6.5 Rough Idle

[swamppop]

I think my last post got erased.
Oh well,
it was about my 6.5 missing at idle.
Misses, idles very rough, shakes the truck, etc.
Runs good at any other rpm.
many new parts, none worked.
6th injector pump replaced about 2 years ago.
Any advise?

[Robyn]

First off

Welcome to TDP

What year is your truck? does it have electronic injection or mechanical.

Once we know this we can move forward on a diagnosis.

Good to have you on board

Robyn

[swamppop]

I sent all info in my first post, but it went blank when I sent it, sorry.
I am a newbie.
1994 3500 xcab 4X4 with a NEW GM CRATE 6.5 with 20k on it.
However it is 7 years old.
Gerhardts in BR, LA. put the motor in with all new parts and I was extremely satsfied with the work.
However, I have sinced moved to the sticks, in NW AR.
This is now a farm truck which idles a lot,
or not, now
No mechanic in town to fix it, none, not even the dealer.
Near Fort Smith.
I have new fuel lines, filters, solindiods, pumps etc.!
1K in parts so far, no change.
At idle the truck shakes so bad you think it was falling apart,
It runs at ANY rpm fine, but not at idle.
My 6th injector pump was about 2 years ago, I hoped that was my last.
Any sugestions welcome, any one wants to fix it, I'll give you directions,
Thanks, Steven

[swamppop]

:( no replies to my ?

[Robyn]

Without seeing the truck in person this is a toughy.
Do a compression test, all cyinders should be over 320.
If compression good then the issue can be either IP or injectors.

If Comp good then get injectors checked for pop and pattern.
Injectors good then IP is to be suspect.
I have seen many issues on these but for just idle to be rough???

Does it smoke a lot when its idling?

If smoking then again injectors possibly bad.
While its idling go through and crack the High pressure lines loose one at a time until you find the cylinder thats not firing.
Are there any codes (SES light on)
Keep us posted.

Robyn

[rameye]

Had a Ford Lehman breakin my chops with same symptoms...

air leak was the culprit...

Check as Robyn advises

[swamppop]

I'm sorry folks, I tried to send a full page with lot's of detail and when I got finished typing it, (I am slow) It went blank and did not post. Timed out or something, for the second time.
I am sooooo mad.:mad:
I will try again later,...
sufice to say all parts are new except IP and main fuel line from tank.
Shakes so bad my rear veiw mirror fell off.
I need help.......
ps we put clear fuel lines and there are still bubbles in them, though only half as much, but no change whatsoever anyway.
Steven

[swamppop]

I'm sorry folks, I tried to send a full page with lot's of detail and when I got finished typing it, (I am slow) It went blank and did not post. Timed out or something, for the second time.
I am sooooo mad.:mad:
I will try again later,...
sufice to say all parts are new except IP and main fuel line from tank.
Shakes so bad my rear veiw mirror fell off.
I need help.......
ps we put clear fuel lines and there are still bubbles in them, though only half as much, but no change whatsoever anyway.
Steven
I'll keep trying to write,
new injectors, fuel filter and houseing, fuel lines, idle soleniod, idle sensor, etc.
SOS code probably caused by me unplugging idle sensor to try and keep my filling in my teeth.
only 20K on this new crate motor

[swamppop]

2 new Injectors were suspect & replaced.
ALL were replaced at install.
No smoke. Runs great from 1K to redline, pulls like a mule.
As long as you are on the gas.
Idles like on 4 or 5 cly, at best. Shakes so bad I think I broke a motor mount.
A brake line wore through from touching the frame.
This has been going on for a while.
I have no code reader or mechanic in my town and no one I know to bring it to who don't just "TRY" something.
@ $1050, a new IP is an expensive try..
Got to be something we missed,...
Gas pedal ohmed out at 13??? I think

[swamppop]

I ran Bio-Diesel but replaced all filters.
Never had a problem with any other equipment I have on the farm.
Ran Stanadyne Injector cleaner from the IP injector dealer/rebuilder from FS, AR. also ran many bottles of LUCAS.
Nothing.
It is hard to start, duh, even put new glow plugs.
I' can't think of much else that we have not done.
6th IP in this truck since I bought in new in 1994.
I have put every one of the 120K on it.
Too many new parts to mention, but now it is just junk if I can't fix it.
help!
Thanks Steven

[swamppop]

I'll keep going while the posts are working,..
New clutch pressure plate, new front end with stabilieser, Rancho shocks, Copper Mudders, Gooseneck hitch, all in one welded class5 tow hitch, K&N, Jarden strait exhaust with no cat, bed liner, chrome box rails and boards,
more, more, more,
this farm truck idles alot, but it was a street truck for 100k.
It has been well cared for, but it is really about to get a match.
help steven

[swamppop]

bidders welcome at this point,
Robyn I would bring it to you if I could,
But it would be a long Miserable trip.
(You are welcome to come here and stay in our guest house, ;)
Is there any way to just jump a new fuel line from tank to pump and see if that works? Assuming an air leak.
If I buy and put in a new IP and that don't fix it, I think I'll have some target practice.
Hope to get some replies.

Thank You all,
I appreciate it!

[rameye]

Ok...

You say you have clear fuel lines with bubbles in them????

