Builds 4508 - Ultra4 Racetruck Build (1 Viewer)

[snivilous]

So my progress over the past 2 weeks:

I ended up making a third lower windshield section, the second one I made didn't fit like I wanted, but this new one fit perfectly and sits nice and low.

I then made a pair of these seat mounts. The seat sliders bolt onto them, and they're welded to the frame and then braced to the side of the frame. It gives me a super strong tie in location for the seats and gets the seats mounted lower than possible with the body, so my head has plenty of clearance from the cage.

The point of all this was so I could start doing the cage pieces near the seats/doors (I gutted the front two doors too).

I then made the horizontal bars that go between the seat and door. I placed them a couple inches below the door.

I then braced the horizontals with a diagonal from the front frame stand off to the door horizontal. Due to the doors I couldn't run a brace from the bottom of the A pillar to the B pillar hoop, so I had to run a shorter brace that goes about 3/4 of the way to the B pillar hoop. I plan to run another diagonal brace from the frame near the B pillar hoop up to where the current diagonal brace for the door tube is. This will make the door area structure super stiff and also stiffen up the A/B pillar hoops and the A pillar frame stand offs.

Today I made new a new V brace in the front, and then braced the A pillar hoop (windshield top tube) to the bottom of the B pillar hoop where the X brace and vertical column behind the seats is. This will drastically stiffen the A pillar hoop, and in the event the windshield section gets crushed makes a direct load path to the back of the cage behind the seats instead of being purely moment resisting (torque resisting) via the A pillar tubes. I assume most people do this, though I haven't really seen it before though admit I've never been around buggies/caged rigs much. I am debating running a tube from the A pillar/roof intersection down to the door horizontal and then bracing down to the A/B hoop or frame, since I'm concerned that there's no stiff load path from the front roof corners down to the frame right now, like I said, it's all a moment resisting setup which isn't ideal especially since the A pillars have a bend in them so they are insanely weak and pre-buckled already.

Here is the cage currently:

I then also put in a horizontal tube in the rear connecting the two roof rail tubes at the tail gate. I have started welding sections of the cage, and am getting near time to start working on the rear of the cage.

I want to make sliders, and am thinking of just taking a hole saw and going through the body for the frame stand offs. The body hangs so far below the top of the frame, and the sliders would get in the way of the exhaust on the passenger side unless I cut the body and move the slider mounts higher. I could also tie into the A pillar frame stand off so then the slider could utilize the strength of the cage if the front hits a rock.

I'm also debating on what to do with spare tires, I'm thinking of having just one and not sure if I want to make an enclosure with the cage to hold it or what... Additionally I have the fuel system planned out so in the next few weeks will get it plumbed up and then the truck will be able to drive again and hopefully go on some mild wheeling trips.

 

[snivilous]

If anyone wants to help with a little diagnosis:

I ordered a bunch of fuel stuff from Summit. Running all AN fuel lines from the fuel cell to the engine (I just ordered the main/pressure line stuff for now). I have a course filter (100 micron) then the fuel pump then a small filter (40 micron) and then a long hose that plugs into the fitting at the driver's wheel well that's the main pressure line.

I ordered this: FiTech EFI Frame Mount Fuel Pumps 40101 fuel pump which is rated at 90psi and 255lph (67gph). I had read that the fuel pressure regulator was set to 45ish psi, I couldn't find a definitive required pressure at the engine so assumed 45psi--thus going with 90psi to be safe, and figured the pressure regulator would just bleed off the excess fuel to the return line.

I did a mock up today, and the engine fired right up! And it ran alright, I turned the truck off to clean some stuff out since i wanted to take it down the road a little since I was excited it was finally running. Go back and the engine just chokes and sputters when I crank it and catches every now and then but dies. It's acting like, if I didn't know better, that it's starving from fuel. When I first fired it up, I had the return line just pouring into a little gas tank. A little bit of gas came out, but not a lot which I thought was weird. Now there's no gas at all coming out of the return line. I have fuel pressure in everything I touched, at least up to the main pressure fitting.

