Team NAXJA/Petty Cash Racing stock class KOH XJ build

[Nimrod]

I don't even try.

Ahh. That explains it.

 

[rockclimber]

I don't even try. I live too far away from the freeway for friends.

more like you don't manufacture any parts we want.:laugh3:

 

[cal]

So second guessing fuel problems, I pulled the cell apart a second time.

Checked every Walbro one at a time, they are not damaged, broken, or clogged, and the plungers plunge correctly.

Replaced the 5/8 pickup hose from the pickup assembly to the bulkhead.

Loaded up. Grabbed Dallas @ SFR and Mike Rollins from SoCal chapter and headed out to the desert for a few hours.

On the way out, passed a truck towing a gooseneck and flat towing a sammy doubles behind it. It was all over the road, sketchy.

Stopped for breakfast. Buttermilk pancakes. Eggs scrambled with cheese. Bacon extra crispy. Hash browns. Coffee. More coffee.

I stopped taking photos for a while here. Got out to Stoddard Valley. Unloaded. Fired up, car sounded good.

Drive about 1/4 mile, and the engine started cutting out again. Damn.

But it was different this time. Before, it would cut out, and stay bad until we killed the engine. Today it would cut out and come right back. Veeery interesting.

Back to camp. Threw a fuel pressure gauge on it. Should sit at 45 psi at idle and go to 50 under load. Was sitting at 45 psi at idle and would drop to 30 under load. Hrm.

Opened the fuel cell up and pulled the pickup assembly out. Dallas removed the walbro's and handed it back to me.

Reassembled, fired car up, fuel pump is quieter, fuel pressure is 50 on the throttle. Threw down a quick 10 miles and it was *mean*. The car was back.

Loaded up and went home.

Took the walbro's apart again. They are in good shape. I see nothing wrong.

James blew through the first one and it was fine. Blew through the second and WHOA it was very restricted. Thats strange.

Looked at it again. WTF, there's like an inch of fuel line there I HAVE NEVER EVEN NOTICED.

Pull the pickup off of one end.

URETHRA! WE HAVE FOUND IT!

That short little chunk of fuel line delaminated and was sucking shut. I think the vacuum from that was sucking the 5/8 hose shut before which it was not recovering from, but this one would open back up after a moment.

You can tell that little internal sleeve has been doing this for a while. All four are like this.

Well, I hate that $.80 in fuel line cost us a DNF at Glen Helen, where we very likely could have won. BUT I am super happy to finally know whats wrong. Ironic that the first diagnosis we made was a problem with the pickups, and after inspecting them 3 times, the problem ended up being with the pickups...

I'll pick up $3 in fuel line this week and fix things back up proper.

Those of you who are localish, I'm throwing my 40th birthday party at the hammers at the end of this month. Come on out, drink a beer, take the car for a hot lap, burn some marshmallows around the fire.

I need to throw out a special thanks to Matt/XCM, Mark/Sidewaysstarion, Mike/MJR, James and Dallas for putting a ton of work or support into tearing this car apart end to end (fuel systems, wiring harnesses, physical engine diags) and putting up with me as I manically go over it again and again.

 

[John D]

Glad you finally figured it out, now go win some races.

 

[Boostwerks.com]

Are you using submersible fuel hose? If not that may have been why it failed.

The stuff is expensive, but required.

 

[JohnX]

All that for some hose.

 

[GSequoia]

All that for some hose.

Hose always cause Cal headache.

 

[scottmcneal]

Hose always cause Cal headache.

:gag:

 

[cal]

Are you using submersible fuel hose? If not that may have been why it failed.

The stuff is expensive, but required.

I would assume, but I bought the pickup assembly from Liquid Iron Industries already built.

You can be sure that's what's going back in though.

 

[StinkyFab]

I've found that even "submersible" fuel hose isn't immune from the attacks of fuel. Just resistant. It seems that normal fuel hose has a lining (as seen here) that protects the inside of the rubber hose from the fuel. The submersible line has this same coating on the outside. Problem is fuel can still attack the rubber at the cut ends of the hose. It takes a while, but I've seen plenty of "submersible" hoses fail. The only ones I haven't seen fail are the little 2" long pieces that come with in-tank fuel pumps. Maybe they are treating the ends, maybe using a different hose? Would be nice to know.

Might also be worth the hassle to find 4 of those little stubby pieces they give you with a new pump. The only other safety measure I can think of is making sure that your connector hoses are short enough that the plastic barb on the walbro pickup is right up against the metal barb of the H-frame with no gap inbetween. At least then the hose is only sealing the connection and can't physically block the flow.

 

[cal]

The only other safety measure I can think of is making sure that your connector hoses are short enough that the plastic barb on the walbro pickup is right up against the metal barb of the H-frame with no gap inbetween. At least then the hose is only sealing the connection and can't physically block the flow.

I was thinking that same thing, but I have to mock it up and test fit. The bottom of the fuel cell isn't really flat, but has low points at both ends with rises before the center flat area. I feel like the pickups need to end up on one side or other of that rise, and not slamming into it.

We'll see. Hose is on order.

 

[rockclimber]

is there a way of doing a direct fitting and eliminating hose all together?

 

[Boostwerks.com]

I've found that even "submersible" fuel hose isn't immune from the attacks of fuel. Just resistant. It seems that normal fuel hose has a lining (as seen here) that protects the inside of the rubber hose from the fuel. The submersible line has this same coating on the outside. Problem is fuel can still attack the rubber at the cut ends of the hose. It takes a while, but I've seen plenty of "submersible" hoses fail. The only ones I haven't seen fail are the little 2" long pieces that come with in-tank fuel pumps. Maybe they are treating the ends, maybe using a different hose? Would be nice to know.

Might also be worth the hassle to find 4 of those little stubby pieces they give you with a new pump. The only other safety measure I can think of is making sure that your connector hoses are short enough that the plastic barb on the walbro pickup is right up against the metal barb of the H-frame with no gap inbetween. At least then the hose is only sealing the connection and can't physically block the flow.

If it's a SAE 30R10 rated hose, it shouldn't contain any rubber that will break down to fuel or ethanol.

http://images.oreillyauto.com/parts/img/documents/gat/gatessubmersiblefuellinehose.pdf

A single pickup and swirl pot might be something to look into. Just saying.

 

[PhotoJared]

That hose was so stupid expensive lol.

I got 2 feet for my LS swap and I was shocked when i saw the price. Its needed though so I get it.

 

[StinkyFab]

I bet when you add up all the parts we replaced trying to find this bad hose that shit was in the thousands of dollars per foot.

 

[cal]

And consider the money spent to run 1/3 of a lap at Glen Helen....

stupid hose.

 

[cal]

Just unloaded the camper so I can drag 43 down to StinkyFab and start going through it.

I guess we're doing this again. Who wants to come play in the dirt with us? Several of our core family members will be MIA this KOH (one is driving in another class, another is his codriver, and 2 are having kids).


Stand by for juicy build updates and fun sponsor announcements!

 

[831_xj]

Whoop whoop! party1:

 

[Carol.92124]

I would suspect I will be there ��

 

[StinkyFab]

and 2 are having kids

Technically 3, but one of us will still be there anyways.