Until those bubbles are gone you cant rule out air in the system....

Make the bubbles all gone....then move on.

Why not just run a hose from your fuel pump discharge up to the filter and fire it up??

That will rule out the section of hose between the pump and filter....run it in clear line...if you have bubbles its either the pump or the line from the tank.

Dont give up...just take 5 and and do a little every day..

[swamppop]

Thanks for the encouragment, I needed that.
I'm just getting frustrated after all this time.
I am going to see what kind of line I can rig up with what I have right now.
going get dirty,,, I"ll keep yall posted!

[Robyn]

Take a 2 gallon can of diesel and run a seperate pump from it to a known good clean fuel filter and to the IP
Run a clear return back to your fuel source
Fire it up and see if your issues go away.
Now if the issues are gone then you need to trace out the fuel system from the tank to the engine.

You could have a tank pickup sucking air.
A fuel line thats leaking air
A fuel filter housing with an issue

You can also install as clear line coming from the filter to the IP as this will tell you if you have an air issue on the supply side of things

Best of luck

Robyn

[swamppop]

long story short,
made a rigging as advised,
lots of info gained from experiment.
Still have bubbles, and a leak, they are on the left, passenger side of truck under the turbo. I can not see them from any angle but I can now see it leaking on the manifold under the turbo. No way to find where.
Any comments welcome.
Pull Turbo?

[rameye]

OK back fron vacation...

That pretty much indicate its either a supply steel line leaking...(unlikely) or a crappy rubber return line...

Yes pull turbo...manifold stays put...couple hours and the job is done....glow plugs too if you havent for a while.

stay on it..

[Scooby]

Is your harmonic balancer ok ?? What about the crank pulley ?? I dont think the crank pulley is your problem, but when mine went bad, I only heard it at idle.

[More Power]

Step one: Verify a good & clean supply of commercial grade #2 diesel fuel. Drain the tank and refill if you're not certain.

Step two: Verify that the fuel filter is clean, installed correctly (no leaks), and that all of the air has been bled.

Step three: Verify that the electric fuel lift pump is generating 4 to 8 psi of fuel pressure while the engine is running.

Step four: Verify that there are no fuel or air leaks in the fuel supply lines. You can pressurize the fuel tank with 5 to a max of 10 psi using a regulated air compressor. An oily rag wrapped around the air hose will seal it well enough when stuffed into the fuel tank filler neck. Check for any fuel leaks - all the way from the tank to the fuel inlet of the fuel injection pump. A visible fuel leak could just as likely be an air leak without the compressor pressurizing the system.

Got to eliminate the above before suspecting something else.

Jim

[Warren96]

Last fall mine was running like that with air bubbles. I ended up replacing all the supply line from the tank. Then the sending unit, then the tank, then a brake line.Anything steel with fuel or brake fluid in that area of the truck started leaking.

[swamppop]

Leaks fixed, Return tube burnt with hole on manifold under turbo, the new fuel line was improperly installed.
Still have bubbles in return lines.
Truck now ALMOST idles, sometimes yes, sometimes no,
At least I/WE (THANKS!) made a change!
The previous experiment with pumping out the bucket stright into the injector produced the same results. Almost, but not quite.
Now what?
Don't say shoot it and buy a new dodge, I already thought if that.
Thanks for any feedback.

[rameye]

Chances are when those bubbles all dissapear it will smooth out nicely...

So basically at this point you need to find the source of the air....

I have found this is best done by replacing sections of the lines with clear tubing and working backward until the source is found.

I know you've bypassed the fuel pump and that line..so you can rule out from the tank to the filter assembly as a problem...(good call Robyn)..

Check the filter assembly as a source of air, line from assembly to pump...check pump bypass, check the returns.

I know a bad injector can let air into the system as it sits, but I dont know if it can do the same during operation.....

Process of elimination at this point..I would like to think it coming in before the IP.

Did you ever verify good operating pressures of the lift pump while running??? Mine is about 8 psi.

[Warren96]

Like ''Morepower'' said have you verified 4 to 8 lbs from the lift pump? Are there any more wet spots under the truck that smell like fuel?

[Robyn]

I would continue to run the little creature on the remote supply until I could be sure it will run AIR FREE before heading off on a crusade to find a leak in the supply system.

If the engine will clear out and run totally smooth and air free you then know that your good to go at the IP.

If you cant get it air free with the remote supply then it has to be an issue with the IP.

Good luck and were here for YA

Robyn

[swamppop]

I'm still trying,...

[More Power]

Still have bubbles in return lines.

I wouldn't worry about the return lines. Shouldn't have any air in the supply lines... :)

Jim

[rameye]

I only mentioned that as it is part of the rule out procedure in my manual as part of a comprehensive exam of the system.

I agree wholeheartedly...no air coming in...theoretically none can exit.

Can a bad injector introduce air during operation???

[pjt97k2500]

Rough starting; sounds at first like it is not firing on all cylinders, lots of smoke, then it will give a little surge and then run smooth. It is using more fuel and smokes more than normal.
I pulled glow plugs, (some were more sooty that others) did a compression test; all over 320 psi, installed new glow plugs, did a voltage check to all glow plugs. Changed fuel filter. Only other things to look at are IP and Injectors. SES light has not come on.
Suggestion? - check injectors?