Author Topic: seals on injector harness  (Read 1026 times)

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Offline sawmillman

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seals on injector harness
« on: December 19, 2019, 02:01:18 PM »
Hello all, I just joined this forum yesterday. I have been reading on here for several months now and have learned a lot. I decided  to  adjust the valves on my 2004 cat c7 today, and while in there I decided to pull the connectors on the injectors to see if they had oil in them. They do. There don't appear to be anything on the connectors that would prevent the oil from going in. I haven't had any problems or engine codes since I've owned this coach. ( 2 years and 15000 miles) Should I go ahead and install the o rings?  thanks Joe

Offline David.e.atherton

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Re: seals on injector harness
« Reply #1 on: December 19, 2019, 07:21:50 PM »
sawmillman, welcome to the Diesel Club. Before we get started on your request I would
recommended few suggestions . Running the overhead on Caterpillar electronic engine
there is a technical information that you need to understand before attempting valve train
adjustment on Caterpillar service information system called SIS. The way it reads, the
Checking of valve lash and adjustment as needed. What this means Intake and exhaust
valves have a .003 plus and .003 minus with electronic injectors and if a .006 feeler gauge
slides in place no adjustment is needed. We have several engine failures because a valve
had dropped inside engine. Second removing valve cover and checking electrical connections
on injectors. What you are looking for, wiggle each connector and is not tight remove electrical
connector you will see oil inside injector and electrical connector. Cleaning both injector
female socket and male electrical wire harness end . Install 12 mm o-ring over male wire
harness electrical end and make sure o-ring fits tight, install into injector female socket and
Snap over wire hold down clip. After holding snap over clip in place check for movement
should be tight. Ask Dave, Dave Atherton Retired Cat Mechanic

Offline sawmillman

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Re: seals on injector harness
« Reply #2 on: December 20, 2019, 11:23:17 AM »
Thanks for the reply and help. Got her back together today.

Offline sawmillman

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Re: seals on injector harness
« Reply #3 on: December 21, 2019, 09:35:48 AM »
Hello Dave, Just a follow up question about the boots on the injector harness. Why do you suppose that my 2004 C7 KAL53629 had no boots on any of the connectors. It appears it left the factory that way. Also I haven't ever had an issue even though all the connectors had oil in it and it has caused some people big problems. I did have a stumble, miss awhile back that cleared up quickly, with no codes and hasn't occurred again, I cant say that caused it. I looked up the harness number you mentioned earlier in this thread and the plug looks just like mine minus the rubber boot.

Offline David.e.atherton

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Re: seals on injector harness
« Reply #4 on: December 21, 2019, 10:22:18 PM »
sawmillman, the answer to your question you missed the meaning of previous post
on this forum. The reason for this post there has been problems in this area where over time these connections ( connection from wiring harness to injector will loosen up and allow
engine oil inside connection and changing value of electrical power to injection. ) there
has been two Caterpillar updates on this problem , one in 2003 and last update in 2010.
The update on injector wire harness connection, replacement of 8 inches wire and new male tip
for each injector as update kit. Note: last update 2010. Going to your findings that there
Is nothing in between present connection and you indicated your engine runs fine that
Is great at present. Let’s go deeper into motorhomes that have injector electrical connection
shut down an injector and engine top speed 40 mph and no power and shut down along
road. Answer call tow truck and take motorhome to unknown shop of which in all cases
Service shop shop will replace problem injector or injectors. The cleaning up of wire harness
connection and injector socket brake cleaner and install a 0-ring on the plastic male end,
than reinstall back into injector makes a tight connection that will keep engine oil out of the
electrical connection that operates the injector. Yes this repair can be easy preformed by
You the motorhome owner for around $ 10.00 and about 2 hours or work. There has been several motorhome repairs made with this reseal o-ring and several years since several of
these repairs been preformed. Last , why does this happen ? With the oil return from injector
to oil pan the extreme hot oil floods the electrical connection and over time the plastic male
end into injector socket will loosen up enough to allow entry off engine oil.  Ask Dave,
Dave Atherton Retired Cat Mechanic

Offline sawmillman

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Re: seals on injector harness
« Reply #5 on: December 22, 2019, 05:37:32 AM »
Ok. Thank you.

Offline gbarney

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Re: seals on injector harness
« Reply #6 on: January 11, 2020, 12:28:20 PM »
I installed the O rings on my 3126 injector connectors several years ago per Dave's instructions. Thank you Dave for saving me from the a visit to a diesel shop. The O rings worked well.

However, I subsequently found a source for the original style packing and have now installed these on all six of my 3126 injectors. For anyone else interested in using the original style packings, here is the source I used:

Shumatt Technology Ltd @ www.shumatt.com

Go to the "For Caterpillar" tab from the home page, then to the "Repair Kit" tab.

Scroll down to about the fifth item, "Caterpillar Injector Plug for Diesel for CAT C7 C9 injector", SKU # Y1C1CATHUEIC7C9.

This plug may look different than yours, but I believe the business end that inserts into the injector, and the packing, are all the same for 3126s, C-7s, & C-9s. I paid $1.00 each for mine, plus $25.00 shipping which is a bit steep since they are shipping from China.

If you only need the packings, just take the packing off the plugs and use them.

I used PayPal as that seemed easiest of their pay options, and the plugs arrived in about a week.

Offline David.e.atherton

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Re: seals on injector harness
« Reply #7 on: January 12, 2020, 03:43:10 AM »
Gbarney,  the little seals were from removed from Caterpillar injector electrical connection on injectors because of problems. Reason being the hot engine oil would break down these little
Bellow type seals in the Caterpillar 3126  A , B and E series engines. The Caterpillar C-7 and
C-9 did not have the bellow type seals. In 2003 the bellow seals were removed in this area and
Update made on the injector electrical connection than again in 2010 and that was the last update made. The update kit first and still available today consist of a injector wiring harness
for inside of valve cover with same ends that you have at present w/out any seal. Than
Available next you can buy just the male end that plugs into injector with a 8 inch pig tail
You remove old end and install new end. Yes the bellow seal will work but that is the reason
they were removed from service. Ask Dave, Dave Atherton Retired Cat mechanic