just looking for some ideas, i thought i knew more about my fuel system than i actually do... just cant solve this problem!

truck is 01 ZR2 Sonoma, 6.0L conversion
ok, so truck ran before swap. has been sitting inside for 2 months. fuel pump is stock. tank has at least 25L of fuel. wiring was not modifed. vette filter GF1822, all new lines from the tank to the engine. 2 sec prime builds about 10psi and drops to 0. truck wont start. pinching return line builds +70psi before i shut it off. i changed my filter and i have same problem.

check valve has been tested - ok
lines are impossible to mix up, feed is 3/8". return is 5/16".

anybody have any ideas what else it might be? ...

 

 

I've seen this problem before. We used a filter from Checkers. For some reason the 5/16" is the feed and 3/8" is the return. Sounds crazy but it worked.

 

thats what ive heard, but if you look at the pic youll notice the size difference between the feed on the pump (F) and the return (R). same on the filter, they are marked.

i think guys are having that size problem with the flex fuel S10 filter.

another thing i should add is my other truck has the EXACT same setup and it works great. never had a problem with it

 

When you say you changed your filter, are you referring to the trucks stock filter, or the CF1822 ? I ran across 2 other threads where brand new vette regulators were DOA. Most that have gone with the WIX/NAPA-Gold version have had no issue.

 

original truck filter was removed, replaced with a new vette filter. that didnt work, so i replaced the vette filter with another new one

 

Interesting problem..... So did the new filter solve your problem????

 

no, it does the same thing with both filters

 

Both filters were the Same brand? Do you have fittings/hoses to run fuel lines directly to the rail? (where I presume youre checking pressure at the rail).

Also, what PCM are you running? Have you tuned out the fuel pressure, fuel level, etc. checks if not using them?

 

If the lines are hooked up correctly, then it would appear that it would have to be the filter/regulator.

 

sorry to thread jack here . but with that 6.0 swap can u use stock 4.3 pump or is there something better i can use?

 

Are the filter lines hooked up correctly? The pressure line is the one on the outside part and the return is the one straight in the middle to the filter

 

one filter is QAP and the other is GKI i think..
yes, my filter is in stock location (mid frame rail) and runs directly to the rail where im checking pressure

pcm is out of a 2002 sierra with everything for the fuel tuned. injector size and tank capacity. there is no fuel pressure sensor.


thats what im thinking, but two new filters are bad??

depends what your power requiredments are. the stock pump and lines are generally capable up to the 430hp mark

this is the majority of what everyone is asking me. the lines are hooked up the way you describe. it is exactly how it is labeled on the filter. it is exactly how my other truck is hooked up. im very certain that this is not the problem

i have put air through the filter and it cannot work using the small line as the feed. the pressure closes off the bypass valve


thanks for the input so far guys, im going to try another filter as soon as i get a chance... just started a new job, so i dont get much time to go parts running

 

Curious if you every resolved this issue? My swap is running now and getting 58-62 psi from the NAPA vette regulator/filter.

 

What's the napa part number?

 

fil 3737

 

i apologize for not following up on this thread... yes, my problem has been solved. first, i placed a restrictor in the return line. basically, a plug with a small hole drilled in it, which worked.

then i bought the same filter from napa, removed the restrictor and everything works as it should