Engine/Transmission (1998.5 - 2002) little help come on guys

[ryecreek]

got nearly zero help here https://www.turbodieselregister.com/forums/showthread.php?t=156189

so i had some time to fiddle so here we go... maybe some of you will chime in

disconnected the pusher, gauge said 0psi told mama kill it

new pump was put on..... SAME result

ok i figure i got 2 that were toast no such luck grab the last on i had in the shop (new lift pump) SAME deal

then i let the mtr run a min. or so to see what happens i hit the purge on the test gauge to crack for air as i did on all the pumps and i see air as i did on the previous two this time it was in a bottle of diesel and a few sec. later(10-15) IT STARTED TO SIPHON FEUL OUT OF THE JUG

any answers to this issue

 

[ASimpson]

do you hear the pushers runningg at all when you hook them up? maybe an electrical problem thats what id be checking if 3 new pumps didnt work. the vp44 will suck fuelclear from the tank so its no suprise it would draw it from a bottle closer to it. if your pusher comes on when the key is turned on check it with a tester at the plug while someone cycles the key.

 

[J.Keith]

I'm having a little trouble understanding exactly what your problem is.

So once it starts it runs fine though right?

How long does it take when cranking before the engine starts?

You say you have 23 psi at the VP with the engine running. Correct?

And you've unpluged or disabled power completly to your pusher pump and it had no noticeable effect?



Sorry if I seem to be backtracking on you but I'm trying to understand the problem. If I missed anything please point it out.



Also do you have any codes?



Jeremy

 

[monkeyman]

If you are pushing 23lb at VP44 it won't last long . I destroyed my first one with that kind of pressure. It does not need that much

 

[ToolManTimTaylor]

got nearly zero help here https://www.turbodieselregister.com/forums/showthread.php?t=156189

:

Great way to start off a thread lookin' for help



Anyhow Too high an inlet pressure during startup will cause hard starts. Now How is the pump wired? (I. E getting it's signal from the oem L. P Harness Or Just Ignition on?) The L. P harness pulses the pump while cranking. If from the ignition, your pumps are firein' away full pressure during startup (Not fun for the VP)



There is a vent on the top of the Tank Module that you may be able to see from up inside the fenderwell. There has been a known issue of them plugging fairly easy. Simple way to tell is after a decent drive stop and imediatly pop the Fuel cap off. If you hear a "Sucking" sound like air rushing in ... there is your answer. Do a search on "plugged vent"



Also you said the truck wasn't driven much due to the problem. How not much is not much? You could have a case of the creepy crawly's in the tank (Algae)



The Bypass may be hanging open in the VP (Factory set to 14. 8PsI if I remember) and anything constantly above that Can weaken the spring and hang it open or cause it to open sooner. If memory serves it's the fitting just forward of the schrader port?? (Someone chime in on that)



Lastly that is a sign of VP failure on a sad note (Hard starts) But all is not lost. Being it's a 2000 you will need to have codes pulled and not just cycle the key. The pressure bleed down you experience is normal so take that off your mind at least.

 

[ryecreek]

Pusher and factory lp connected last night at idle made 24psi(pusher wired off lp hot with a relay)

while idling i pulled the fuse to the pusher psi went to 0psi so i shut it down immidatly

that is when i started install my spare lift pumps BTW they where all new.

every one produced the same result. let me back up alittle too.

not idling but cycling the lp with the key i see 8psi if i purge my test gauge so apparently the lp is doing somthing.

on the last lp i installed i ran it 30 seconds or so 0psi can fell the pump running try the purge on the test gauge to see for air (purge hose ran into anempty rotella jug) i see alittle air (probably normal after a lp change) the 10-15sec later the bubbles start going the other way. hope that is alittle more helpful

ToolManTimTaylor

Not driven much to me is once or twice a week

on the tank deal i have never noticed the tank under vacuum should it be or not

I have replaced as well as tested the overflow/bypass and your correct on the location 19mm wrench fits it

had a budddy scan it a weekago his snap on scan tool only brought 1 code somthing to the extent of lp overpressure if i remember we thought nothing of it as we were looking for abs codes if i can ill scan it again tomorrow if i have time to see him

and sorry about the opener





oh another question

have a flat bed i have good access to the top of the tank. can i pressure or vacuum test through the supply and return (plug 1 test the other) without damage to any thing?

 

[CFAR]

Do you have a bypass on the pusher pump?

If not how would the lp get fuel by the pusher?

If you do have a bypass, it might not be getting enough by the pusher and thats why its syphoning out of the bottle.

 

[ryecreek]

no bypass

i'm gonna try that now

i need a black keyboard because this white one sure getting greasy

 

[ryecreek]

bypassed pusher and wouldn't ya know 14psi. at idle from oem lift pump thank you CFAR

still hope to hear somthing about pressure/ vacuum testing still think i may be getting air

time to build a pusher bypass

later