Need Help

[dflaugh]

Needing some help on what seems to be injector electrical problem.Truck suddenly started running very rough and made some nasty noises-was almost home so nursed it about 1 mile.Only code showing was for #2 intake heater.(cleared and has not come back)Checked electrical connections-unplug and replug-no change.Did return flow test-Cp3 and injectors-good.Checked all injector solenoids-all good.When testing wires I found my ??On injectors 1 &2 brown wire to orange wire-continuity,same on 5 & 6 but on 3 & 4 no continuity.Is this likely my problem and where should I go next.Thanks for the help,Darman

 

[dflaugh]

pulled the plugs at the ecm(the one side of plug C-2 has oil contamination)Tracked wires,high side wires? show .8 ohms Testing low side wires-they light up in multiple pins,and show 79 ohms.I am cleaning up the plug and check again.I really am not sure what is causing such a high resistance.Thanks,Darman

 

[sag2]

If you have an injector circuit fault like high/low resistance it should set a fault code.

 

[dflaugh]

I'm not getting any codes(very frustrating)But the engine runs very rough.It will start and run just enough to move it in and out of my shop.The only things I am coming up with still to check is, pressure relief valve and wherever the ECM is grounded.Any thoughts on what else to check would be much appreciated!Thanks,Darman

 

[Killer223]

start with valve cover off, take one wire off an injector at a time till no change. when found, replace injectors. or wiring harness.

 

[jghflys]

I would start with checking the voltage on each battery to ground with the engine running. Should be around 14 volts and both batteries within a few tenths of a volt of each other. Our trucks need a good solid electrical system to run well.

 

[Ozymandias]

What are you using to read codes, make diagnosis?

 

[dflaugh]

OK,I think I am getting somewhere.With all the testing I had done I really didn't Think killers suggestion was going to do anything and it wasn't untill I got to #6.Took the wire loose and totally no change.I figure since I have no codes I will block off #6 and redo my return flow test,I had 75 ml last time on all injectors -maybe most of that is coming from #6.That same #6 is what killed my engine 2 years ago-was washing the cylinder down.Also 14.59 v on both batteries and I'm using my Smarty Jr. to read and clear the codes.All help and comments appreciated.Thanks,Darman

 

[Ozymandias]

Switch injectors 5&6 for example to see if it is the injector OR the harness.

 

[dflaugh]

I just switched #6 and #4 -still getting same result on #6.Have a mechanic telling me I need to do compression test next.Do not have stuff to do compression test is there some other way I could test to know that I have good compression.Still no codes showing.Thanks,Darman

 

[dflaugh]

Also don't know why my profile is not showing up with my post??Darman

 

[jghflys]

I just switched #6 and #4 -still getting same result on #6.Have a mechanic telling me I need to do compression test next.Do not have stuff to do compression test is there some other way I could test to know that I have good compression.Still no codes showing.Thanks,Darman

Do you know anyone with a borescope? You can look inside the cylinder for damage or scoring. If you use one with a small mirror put some tape on it so you do not knock the mirror off in the cylinder.

 

[dflaugh]

I'm going to do some more testing on electrical,then a flow test to make sure fuel tube is ok,then head toward a compression test.Guy at a local shop said he would bring his tester to my house if I pull the injectors.I will see if he has a borescope.Thanks,Darman

 

[sag2]

Just get the Harbor Freight tool.

 

[DavidC]

Just get the Harbor Freight tool.

Harbor freight has a diesel compression tester ?

 

[Wayne M.]

Harbor freight has a decent snake camera. The head should fit in the injector nozzle opening.

 

[dflaugh]

Tested all injector wiring from ECM plug up through injector.(high side to low side from ECM)was consistent on all circuits-2.3 ohms.Did the return flow test just make sure no fuel tube problems-less than 50 ml.Heading towards compression test now,If my friend at the local shop can't get here I will look at ordering from harbor freight.Thanks, Darman

 

[dflaugh]

No compression on #6,20,000 miles on rebuild,engine is coming back out-will let everyone know what we find.Thanks Darman

 

[dflaugh]

So... an update.The engine out ,head off,#6 exhaust valve has edges broken off-so no compression.Piston top is beat up,but cylinder looks like it will be ok with hone.Both of my turbos are ok no sign of ant pitting or debris going through them.(a miracle)!!So I take the head to the machine shop today and I am telling the employee that I would like an opinion on what caused the problem and the shop owner walks up right then and goes there's your problem and points.I'm not seeing anything but what I saw before.He says see that "o" on that valve-look at where it is on the other cylinders!It had been installed. at previous shop in wrong hole,and has a different angle and cut.Mystery solved at how much $$$.Will update again when truck is back together-Thanks for the input,Darman

 

[Ozymandias]

Oh Boy, what a mess..