Auto trans upshift problem

[TimmyG]

Just noticed this cap is cracked...is it leaking? Don't know. 

[datzenmike]

Probably the fuel bowl vent to a charcoal canister. The canister simply saves the fumes from escaping into the environment

[TimmyG]

1 minute ago, datzenmike said:

Probably the fuel bowl vent to a charcoal canister. The canister simply saves the fumes from escaping into the environment

 

Yeah that's what it's meant for...but it's capped. It looks like it's only passage leads to the bowl. So I guess it wouldn't create a vacuum leak or affect how it runs ?

[datzenmike]

No.

[Charlie69]

12 hours ago, datzenmike said:

Probably the fuel bowl vent to a charcoal canister. The canister simply saves the fumes from escaping into the environment

That is correct Mike put a hose on it and throw that shit cap in the garbage.

 

I have not read the complete thread in a while so I am lost at what your goal is here.  Are you trying to eliminate the emissions on this truck. I will take some pictures of my 86 with the Weber DGEV 32/36.  I have the canister hooked up and the EGR, I run vacuum straight from the Weber to my distributor.  I will get some pictures up soon.

 

 

Edited September 29, 2019 by Charlie69

[datzenmike]

Charlie there is a problem with the up shift which is probably not the transmission but an engine performance problem when subjected to a prolonged acceleration through second. The engine begins acting up and the transmission won't up shift. If you are in third and kick down it will rev up and shift back into third.

 

Plugs look a little lean to me, what do you think?

 

 

Has a Weber that had a bad vacuum leak, now fixed, but continues to (I think) run lean.

[Charlie69]

Looking at the carb inside in the picture above. I would pull the carb disassemble it and soak it for a couple hours in a good carb cleaner rinse well with water and blow out with compressed air.  Before doing this contact Pierce Manifolds and order a major kit and all the adapter gaskets new.  Rebuild & reinstall the carb.  Get the truck up to operating temp and spray with carb or brake cleaner or even WD40 around the base of the carb and all the vacuum connections with the engine running, if the idle speeds up you have a vacuum leak.  The adapters are notorious sources of vacuum leaks.  When I install a Weber I always use red Loctite on the studs to the manifold and the bevel head allen screws to the manifold.  I also if possible use the 1 piece adapters as apposed to the 2 piece adapters.

 

The plugs are to lean.  There is a gasket and a filter under the brass nut on the opposite side of the the fuel line.

Edited September 29, 2019 by Charlie69

[TimmyG]

2 hours ago, Charlie69 said:

Looking at the carb inside in the picture above. I would pull the carb disassemble it and soak it for a couple hours in a good carb cleaner rinse well with water and blow out with compressed air.  Before doing this contact Pierce Manifolds and order a major kit and all the adapter gaskets new.  Rebuild & reinstall the carb.  Get the truck up to operating temp and spray with carb or brake cleaner or even WD40 around the base of the carb and all the vacuum connections with the engine running, if the idle speeds up you have a vacuum leak.  The adapters are notorious sources of vacuum leaks.  When I install a Weber I always use red Loctite on the studs to the manifold and the bevel head allen screws to the manifold.  I also if possible use the 1 piece adapters as apposed to the 2 piece adapters.

 

The plugs are to lean.  There is a gasket and a filter under the brass nut on the opposite side of the the fuel line.

 

Charlie, all good advice. At this point I have changed the vacuum line routing (which were incorrect). I have the ported vacuum from carb split between the distributor and the charcoal canister. The canister is also hooked to manifold vacuum and to the fuel tank (basically stock routing). That's why I wasn't concerned when I saw the cap on the carb vapor vent fitting, until I saw a crack in the rubber...afterwards realizing it won't create a vacuum leak. I'm still learning. 

 

That first try fixed the upshift/engine stumbling at WOT in 2nd issue. Truck ran much better, even noticeably better at idle and part throttle....until the next time I drove it. Problem came back the next day. Stumbling/cutting out in 2nd at WOT. No 3rd upshift until you let out. This only happened if you're coming out of first. WOT from a stop then into 2nd (still WOT) and attempting to make it all the way into 3rd. The drama always starts at or above 5,000 rpm. The only reason I keep doing this WOT drag race is to make sure it's actually fixed. Haha. 

