clear return line (Im sure we mentioned before)

Proper fuel pressure for a db2 is 3-5psi normal but never over 8psi
Proper fuel pressure for a ds4 is 8-14 psi.
Too low of pressure will cause hard starts for either.

As mentioned- when you wait to start for glow plugs- it should build full pressure and remain there when starting and running. A dip of some pressure when accelerating hard is ok but shouldn’t fall out of spec. Faster Wear occurs under spec and really bad under 1psi
 
Bezzer said:
Will L: Where do I look to see if it's a "db2 or db4"?
I'll get back to the other questions you asked after I get this info.
Click to expand...
And the DB2 will have a throttle control cable to the IP.
Like a manual throttle cable.
The DS4 is a fly by wire and the throttling is controlled by the ECM/POWER TRAIN CONTROL MODULE.
 
jrsavoie..... when the key is on --the fuel pressure reads 5 lbs while the glow plugs cycle. And it takes about 5 seconds and the pump stops. The glow plugs take a take of 10 seconds before they turn off.
Where do I find out about the lift pump relay?

The PMD went out at 70,000 miles and I installed longer PMD kit to the front of the grill. Works find at 80,000 miles.

ak diesel....I have done the clear line and there are no bubbles with engine running.
While sitting in the garage there are no signs in the clear line of it loosing fuel after a week.

Will L. & dbrannon......It is a "drive by wire" pedal.

I've listed a lot of information on earlier posts about these subjects but can't find the post at this minute. But I've included a picture of the motorhome.
Will L....I have tried many times to put a "signature" and had no luck even asking the web page people.
 

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Ok you have a DS4 electronic IP. you need to be seeing at least 8-14 psi with the key on engine off. and should stay above 5psi when idling. I would suspect you have a weak LP or a fuel filter that is partially clogged.
 
For the signature line: scroll to top of page and you will see your meme- the boue circle with B in it. Circled in red in pic (but mine is of my hummer)Click that.
Then a page will open, scroll down and you will see the word “signature” (next pic- circled in red) click that. Then you can type in the details there.
Year, make, model, include “RV”. Include ds4. Note wether it is a side mount turbo or centermount. Include any updates and modifications already done like clear return line, gauges, etc.

IMG_3035.jpegIMG_3036.jpeg
 
Problem still continues -hard to start after sitting overnight.
Here's the information you asked for: Electric drive by pedal.
Passenger side mounted turbo. Borg-Warner/HI GM 2

Clear line no bubbles except when not running bubble on top of hose.

K&N air fitler

3" OD straight exhaust pipe (no muffler)

Leroy's fuel pressure system with 15 lb. gauge. (shows 5 lbs. when pumped up- takes 5 seconds to pump up and then stops)

Scan Gauge II monitor that connects to the OBD II that reads rpm- water temp- trans temp- voltage while driving.

New glow plug controller- New 60G glow plugs.

Just had original fuel injectors rebuilt.

9 blade GM fan with heavy duty clutch.

12 V battery boost.

Oil pressure driving 40 lbs/idle 20 lbs

4L80 transmission
 
jrsavoie: There is no internal fuel pump in the fuel tank. The lift pump is what pumps the fuel from the tank.


You're other question I listed in the post above . "Leroy's fuel pressure system with 15 lb. gauge. (shows 5 lbs. when pumped up- takes 5 seconds to pump up and then stops)"

There is no reading on the gauge till you turn the key on.


For others that don't know what I have: I have a '96 Safari Motorhome with a 6.5TD which has around 80,000 miles now.
 
Bezzer said:
jrsavoie: There is no internal fuel pump in the fuel tank. The lift pump is what pumps the fuel from the tank.


You're other question I listed in the post above . "Leroy's fuel pressure system with 15 lb. gauge. (shows 5 lbs. when pumped up- takes 5 seconds to pump up and then stops)"

There is no reading on the gauge till you turn the key on.


For others that don't know what I have: I have a '96 Safari Motorhome with a 6.5TD which has around 80,000 miles now.
Click to expand...
Does your fuel pressure show 5 lbs immediately when you turn.the key to on?

Or does it take a second for the fuel pressure to come up.?

Maybe others could comment on any leak down you're having.

Seems to me the gauge should read 5 psi almost instantly when you turn the key to run.
 
Will L. wrote and asked me to list all the information on Post 13. Seems like all that you're asking me is answered on post 10 and post 13.
Still waiting to hear Will L's idea on the answers on Post 13.
There are no bubbles at all in the clear hose.
 
Ok- ds4 barely getting fuel, appears to leak down due to bad check valve as AKDD pointed out, and takes a while to build that amount of pressure…

Cycle the key 3 times through the glow cycle, while watching the fuel pressure gauge. Then start. Please describe what happens or make a video of it if possible and post a link here to the video.

If you can make a video from another phone/ camera at the same time showing the exhaust pipe and link that also- it would help.
 
5psi isn't enough pressure for a ds4 electronic IP long term but should at least still run and idle fine, under load it will starve for fuel.

you installed 60g glos plugs. on the first initial key on before start, how long does the wait to start light stay on until it turns off? do this... key on and count 1-1000, 2-1000, 3-1000... until the light turns off and report back. I feel like it's not enough time for the 60g's what is your outdoor temps like outside when you start it and it acts like this?

both of my trucks needed longer time for the wait to start light when I installed the 60g's at a minimum they both needed 8 seconds of run time. granted both of my trucks have 300k miles on them.
 
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