The fuel pump "claims" it's rated to 600hp, which not that that means much but I would think it would be moving more than enough fuel for the engine. Any thoughts? It might just be the ECU is confused, so I'm gonna let it sit for awhile. Obviously running an engine for a bit, then turning it off and back on, after it's been sitting for awhile can trick it a little. I also obviously would have a CEL (though there's no dash) since I yanked the rear O2 sensor when I cut everything from the cats back.

Am I missing something obvious? The truck ran for a few minutes before I turned it off, and now is lucky to catch.

 

[scottryana]

I would guess that there isn't a drainback valve? So the line empties back into the tank. Do you have a manual fuel pump switch? Most people who have a setup like this will have a way to flip the pump on and watch the fuel pressure in the rail and won't kick on the ignition until the fuel pressure reaches 43psi.

If anyone wants to help with a little diagnosis:

I ordered a bunch of fuel stuff from Summit. Running all AN fuel lines from the fuel cell to the engine (I just ordered the main/pressure line stuff for now). I have a course filter (100 micron) then the fuel pump then a small filter (40 micron) and then a long hose that plugs into the fitting at the driver's wheel well that's the main pressure line.

I ordered this: FiTech EFI Frame Mount Fuel Pumps 40101 fuel pump which is rated at 90psi and 255lph (67gph). I had read that the fuel pressure regulator was set to 45ish psi, I couldn't find a definitive required pressure at the engine so assumed 45psi--thus going with 90psi to be safe, and figured the pressure regulator would just bleed off the excess fuel to the return line.

I did a mock up today, and the engine fired right up! And it ran alright, I turned the truck off to clean some stuff out since i wanted to take it down the road a little since I was excited it was finally running. Go back and the engine just chokes and sputters when I crank it and catches every now and then but dies. It's acting like, if I didn't know better, that it's starving from fuel. When I first fired it up, I had the return line just pouring into a little gas tank. A little bit of gas came out, but not a lot which I thought was weird. Now there's no gas at all coming out of the return line. I have fuel pressure in everything I touched, at least up to the main pressure fitting.

The fuel pump "claims" it's rated to 600hp, which not that that means much but I would think it would be moving more than enough fuel for the engine. Any thoughts? It might just be the ECU is confused, so I'm gonna let it sit for awhile. Obviously running an engine for a bit, then turning it off and back on, after it's been sitting for awhile can trick it a little. I also obviously would have a CEL (though there's no dash) since I yanked the rear O2 sensor when I cut everything from the cats back.

Am I missing something obvious? The truck ran for a few minutes before I turned it off, and now is lucky to catch.

 

[snivilous]

I would guess that there isn't a drainback valve? So the line empties back into the tank. Do you have a manual fuel pump switch? Most people who have a setup like this will have a way to flip the pump on and watch the fuel pressure in the rail and won't kick on the ignition until the fuel pressure reaches 43psi.

So I have the return line off the engine just pouring into a Jerry can since I don't have enough hose to go to the tank, though there's nothing flowing out of it regardless.

The fuel pump is on a manual switch yes, I don't have a pressure sensor on the fuel rail but know I have some pressure at least in the hose, so there's definitely fuel flowing to the engine but that's all I can say.

 

[snivilous]

Got it! I know nothing about fuel systems so read a little. The fact there's no fuel coming out the return means the regulator isnt actuating to relieve pressure. This means not enough fuel pressure! So assuming the pump worked fine since it was brand new I worked through what would clog it. Turned out when I dunk the hose in a Jerry can it runs great! So for some reason the fuel cell pickup is barely picking up any fuel. I'll put more gas in, it's a 32gal tank and has like 5gal in it so maybe that's all it is. Otherwise not sure or maybe I'm using the tank wrong or something... But all the lines and filters and pump works right! Now to make that fuel cell do the same!

 

[snivilous]

IT'S ALIVE!!!

