• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

How to change square fuel filter 1991 6.2

orrum

orrum

New Member
Messages
1,294
Reaction score
2
Location
Orrum North Carolina
Got my fuel pressure gauge installed and towed my horse trailer today and the fuel pressure dropped below 4 lbs, Hope changing the fuel filter will help. I found a thread for the 6.5 round one but I have the old square one on the back of the motor. Saw some posts where people have leakage problems after changing and I want to avoid that. I want to change the oil filter while I am at it with the oversized 2 qt one and also grease it. Newbie here to diesels but am really enjoying my truck so far. Thanks in advance for your info.
 
Well seeing as how you have an electric LP with a primer switch it's easy. Just open the snaps, unplug the old one, plug in the new one. Snap it back down and then open the bleeder screw on the top rh corner and run your LP until fuel comes out nice and strong. Close it then fire it up foot to the floor and then keep the rpms up for about 30 seconds or so(Not WOT) and should be good to go. The older trucks with Mech LPs were a royal PIA. Had to connect a hand pump to that bleeder.
 
Hey thanks Ace I will do it Monday. Why does folks have problems with leaking after they change them, I have seen several articles on the inter net about u should take them out ond put a round one in. That sounds simple enough other than the fact that with a spin on u could fill it with diesel and not have to worry about bleeding. Cant wait to get all my filters and Walbro on and see how the wvo blend goes.
 
Dunno. I have had many trucks with the square one and none of them leaked although I think Dave might have had a bad one IIRC. I was planning to use the later model one off a 6.5 on my 86 6.2 gotta figure out how wire it to existing wiring.
My only issue with them is if you have a mceh LP they are a PIA to purge. There is no real way to pre fill them so a hand pump is required.
 
Hey on a 6.5 u gotta do the feed the beast thing to open the filter outlet up, so what about my square one is it like that or is it opened up better from the factory?
 
Hey Ace I finally changed my square filter today! What a difference in the fuel presure, it went from 2psi with my new Walbro to 8psi at idle! It was stopped up. Thanks for the how to do it partner, it went smoth!
 
Catching heck from my wife because I cannot get my '89 6.2 Suburban primed and back on the road. I had just finished doing a service (oil,filter,lube etc), so I was just about done and I changed the "square filter of doom". Lost fuel system prime and have not gotten it back since. I need to get my burb back on the road. New to the forum, need help getting it going again. In my great ignorance of trying to prime the system and getting it going again I started it for too long of a cycle and bang!!! There went a starter bolt giving up the ghost inside of the housing. Now I have to drill and tap the bolt hole. It is more of a time consuming issue more than anything. I just want my Detroit humming again!!! Help guys!!!
 
The information appears to be in post #2, I'm not familiar with these myself.
 
Dont crank it very long, then let it sit a long time to cool b4 cranking again. Ace says to drain it out of the bleeder valve. In other words just loosen the screw with the x in it on top of the FFM and crank the engine some to get the air out. U will be able to tell when the air is gone cause u will get a clear stream of diesel out the port. If after a short cranking spell the diesel still has air stop cranking and go do something for a while so it can cool then come back and crank again. I put two new filters plus a bunch of new line on mine and still got it bled easy. I think u r cranking to start and not to bleed. I cranked mine about 10 seconds at a time, I felt better safe that way.
 
He has a mech LP. BTW to answer your question about "Feed The Beast" It is unnecessary and a waste of effort on a DB2 Equipped truck. It will still be restricted at the inlet. The Factory Fuel supply system is more than adequate to supply even a turned up DB2.
 
Tahoe was a 95 with a DS4 elec pump. That is the only truck I ever did it too. Unless you are running a tune it's not really necessary IMHO.
 
You must log in or register to reply here.
Back
Top