BLT's Butter Yellow '84 4x4 ongoing love/hate relationship

[bigleagueteague]

Hey, y'all. Figured it's time to start my own thread. I keep coming back here to find tips and tricks and have posted in various threads a few times since I got the thing July '21.

 

I bought the truck in Portland, OR from an 18-year-old that had done some stupid stuff to the harness to wire in LEDs and focused on tinting windows rather than getting the thing running right. Should have done more due diligence/held off until I had a little money to buy a better condition 720, but I bought the thing for probably too much and started my love/hate relationship (mostly love) and learning experience. I had done basic fluid changes, replaced brake pads and rotors, etc. before getting the 720, but it has had me learning A LOT. I'm a sucker for the seamed bed and butter yellow paint.

 

The body is straight and on the surface, it didn't look like a total rust bucket. Bed seams were a little rusty but looked salvageable. A peek in the front wheel wells revealed a little rust near the floor pan body mounts, but nothing I thought was over the top. It seemed to run pretty well, the transfer case worked well, the trans felt pretty good, blah blah.

 

Once I made it back to Boise, I found/did:

*Ripped up the carpet and found I'd bought a rust bucket – I have a major floor pan project on my list of to-dos. There are some concerning rust holes below the driver's side corner of the windshield and a couple of small holes in the bed (and who knows how many spots I haven't found yet)

*The motor (unknown miles, not the original – kid killed that one) has pretty good compression and lots of leaks – most of these have been fixed, seems like there might be an oil pan/rear main leak.

*The trans showed its age when temps got cold and the synchros stopped working (temporary solution here).

*Most fluids have been replaced.

*Fixed a nasty Weber adapter vacuum leak.

*Replaced exhaust manifold gaskets to fix an exhaust leak that fried the valve cover gasket

*Replaced plugs - NGK...

*Got timing where it should be ~3deg. (maybe not perfect for the Weber)

*Replaced driver-side window rummer/felt

*Replaced the busted coolant overflow tank

*rebuilt the headlight section of the wiring harness

*replaced some corroded fuse box connections

 

Lots more to do.

 

Here she is:

 

 

 

 

[bottomwatcher]

Looks good!

[datzenmike]

Worth fixin'.

[bigleagueteague]

OK, so here's my current problem for y'all. I'm doing some frankensteining, but I feel someone with more experience than me might have some helpful thoughts on where I should look next.

 

Weber + emissions stuff. Starts fine when cold, dies when warmed up, won’t start again until cold.

 

I’ve been trying to get the 720 to point that might pass a visual emissions inspection. I bought a “rebuilt” Hitachi off a guy on Facebook – showed up with busted choke linkage and a torn dust boot. Needless to say I was pretty bummed to have wasted good money. One day I might yank parts from my other Hitachi to replace the busted parts on the rebuilt one, but that’s a job I’m not excited about right now.

 

So, I gave up on that idea and tried to put together an emissions system that “works” with the 32/36 Weber so that I can try to play stupid with an emissions tester. I followed the setup Thomas Perkins used with his Weber, hooking up the:

EGR & BPT

TVV

Spark control valves

3 hose vapor canister (“fuel tank”, “dist vc”, and “purge”)

 

 I can confirm the choke closes when starting cold. I am also running an idle cut solenoid. I replaced all the vacuum hoses, but haven’t double checked for leaks yet. I replaced spark plugs. The EGR diaphragm seems to move freely but I'm not sure if it’s getting stuck open when warm (doesn't seem like it should take so long to close before it starts again). Haven’t tested the TVV valve.

 

Here’s what happens: Temp gauge gets up to about mid-gauge and then the thing dies when revs drop - coming to a stop and idling. Once up to temp and under load the motor you can feel it hesitate a little along with an intermittent loss of power – signs that the thing’s going to die at the next stop light. Once it’s dead, there’s no getting it going again until it’s cold (~1hr sitting).

 

The first time this happened, the TVV valve wasn’t hooked up, the vapor canister wasn't hooked up. It has happened again with the TVV valve hooked up and the vapor canister.

 

The thing ran pretty well (needed a tune) before I messed around. I can’t get the motor warmed up and running long enough to tune the Weber according to the best lean idle instructions. Pretty sure my timing is around 3 deg.