I got the correct length hose today so the return line actually went to the tank, and then screwed around with the fuel cell and found out the pickup hose inside of the fuel cell was kinked and was my issue the entire time. Once that was done I took it for a spin! It's nice when the forest service is behind your property

Obviously there's still TONS to do, but even though I just putted around it was a blast and a good motivator to finally be able to take it down a trail for the first time! I've been talking to some of my buddies and I think I will have shop space when I go back to school in September, so I can keep working on the truck and actually have a realistic chance of being able to race KOH in January.

And the final news, is one of my buddies in Utah picked up a set of 80 series axles yesterday! They're both geared to 5.29, front has a spartan and the rear has a spool. Rear is obviously trussed and also has disc conversion brackets. Apparently they (or one of the axles) was regeared by @ILean which is kinda cool, I didn't even realize you're in Utah (I go to school at USU). And all of that for $1000! I will probably just swap 3rds and the disc hardware over, I don't think I'll have enough time to relink the truck--so I'll just have a full set of spares and a set of axles ready to be cut up once I eventually 3 link the front. Pretty cool!!!

 

[scottryana]

Looks great!

 

[I Lean]

Congrats on driving it!

Kinda funny you bought those axles, I noticed they were for sale on a local forum.

Besides the third members, I don't think they'll be much good as spares for you though. The birfs are different, the rear housing and shafts are different, you already have rear discs as well as larger front discs (and calipers?)...

 

[snivilous]

Congrats on driving it!

Kinda funny you bought those axles, I noticed they were for sale on a local forum.

Besides the third members, I don't think they'll be much good as spares for you though. The birfs are different, the rear housing and shafts are different, you already have rear discs as well as larger front discs (and calipers?)...

Oh wow, I didn't realize there were that many (or any) differences in 80 series axles. Hell, I know so little about 80s and haven't paid attention I didn't even know my rear axle already had discs! Good thing the 3rds will work, otherwise I would've completely wasted $1000!

 

[scottryana]

The early 80's had:

- Different length birfields to the C clip
- Rear drums
- and the housings are different between elocked and non-elocked.

Oh wow, I didn't realize there were that many (or any) differences in 80 series axles. Hell, I know so little about 80s and haven't paid attention I didn't even know my rear axle already had discs! Good thing the 3rds will work, otherwise I would've completely wasted $1000!

 

[I Lean]

The early 80's had:

- Different length birfields to the C clip
- Rear drums
- and the housings are different between elocked and non-elocked.

....and the early, drum-brake axles were semi-float C-clip, rather the full float.

 

[snivilous]

No real progress on the 80 in the past two weeks. I was out of town for a week, and then last week just worked on other projects that I need to finish before heading to school at the end of August. Yesterday I finally took the 80 out for its first "real" trail, though in typical Colorado fashion it was nice weather when we left the house and not too far down the trail it was pouring rain; consequently I didn't get any decent pictures...

My girlfriend and I ended up hiding under a tarp to try and stay somewhat dry and still got soaked. I think in the future I'll make removable plexiglass windshield/windows to make it comfortable in bad weather.

Still fun to finally take the truck out and see how it trailered. The 80 did fine for the most part considering it's essentially stock at this point (not like we did anything hard though). I did have some weird issues with the fuel pump where it didn't seem to be sucking fuel or building pressure, but when I would stop and get out and move the pump (it's just losely zip tied in the back) it would seem to work again. Obviously since everything is roughly thrown together, that alone might be the issue, but kind of weird the engine would start dying and I would just touch the pump and it would be fine again. I had one instance where the engine died, and once it died I heard the pump come under load and build pressure and the truck fired right up again. Not sure if I'm doing something wrong with the fuel system (like maybe there's supposed to be back pressure from the return line, or the fuel pressure regulator is diverting too much pressure to the return line since the pump is too big?). And I filled the cell halfway full before the trip so it definitely should be picking up fuel, but maybe the pickup line is all jacked up again...

