C-7 CAT air in Fuel

[Scott B]

Had a wierd one with this Engine.05 C-7 ACCERT would only miss under load only and not all the time. You would have to have it to the govenor also to make it do this.Passed all the Injector and ICP tests.So Pulled the fuel return off put it in a five gallon bucket and Had someone mash it down to the govenor and it poured Air bubbles out of the return line.Checked the Torque on all of the Inj holdown bolts and got 10" lbs more till it clicked off on 4 out of 6.CAT said pull them all.Every cup had some combustion residue in it.Two of them were badly trashed with carbon and you could see where the gases were blowing up around the Inj body and up past the bottom o-ring into the fuel well. They do Not use a copper washer on there tips to seal to the bottom of the cup.They use a small Viton composite O-ring that I am guessing actually burns to seal type thing.It seems to work well.I have pulled them before on other C-7's and found just a slight remnant of it in the cup, But the cups were Basically clean and No evidence of combustion gas entering up through.All this mess I found was from Improper installation/torque proceedure.I dont think any of these Injectors were every seated right to begin with before they torqued them at the Factory.

[HeuiTim]

Just remember CAT requires ALL hold down bolts be discarded and replaced on ALL electronic engines.

[HeuiTim]

Just remember CAT requires ALL hold down bolts be discarded and replaced on ALL electronic engines. Also CAT has a new set of seals for these injectors, The metal top ring is no longer used, replaced by a plastic split ring. The metal ring destroys the head as well as the rubber ring.

Truck Engine News

Media Number -SEBD6792-00 Publication Date -01/07/2006 Date Updated -01/07/2006

 

 

i02573822

 

 

A New Backup Ring for the Fuel Injector Group is Now Available {1251, 1254, 1290}

SMCS - 1251; 1254; 1290

 

 

Engine:

 

C7 (S/N: FML1-UP; KAL1-UP; FMM1-UP; SAP1-UP; WAX1-UP)

 

C7 TRUCK ENGINE (S/N: NPH1-UP)

 

C7 TRUCK/BUS (S/N: YPG1-UP)

 

C9 (S/N: MTB1-UP; SRB1-UP; 9DG1-UP; C9S1-UP)

 

C9 ON-HIGHWAY (S/N: ETK1-UP)

 

A new 293-0730 Backup Ring has been released for use in all C7 and C9 On-highway Engines. The new backup ring improves the sealing of the fuel injectors. The new backup ring must be used in conjunction with the O-rings that are listed below. Refer to Illustration 1 for the locations of the O-rings and the backup rings.

 

If oil is leaking past the injectors and/or if a 164-11 diagnostic code is logged, replace all of the O-rings and backup rings.

 

If one O-ring needs to be replaced, Caterpillar recommends replacing all O-rings and all of the backup rings on all of the injectors.

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View Image

 

 

 

 

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Illustration 1 g01290015

 

(1) 238-8091 Fuel Injector Gp

 

(2) 293-0730 Backup Ring

 

(3) 148-2903 O-Ring Seal

 

(4) 149-5240 Backup Ring

 

(5) 109-3207 O-Ring Seal

[Scott B]

Yep I get the tk engine news sent to me at Home.(Which CAT is considering doing away with since it it also available On-Line) but usually dont read all of them as I should.We had the Old style O-rings in stock with steel back ups and luckily I checked before Installing and Had to order the New style backups.Installing New Holddown bolts is pretty much Burnt into my Brain from doing them for so long.But sometimes if you rushing things well everyone knows what can happen there.

[HeuiTim]

rushing around forgetting to lube the o-rings. I just did a C9 and cleaned, resealed and installed the injectors, had them all torqued, and the thought crossed my mind, I never lubed them up. I had applied oil to the seals when i put them on the injectors, It runs good so nothing was cut but i got lucky. The updated seals are one of cats better ideas. Every c7/c9 injector i pulled always has the flat rubber ring cut by the steel,

[Keith Browning]

Ford has recommended dipping the injectors in oil before installing which is something I have always done and continue to do...well, I have progressed to a Poland Spring sport bottle with the snap top. I still get the injectors and o-rings completely coated but the squirt bottle makes less mess and I don't have that open plastic container hanging around the bench anymore. For what it's worth, I also use that squirt bottle for lubing fuel and oil filter cap o-rings.

 

Almost forgot my question: Does CAT recommend dipping the injectors?

[DwayneGorniak]

I keep an old friction modifier bottle full of oil. Also one with trans fluid for tranny or t-case applications. They work great and no mess left around.

[eastendpowerstroke]

I got one of those red catsup squirt bottles for trans work, but for injectors I just use a rinsed out coffee cup full of the bulk oil from the pumper to dip the injectors in then dump it and toss it out when I'm done because if it is on my bench I'll spill it every time..

[Scott B]

Ford has recommended dipping the injectors in oil before installing which is something I have always done and continue to do...well, I have progressed to a Poland Spring sport bottle with the snap top. I still get the injectors and o-rings completely coated but the squirt bottle makes less mess and I don't have that open plastic container hanging around the bench anymore. For what it's worth, I also use that squirt bottle for lubing fuel and oil filter cap o-rings.

 

Almost forgot my question: Does CAT recommend dipping the injectors?

CAT just instructs lubing the O-rings and really doesnt specifie dipping it in Oil that I am aware of.But they revamp so many proceedures and such it could be that way now.International has recently posted a SFN about how they want the HEUI injector stored while out of the Head.They want you basically submerge it in oil.They state this will prolong Injector life.I imagine from dry firing when you have it back together,Just a small amount of Oil getting into the fuel Inlet will cushion the Needle inside the tip when it fires if the fuel isnt in there yet..They always want you to prime the system anyways and state that Dry firing will damage the Needle and Crack the tip.On the DT's there is a primer pump for fuel so it is possible.Plus I always leave the cam sensor disconnected while cranking till I see Oil pressure on the dash gauge.On the VT's there is No primer pump,But I do the same leaving the Cam sensor unhooked till I see Oil pressure on the dash.

[HeuiTim]

Like Scott says, CAT keeps changing their mind, now, for a while now CAT says c7 and C9 hold down bolts are re-useable. I could not believe they changed their minds again, but they do only get 10ft/lbs so it does make sense. Humans forget steel does not have feelings. We see repeated shade tree failures on HD's which are stretched pretty good upon install. I think the indies are replacing injectors and reusing the bolts. We end up replacing all 6 and send them down the road. The customer interview usually starts with "I just had #5 injector replaced in soandso"