 

I decided to check the carb mounting bolts at some point during all this and they were loose. Tightened them. Made no difference. Sprayed carb cleaner at the base where the adapter plate is while truck was running. Engine bogged so hard it almost died. I ordered the base gaskets for carb/adapter/manifold. 

 

Next I changed the fuel filter per Mike's advice. Old one looked pretty bad. After changing that, fixed the problem again! Truck flew into 3rd at WOT like a bat outta hell. 

 

Next time I drove the truck, same story. Problem came back. Now I had the gaskets sitting on my kitchen table. So I pulled off the carb and found the adapter plate allen bolts so incredibly loose I could barely wiggle the right side of the adapter plate while it was still on the manifold. Not cool. 

 

Cleaned some things and reassembled with new gaskets at base. Used blue locktight on everything. Went for a test drive and the truck ran WORSE than ever. Now stumbling so hard at 5,000 in 2nd that it was cutting out, bucking, and even engine deceleration while still WOT. Let off the gas and it shifted into 3rd then continued to stumble and cut out. That's never happened. 

 

Cleaned the air filter, which was disgusting and should have been done sooner, then double checked everything. Went for another test drive and truck was back to its original severity of problem. Not the increased severity anymore. 

 

It seems very random, but something is going on. That's why I took the carb apart to check the float and learn about jets. The fuel screen in the carb fuel inlet was not gunked up. 

 

My coils are firing same strength at idle when I did a visible arc test. The gap on the plug I removed first was dead on. The wires, cap, and rotor look fine. 

 

I don't know my fuel pressure... I dont think getting a regulator will solve it at this point because if it were too high we wouldn't have this problem. 

 

Maybe today I will buy some fuel hose and measure the amount pumped in 60 sec per Mike's suggestion. I'm starting to think it's a jetting issue now. 

 

Edited September 29, 2019 by TimmyG

[Charlie69]

Did this truck sit for a long time?  Reason I asked is you changed the filter and it ran great then went back to the problem.

 

What fuel pump is in the truck?  Is it the stock one like the picture below.

 

 

 

[TimmyG]

Update. Got truck running noticeably better, but still not 100% trouble free.

 

 

After racking my brain and looking over everything again, I noticed the PCV fitting appeared to be leaking from the threads at the manifold. (Don't mind the rounded edges where my adjustable wrench slipped 🥴.) 

 

Tightened it and got probably a full turn on it, or close to that. I can't confirm it was leaking before, but it probably was. After tightening it I cranked her up and shot some brake clean on it. No leaks. 

 

Idle was nice and smooth once truck warmed up. Test drive netted me better low/mid throttle response taking off normally. The usually cutting out for a moment when giving her too much skinny pedal is gone except for when in 3rd at above 3,000 rpms or so when it does not kick down a gear. I noticed it still cuts out if you floor it in 3rd suddenly with rpms around 3,500. 

 

The dreaded no upshift into 3rd under hard load/drama at 5,000 rpms in 2nd is still present. Not as dramatic, but still there. 

 

Overall, the truck runs better than ever so far in my 4 weeks of owning it. Still thinking it's a lean issue. Jets maybe? What about those plugs...are they ok to run? I planned to change them, but wanted to sort this lean issue out first. 

Edited September 29, 2019 by TimmyG

[TimmyG]

@Charlie69 I don't think the truck Sat for a long time...it might have sat for a few months at most, if at all. The tank is dented in pretty badly at the drain plug. 

 

It appears the have the stock fuel pump. I will get a pic. 

[TimmyG]

Side note, the truck is pretty solid considering it's tolerating all these WOT runs 🤪. It finally showed some weakness. 

 

 

Tightened the hose clamp mega tight (was not loose) and the leak stopped. I think the hose is on it's way out. Probably been on there for a while. 

[TimmyG]

Fuel pump

 

 

[datzenmike]

The bottom of the electric fuel pump twists off to get at the internal fuel filter.

[TimmyG]

1 minute ago, datzenmike said:

The bottom of the electric fuel pump twists off to get at the internal fuel filter.

 

I did not know this. Will it drain all my fuel out? I have almost half a tank. 

[datzenmike]

There will be gas spilled but I don't think it will siphon out. Clip some vice grips on the rubber fuel line just in case. It won't hurt to check this just for peace of mind but lack of flow won't in itself cause a constant lean condition. Lack of flow would show up as constantly like it's running out of gas.