I also welded up a quick exhaust to the truck to make it not so deafening which actually turned out really nice, I stole a Magnaflow muffler off a second FJ40 I have and welded that to the stock exhaust where it's cut off at the firewall and then bent some tube and welded some extra 2" DOM to the muffler so it dumps in front of the rear tire. I'll have an exhaust shop make a good exhaust in the future, but I'll probably keep my custom exhaust on until the end so I don't bother anyone/deafen myself every time I turn it on.

So near term plans: I live for Utah in 3.5 weeks for school and will be towing the 80 out and have shop space setup to drop the truck off and work on when I get there. The cage is actually a lot further along than I thought and there's not much more big stuff to ad. Once the main cage is fully welded (so minus gussets and tabs, etc) I plan to build a dash and then I will start seriously doing electrical work, gauges, fuel system routing, fuel cell/spare tire/tool mounting, firewall, etc. I probably won't start on suspension until I get to Utah. I ordered 4x4labs front and rear bumper kits two weeks ago, so hopefully those show up before I head to school, and I plan on making sliders myself.

 

[snivilous]

--If you don't want to read all this, I could use some help: I am having engine sputtering issues when going up a steep hill. Fuel pump, pickup, fuel pressure, filters, all seem to check out okay. It will go up the hill slow just fine, but anything over 2mph is either too bumpy or too much load (in low range) and starts to sputter. On level/bumpy ground the truck runs totally fine with no sputtering, even going from a full stop to floored and doesn't miss a beat. What would make the engine sputter from being at a slope? The fuel cell is half full and the pickup is at the back of the tank so there should be plenty of fuel. Ideas?

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I messed with the fuel system a little yesterday to try and troubleshoot the issues I was having. I adjusted the fuel pickup to make sure it wasn't kinked and was on the bottom of the tank, mounted the fuel pump better, and then added some new AN fittings to properly route the return and vent lines. I then went for a quick drive.

The truck seemed to run totally fine at first, but when I got to this steep hill on this loop I run I started having issues again. Nowhere near as bad as the other day, but the engine would start sputtering if it started bumping around/going faster up the hill it seemed like. If I let off the gas and went slow it would do fine, but anything over 2mph was either too bumpy or too much engine load (in low range) and the engine would start sputtering.

At the top of the hill I looked the fuel delivery system over but everything looked and sounded fine. It almost seemed like it wasn't picking up fuel, but I had the fuel pickup at the back of the cell and is half full of gas so it should be picking up totally fine.

On mostly level ground the truck runs fine, it seems to only have issues going up hill.

When I got home I pulled everything apart again and moved through it testing it. The fuel pickup hose is fine, my two filters (100 micron before pump, 40 micron after pump) are both fine, and there's fuel pressure at the banjo bolt going into the stock filter (not sure how much though). I thought maybe the stock filter is clogged, so started pulling that until I gave up since it was late and the stock filter is a total pain in the ass to get to. There is constant fuel pressure at the return line (when parked), which leads me to think the stock filter isn't the issue so not sure if I should continue to pull it....

When I get home today I'm gonna pull the plugs and see if that reveals anything, I'm thinking maybe the fuel pressure is too high or the regulator is screwed up. I have a 90psi fuel pump and as far as I can find the stock regulator is supposed to be at 45psi, I haven't found anything about having too high of pressure since the regulator should control it though... But pulling the plugs and seeing if they're fouled should shed some light. I've read lots of plausible issues, but nothing consistent. The fact the engine runs fine everywhere else throughout the rev/gearing range but not at a steep angle is puzzling me... I have a tentative trip to Moab on Sunday so trying to get the truck to a good shape to do some easy trails, but right now I wouldn't want to do any trails since the thing is sketchy if it'll even run when tipped backwards much....

Any advice is appreciated! Hopefully I'll come to some conclusions later today.

 

[artech]

Could this be from the ECU wires chafing on the edge of the glove box bracket? Seems like this would get worse on an incline. Only other thing I can think of would be related to crap and debris in the fuel tank, but you drained it already, right? Any nastiness come out then? Shouldn't be the fuel filter since it would run the same regardless of angle. I'd try checking the air intake hose, maybe it cracked and the movement of the engine under load is causing it to leak air? Sorry can't think of more right off...

