Engine/Transmission (1998.5 - 2002) VP Air lock??

[BWagnaar]

So for about a year now my truck will randomly not start after it has been started a few times during the day (running around town from place to place), it will usually start fine if its been sitting over night or all day while at work.

I'll have this problem for a couple of weeks or what not, then it will go away and be ok for a few months. It would do this when it was stock, no chip, just intake and exhaust. I've recently got the truck running with a new transmission, Jammer 3 tips, TST, and Superchip... . Now its starting to not start again...



When it doesn't want to start it will just turn over and not catch, as if there is air in the line. It throws no codes, checked with 3-key on method, Superchip, and Snap-On scanner. Blipping the key to get the LP running to "prime its self" doesn't work, no matter how many times you do it. The first time i posted this some one said maybe the lines are leaking. I've checked all the line, and there has never been a leak. I thought it was my fuel pressure line causing problem so i took that off for about 7 months and it would still do it.



What seems to work every time is jumping up, cracking #1,3,4 lines and crank ing it over for a second and then let it prime its self while i close the lines, that will usually do it. I spent almost an hour to day in a parking lot trying to prime the FREAKING LINES, and could barely get any fuel to come out of the 1 and 3 lines. I thought i wasn't primed up to the VP so i took my FP line off and blipped the key... bad idea, there was plenty of fuel there and i got the FP line back on while it was priming.

I would try to start it every which way, no throttle, half throttle, full throttle, rolling on the throttle.



My main question (after all this bs) is HOW IS AIR GETTING IN THE VP??

Is there anything else i can do beside just replacing the VP, fuel pressure is good.



WHAT IS LEFT??!!!!:{

 

[paulb]

Is the fuel tank being vented properly? Check the vent at the top of the tank and make sure it doesn't still have a light blue plastic cap over it. For testing purposes you can leave the fuel cap slightly loose, and see if that helps. You said the fuel pressure is good... What is it?



Paul

 

[csutton7]

I'd replace your overflow valve---chris

 

[BWagnaar]

When it first posted this problem, someone mentioned a valve in the return line that stops the fuel from draining out of the VP. I bought the freaking $50 banjo bolt and replaced it... didn't help. I can't remember if that was called the overflow valve, if its not could you explain what/where it is?
Before i added the Holley Blue pump last night, i would have about 14-15psi at idle. With the TST and Superchip i could bring the pressure down to 2-3psi. This was done only 2 or 3 times and for maybe a second or two, I knew that was way to low and stayed out of the throttle (which was really difficult!) Now (when i can get the truck started) the psi is over 15 at idle and can barely bring it down to 7-8psi at WOT.

I've triple triple checked the fuel lines and still no leaks or seaps. I have also noticed that the lines are a lot harder to bleed lately, i can be bleeding the system for an 30-45 minutes (beating the starter to death) and there will barely be any fuel coming out of the lines. I have over 15psi at the inlet to the VP cause that is where my FP line is hooked up to.

Thanks for the help.

 

[csutton7]

injector problem---change these out to see if that's your problem

orings on crossovers---replace them

overflow valve---cross this off the list since you've changed it

air leaks---but it seems you've double checked this

vp going south--weird it's not throwing codes, but maybe just maybe something crazy it going on---



I'd do the first two and see if that helps----chris

 

[BWagnaar]

Is there a valve in the return line on the back of the head? I'll try the o-rings.

 

[BWagnaar]

Well the problem has pretty much gotten worse. After the truck has started and i shut it off it wont start back up again no matter how long the truck had been running. Yesterday it left me in Concord in 100 degree weather crawling all over the truck sweating like a pig for about an hour and half, i was about 2. 5 hours from home.

I have been noticing that the injector lines haven't been bleeding as easy. At first i could get all of them to bleed with in 5-10 minutes, but now it take me about 30 minutes to get one (#3) to bleed and and then the rest wont bleed. While i'm cranking the motor it will squirt fuel out but as the LP runs nothing else will come out. If i crack the supply line to the VP it bleeds instantly like there wasn't really any air there.

I tried taking the gas cap off it stilll didn't want to start, i just had to bleed the pig for about an hour and finally got # 3,4,5 bleed and then held the throttle down about half way to get it started.

I notice too that once i was getting some of the lines to bleed, that my FP gauge would return to zero very slowly as if the system was sealed and holding pressure. All the other time once the LP turns off the pressure drops to zero quickly. So i thought there might be a vacuum on the fuel system and when i shut the truck off it would suck fuel out of the supply line back to the tank. So when i got home i popped the fuel tank cap off and shut truck off, the FP dropped as fast as it could. I tried to restart it and it would start.



I have a feeling that all i can do is pull the VP out and have it tested. BUT, i'm a little ****** off becuase it has done this before randomly and then it goes away for a while. Its just doing it REALLY bad this time. I would hate to pull the VP and than find out nothing it wrong with it. BUT I WORK ON MY TRUCK MORE THAN I DRIVE IT.....



I'm starting to loose my patience with this truck

 

[csutton7]

no valve at the back of the head--only at the VP---I'm pretty sure your VP needs replacing---chris