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New member

Re: HEUI Fuel injectors - fuel in oil

Hi l have engine of Perkins generator with HEUI fuel system which i is mixing fuel in the oil, in two week the oil increases by five litters. It's a new engine which has worked for only one year. I suspected the in injection pump when opened l found one of the six springs broken and l had to replace it but the challenge persisted, l need assistance.
New member

Re: HEUI Fuel injectors - fuel in oil

[ Edited ]

C7 only, not available for the C9 or 3126 as 3 months ago. Cat media letter; 

M0081390 CAT MEDIA LETTER

Part number; 

20R6642 PUMP W/ FIL KIT, 

 

Cat sells a dye you pour into the fuel fil and run for 30 seconds then use a black lite to search for fuel leaking at the injectors under the valve cover.

FUEL ADDITIVE 1U5574

 

Adept Ape has a good youtube video on the C7 filter kit and info on the oil cooler warpage here; https://www.youtube.com/watch?v=MzUojErZRyU

 

My HEUI was leaking oil where it mounts to the front housing surface and found a spec of cat yellow paint stuck to the large o-ring mating surface. Also getting 3 or 4 percent fuel dilution per Polaris Labs oil analysis, going to try the dye method of detection first.

 

Regular Contributor

Re: HEUI Fuel injectors - fuel in oil

Recently Cat have released an inline filter kit to filter the oil into the HEUI Pump. I do not know the micro rating of this filter if it is any finer than the 1R-1807 advanced high efficiency oil filter or is it purely to protect the pump if or when the engine oil filter bypasses. It seems it has nothing to do with protecting the injectors in the event of a HEUI pump failure but more over protect the pump and hopefully prevent pump failures ? But due to pyhsical limitations in the bus installation our customer is unable to fit the DTRB Pumps so pump failures may continue although most of there pump failures are loss of control  and do not generate failure debris.

Very recently cat have upgraded the C7 and C9 injectors to include a fuel screen to protect the injector from debris in the fuel system but nothing on the oil side of things.

New member

Re: HEUI Fuel injectors - fuel in oil

C9 and c7 is common problem to have fuel dilute in oil. The injector not reliable. If the fuel pressure is 90-100psi when on load most probably u have this issue!sooner or later. Not like the old cat 3126 model. The injector big and strong.
Regular Contributor

Re: HEUI Fuel injectors - fuel in oil

Hello Ram11,

 

I am requesting additional information with your troubleshooting suggestions for fuel dilution in C7 and C9 HEUI.

When you pressurise the fuel rail where are you looking for evidence of leakage ? Out of the oil spill port of injector?

We are TEPS,AMD & ISD Second level dealer and have a fleet of 100 C7 WAX powered buses in our area.

I have thought of using black light but access to the top of engine in these buses is through a floor plate inside the bus and HEUI engines throw a tremendous amount of oil when running with valve cover removed which would end up on the hood lining and all over the seats. We have concluded over the years that if the outside seals where to leak then due to the high oil pressures involved we would have oil in fuel first. With black light being somewhat impractacle for our installation we change out all injectors. 

New member

Re: HEUI Fuel injectors - fuel in oil

 
New member

Re: HEUI Fuel injectors - fuel in oil

My Delimber is 320B excavator, keeps making oil... I have replaced the injection pump 3 times, remaned pump from Caterpillar, It is in 70 hours time its making 5 gallons of oil extra, so we have to change the oil continuously. we have changed transfer pump 3 times also. It has 6 new injectors and nobody has any more suggestions. No blow by, excellent power, starts good. We have talked to Cat Tech.. The Garage in Brewer Maine, 3066 Engine Mitzabichi. This is really a puzzle.. Is there anybody out there that has the same problem. Would appreciate some suggestions.

New member

Re: HEUI Fuel injectors - fuel in oil

I just replaced the pump on a 320E the seal had blown. This machine only has 730 hrs on it. 

Contributor

Re: HEUI Fuel injectors - fuel in oil

Dear cat dealer, thanks for the info.....that is the new skill for troubleshooting. I will looking forwards with that.....Tnx a lot...

Cat Dealer
Dealer

Re: HEUI Fuel injectors - fuel in oil

All of the above  are good techniques. Fine out how much fuel is in the oil by SOS. Depending on your engine model....... We've had good luck by pressurizing the cylinder head fuel galley with regulated air after capping the return port. And checking each injector for signs of leakage. In my opinion 30psi would be a good starting point. Another method is to use leak detector dye with a UV light. This method works best in low light condition.

WORK SMART BE SAFE.