 

[ppc]

Does your tank have baffles? Even though your tank is half full the type of conditions you have indicated the fuel is sloshing around and you could easily have pump cavitation.

 

[snivilous]

TL;DR: I'm slowly figuring out the fuel supply issue, and it seems to be something blocking fuel flow before the pump.

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I spent half of yesterday troubleshooting more. I pulled the stock filter, and luckily the stock filter inlet banjo bolt is the same as the fuel rail inlet banjo bolt so I was able to bypass the stock filter and the kinked fuel line going from it to the fuel rail, so now it's essentially all my stuff running straight to the fuel rail. Though unsurprisingly that didn't fix the issue, but at least I got rid of some clutter and the stock filter that's useless now and perishable.

I seem to have narrowed the issue down to being fuel pickup. The truck still runs totally fine until I hit the steep hill, and then 30 seconds into climbing it the truck starts sputtering. From that point forward, regardless if I'm parked on flat ground or at an angle, the truck will not rev up without sputtering. I pulled the return line to see fuel flow back to the tank, and found that when I hit the gas the return line flow stops--this is a 90psi pump and the injectors need ~45psi, meaning I should have quite a bit of flow regardless how open the injectors are.

Additionally, I can hear the pump come under load at idle but when I hit the gas the pump revs out the same time the return line fuel flow stops, this indicates that somewhere from the fuel cell to the pump there is something preventing fuel flow. If the issue was after the pump then the pump would be under load continuously, but since it can be heard that it's sucking air the issue is before the pump.

I played with a couple variations of the pickup in the tank and even talked to Jaz customer service who was pretty useless. Long story short, in one test I did after the truck was sputtering, I took the fuel line that plugs into the top of the cell and the return line and stuck them in a 5 gallon jerry can and the truck ran totally fine. Went down the hill and back up with no sputtering. This was ONE quick test, but seems to indicate the same as previous assumptions that something about the fuel cell is preventing pickup.

Another thing to note, is the Jaz pickup hose has this swivel fitting on the top, so the hose inside the tank can rotate relative to the fitting until it gets torqued down and then it can't rotate. I'm suspicious that that fitting isn't sealing... a guy on the 4600 page on facebook also suggested that he had issues where the pickup hose would collapse under vacuum. My plan for later today is pull the fuel lines and pre-pump filter and make sure the lines aren't clogged (I already checked the filter and it's fine), and then hook up the Jerry can again and do the full test loop I'm running and make sure the Jerry can method wasn't just a temporary fix but works for the whole 15 minute loop. If that is verified, I then plan to remove one of the intermediary sections of fuel hose that connects the pre-pump filter and the pump, bolt the filter to the pump directly, and use that short section of fuel hose and stick that inside the fuel cell. That will eliminate all of Jaz's pickup pieces with the exception of the fuel pass through fitting, which is just an AN fitting and looks fine so I trust it.

@ppc I would agree it seems like a fuel sloshing issue, but I have foam for internal baffling and the tank is 90% full and the issue even happens after I've come to a stop and just let the truck sit idling.

 

[snivilous]

I figured the issue out! It was the fuel pump all along! Yesterday I went for a test drive with the jerry can to see if it was anything to do with the cell, and on my test loop the sputtering happened again. But I was able to get a repeatable procedure down to stop it: I would turn the pump off so the engine would run dry and die, crank it for 5 seconds, turn the pump on and then there would be no sputtering. My theory is that the fuel pressure was way too high and overwhelming the regulator, and by doing the crank method it would relieve the fuel pressure built up and run fine until the pressure overwhelmed the regulator again. Last night I jerry rigged another jerry can and the stock pump which I still luckily had, and didn't have any issues!

