You need to bleed the air at the isolator, not the gauge. I believe you'll have to pull the isolator off and push the diaphragm back towards the fuel side (have to use a pencil or something from the gauge side).

Hope this helps.

 

I pushed the diaphram down and filled it with coolant before I connected any lines. So I believe it something else. Thanks though

 

Yes but bleeding it at the gauge will allow that diaphragm to move.

 

Have you considered the possibility that the problem may be your pump and not your gauge. When I had problems with my gauge (isolating fluid had leaked out), the gauge was slow to respond. It would climb to around 10psi and stay there, idle or wot. I don't think that restarting the truck would some how self correct a mechanical gauge problem. I would redo the gauge plumbing. disconnect all fittings and re-bleed everything. I didn't find my problem till I did this. even though I had lost all of the isolating fluid the plastic line still had a green tint and looked like fluid was in it. If the problem is still there it maybe time to replace the pump.

 

If you have the factory lift pump, it may be on the way out. Spend the money and get decent aftermarket unit. You're gonna need it anyway. No sense in wastin the VP.

As for the isolator, a little air on the gauge side won't hurt a thing. Be sure to do as BLG23 said and make sure the diaphram is pushed in towards the fuel side. If it's not, the fuel has nothing to push on and wont transfer that pressure thru the diaphram and into glycol then on up to the gauge. After you re-connect everything, THEN bleed the fuel side only.

 

Ok guys. I appreciate the advice. When I installed the issolator I pushed the diaphram down, so I know its not up. After I did that I filled th issolator with coolant. Keeping it up right the whole time I then connected the gauge hose loosley. I filled the suplied syringe with coolant and proceded to fill the hose. When coolant started to come out of the fitting at the issolator I had my helper (my girlfriend) tighten the fitting while I was still applying pressure with the syringe. There was about an inch and a half of air at the end of the line and I connected it to the gauge. I then connected the fuel line to the issolator. I tried to cycle the lift pump by turning the key to 'on' but couldn't get any air out of it. So we started the truck and fuel and air started to escape the bleeder valve on the isolator. The truck then died starved for fuel. Turned the key on and off a few times to cycle the pump and again no air or fuel escaped the bleeder valve. So we cranked it over. Took about five attempts but it finially started back up. This time more fuel and air came out of the bleeder valve. I kept it open untill it seemed like a a steedy stream of fuel was escaping.

The gauge doesn't seem erratic, it works smoothly and doesn't jump. It just dies at stop signs. if its dead and I'm going down the road I can depress the clutch and turn the key off and back on as quick as I can (fast enough the motor is still turning and I don't have to use the starter to start it). And the gauge will instantly jump to around 10 psi. Its like I'm reseting the lift pump and its kicking on. Is there any way to test this theroy? I don't have any codes.

 

opps double post

 

Sounds to me like it's could possibly be the lift pump then. Just like Sublime said, no sense wasting a good vp, the lift pumps are junk, I don't care what kind of pressure it's sending. So my 2 cents, order an aftermarket pump.

 

grrr....i was afraid of this. its been running fine, or seems to anyway. why would the lift pump act like this then? i know i need an AirDog. i just dont have the money for that right now. im saving up for it but its been a slow ars summer around here for mowing yards...

the lift pump runs fine for the first few minutes then cuts down to about 2-3psi or less. especially when i stop. and then with the turn of the key i can 'reset' it. i just dont understand why its like that... just looking for a little education on the subject. the gauge seems to be working like it should. i could probably take a video of it for ya'll if ya'd like to see it. shouldnt there be codes if the lift pump is failing?

 

The problem with this situation is that the only way to tell if your LP is working correctly is to hook it up to a gauge. I would double check (even though you said it's installed correctly) your gauge hookup and go through the bleeding procedure again b/c it doesn't hurt to rule that out.

There won't be any codes when the LP is failing but there MAY be when the VP is failing. Have you checked to see if you have any codes present or not?

 

Ok so because its was so much fun the first time I redid the whole thing and rebleed everything. I'm still having the exact same results. I'm leaning towards the lp...

 

Did you or did you not ask for ideas/help? We've all given you possible solutions and re-installing the gauge was one of them. If you think it's the LP, then replace the LP. There is no way to tell if your LP is going bad unless you hook a gauge up to it. If your gauge is working correctly, then your LP is obv. not keeping a consistent flow to the VP and looks to be going bad. There won't be any codes for a LP failure. When you start to see codes, it's too late.

 

im not sure what warrented the snyd remark, but i appreciated the help and took the advise. after replumbing the gauge i agreed with you on the lift pump. :confused013: probably gonna order one tomorrow even though my bank account hadnt planed on it.

 

Not really a snide remark was just re-emphasizing my point, good luck, hope this eleviates your problems.

 

one thing that helps is go down to your local harbor freight and pick yourself up a fuel injection pump tester. its like 12-25 bucks depending on sales and such and made by U.S. General. use it to double check it. mine is reading low (like 3 psi low) so im ditching the isolator idea and just running the fuel into the cab with an on/off valve just in case.