Diesel Place banner

1 - 16 of 16 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
The problem first appeared months ago with little symptoms: just little hesitation after engine was started and after a short while engine was back to normal. However it has slowly gotten worse. Now after engine start, it hesitates badly and sometimes even stalls.


This happens with both hot and cold engine. It starts right up but starts hesitating badly after about 5 seconds of idle. It lasts about 15-30 seconds and then starts running normal. No smoke and drives just fine after this. Often it is so bad that the engine stalls and takes lot of cranking / giving more gas to get it running.


New fuel pickup in the tank, fuel lines, fuel filter and fuel pump (acdelco) were installed about a year ago. Car has mechanical IP which was rebuilt few years ago and marine injectors installed. I tested 7 of the 8 injectors with a cheap injector tester which showed injectors popping between 1750-1900psi with ok spray pattern in each and no leaking. I don't know how old the glow plugs are. Engine was rebuilt some years ago and eaton m112 installed.

The engine shakes a bit on idle which goes away when giving bit more gas.



I'm out of ideas what to check. Suggestions are appreciated.
 

·
Ex- 6BT Square Body Man
Joined
·
9,756 Posts
Put a clear line on the return off the injection pump and see if there are any air bubbles.
Ideally after sitting overnight you want a small bubble the next morning, if the line is empty then there is a air leak between the tank and injection pump.
Also take off the fuel cap/s and see how it runs.
 

·
Registered
Joined
·
3,640 Posts
Sounds like air getting in somewhere to me.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #4
Thanks. Air was my guess also but I have not found the source yet. I will re-check all hose clamps and filter housing. All hoses are new so there should not be any cracks. Filter housing is a generic one from local parts store, probably for farm equipment :)
I was aware of the clear return line hose trick but never tried because the hose is no longer easily accessible. I will have to try it.


How removing the fuel filler cap can affect the engine running?
 

·
Ex- 6BT Square Body Man
Joined
·
9,756 Posts
How removing the fuel filler cap can affect the engine running?

If it's a gasser cap it won't vent properly and a vacuum gets created in the tank.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #6
legendman: Thanks for the tip. Keeping the cap slightly open did not have an effect on the issue but the cap might be from the time before engine swap so I might get a new one at some point.


I checked all clamps at the fuel filter with no effect. Still need to check at the fuel pump and at the injection pump which is hard to reach. Any other places I should check for air leaks? There is no diesel visible anywhere.
 

·
Ex- 6BT Square Body Man
Joined
·
9,756 Posts
I was aware of the clear return line hose trick but never tried because the hose is no longer easily accessible. I will have to try it.

:think: Huh? Where you put the clear line should be easily accessible on a K1500. It's right on top of the injection pump.




Also, try cracking each injector line while it's running to see if there is any change in idle. Crack a line and you should notice the idle change and it stumble.


Also check the light load advance, instructions are in the student manual.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #8
:think: Huh? Where you put the clear line should be easily accessible on a K1500. It's right on top of the injection pump.

The custom intake covers the IP and makes it difficult to access.


Also check the light load advance, instructions are in the student manual.

I pressed the light load advance arm while engine was idling but did not notice any change in RPM or engine sound. There was however a rattling or "clinking" noise when pressing the arm and it sounded like it was coming from the IP. Looking at the manual and videos found in the forum, I assume there should be a clear change in the RPM?
 

·
Ex- 6BT Square Body Man
Joined
·
9,756 Posts
The custom intake covers the IP and makes it difficult to access.





I pressed the light load advance arm while engine was idling but did not notice any change in RPM or engine sound. There was however a rattling or "clinking" noise when pressing the arm and it sounded like it was coming from the IP. Looking at the manual and videos found in the forum, I assume there should be a clear change in the RPM?

Take the intake off and run it, this check is very important, you will be going around in circles if there is air causing these issues.
While running there might be some very small bubbles, but the key indicator of a air leak is the line being clear after sitting over night.



Yes, the idle should fish bite, I think you need to bump the timing to the drivers side. About a dimes width then check again.
 

·
Registered
Joined
·
6,202 Posts
We need pic's of this cause the return line comes right off the front of the IP by the rad hose ... shouldn't be that hard to do ...




:nopics:
:nopics:








I would say the timing could be bumped up and see what happens or the advance system isn't working, try bumping it 3 time up and get back to us, but don't drive it that far advanced till we get back to you.



You can install check valves from Eburp but the are a hack way of patching a leaking system. You still have leaks but the check valve stops the fuel from running back the fuel lines.


Any loose, cracked, rusted rubber or steel line from the IP inlet & the fuel filter & tank switching valve if you have dual tanks alllll the way back to include the fuel line on the sender in the tank can be your problem .... fun eh ...


I pressurize the fuel system to find leaks like this, no more than 5 psi ... and we can walk you through this if you want to do this as there are a few ways of doing it.



Did I mention ...



:nopics:


:bigglasse
 

·
Registered
Joined
·
6 Posts
Discussion Starter #11
We need pic's of this cause the return line comes right off the front of the IP by the rad hose ... shouldn't be that hard to do ...

Yes I know where to find the return line. It is just hard to access. Same thing if I want to change timing. Bit of a design flaw with the intake :(


But adding the clear line is on my todo-list. Thanks for the tips.
 

Attachments

·
Ex- 6BT Square Body Man
Joined
·
9,756 Posts
I could see where having a blower on it might cause an accessibility problem for the return line :D
 
  • Like
Reactions: Bigboytoys

·
Registered
Joined
·
6,202 Posts
Well there's your problem ...


And I'll cure that issue when you send that useless POS to me !!


Ha ha ... hola F.... a Eaton blower, that's cool !! Not very often I skip reading the sig line to new post when on my lap top, by phone it doesn't show unless I exit "enhanced view"


Instant boost right off the bottom end must be so nice!!



:bigglasse
 

·
Registered
Joined
·
6,202 Posts
Hmmm just noticed something, is the CDR a turbo vs or the original NA vs ...? Cause there is a difference.


:bigglasse
 

·
Registered
Joined
·
6 Posts
Discussion Starter #15
To anyone who finds this thread, I did find the problem eventually. Problem was actually diesel lift pump that was installed when rebuilding fuel lines. Pump started when ignition was turned on but shut down after few seconds. This went un-noticed and engine was pulling diesel from the tank without lift pump but still ran ok. Fixing pump wiring, fixed the problem.

The issue with lift pump was that the car had originally a gasoline engine and pump was wired to the original fuel pump wiring which was controlled by the ECM. I believe it was expecting a signal from ignition module but without it, decided that engine was not running and shut power to fuel pump :)
 

·
Administrator
Joined
·
16,326 Posts
Glad you found and resolved the issue.
Thanks for giving us an update!

(y)
 
1 - 16 of 16 Posts
Top