Engine flutter on C9

[Vetech63]

I may have already found the issue but I have a couple of questions anyway. The Cat dealer has come out about 3 weeks ago and hooked up to this D6T to check a high idle flutter in the engine. They showed that #1 and #5 injectors were faulty to some degree. The customer bought replacement injectors (all 6) and a new internal injector wire harness that I recommended. I found oil in the injector wiring harness plug which is possibly what was causing the issue but since the machine has 8000 hours and the injectors were already purchased, they have decided to go ahead and replace them all along with the harness.

I have a couple of questions …..
1. Does Cat make a removal tool for these? I am assuming they do as I really don't want to heel bar these out of the head (there really isn't enough room to do this anyway.)
2. Can I evac the fuel from the head galley efficiently enough by unhooking the fuel inlet line at the head and blowing compressed air through it? I don't want a lot of fuel running off into a cylinder when I remove the first one. How would you go about this yourself?

 

[Nige]

R&I injector procedure attached. Small heel bar is the weapon of choice.
A small flat screwdriver works on the electrical connectors.
You could do what you are planning but another way to get any left-over fuel out of the cylinders and be 100% sure nothing is left over is an oil sampling suction gun.

 

[Cmark]

C9s are pretty easy.

• Yes there is a special tool but it's crap. Stick with the heel bar. They shouldn't be in there very tight.
• Yes you can empty the fuel gallery with air. Obviously it needs to be clean and dry air. Also the engine oil gallery. You will still need something to suck the oil out of the cylinders though some will inevitably get in there. I have one of those air-powered solvent spray guns with a piece of copper tube stuck in the end of the suction hose.
• The trim codes will need to be changed using ET.
• Use new bolts for the injectors.

 

[Mobiltech]

I use the equivalent of a mini suck bucket and a varsol spray gun to remove oil and fuel from each cylinder prior to injector install. I have a small air brake plastic line that goes into the cylinder and out to a small jug. I then connect the varsol spray gun to the jug to create a vacuum. The fuel and oil end up in the jug.

 

[Vetech63]

Great info fellas! Thank You.

 

[Vetech63]

What is the injector bolt torque on these?

 

[Cmark]

"Install unit injector (5) in the cylinder head. Position the unit injector into the cylinder head. Use Tooling (C) to install the unit injector into the cylinder head. Install socket head bolt (6) on the exhaust side of the bracket. Tighten the exhaust side of socket head bolt (6) until the bolt is seated. Tighten the inlet side of socket head bolt (6) to a torque of 12 ± 1 N·m (9 ± 1 lb ft)."

 

[Vetech63]

Thanks fellas! Everything worked out great on my end. Cat will be here next week to do the trim values.

 

[Nige]

Uploading the appropriate E-Trim files will only give the final 1/10 of a percent of performance/efficiency. It'll run fine until then, IIRC the Service Manual even says something to that effect.

 

[Mobiltech]

I know you're already past this step but heres pictures of my mini suck bucket.

 

[Vetech63]

Well, the drama continues...…..LOL This engine had the trim files installed and the customer took the machine out for its first job, it ran less than 2 hours then started to misfire. I had CAT come out and hook it up to ET again, #4 injector failure. He said this was pretty common . What say you guys? A high failure rate on these rebuilt injectors?

 

[Nige]

Infant mortality on all types of Reman injectors is a well-known phenomenon. So much so that at various times in the past Cat discontinued the Reman product applicable to various new Part Numbers.
3400E HEUI injectors I think after various attempts they basically gave up on it and only supplied new - and from a quick check on SIS that still seems to be the case.
Of course this might have had a lot to do with cost of overhaul vs new cost considering Reman vs New selling prices, but I was not privy to that side of it.

 

[John C.]

The quality of exchange components went in the crapper years ago with the advent of production line techniques for teardown and assembly and right to work states. Part comes into the line and one person tears the item down and drops all the parts in a bucket and sends it down the line. Next guy cleans the parts and puts them in a different bucket. Next guy decides what to replace based on reusable parts guidelines and order the parts. Last guy assembles the unit based on the parts supplied and not on judgement of fit and finish. It affects everything from fuel injectors, water pumps, turbo chargers, complete engines, starters, alternators, hydraulic pumps, brake calipers and electronic parts. The more complicated the component, the higher the failure rate.
It works the same with dealer mechanics. Field wrench isn't supposed to rebuild anything, only remove and reinstall components. Engine rebuilder in the shop makes few decisions on how to rebuild an engine. He's a monkey that tears the engine down and sends out the main components, block, heads, crank and camshafts, to a machine shop and lets them decide what work needs to be done. It comes back and they reassemble the unit with exchange components, fuel pumps, injectors, water pumps and turbo chargers. It might see a dyno for run in and then get sent out. Twelve hours later when something dies, the field wrench is back out doing the remove and reinstall. I have a client with a D6 on the second "rebuilt" motor in less than 100 hours.
To me it's part of the mind set of removing old iron from production. The cost of exchanges is about the same as rebuilding and has an insurance policy called warranty. Problem is that warranty doesn't cover lost production and rebuild can't currently be financed. Buy a machine and work it through the warranty coverage time, dump it and start over on another new machine. Dump the added cost into the customer's bill.

 

[Nige]

Nail - head - hit

 

[Mark250]

Before you go any further you need to check a few things.
Remove the fuel check valve in the back of the head and disassemble to check for small pieces of metal. lf you have it is a sign that the Huei pump is failing.
The next step involves removing the top of the Huei pump to check for metal around the solenoid
BUT be aware you can not buy the gasket so be very very carefull when you remove it.
In most cases it comes off with gasket intact
if you find metal, throwing injectors at it is a waste of time and money.
The pump needs to be replaced
At the bare minimum the fuel and oil rails in the head need to be flushed out

 

[Nige]

Mark, am I right in thinking that there is a procedure somewhere detailing the cleaning of the fuel and oil rails in the head..?

 

[Mark250]

There is Nige. I will post later or you can if you like. My internet is a bit flakey at the moment

 

[Nige]

No worries. Here it is.
I'll fire you some photos later. We just finished replacing the chassis centre crosstube on an MSY truck. Major surgery.