I have a 94 690 ELC I purchased from auction that’s had a world of issues. The main one I have right now is air getting in my fuel. I’ve replaced the water separator filter, the line from that to the lift pump, brand new lift pump, and a new glass fuel filter. I’m priming the system exactly like the manual says, the machine will work great for about 20 minutes then fall on its face and die, and will not restart unless I prime the fuel again or let it sit for 10 minutes, and it seems to have air bubbles in the glass filter. I left the fuel tank cap off to see if there was too much vacuum but the breather seems to be working. Any ideas?
Welcome to HEF Mike . Whats the machine serial # ?
It’s 559602, it’s the one with the small lift pump and glass fuel filter box
And thanks Dave! I feel I’ll be here a lot more in the future as my dream is buy fix and sell used equipment! Starting from the bottom so wish me luck!
The water separator filter heads are known to suck air. Does the filter head have a primer pump ? You could temporarily bypass the water separator filter as a test. Lots of fuel at the fuel shut off valve ? Some of the early shut off valves (no serial# listed) had a filter attached in the tank. Water separator filter look like below ?
I will try and bypass this filter temporarily, and yes it does have a primer on top but not like the one you pictured, it’s this one (I have since replaced the filter)
Also Dave, I cannot find the fuel shut off. Nothing on the line between the tank and separator or anywhere else I can find
A machine that old has probably been modified because of past issues
It definitely has, the electric throttle doesn’t work at all, has a manual throttle installed but that’s a task for another day.
559602, That is the large serial # break for the main components installed ie: hydraulic pump and engine. What’s the last six digits of your machine.
You picked a hell of a machine to start learning on! LOL Dave and MG are the best here on Deere so you are in excellent hands.
543693
If bypassing the water separator doesn’t help, run the engine temporarily from a clean 5 gallon fuel pail.
It seems the machine will only die out when I’m working it. I can leave it run and idle and even high idle for hours and it’s fine
To be honest I haven’t left it sit and idle long but it seems to always be fine until I start working it and it’s hot
Ok so I ran the machine again, it worked wonderfully for 20 minutes then same issue without the water separator. I took a photo of the glass filter and you can see the huge amount of bubbles in there, this is what happens as it as it starts spitting and shuddering and dies
Sure sounds like the lift pump is sucking air or just starving for fuel . Change the fuel line from the tank to the fuel lift pump maybe the hose is collapsing. What’s the inside of the fuel tank look like ? Run the engine hard from a 5 gallon fuel pail.
Not to be a dick Mike, but come on ! You know the expression “garbage in garbage out“. Just the facts man !
Pull that filter and clean the seal surfaces on the filter and the base. Air will be intruding from the suction side of the lift pump to the tank somewhere. Look for cracks in any fuel hose also
I’ve replaced the line from separator to lift pump already, I guess I need to try and replace from separator to tank now but no idea how to access the bottom of the fuel tank. Inside tank doesn’t look bad but it’s also half full of fuel so it’s hard to tell, I did notice that when I removed the fuel line from tank to separator so I could bypass the filter, fuel flowed out but not in a steady stream… when I held the line towards the ground fuel came out but was more dripping then streaming, should it be a steady stream coming out?
I bypassed the water separator filter and still have the same issues.
Should be a full stream from the hose. The fitting in fuel tank is a couple of inches off the bottom of the tank floor
Ok I’m looking at the pickup in the tank and tank hose next I guess. No idea how to get this tank out if assume you need to remove the hydraulic tank?
Unless someone has installed some bottom guarding (hopefully removable) , the fuel tank drain and the fuel shut off valve in the bottom of the fuel tank should be readily visible from underneath.
Well Dave, I hooked it up to a 5 gallon jug and it ran perfectly till the jug ran empty.
Id be pulling the fuel tank off to and steam clean it. Likely dirt/algae sitting at the bottom of the tank that when sloshed around enough, causes your restriction to the separator filter. I think these machines had two straps mounted around the tank to remove but don't hold me to that. I checked this one out a bit at the last RB auction out of Debert and looked like it was a forestry/harvester machine at one point in its life so there may have been some aux guarding added for fuel and hydraulic tanks making removal a bit more difficult.
Be happy you didn’t buy it lol, the one that just sold yesterday was even worse then this one. Luckily I know for sure now it’s dirt in bottom of tank. When I went to pull the drain plug…. Nothing came out. Took a good punch from a Screw driver to get her cleared
Gonna replace fuel line anyway and vacuum out the tank the best I can, seems like a c*%#t to get out of the machine
I had the same problem with my CAT 320C and it was at the dealer at the time. They ended up taking the fuel tank out, cleaning it, pressure washed it, etc because the replacement tank was really expensive. So far their work has turned out to work fine. Sounds like you're in a good track. Hope you don't have to take it out and pressure wash it etc
If anything I will pressure wash it inside the machine I’ve been looking at taking it out and it seems I need to remove the hydraulic tank which is definitely not happening after just flushing and replacing that system
What you also want to do before you finnish up cleaning the tank is to blow with good compressed air through the fuel suction line and into the tank. That way you most likely get cleared out any sludge etc sitting in the pickup tube in the tank. Othervise you could end up having the same problem after cleaning.
Yes absolutely going to do this as well. I ended up getting a new fuel line made so just vacuum the tank and clear that pickup and I should be good to go.