Has anyone experienced air problems with a Pre CAT fuel filter installed under the air box? My dad is experiencing issues with his. Originally he installed the Pre CAT on the frame rail like I did and all was good. However, when he installed a larger fuel tank he had to relocate the filter.


When he first installed the larger fuel tank he left the CAT filter off the truck and it ran good. Later he reinstalled the CAT filter in the pre OEM position and mounted it under the air box. Ever since doing this he has no start or start/stall conditions when the truck sits for more than a day.http://www.dieselplace.com/forum/smileys/Ermm.gif When this happens he just opens the bleeder, primes the system and within a few pumps of the primer fuel sprays out of the bleeder; then he closes the bleeder screw and the truck starts right up. He has gone through all of the connections looking for any leaks but has not found any.


Recently he relocated one of the fuel hoses as it was routed high up along the air intake tube. This has not helped the air/stall problem.


I have been searching this excellent forum and the best I can tell he might have better luck with the filter mounted in the second alternator position or back by the rear wheel, similiar to the Nictane position. Other than that it seems a lift pump is the only other thing that has proved to cure the air/no start problem? From all the searching and reading here I believe the issue is air that naturally exists in the fuel is collecting in the filter or the fuel hose(s).


I'd prefer to avoid a lift pump as his Duramax is stock other than a drop-in K&N air filter.


Any experience with this, suggestions, opinions?


Thank you

lttlfeller,


I think there was another person here who had a CAT filter POST oem filter and had no start problems.


The issue was an O-ring was needed on the neck where the filter screws on.


Also--there is a Baldwin equivalent high efficency filter that has an O-ring incorporated in the design--so I read.


Do a search for no start conditions and you might find the thread.

lttlfeller,


I have had a CAT750 post OEM on the 2nd alternator mount for 12,000 miles with no problems. http://www.dieselplace.com/forum/smileys/Clap.gif

make sure you have some sort of sealant on the lines where they screw into the filter head...that was the cause of my air problems...

lttlfeller, Your dad's issues are exactly what I had for a time. I had my CAT under the airbox for a short period of time and had air issues immediately, and it continued until I moved it to the AC bracket position. It worked flawlessly there (over a year) until last spring, shortly after a filter change, when the air issue started again. I installed an o-ring on the threaded pin and problem solved.


All the help I got on this site was the reason I have been so successful with my filtration. I suggest that your dad put an o-ring on the threaded pin (I dont remember the exact size) that will seal dirty side from the clean side of the filter. If after the o-ring is installed and if your dad continues to have air, move the unit to the AC bracket. Much easier to access for filter replacement, and easier to show off. http://www.dieselplace.com/forum/smileys/Cool.gif


My CAT is post OEM.

I would put it up next to the A/C compressor. It is a lot easier to work on. Later! Frankhttp://www.dieselplace.com/forum/uploads/A37_112_1276.JPG

You will have problems with any filter mounted under the air box unless you add a lift pump. Good old mother nature will see to it. When mounting the filter low it allows the High pressure pump to drain back into the filter after shutting the vehicle off. The lift pump will keep the filter full of fuel preventing this problem. The other soloution would be to add a one way valve into the outlet line after the low mounted filter to prevent drainback. By moving the filter to higher than the High Pressure pump location it doesn't allow drainback which also solves the problem.

There is a check valve in the OEM head to prevent drain back. It is hard to get all the air out with that location. I did not like that location three years ago and still don't. Later! Frank

Damm Frank that engine is spotless. What is your secret? http://www.dieselplace.com/forum/smileys/Big Smile.gif

I would like to lie with a BS story but I can't. I install this setup to make a few bucks. The photo is of an 04 I did a few months ago. Later! Frank http://www.dieselplace.com/forum/smileys/Big Smile.gif

I am a new guy. Hope can discuss more about the topic with you.http://www.dieselplace.com/forum/smileys/Cool.gif

A winning combination is hard to beat, huh, Frank! Any luck finding a Cat or Fleetguard head?

Frank, where can I get the mount & filter kit you show in your picture, and what kind of price tag?

I appreciate all of the replies. Thank you for the information. Last night my dad changed both filters and added an O-ring to the threaded neck on the CAT filter base.


We figured that was the easiest next step. I'll let you know if this corrects the start/stall problem.


Thanks

lttlfeller, keep us posted. If the o-ring fixes your issue with the filter in its present position, you may well open up a can of worms worth fishing with !!!!! http://www.dieselplace.com/forum/smileys/Confused.gif


oh my, what is gonna happen now?

Will do Mitchagain. So far it is lookin' good. After two days the truck started with no stall. Now, he has been letting it sit since Saturday and will be driving it on Thursday and all weekend, on a trip. So, I should have confirmation early next week... fingers are crossed.

Well, no luck. He started the truck last Wednesday and did not make it out of the driveway. Looks like he will have to move the filter to the second alternator position.


It will probably be a while until he moves the filter but I'll try to remember to keep this thread updated.


Thanks!