 

Any thoughts on what might be going on? Thanks y’all

[bottomwatcher]

I have had this happen with both fuel and spark issue. The first remedy is free. With a small wire brush clean all of your connections starting at the battery then coils, grounds to engine,body everywhere you see a screw or bolt holding a wire disconnect and clean. Chance of fixing this? Low but you want to start with clean circuits. Heat can do funny things. Next is your heat tube attached to the exhaust manifold? I am guessing Portland is pretty cold and carb icing could be an issue. Seems counterintuitive but you may not be waiting for the engine to cool but the carb to warm before it restarts.

[bigleagueteague]

Thanks. I'll check connections.

 

The truck's in Boise these days, and yes it's relatively cold 20s-30s right now. What puzzles me is that this was not an issue before the EGR w/ tube & manifold (off a junker) got hooked up. Carb icing has never been a problem. There's no heat tube attached to the ex manifold b/c I'm running a 32/36 weber.

[Stoffregen Motorsports]

Shifting sucks when it's cold? Try different trans fluid. I use Redline MT-90, but there are others that work well too.

[Thomas Perkins]

Awesome looking truck...Show pictures of the engine and we can see what is really going on...Seem's someone has took stuff off.Ain't no telling what they have done.My timing has never ever been a issue,never adjusted it,in the same spot for it's life.Same distributor,same oil pump.The reason it is good,cause I have never touched it.Just cause you get a FSM book means you can fix it.I have mine serviced by a Nissan pro.I am a pro at replacing junky Honda small engine carbs,lol.One thing that happened long ago.When I got my 720,it had a 30 amp fuse in the second slot of the fuse block,I put the right one in it and it would not stay running. I took it to two different places and they couldn't figure it out and it is still in there and that was back in 96.So It won't run with the right fuse and nothing has happened.So all ya'll that says it will do damage,when in 50 more years.That is the way it is in my Nissan.Here is my fuse block set up.Your heard that saying,if it ain't broke don't f with it.He did have a alarm and a tow wiring connected to it.I got rid of the alarm and his rigged up stuff in the fuse box.I do have a complete new heating and air that has been rewired but that has nothing to do with 30 amp fuse.The 20 amp fuse connector is really melted.it use to pop out when Iwas using the A.C.I had to reach down pull cover off and push fuse in.Now it is not a Issue cause jack has rewired it and I no long have the blower motor,gone with all the other junky Nissan heating and air stuff.Good luck finding a new heater core.

Edited March 4, 2023 by Thomas Perkins

[bottomwatcher]

1 hour ago, bigleagueteague said:

Thanks. I'll check connections.

 

The truck's in Boise these days, and yes it's relatively cold 20s-30s right now. What puzzles me is that this was not an issue before the EGR w/ tube & manifold (off a junker) got hooked up. Carb icing has never been a problem. There's no heat tube attached to the ex manifold b/c I'm running a 32/36 weber.

Your changing clues. Next time it dies force the choke closed and see if it starts you may have a large vacuum leak causing it to run too lean. Otherwise what else would be changing between hot and cold. Also in cold climates some people have modified the stock air cleaner to fit the Weber. You can run the stove pipe and it might help you sneak through emissions if you have them.

[bigleagueteague]

Changing clues? Portland to Boise? I mentioned the truck lives in Boise now and it's in my location info.

 

First time it died like this I checked to make sure the choke was engaging and found it was. Still wouldn't start.

 

I was wondering whether the EGR may be opening and causing too rich of a mix leading to the no start issue. When I replaced the plugs I found the old ones were pretty carbon coated and ugly. I've thought it smelled pretty rich each time it dies and I'm under the hood trying to figure the problem out.

 

The first time it happened I didn't have a vacuum line between the EGR and the weber vacuum port. I assumed without vacuum from the carb side the EGR wouldn't open. I guess I'm not totally sure how the EGR works, but I'm thinking it might be triggering this problem.

 

I can take a picture of my vacuum lines tomorrow but they pretty much align with Thomas Perkins' lines in this video.

[bigleagueteague]

7 hours ago, Stoffregen Motorsports said:

Shifting sucks when it's cold? Try different trans fluid. I use Redline MT-90, but there are others that work well too.

Yup, shifting went to shit once the temps dropped below 40. Sometimes it would fight me trying to shift from neutral into gear. Tried Redline out and it seemed too heavy for the synchros. I switched to AC Delco synchromesh fluid and it shifts waaaay better now.

[Stoffregen Motorsports]

You tried Redline MT-90? It is made specifically for brass synchros.

 

Other Redline gear oils may be too stiff.