This morning I called all over and no one sold an inline pump that put out 38-45psi (what the fuel rail is supposed to read, so I assume that's what a safe max pressure is) so I ended up rigging up the stock pump inside the fuel cell. Luckily I have enough AN fittings laying around, so I was able to stick the pump (along with its little pickup sock) in the back corner and have the pickup sock kind of under the foam and then a hose going up a nipple attached to the fuel cell pass through and back through all my fuel lines. And it works great! I had to drill a hole in the filler cap (which I don't plan to use) and put a grommet in and sealed it up, but otherwise the fuel cell itself isn't modified and the stock pump obviously works!

So that was a huge relief so I can still do my Moab trip. After that I swapped the 35s from my FJ40 over and added some Spidertrax spacers I ordered the other day since the 15" beadlocks don't fit over the calipers, and the thing looks AWESOME! Finally looks like an offroad truck having real rubber on it.

And the last thing I did (yesterday) was added a second brace from the roll cage down to the steering column, and fully welded that along with the previous little mount so the steering column is super stiff which made a big difference over the temporary tack job I had before.

I leave for Moab on Sunday, and before then I plan to rig up some 3 point seat belts I have laying around, rip out a lot of the remaining wiring, pull the sway bars, and finish some welds on the cage and maybe add some material for the fuel cell and spare tire in the back. I'm super happy though! The truck looks good and for the first time it's running without issue!

 

[2fpower]

Looking forward to MOAB pics.

 

[Tools R Us]

TL;DR: I'm slowly figuring out the fuel supply issue, and it seems to be something blocking fuel flow before the pump.

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As you are finding out, FI pumps don't suck for s***! There cant be any restriction on the inlet side and should have large diameter inlet hose like 5/8", or best, none, right in the tank, where they only have to push. Likely what you are experiencing; when there is big fuel demand, the intake is too restrictive, some fuel flashes to vapor, pump cavitates, cant pump vapor. When the load is lowered it recovers. This is way common with conversions and can kill otherwise good pumps

 

[snivilous]

Well Moab turned out great as always! My buddy @srqfabrications flew in on Saturday, we prepped the truck all morning Sunday and rolled out and finally came home on Wednesday.

We decided to just keep the fenders off since they were rubbing bad with the 35s on and no bump stops. My buddy prettied up the wiring a LOT, plus I welded up all the cage joints, pulled the rear window, added 3 point seat belts, and a bunch of other little things before the trip. We didn't find anyone to go with us which sucked, but as we were getting food and water in Moab we came out to a guy in a 3rd gen 4Runner checking the truck out and ended up running Hell's Revenge with him. Although I have been testing the truck quite a bit lately, it was good to run a trail with someone else to make sure if anything issues came up right away we wouldn't be alone.

[/IMG]

After Hell's Revenge the guy with the 4Runner left to head back to Grand Junction, so for the rest of Monday and Tuesday we wheeled alone and actually didn't see a single rig either. I had texted my girlfriend where we were heading and a timeline of when we should be back in case something happened, plus of course we had a full tool set, 7 gallons of emergency water, plus drinks, snacks, first aid kit, fire starting supplies, space blankets, 5 gallons of extra gas, etc. I was uncomfortable going alone, but we weren't gonna do anything hard and people knew where we should be and we had enough supplies to survive long enough for a search party, plus were only a few miles from Moab/the Tundra at a time.

Monday afternoon we did Poison Spider Mesa.

At the top of the Mesa we decided to run all the way north on Golden Spike and then to Gold Bar Rim and finally to the highway. I had heard this was a multi-hour trip that's usually an all day run, but the map said that Poison Spider Mesa loop was roughly the same length as running all the way north to the highway so we figured it couldn't be that bad and would mean we wouldn't be re-running a trail in reverse. By the end we had the pedal down to make sure we wouldn't be going down the highway in the dark, and ended up getting back to our hotel around 8:30pm.

The only issue we ended up having was the fuel return line slid off (it wasn't hose clamped down or anything), but luckily it happened right as a got to an obstacle and my buddy hopped out and it slid off right then so we only lost a few drops of fuel before shutting the pump down.

That wrapped up Monday.