[TimmyG]

The little filter inside the pump.

 

[datzenmike]

See if the one on the parts truck will work. The Nissan number is 16406-29900. I think there was something on a Volkswagon that was similar. There is also a magnet on the bottom cap.

[TimmyG]

2 minutes ago, datzenmike said:

See if the one on the parts truck will work. The Nissan number is 16406-29900. I think there was something on a Volkswagon that was similar. There is also a magnet on the bottom cap.

 

Yes it has the magnet in the bottom cap. This filter looks pretty brown, huh. Thanks for the part #

[TimmyG]

Parts truck has a different pump. No idea if it works. Assuming it does because I was told the truck would start up (no battery), even though the motor was blown. That was 6-8 weeks ago.

 

[datzenmike]

Looks like someone has replaced it. Some later engines (April '85 and on) had EFI and used a high pressure pump. Does the parts truck have one ore two  wingnuts holding the air filter on??? If one then you could use this pump.

[TimmyG]

Parts truck was built late 83

[Charlie69]

Here is a filter on ebay.

 

https://www.ebay.com/itm/GENUINE-NISSAN-1980-1986-720-PICKUP-FUEL-PUMP-FUEL-FILTER-NEW-OEM/162069082657?fits=Model%3A720|Make%3ANissan&epid=1522208899&hash=item25bc11f221:g:axQAAOSw-YBXGVCp

 

Rinse your old filter real well with gasoline. and put it back in if it does not fall apart.  Have you changed the fuel filter above it?  Those look like factory fuel lines it would not hurt to change them also.  Could be a crack and sucking air.    I hope you have anothere inline fuel filter between the pump and the and the carb inlet.  By the way I would start looking for a fuel tank.  That is rust in the fuel pump filter that made it through the inline above it.

 

The factory fuel pumps are the best, whenever I am in a wrecking yard and find one I buy them if they do not work I take them back for refund.  In all the years I have been buying them used I have only had 1 bad one.

[TimmyG]

29 minutes ago, Charlie69 said:

Here is a filter on ebay.

 

https://www.ebay.com/itm/GENUINE-NISSAN-1980-1986-720-PICKUP-FUEL-PUMP-FUEL-FILTER-NEW-OEM/162069082657?fits=Model%3A720|Make%3ANissan&epid=1522208899&hash=item25bc11f221:g:axQAAOSw-YBXGVCp

 

Rinse your old filter real well with gasoline. and put it back in if it does not fall apart.  Have you changed the fuel filter above it?  Those look like factory fuel lines it would not hurt to change them also.  Could be a crack and sucking air.    I hope you have anothere inline fuel filter between the pump and the and the carb inlet.  By the way I would start looking for a fuel tank.  That is rust in the fuel pump filter that made it through the inline above it.

 

The factory fuel pumps are the best, whenever I am in a wrecking yard and find one I buy them if they do not work I take them back for refund.  In all the years I have been buying them used I have only had 1 bad one.

 

Thanks for the link!

 

The $4 filter above the fuel pump was changed this past week.

 

The lines look pretty dirty, but if they were cracked wouldn't they leak? 

 

I do not have an inline filter between the pump and the carb. I have seen those who do. Didn't know if it was necessary. 

 

I wondered why that little fuel pump filter was so brown... sigh. I have another fuel tank from my parts truck and that truck generally has less rust on it's frame. I was planning on swapping the tanks anyway because this tank on my running truck is dented badly on the bottom at the drain plug (that area is also covered in gas residue).

 

I just gave away a parts truck that I stripped down first, but I did not save the fuel pump. It was a 4x4 and the pump was caked in dried mud. I didn't know those pumps were valuable.  

 

 

 

Edited September 30, 2019 by TimmyG

[TimmyG]

1 hour ago, datzenmike said:

Looks like someone has replaced it. Some later engines (April '85 and on) had EFI and used a high pressure pump. Does the parts truck have one ore two  wingnuts holding the air filter on??? If one then you could use this pump.

 

Maybe I will try the parts truck pump. I guess I'd better buy some butt connectors. I must have lost my box of electrical crap when we moved last time. Ugh. I bet I know where it's at in the old garage. If only I had that massive garage now. So many regrets. Lol